JP5962828B2 - Method for producing embryo by in vitro culture, and method, apparatus, and system for selecting embryo - Google Patents

Description

  The present invention relates to a method for selecting embryos having a high conception rate from mammalian embryos obtained by in vitro culture, and to produce embryos having a high conception rate from mammalian fertilized eggs (synonymous with zygotes) by in vitro culture. The present invention relates to methods and methods for producing mammals using embryos obtained by these methods.

  In many mammals such as cows, a technique for obtaining a fertilized egg by in vitro fertilization and generating an embryo from the fertilized egg by in vitro culture has been established. The obtained embryo is transplanted into the uterus of a recipient female individual and fertilized to obtain a litter.

  However, in vitro cultured embryos have a problem that the conception rate is low. For example, in the case of cattle, it is 40 to 50%, and the success rate of human pregnancy is about 25 to 35%. Possible causes include growth failure due to the difference between the in vitro culture environment and the in vivo environment.

  Attempts have been made to develop a method for selecting embryos having a high conception rate based on morphology and biochemical indicators.

  Non-Patent Document 1 discloses that in fertilized human eggs, the fertility rate differs depending on the number of cells and fragmentation during the third cleavage.

  Non-Patent Document 2 discloses that, in human fertilized eggs, the fertility rate is improved when there is little fragmentation during the third cleavage.

  Non-Patent Document 3 and Non-Patent Document 4 describe that chromosomal aberrations are particularly likely to occur in bovine fertilized eggs when the number of cells at the third cleavage is not 5-8 cells.

  Non-Patent Document 5 describes that in fertilized bovine eggs, the fertility rate varies according to the respiration rate (oxygen consumption), and that the fertility rate is highest when the respiration rate is 0.78-1.10 nl / h. .

  In Non-Patent Document 6, in the fertilized pig, the number of cells at the initial cleavage, the time to reach the initial cleavage, the uniformity of the two cells at the initial cleavage, the number of cells at the second cleavage, the amount of amino acids, etc. The relationship between the combination of multiple indicators and the blastocyst rate has been studied.

  Patent Document 1 discloses an invention relating to an embryo quality evaluation method. This document describes that asynchronous cell division and fragmentation during fragmentation can be used as an index for quality evaluation. It is also described that these indices may be combined with other indices such as respiratory rate.

  Patent Document 2 discloses an apparatus and method for measuring oxygen consumption per single embryo in order to evaluate embryo quality.

  Thus, the relationship between individual indicators and embryo quality has been investigated. However, there is no prior art that specifically examines the relationship between the combination of a plurality of indices and the conception rate. Furthermore, in the case of cattle, even the relationship between individual indicators and conception rates has hardly been investigated.

  On the other hand, in culturing fertilized eggs of non-human mammals, a droplet of a culture solution is placed in a well on a culture vessel, the surface of the microdroplet is coated with mineral oil, and a plurality of fertilized eggs are contained in one droplet. It was usual to carry out by the method of putting (droplet method). In this method, it is difficult to distinguish and manage individual embryos, so only the morphology observation results of embryos at the completion of culture (early blastocyst stage, blastocyst stage or expanded blastocyst stage) are used as indices. The quality of the embryo is determined. In the conventional embryo culture method, data is acquired by tracking the growth process of the embryo from the initial cleavage to the completion of the culture over time, and the data at different time points are combined to be used as a selection index for high conception embryos. This has been difficult and has not been studied in the past.

Special table 2009-539387 Japanese Patent No. 3693907

Human Reproduction Vol.16, No.9 pp. 1970-1975, 2001 Human Reproduction Vol.17, No.9 pp. 2402-2409, 2002 BIOLOGY OF REPRODUCTION 63, 1143-1148 (2000) Journal of Reproduction and Development, Vol.54, No.6, 465-472 (2008) Human Reproduction Vol.22, No.2 pp. 558-566, 2007 BIOLOGY OF REPRODUCTION 77, 765-779 (2007)

  An object of the present invention is to provide a means for efficiently obtaining a mammalian embryo having a high conception rate.

  The present inventors have applied for a patent as Japanese Patent Application No. 2010-022463, using a culture vessel capable of individually managing cells (shown in FIGS. 1a to 1f of the present application), from the initial cleavage to the completion of culture (early scutellum) Data were obtained by tracking the growth process of the embryo up to the blastocyst stage, blastocyst stage or extended blastocyst stage over time. Then, the relationship between the data obtained at different time points for one embryo and the conception rate was examined. As a result, it was surprisingly found that embryos satisfying two, three or four of the predetermined conditions at four different embryonic developmental stages show a high conception rate, thereby completing the present invention. It was.

The present invention includes the following inventions.
(1) A method for selecting a mammalian embryo cultured in vitro from a fertilized egg,
Time from fertilization to completion of the first cleavage;
Morphology at the stage after the first cleavage and before the second cleavage;
Morphology at the stage after the third cleavage and before the fourth cleavage; and oxygen consumption at the early blastocyst stage, blastocyst stage or extended blastocyst stage;
The method comprising the step of selecting an embryo using two or more of them as indicators.
(2) The embryo selected in the above process has the following conditions:
Correlation between the time from fertilization to completion of the first cleavage and the time from embryo fertilization to completion of the first cleavage and the probability that the embryo has a normal number of chromosomes at the blastocyst stage Based on the relationship, the time has been confirmed that the probability is 40% or more (condition d1), the time from fertilization to completion of the first cleavage is The relative expression level is 0.45 based on the correlation between the time until the split is completed and the relative expression level of the gene IGF2R at the blastocyst stage of the embryo, where the expression level of the gene H2AFZ is 1. And the time from fertilization to completion of the first cleavage is the time from fertilization to completion of the first cleavage. Based on the correlation with the relative expression level of the gene IFN-tau at the blastocyst stage of the embryo, with the expression level of the gene H2AFZ as 1. It Relative expression level that satisfies at least one condition may become 0.2 or more it is time has been confirmed (condition d3), it is selected from (condition d);
2 cells and no fragmentation at the stage after the first cleavage and before the second cleavage (condition a);
5 cells, 6 cells, 7 cells, or 8 cells and no fragmentation after the third cleavage and before the fourth cleavage (condition b); and the early blastocyst stage, scutellum The oxygen consumption at the blastocyst stage or the expanded blastocyst stage is the oxygen consumption of the embryo at the early blastocyst stage, the blastocyst stage or the expanded blastocyst stage, and the probability that the embryo reaches the escape blastocyst. The oxygen consumption is confirmed to be 50% or more based on the correlation (condition c);
The method according to (1), wherein the embryo satisfies two or more of the above.
(3) the mammal is a cow,
In condition d, the time from fertilization to completion of the first cleavage is 27 hours or less,
Oxygen consumption under condition c is 0.91 × 10 ^-14 mol s ^-1 or more per single embryo
Method (2).
(4) A method for producing an embryo from a fertilized egg of a mammal by in vitro culture,
Time from fertilization to completion of the first cleavage;
Morphology at the stage after the first cleavage and before the second cleavage;
Morphology at the stage after the third cleavage and before the fourth cleavage; and oxygen consumption at the early blastocyst stage, blastocyst stage or extended blastocyst stage;
The said method including the selection process which selects an embryo by using 2 or more of them as a parameter | index.
(5) The embryos that are selected in the selection step have the following conditions:
Correlation between the time from fertilization to completion of the first cleavage and the time from embryo fertilization to completion of the first cleavage and the probability that the embryo has a normal number of chromosomes at the blastocyst stage Based on the relationship, the time has been confirmed that the probability is 40% or more (condition d1), the time from fertilization to completion of the first cleavage is The relative expression level is 0.45 based on the correlation between the time until the split is completed and the relative expression level of the gene IGF2R at the blastocyst stage of the embryo, where the expression level of the gene H2AFZ is 1. And the time from fertilization to completion of the first cleavage is the time from fertilization to completion of the first cleavage. Based on the correlation with the relative expression level of the gene IFN-tau at the blastocyst stage of the embryo, with the expression level of the gene H2AFZ as 1. It Relative expression level that satisfies at least one condition may become 0.2 or more it is time has been confirmed (condition d3), it is selected from (condition d);
2 cells and no fragmentation at the stage after the first cleavage and before the second cleavage (condition a);
5 cells, 6 cells, 7 cells, or 8 cells and no fragmentation after the third cleavage and before the fourth cleavage (condition b); and the early blastocyst stage, scutellum The oxygen consumption at the blastocyst stage or the expanded blastocyst stage is the oxygen consumption of the embryo at the early blastocyst stage, the blastocyst stage or the expanded blastocyst stage, and the probability that the embryo reaches the escape blastocyst. The oxygen consumption is confirmed to be 50% or more based on the correlation (condition c);
The method of (4), wherein the embryo satisfies two or more of the above.
(6) the mammal is a cow,
In condition d, the time from fertilization to completion of the first cleavage is 27 hours or less,
Oxygen consumption under condition c is 0.91 × 10 ^-14 mol s ^-1 or more per single embryo
Method (5).
(7) A step of transplanting an embryo selected by any one of the methods (1) to (3) or an embryo produced by any one of the methods (4) to (6) to a female individual for conception. A method for producing a mammal individual, comprising:
(8) An embryo sorting apparatus for sorting a mammalian candidate embryo cultured in vitro from a fertilized egg,
Including a determination unit and an analysis unit,
The discrimination unit is
Determine whether or not the first index information regarding the time from fertilization to completion of the first cleavage satisfies the first index selection criterion condition regarding the time from fertilization to completion of the first cleavage A first index discriminating unit,
The second index information regarding the morphology of the candidate embryo after the first cleavage and before the second cleavage is the second index selection criterion condition regarding the morphology after the first cleavage and before the second cleavage A second index discriminating unit that discriminates whether or not
The third index information regarding the morphology of the candidate embryo after the third cleavage and before the fourth cleavage is the third index selection criterion condition regarding the morphology after the third cleavage and before the fourth cleavage The third index discriminating unit for discriminating whether or not the condition is satisfied, and the fourth index information regarding the oxygen consumption in the early blastocyst stage, blastocyst stage or expanded blastocyst stage of the candidate embryo, M out of the fourth index discriminating units for discriminating whether or not the fourth index selection criterion condition regarding the oxygen consumption at the blastocyst stage, blastocyst stage or expanded blastocyst stage is satisfied (M is 2, 3) Or a number of 4)
The analyzing unit analyzes a candidate embryo satisfying N or more (N is a number of 2 or more and M or less) among the conditions determined in the determining unit as an embryo to be selected, The embryo sorting apparatus.
(9) The embryo sorting apparatus according to (8), further comprising an image extraction unit,
When the determination unit includes the first index determination unit, the image extraction unit, from the image of the candidate embryo, a threshold value for the time from fertilization to completion of the first cleavage in the first index selection criterion condition Including a first image extraction unit that extracts an image at the time of the above or an image capable of confirming the completion time of the first cleavage, and the first index determination unit is an image extracted by the first image extraction unit To determine the information generated based on the first index information,
When the determination unit includes the second index determination unit, the image extraction unit extracts, from the candidate embryo image, an image at a stage after the first cleavage and before the second cleavage. Including an extraction unit, the second index determination unit determines the information generated based on the image extracted by the second image extraction unit as the second index information,
When the determination unit includes the third index determination unit, the image extraction unit extracts, from the candidate embryo image, an image at a stage after the third cleavage and before the fourth cleavage, The embryo sorting apparatus including an image extracting unit, wherein the third index discriminating unit discriminates information generated based on the image extracted by the third image extracting unit as the third index information.
(10) An embryo selection system for selecting a mammalian candidate embryo cultured in vitro from a fertilized egg,
(9) embryo sorting apparatus;
An imaging device that images the candidate embryo and outputs the captured image to the image extraction unit;
When the discriminating unit includes the fourth index discriminating unit, the oxygen consumption at the early blastocyst stage, blastocyst stage or extended blastocyst stage of the candidate embryo is measured, and the measured oxygen consumption The embryo sorting system further comprising an oxygen consumption measuring device that outputs a quantity value to the fourth index determining unit.
(11) A program for causing a computer to execute an embryo selection method for selecting a mammalian candidate embryo cultured in vitro from a fertilized egg, the method including a discrimination step and an analysis step,
The discrimination step is
Determine whether or not the first index information regarding the time from fertilization to completion of the first cleavage satisfies the first index selection criterion condition regarding the time from fertilization to completion of the first cleavage A first index discrimination step,
The second index information regarding the morphology of the candidate embryo after the first cleavage and before the second cleavage is the second index selection criterion condition regarding the morphology after the first cleavage and before the second cleavage A second index determination step for determining whether or not
The third index information regarding the morphology of the candidate embryo after the third cleavage and before the fourth cleavage is the third index selection criterion condition regarding the morphology after the third cleavage and before the fourth cleavage The third index determination step for determining whether or not the condition is satisfied, and the fourth index information regarding oxygen consumption in the early blastocyst stage, blastocyst stage or expanded blastocyst stage of the candidate embryo, M in the fourth index discrimination process (M is 2, 3) that determines whether or not the fourth index selection criteria condition regarding oxygen consumption at the blastocyst stage, blastocyst stage or expanded blastocyst stage is satisfied Or a number of 4)
The analysis step includes an analysis step of analyzing a candidate embryo satisfying N or more of the conditions determined in the determination step (N is a number of 2 or more and M or less) as an embryo to be selected,
The program.

The present invention further includes the following aspects.
(12) In a method of generating an embryo from a human fertilized egg by in vitro culture,
Time from fertilization to completion of the first cleavage;
Morphology at the stage after the first cleavage and before the second cleavage;
Morphology at the stage after the third cleavage and before the fourth cleavage; and oxygen consumption at the early blastocyst stage, blastocyst stage or extended blastocyst stage;
A method of predicting embryo fertility using two or more of these as indicators.
(13) The following conditions:
Correlation between the time from fertilization to completion of the first cleavage and the time from embryo fertilization to completion of the first cleavage and the probability that the embryo has a normal number of chromosomes at the blastocyst stage Based on the relationship, the time has been confirmed that the probability is 40% or more (condition d1), the time from fertilization to completion of the first cleavage is The relative expression level is 0.45 based on the correlation between the time until the split is completed and the relative expression level of the gene IGF2R at the blastocyst stage of the embryo, where the expression level of the gene H2AFZ is 1. And the time from fertilization to completion of the first cleavage is the time from fertilization to completion of the first cleavage. Based on the correlation with the relative expression level of the gene IFN-tau at the blastocyst stage of the embryo, with the expression level of the gene H2AFZ as 1. It Relative expression level that satisfies at least one condition may become 0.2 or more it is time has been confirmed (condition d3), it is selected from (condition d);
2 cells and no fragmentation at the stage after the first cleavage and before the second cleavage (condition a);
5 cells, 6 cells, 7 cells, or 8 cells and no fragmentation after the third cleavage and before the fourth cleavage (condition b); and the early blastocyst stage, scutellum The oxygen consumption at the blastocyst stage or the expanded blastocyst stage is the oxygen consumption of the embryo at the early blastocyst stage, the blastocyst stage or the expanded blastocyst stage, and the probability that the embryo reaches the escape blastocyst. The oxygen consumption is confirmed to be 50% or more based on the correlation (condition c);
The method according to (12), wherein an embryo satisfying two or more of the above is predicted to be an embryo having a high conception rate.

  According to the present invention, it is possible to efficiently obtain a mammalian embryo having a high conception rate.

It is a top view which shows the culture container C which can be used for implementation of the method of this invention. FIG. 1b is a cross-sectional view taken along line Ia-Ia in FIG. 1a. FIG. 1b is a partially enlarged view of the cell accommodating part in FIG. 1a. FIG. 1b is a cross-sectional view taken along line Ib-Ib in FIG. 1c. FIG. 2 is a partially enlarged view of a microwell in FIG. 1c. FIG. 2 is a cross-sectional view taken along the line Ic-Ic in FIG. 1e. FIG. 2 shows the relationship between the number of cells and oxygen consumption in the preliminary study. Fig. 3 shows the relationship between the first cleavage pattern after 31 hours of fertilization and the rate of apoptosis positive cells in the preliminary study (Fig. 3 (a)), the relationship between the presence of fragmentation and the rate of apoptosis positive cells after 55 hours of fertilization. (Fig. 3 (b)), the relationship between the number of blastomeres 55 hours after fertilization and the rate of apoptosis positive cells (Fig. 3 (c)), the relationship between the oxygen consumption after 168 hours of fertilization and the rate of apoptosis positive cells (Fig. 3 (d)). Fig. 4 shows the relationship between the first cleavage pattern 31 hours after fertilization and zona pellucida escape (Fig. 4 (a)), and the relationship between blastocyst stage and zona pellucida 168 hours after fertilization (Fig. 4). (b)) shows the relationship between oxygen consumption and zona pellucida escape after 168 hours of fertilization (FIG. 4 (c)). FIG. 5 shows the relationship between the first cleavage pattern 31 hours after fertilization and oxygen consumption in the preliminary study. FIG. 6 is a schematic block diagram showing an embodiment of the embryo sorting apparatus of the present invention when M = 4 and N = 2-4. FIG. 7 is a schematic block diagram showing an embodiment of the embryo sorting apparatus and embryo sorting system of the present invention when M = 4 and N = 2-4. FIG. 8 is a schematic block diagram showing an embodiment of the embryo sorting apparatus and the embryo sorting system of the present invention when M = 4 and N = 2-4. FIG. 9 is a schematic block diagram showing an embodiment of the embryo sorting apparatus of the present invention when M = 3 and N = 2-3. FIG. 10 is a schematic block diagram showing an embodiment of the embryo sorting apparatus of the present invention when M = 2 and N = 2. FIG. 11 is a schematic block diagram showing an embodiment of the embryo sorting apparatus and embryo sorting system of the present invention when M = 3 and N = 2 to 3. FIG. 12 is a schematic block diagram showing an embodiment of the embryo sorting apparatus and embryo sorting system of the present invention when M = 3 and N = 2 to 3. FIG. 13 is a flowchart showing an embodiment of a method for sorting embryos using the embryo sorting apparatus of the present invention. FIG. 14 is a flowchart showing an embodiment of a method for sorting embryos using the embryo sorting apparatus of the present invention (M = 4, N = 2). FIG. 15 is a flowchart showing an embodiment of a method for sorting embryos using the embryo sorting apparatus of the present invention (M = 4, N = 3). FIG. 16 is a flowchart showing an embodiment of a method for sorting embryos using the embryo sorting apparatus of the present invention (M = 4, N = 4). FIG. 17 is a flowchart showing one embodiment of a method for sorting embryos using the embryo sorting apparatus of the present invention (M = 3, N = 2). FIG. 18 is a flowchart showing one embodiment of a method for sorting embryos using the embryo sorting apparatus of the present invention (M = 3, N = 3). FIG. 19 is a flowchart showing an embodiment of a method for sorting embryos using the embryo sorting apparatus of the present invention (M = 2, N = 2). FIG. 20 is a flowchart showing an outline of a method for sorting embryos using the embryo sorting apparatus of the present invention. FIG. 21 is a flowchart showing an outline of a method for selecting an embryo using an embodiment of the embryo selection apparatus of the present invention. FIG. 22 is a flowchart showing an outline of a method for selecting an embryo using an embodiment of the embryo selection apparatus of the present invention. FIG. 23a shows information for specifying individual candidate embryos stored in advance in the method of selecting an embryo using the embryo selection apparatus of the present invention. FIG. 23b shows the results generated in the second index discrimination step of the method for sorting embryos using the embryo sorting apparatus of the present invention. FIG. 23c shows the result generated in the third index discrimination step of the method for selecting an embryo using the embryo sorting apparatus of the present invention. FIG. 23d shows the results generated in the fourth index discrimination step of the method for sorting embryos using the embryo sorting apparatus of the present invention. FIG. 24 shows a preferred embodiment of the hardware configuration of the embryo selection system of the present invention. FIG. 25 shows the correlation between the first cleavage time and the proportion of embryos having a normal chromosome number. FIG. 26 shows the correlation between the first cleavage time and the expression levels of the genes IGF2R and IFN-tau.

  In the present invention, mammals refer to warm-blooded vertebrates, for example, primates such as humans and monkeys, rodents such as mice, rats and rabbits, pets such as dogs and cats, and cows, horses, pigs, Examples include livestock such as sheep. The method of the present invention is typically used for non-human mammals (mammals other than humans). In the present invention, “human” refers to Homo sapiens. “Monkeys” refers to non-human animals classified as Primates. “Mouse” refers to Mus musculus. “Rat” refers to Rattus norvegicus. “Rabbit” refers to animals classified in the family Leporidae. “Dog” refers to animals classified as Canis lupus, typically Canis lupus familiaris. “Cat” refers to an animal classified as Felis silvestris, typically a Felis silvestris catus. “Bovine” refers to animals classified in the genus Bos (Bos), typically Bos taurus and Bos indicus. “Horse” refers to Equus caballus. “Pig” refers to animals classified as Sus scrofa, typically Sus scrofa domesticus. “Sheep” refers to Ovis aries.

  After fertilization, the fertilized egg of a mammal increases in cell number from the 2 cell stage, 4 cell stage, and 8 cell stage by cleavage, and after passing through the morula, the blastocyst (early blastocyst to escape blastocyst) Cell). The embryo to be selected or produced in the present invention is an embryo that has developed until the 8th cell stage (that is, after the end of the third cleavage), and is a morula, early blastocyst, blastocyst, expanded blastocyst And escaped blastocysts, typically early blastocysts, blastocysts, expanded blastocysts and escaped blastocysts. Early blastocysts, blastocysts, expanded blastocysts and escaped blastocysts comprise external cells that have the potential to form the placenta and inner cell masses that have the potential to form embryos.

The inventors surprisingly found that
Morphology at the stage after the first cleavage and before the second cleavage;
Morphology at the stage after the third cleavage and before the fourth cleavage;
Oxygen consumption at the early, blastocyst or expanded blastocyst stage;
It was found that embryos with a high conception rate can be predicted by using two or more, preferably three of them as indices. When only one of the three indicators is used as a predictive indicator, or one of the three indicators and other known indicators (for example, morphological quality is Code 1 and the blastocyst has reached an expanded blastocyst Etc.) and used as a predictive index, embryos with a high conception rate cannot be selected.

More specifically,
2 cells and no fragmentation at the stage after the first cleavage and before the second cleavage (condition a);
Be 5 cells, 6 cells, 7 cells or 8 cells and have no fragmentation after the third cleavage and before the fourth cleavage (condition b);
Oxygen consumption at the early blastocyst stage, blastocyst stage or extended blastocyst stage is the oxygen consumption of the embryo at the early blastocyst stage, blastocyst stage or extended blastocyst stage and the embryo escapes Based on the correlation with the probability of reaching the blastocyst, the oxygen consumption is confirmed to be 50% or more (condition c);
It was found that embryos satisfying two or more of them have a high conception rate.

  In the present invention, the condition b may be a condition of “6 cells, 7 cells or 8 cells and no fragmentation in the stage after the third cleavage and before the fourth cleavage”.

Furthermore, the inventors further include the above three indicators:
Predict embryos with high conception rate by using 2 or more, preferably 3 or more, more preferably 4 out of 4 indicators including the time from fertilization to completion of the first cleavage Found that it is possible to do.

In particular,
Correlation between the time from fertilization to completion of the first cleavage and the time from embryo fertilization to completion of the first cleavage and the probability that the embryo has a normal number of chromosomes at the blastocyst stage Based on the relationship, the time has been confirmed that the probability is 40% or more (condition d1), the time from fertilization to completion of the first cleavage is The relative expression level is 0.45 based on the correlation between the time until the split is completed and the relative expression level of the gene IGF2R at the blastocyst stage of the embryo, where the expression level of the gene H2AFZ is 1. And the time from fertilization to completion of the first cleavage is the time from fertilization to completion of the first cleavage. Based on the correlation with the relative expression level of the gene IFN-tau at the blastocyst stage of the embryo, with the expression level of the gene H2AFZ as 1. It Relative expression level that satisfies at least one condition may become 0.2 or more it is time has been confirmed (condition d3), it is selected from (condition d);
Said condition a;
The condition b; and the condition c
It has been found that embryos satisfying 2 or more, preferably 3 or more, more preferably 4 of them have a high fertility rate.

  The culture instrument used in the present invention is not limited to the culture instrument shown in FIG. 1 used in Experiment 1, and any culture instrument can be used. In the present invention, in vitro culture for generating embryos from fertilized eggs is preferably performed using a culture instrument that can be individually managed.

  Various conditions such as the medium used for embryo culture, temperature, atmospheric gas composition, and the like may be those usually used depending on the species of mammal.

Typical culture conditions for bovine embryos are preferably 38.0-39.5 ° C, more preferably 38.5-39 ° C, medium such as SOF (synthetic fallopian tube fluid), modified SOF, IVD-101, TCM199, CR1aa Saturated humidity, 4.5 to 5.5% CO ₂ and residual air (for example, saturated humidity 5% CO ₂ /95% air), saturated humidity 4.5 to 5.5% CO ₂ and 4.5 Conditions such as a gas such as a gas containing ˜5.5% O ₂ and the remaining amount of N ₂ (for example, saturated humidity, 5% CO ₂ /5% O ₂ /90% N ₂ ) can be employed.

  As typical culture conditions for pig embryos, conditions such as culture media such as NCSU23, TCM199, and PZM5 can be employed.

  The method for obtaining a fertilized egg (zygote) is not particularly limited. A fertilized egg can be produced from an egg cell and a sperm by in vitro fertilization.

  The morphology can be observed by non-invasive means such as microscopic observation. In general, the morphology is observed at a magnification of 40 to 200 times.

  In the present invention, “fragmentation” refers to a phenomenon in which fragmented cells (cytoplasmic globules) are observed in addition to the original cells that have been cleaved. An “non-fragmented” embryo refers to an embryo in which no fragmentation is observed. In the “fragmentation” in the present invention, it does not matter whether the nucleus is contained in fragmented cells (cytoplasmic globules).

  The number of cells contained in the embryo is determined visually from an image observed under a microscope. In the case of cattle, the number can be counted visually up to about 8 cells.

  Based on the correlation between the time from fertilization to completion of the first cleavage and the probability that the number of chromosomes in the embryo at the blastocyst stage is normal, the probability is 40% The time that has been confirmed to be above will be described. In preliminary studies, the present inventors conducted a period of time from fertilization to completion of the first cleavage (hereinafter sometimes referred to as “first cleavage time”), and the embryo blastocyst stage. The probability that the number of chromosomes is normal is correlated, and when the first cleavage time is below the threshold, the probability that the number of chromosomes in the embryo at the blastocyst stage is normal tends to increase dramatically. Yes. For mammals other than cattle, under the in vitro culture conditions substantially the same as those used in the method of the present invention, the time from fertilization to completion of the first cleavage and the blastocyst of the embryo The correlation with the probability that the number of chromosomes in the period is normal can be confirmed in advance. And in order to select embryos with high conception rate, it is effective to select embryos with the first cleavage time that have been confirmed to have a probability of 40% or more. In such a case, it is possible to select an embryo having a first cleavage time that has been confirmed to be 50% or more in the case of the probability, and 60% or more if the number of selection is to be further reduced.

  The definition of the blastocyst stage is as described later. An embryo having a normal number of chromosomes refers to an embryo in which the nuclear phase of all analyzed cells has a normal number of autosomes and sex chromosomes according to the animal species. For example, in the case of cattle, embryos whose nuclear phase is 58 autosomes and 2 sex chromosomes (2n = 60) are the embryos with normal chromosome numbers, and the other embryos have chromosome numbers. Use an abnormal embryo. The nuclear phase (number of chromosomes) of mitotic cells can be analyzed by Giemsa staining. Embryos with more than one mitotic cell are considered analyzable embryos.

  Correlation between the time from fertilization to the completion of the first cleavage and the relative expression level of the gene IGF2R at the blastocyst stage of the embryo, with the expression level of the gene H2AFZ being 1, Based on the relationship, the “time when the relative expression level is confirmed to be 0.45 or more” will be described. In the preliminary study, the inventors correlated the first cleavage time of the bovine embryo with the expression level of the gene IGF2R at the blastocyst stage of the embryo, and the first cleavage time is below the threshold. In addition, IGF2R expression level at the blastocyst stage of the embryo has been found to increase. For mammals other than cattle, under the in vitro culture conditions substantially the same as those used in the method of the present invention, the time from fertilization to completion of the first cleavage and the blastocyst of the embryo The correlation with the relative expression level of the IGF2R at the stage with the expression level of the gene H2AFZ as 1, can be confirmed in advance. In order to select high conception embryos, it is effective to select embryos having the first cleavage time in which the relative expression level of IGF2R is confirmed to be 0.45 or more. If it is desired to narrow down, the relative expression level is 0.50 or more, and if it is desired to narrow down the selection number, it is possible to select an embryo showing the first cleavage time that has been confirmed to be 0.60 or more. .

  In condition d3, `` the time from fertilization to the completion of the first cleavage and the relative expression level of the gene IFN-tau at the embryo's blastocyst stage, with the expression level of the gene H2AFZ being 1. The time when the relative expression level is confirmed to be 0.2 or more based on the correlation of “ In the preliminary examination, the present inventors correlated the first cleavage time of the bovine embryo with the expression level of the gene IFN-tau at the blastocyst stage of the embryo, and the first cleavage time was below the threshold value. Then, the expression level of IFN-tau in the blastocyst stage of the embryo has been found to increase. For mammals other than cattle, under the in vitro culture conditions substantially the same as those used in the method of the present invention, the time from fertilization to completion of the first cleavage and the blastocyst of the embryo The correlation between the expression level of IFN-tau and the relative expression level of the gene H2AFZ as 1 can be confirmed in advance. In order to select high conception embryos, it is effective to select embryos with the first cleavage time that have been confirmed to have a relative expression level of IFN-tau of 0.20 or more. If you want to narrow down the number, select the embryo with the first cleavage time that has been confirmed to have a relative expression level of 0.25 or more, and if you want to narrow down the number of selections, it should be 0.30 or more. Can do.

  The expression levels of genes IGF2R, IFN-tau, and H2AFZ can be evaluated based on the amount of mRNA (cDNA amount), respectively.

  The bovine IGF2R gene (SEQ ID NO: 13), IFN-tau gene (SEQ ID NO: 14), and H2AFZ gene (SEQ ID NO: 15) are assigned Accession Nos. NM_174352.2, X65539, and NM_174809, respectively, and are registered in GeneBank. IGF2R is a kind of imprint gene. IFN-tau is a kind of implantation related gene. H2AFZ is a kind of housekeeping gene used as an internal standard in the present invention. Homologous genes having substantially the same functions as bovine IGF2R gene, IFN-tau gene, and H2AFZ gene in other animal species other than bovine are defined as IGF2R gene, IFN-tau gene, and H2AFZ gene in the animal species, respectively. can do. For example, sheep IGF2R gene, IFN-tau gene, and H2AFZ gene are genes registered under GeneBank Accession Nos. AF353513.1, NP_001095205.1, and NP_001009270.1, respectively.

  The condition d is a condition that satisfies at least one, preferably at least two, and more preferably three of the conditions d1, d2, and d3 related to the first cleavage time. The condition d is particularly preferably a condition that the condition d1 is satisfied, a condition that both the conditions d2 and d3 are satisfied, or a condition that all the conditions d1, d2, and d3 are satisfied.

  In the case of bovine embryos, it is effective to select embryos with a first cleavage time of 27 hours or less in order to select high conception embryos that satisfy condition d. If so, embryos with a first cleavage time of 26 hours or less can be selected. If the threshold for the first cleavage time is too long, the total number of embryos to be selected increases, and even low-quality embryos are included, resulting in a decrease in conception rate. If the first cleavage time threshold is made too short, there will be no difference in quality because all embryos are of sufficient quality, but the total number of embryos selected will be reduced, resulting in fewer embryos available for transfer. There is a demerit.

  Completion of the first cleavage can be confirmed by observation using a microscope or the like. When the embryo is observed at the first cleavage time threshold (for example, 27 or 26 hours after fertilization) and it is confirmed that the first cleavage is complete, the first cleavage time is below the threshold. When it is determined that the first cleavage is not completed, it can be determined that the first cleavage time is longer than the threshold value. The embryo can be observed over time to confirm the first cleavage time, and the first cleavage time can be compared with a threshold value.

  The embryo at the stage after the first cleavage and before the second cleavage is, in the case of a bovine embryo, a stage 20 to 40 hours after fertilization, typically 28 to 33 hours after fertilization under normal in vitro culture conditions. Refers to the embryo. In culture of other mammalian embryos, it is easy to identify embryos at this stage by observation. Until embryo development is performed in the same in vitro culture conditions in advance, and the majority of normal embryos (preferably 70% or more, more preferably 80% or more) finish the first cleavage and start the second cleavage If the time zone based on the time of fertilization is known, embryos in this time zone can be regarded as embryos in the “stage after the first cleavage and before the second cleavage”.

  Although the timing of cleavage differs depending on the animal species, the approximate time zone as described above is known for the same animal species. On the other hand, even with the same animal species, there are some individual differences and variations as described above. In the case of cattle, there are many embryos that have not undergone the first cleavage at a time earlier than 20 hours after fertilization, and many embryos that have undergone the second cleavage at a later time than after 40 hours. A person skilled in the art appropriately selects a time zone in which the majority (preferably 70% or more, more preferably 80% or more) of embryos have finished the first cleavage and before the second cleavage. Can do. A predetermined index can be acquired by performing morphological observation during the time period. As for other mammals, although the timing of cleavage of individual embryos varies as described above, the majority (preferably 70% or more, more preferably 80% or more) of embryos are “after the first cleavage. In addition, it is possible to appropriately select a time zone that is “the stage before the second cleavage” and acquire a predetermined index in that time zone.

  Embryos at the stage after the third cleavage and before the fourth cleavage are, in the case of bovine embryos, the stage 36 to 108 hours after fertilization, typically 40 to 96 hours after fertilization under normal in vitro culture conditions. Refers to the embryo. In culture of other mammalian embryos, it is easy to identify embryos at this stage by observation. Until embryo development is performed in the same in vitro culture conditions in advance, and the majority of normal embryos (preferably 70% or more, more preferably 80% or more) finish the third cleavage and start the fourth cleavage If the time zone based on the time of fertilization is known, embryos in this time zone can be regarded as embryos in the “stage after the third cleavage and before the fourth cleavage”. Although the timing of cleavage of individual embryos varies for each mammalian species, the majority (preferably 70% or more, more preferably 80% or more) of embryos are “after the third cleavage and the fourth egg. It is possible to appropriately select a time zone that is a “prior stage” and obtain a predetermined index in that time zone.

  An embryo at the early blastocyst stage, blastocyst stage or extended blastocyst stage is any stage of development from the early blastocyst stage to the extended blastocyst stage. A certain embryo. In the case of a bovine embryo, it refers to an embryo at a stage 120 to 216 hours after fertilization, typically 144 to 192 hours after fertilization under normal in vitro culture conditions. In culture of other mammalian embryos, it is easy to identify embryos at this stage by observation. Embryo development is performed in advance under the same in vitro culture conditions, and the majority of normal embryos (preferably 70% or more, more preferably 80% or more) is either from the early blastocyst stage to the extended blastocyst stage. If the time zone based on the time of fertilization at the developmental stage is known, embryos in this time zone are regarded as embryos in the “early blastocyst stage, blastocyst stage or extended blastocyst stage” be able to. Although there are variations in the degree of development of individual embryos for each mammalian species, the majority (preferably 70% or more, more preferably 80% or more) of embryos are "early blastocyst stage, blastocyst stage" Alternatively, it is possible to appropriately select a time zone that is “expanded blastocyst stage” and obtain a predetermined index in that time zone.

  The definitions of “early blastocyst”, “blastocyst” and “expanded blastocyst” are Robertson I, Nelson RE (1998) Certification and identification of the embryo. In: DA Stringfellow and SM Seidel, Editors, Manual of the It is described in the international embryo transfer society, IETS, Savoy, Illinois 103-116, and will be described in detail below for reference, although it will be clear to those skilled in the art.

  “Early blastocyst” refers to an embryo at a time when the blastocyst cavity (blastocoel) becomes visible under a microscope. Early blastocysts have a ring-like morphology.

  “Blastocysts” are those in which early blastocysts have developed, trophoblast cell layers have been separated, and the inner cell mass has been darkened so that they can be clearly distinguished from each other. The blastocyst space broadly expands into the clonal space until it almost fills the clonal space.

  “Expanded blastocyst” means that the blastocyst develops and the expansion of the blastocyst cavity becomes remarkable, and the overall size increases (1.2 to 1.5 of embryo size up to the blastocyst stage) At the same time, it refers to an embryo whose zona pellucida thickness has been reduced to about 1/3.

`` Based on the correlation between the oxygen consumption of embryos in the early blastocyst stage, blastocyst stage or expanded blastocyst stage and the probability that the embryo reaches the escape blastocyst, the probability is 50% or more “Oxygen consumption confirmed to be” will be described. In preliminary studies (Experiment 2), the oxygen consumption of bovine early blastocyst stage, blastocyst stage or expanded blastocyst stage embryos, and the probability that the embryo reaches the escape blastocyst It has been found that when the oxygen consumption exceeds a threshold value, the probability that the embryo reaches the escaped blastocyst increases dramatically. For mammals other than cattle, the oxygen consumption of the embryos in the early blastocyst stage, blastocyst stage or expanded blastocyst stage can be obtained under substantially the same in vitro culture conditions as those used in the method of the present invention. The correlation with the probability that the embryo reaches the escaped blastocyst can be confirmed in advance. In order to select embryos with high conception rate, it is effective to select embryos with oxygen consumption that has been confirmed to have a probability of 50% or more. Can select embryos having an oxygen consumption of which the probability is confirmed to be 85% or more. In the case of bovine embryos, in order to select high conception embryos, the oxygen consumption at the early blastocyst stage, blastocyst stage or extended blastocyst stage is 0.91 × 10 ^-14 mol per embryo. It is effective to select embryos that are s ^-1 or higher, and if you want to narrow down the number of selections, you can select embryos that are 1.11 × 10 ^-14 mol s ^-1 or higher per single embryo . If the selection index value of the oxygen consumption is too low, the total number of embryos to be selected increases and even low quality embryos are included, resulting in a decrease in conception rate. If the selection index value for oxygen consumption is too high, there is no difference in quality because all embryos are of sufficient quality, but the total number of embryos selected is reduced, so the number of embryos that can be used for transplantation is reduced. There are disadvantages.

  The oxygen consumption per single embryo can be measured non-invasively using a commercially available device such as the SECM system (HV-405; Hokuto Denko Co., Ltd.). Oxygen consumption can be measured in a respiration assay medium (eg, ERAM-2 (embryo respiration assay medium-2, manufactured by Functional Peptide Laboratories), etc.) under substantially the same temperature conditions as in vitro culture conditions. Preferably it is measured.

  A first aspect of the present invention is a method for selecting a mammalian embryo cultured in vitro from a fertilized egg, wherein at least two, preferably at least three, more preferably four of the above four indicators are selected. It is a method characterized by obtaining, evaluating, and selecting an embryo based on the evaluation result. In the selection step, embryos satisfying at least two, preferably at least three, and more preferably four of the above conditions a to d are selected. The embryo to be selected is preferably an embryo cultured in vitro from the early blastocyst stage, blastocyst stage or extended blastocyst stage, but the time from fertilization to completion of the first cleavage is the first egg If two or more of the morphology at the stage after cleavage and before the second cleavage and the morphology at the stage after the third cleavage and before the fourth cleavage are used as indicators, the two-cell stage (i.e., the first egg It may be an embryo cultured in vitro until any developmental stage after the end of cleavage) or after the 8-cell stage (ie after the end of the third cleavage). The person who performs this selection method and the person who performs the method of producing an embryo by in vitro culture may be the same or different.

  The second aspect of the present invention is a method for producing an embryo from a fertilized egg of a mammal by in vitro culture, and includes the above-described selection step. Embryos are preferably cultured in vitro to the early blastocyst stage, blastocyst stage or extended blastocyst stage, but the time from fertilization to completion of the first cleavage, after the first cleavage and the second cleavage When using two or more of the morphology at the previous stage and the morphology after the third cleavage and before the fourth cleavage as an index, the 2-cell stage (i.e. after the first cleavage) or 8 cells In vitro culture can be performed until an arbitrary developmental stage after the stage (ie, after the end of the third cleavage) and used for the subsequent use.

  A third aspect of the present invention is a method for producing a mammal individual, comprising a step of transplanting and fertilizing a female individual with an embryo selected by the above selection method or an embryo produced by the above production method. Usually, a female individual (recipient) undergoing transplantation is in a pseudopregnant state, and an embryo is transplanted into the uterine horn, fallopian tube, etc. of the female individual. After conception, the step of obtaining a litter and the step of growing a litter to obtain an individual can be performed by conventional methods.

<Embry sorting device, embryo sorting system, embryo sorting method>
The present invention also relates to an embryo selection apparatus for selecting a mammalian candidate embryo cultured in vitro from a fertilized egg, which can realize the method of the present invention.

  The embryo sorting apparatus of the present invention includes a discriminating unit and an analyzing unit, and in the discriminating unit, M pieces of M (M is 2, 3, or 4 is a number that satisfies the screening criterion condition defined in advance, and the analysis unit determines that the number of conditions determined by the determination unit is N (N is a number from 2 to M) A device characterized in that a candidate embryo satisfying the above is analyzed as an embryo to be selected. The specific numbers of M and N can be appropriately determined according to the purpose. An embryo with a high conception rate can be selected as the value of N increases, but the number of embryos used for transplantation tends to decrease.

  Hereinafter, an embodiment of the embryo sorting apparatus of the present invention in which M = 4 and N = 2 to 4 will be described with reference to FIGS. 6 to 8, and the embryo of the present invention in which M = 3 and N = 2 to 3 will be described. One embodiment of the sorting apparatus will be described with reference to FIGS. 9, 11 and 12, and one embodiment of the embryo sorting apparatus of the present invention with M = 2 and N = 2 will be described with reference to FIG. The scope of the invention is not limited to the illustrated embodiments.

  FIG. 6 is a schematic block diagram showing a functional configuration of an embryo sorting apparatus 600 which is an embodiment of the embryo sorting apparatus (M = 4, N = 2 to 4) of the present invention. The embryo sorting apparatus 600 includes at least a determination unit 670 and an analysis unit 610, and includes a storage unit 601 as necessary. The storage unit 601 may be connected to other parts of the embryo sorting apparatus 600 via a network so that data can be stored and read. The embryo sorting device 600 can be configured by an information processing device such as a computer. An input device 611, an output device 612, and the like are connected to the embryo sorting device 600 as necessary.

  The determination unit 670 includes at least a first index determination unit 606, a second index determination unit 607, a third index determination unit 608, and a fourth index determination unit 609. Usually, the first index information acquisition unit 602 and the second index An information acquisition unit 603, a third index information acquisition unit 604, and a fourth index information acquisition unit 605 are included.

  The storage unit 601 includes a first index selection criterion condition regarding a time from fertilization to completion of the first cleavage, a second index selection criterion condition regarding a form after the first cleavage and before the second cleavage, Third index selection criteria for morphology at the stage after the third cleavage and before the fourth cleavage, and the fourth index for oxygen consumption in the early blastocyst stage, blastocyst stage or expanded blastocyst stage Information relating to the selection criterion conditions and the number N of conditions among the conditions that should be satisfied by the embryo to be selected is stored. Such information is stored in the storage unit 601 in advance.

  Specifically, the “first index selection criterion condition regarding the time from fertilization to completion of the first cleavage” includes the above-mentioned condition d. When the embryo sorting apparatus 600 is used for sorting bovine embryos, the condition d is preferably “the time from fertilization to the completion of the first cleavage is 27 hours or less” or “from fertilization” The time until the completion of the first cleavage is 26 hours or less.

  Specifically, the “second index selection reference condition regarding the form after the first cleavage and before the second cleavage” includes the above-mentioned condition a.

  Specifically, the “third index selection reference condition regarding the form after the third cleavage and before the fourth cleavage” includes the above-mentioned condition b.

Specifically, the “fourth index selection criterion condition regarding oxygen consumption in the early blastocyst stage, blastocyst stage or extended blastocyst stage” includes the above-mentioned condition c. When the embryo sorting apparatus 600 is used for sorting bovine embryos, the condition c is preferably “the oxygen consumption at the early blastocyst stage, blastocyst stage or expanded blastocyst stage is 0.91 per embryo. ^{X10 -14} mol s ^-1 or more '' or `` Oxygen consumption at early blastocyst stage, blastocyst stage or extended blastocyst stage is 1.11 × 10 ^-14 mol per embryo The condition is “s ⁻¹ or more”.

  The first index information acquisition unit 602 acquires first index information regarding the time from fertilization to completion of the first cleavage of the candidate embryo, and inputs the first index information to the first index determination unit 606. Specifically, the first index information may be data indicating a time (first cleavage time) from fertilization to completion of the first cleavage of the candidate embryo, or the first index selection criterion It may be data indicating whether or not the first cleavage is completed at the time point of the threshold value of the first cleavage time defined in the conditions. The first index information may be input to the first index information acquisition unit 602 by the user via the input device 611, or may be input from the first image analysis unit as will be described later.

  The first index determining unit 606 determines whether or not the first index information of the candidate embryo satisfies the first index selection criterion condition stored in the storage device 601. Specifically, when the first cleavage time of the candidate embryo is equal to or less than the threshold value of the first cleavage time in the first index selection reference condition (or the completion of the first cleavage of the candidate embryo is the first egg The first cleavage time of the candidate embryo is determined to satisfy the first index selection criterion condition, and the first cleavage time threshold value in the first index selection criterion condition is determined. If it is greater than (or the completion of the first cleavage of the candidate embryo has not been confirmed at the time of the first cleavage time threshold), it is determined that the first index selection criterion condition is not satisfied.

  The second index information acquisition unit 603 acquires second index information related to the morphology of the candidate embryo after the first cleavage and before the second cleavage, and inputs the second index information to the second index determination unit 607. Specifically, the second index information includes data indicating the number of blastomeres of the candidate embryo at the stage after the first cleavage and before the second cleavage, and data indicating the presence or absence of fragmentation. The second index information may be input to the second index information acquisition unit 603 by the user via the input device 611, or may be input from the second image analysis unit as will be described later.

  The second index determining unit 607 determines whether or not the second index information of the candidate embryo satisfies the stored second index selection criterion condition stored in the storage device 601. Specifically, the number of blastomeres in the stage after the first cleavage and before the second cleavage of the candidate embryo is within the range of the number of blastomeres defined in the second index selection criteria condition, and When there is no fragmentation at the same stage, it is determined that the second index selection criterion condition is satisfied, and in other cases, it is determined that the second index selection criterion condition is not satisfied.

  The third index information acquisition unit 604 acquires third index information regarding the morphology of the candidate embryo after the third cleavage and before the fourth cleavage, and inputs the third index information to the third index determination unit 608. Specifically, the third index information includes data indicating the number of blastomeres at the stage after the third cleavage and before the fourth cleavage of the candidate embryo, and data indicating the presence or absence of fragmentation. The third index information may be input to the third index information acquisition unit 604 by the user via the input device 611, or may be input from the third image analysis unit as will be described later.

  The third index determining unit 608 determines whether or not the third index information of the candidate embryo satisfies the stored third index selection criterion condition stored in the storage device 601. Specifically, the number of blastomeres in the stage after the third cleavage of the candidate embryo and before the fourth cleavage is within the range of the number of blastomeres stipulated in the third index selection criteria condition, and If there is no fragmentation at the same stage, it is determined that the third index selection criterion condition is satisfied, and in other cases, it is determined that the third index selection criterion condition is not satisfied.

  The fourth index information acquisition unit 605 acquires fourth index information related to oxygen consumption in the early blastocyst stage, blastocyst stage or extended blastocyst stage of the candidate embryo, and a fourth index determination unit 609 To enter. Specifically, the fourth index information includes data indicating the value of oxygen consumption at the early blastocyst stage, blastocyst stage or extended blastocyst stage of the candidate embryo. The fourth index information may be input to the fourth index information acquisition unit 605 by the user via the input device 611, or may be input from the oxygen consumption measuring device as will be described later.

  The fourth index determination unit 609 determines whether or not the fourth index information of the candidate embryo satisfies the stored fourth index selection criterion condition stored in the storage device 601. Specifically, the oxygen consumption value at the early blastocyst stage, blastocyst stage, or expanded blastocyst stage of the candidate embryo is equal to or greater than the oxygen consumption threshold defined in the fourth index selection criteria condition. If it is, it is determined that the fourth index selection criterion condition is satisfied, and it is determined that the fourth index selection criterion condition is not satisfied when the value of the oxygen consumption amount of the candidate embryo is smaller than the threshold value.

  Based on the results of the first index discriminating unit 606, the second index discriminating unit 607, the third index discriminating unit 608, and the fourth index discriminating unit 609, the analysis unit 610 performs the first index selection criterion condition, the second index selection criterion condition In the third index selection criterion condition and the fourth index selection criterion condition, it is determined whether or not the number of conditions satisfied by the candidate embryo is equal to or greater than the stored number N. A candidate embryo is concluded to be selected (“good”), and if it is less than N, it is concluded that the candidate embryo should not be selected (“bad”).

The analysis unit 610 generates an analysis result. The generated analysis result can be output via the output device 612. The output device 612 may have any form such as a display or a printer. The analysis result may be stored in the storage unit 601. The output or stored analysis results can include, for example:
・ Information to identify candidate embryos (information indicating the position by coordinates etc.)
・ Good / bad analysis result ・ First index information ・ Second index information ・ Third index information ・ Fourth index information ・ Distinction result based on first index information ・ Determination result based on second index information ・ Third index information Discrimination result based on 4th index information

  The first index information, the second index information, and the third index information input to the embryo sorting apparatus of the present invention are based on the judgment of the user or image processing technology based on the candidate embryo image captured at a predetermined stage. Can be generated.

  The embryo sorting apparatus of the present invention can further include a configuration for extracting an image that is referred to in order to generate the first index information, the second index information, and / or the third index information. An example of an embodiment of an embryo sorting apparatus having this configuration is shown in FIGS. 7 and 8, the configuration indicated by reference numerals 701 to 712, 770, 801 to 812, and 870 has the same characteristics as the configuration indicated by reference numerals 601 to 612 and 670 in FIG.

  The embryo sorting apparatus 700 shown in FIG. 7 includes an image extracting unit 780 that extracts an image that is referred to in order to generate first index information, second index information, and third index information. The image extraction unit 780 includes at least a first image extraction unit 721, a second image extraction unit 722, and a third image extraction unit 723, and usually further includes an image acquisition unit 720.

  The image acquisition unit 720 acquires image data of a candidate embryo imaged by an imaging device such as a video camera, and inputs the image data to the first image extraction unit 721, the second image extraction unit 722, and the third image extraction unit 723. The image may be a moving image or a still image.

  The first image extraction unit 721, from the acquired image of the candidate embryo, the image of the candidate embryo at the time point of the threshold time from fertilization to the completion of the first cleavage in the first index selection reference condition, Extract an image that can be used to confirm the completion time of egg breaking. The first image extraction unit 721 can refer to threshold information stored in the storage unit 701 as necessary. The extracted image can be output as an image visually distinguishable by the user by the output device 712. The user can generate first index information based on the image extracted by the first image extraction unit 721 by visual discrimination, and input the information to the first index information acquisition unit 702 via the input device 711. it can.

  The second image extraction unit 722 extracts an image at a stage after the first cleavage and before the second cleavage from the acquired candidate embryo image. Information on the time corresponding to the “stage after the first cleavage and before the second cleavage” for the candidate embryo can be stored in the storage unit 701, and the second image extraction unit 722 can store this information as necessary. You can refer to time information. The extracted image can be output as an image visually distinguishable by the user by the output device 712. The user can generate second index information based on the image extracted by the second image extraction unit 722 by visual discrimination, and input the information to the second index information acquisition unit 703 via the input device 711. it can.

  The third image extraction unit 723 extracts an image at a stage after the third cleavage and before the fourth cleavage from the acquired candidate embryo image. Information on the time corresponding to the “stage after the third cleavage and before the fourth cleavage” for the candidate embryo can be stored in the storage unit 701, and the third image extraction unit 723 can store this information as necessary. You can refer to time information. The extracted image can be output as an image visually distinguishable by the user by the output device 712. The user can generate the third index information based on the image extracted by the third image extraction unit 723 by visual discrimination, and input the information to the third index information acquisition unit 704 via the input device 711. it can.

  The generation of the first index information, the second index information, and the third index information based on the image can be automatically executed using image analysis processing software or the like. An example of this embodiment is shown in FIG. 8, the configuration indicated by reference numerals 820 to 823,880 has the same characteristics as the configuration indicated by reference numerals 720 to 723,780 in FIG. The embryo discrimination device 800 further includes an image analysis unit 890. The image analysis unit 890 performs image analysis processing based on the image extracted by the image extraction unit 880, generates first index information, second index information, and / or third index information, and inputs them to the determination unit 870 To do. The image analysis unit 890 includes a first image analysis unit 831, a second image analysis unit 832, and a third image analysis unit 833. The images extracted by the first image extraction unit 821, the second image extraction unit 822, and the third image extraction unit 823 are input to the first image analysis unit 831, the second image analysis unit 832, and the third image analysis unit 833, respectively. Is done. The first image analysis unit 831, the second image analysis unit 832, and the third image analysis unit 833 generate first index information, second index information, and third index information by image analysis processing, respectively, and the first index information The information is input to the acquisition unit 802, the second index information acquisition unit 803, and the third index information acquisition unit 804. Input the first index information, the second index information, and the third index information generated by the image analysis processing to the first index information acquisition unit 802, the second index information acquisition unit 803, and the third index information acquisition unit 804 Before, each index information is output to the output device 812, and each index information is output from the first image extraction unit 821, the second image extraction unit 822, and the third image extraction unit 823 to the output device 812. The index information is verified against the extracted image, and if it is determined to be appropriate, each index information is input to the first index information acquisition unit 802, the second index information acquisition unit 803, and the third index information acquisition unit 804. If it is determined to be invalid, the corrected index information generated by the user is input via the input device 811 to the first index information acquisition unit 802, the second index information, as described for the embryo sorting apparatus 700. The acquisition unit 803 and the third index information acquisition unit 804 may be configured to be input.

  The embryo selection apparatus of the present invention can constitute an embryo selection system for selecting a candidate embryo of a mammal cultured in vitro from a fertilized egg in combination with an imaging apparatus and an oxygen consumption measuring apparatus. The embryo sorting systems 740 and 840 shown in FIGS. 7 and 8 are an example of the embodiment.

  Embryo sorting systems 740 and 840 include at least embryo sorting devices 700 and 800, imaging devices 750 and 850, and oxygen consumption measuring devices 760 and 860.

  The imaging devices 750 and 850 capture the candidate embryo and output the captured images to the image acquisition units 720 and 820. The imaging devices 750 and 850 are not particularly limited as long as they can capture a moving image or a still image of a candidate embryo during in vitro culture in combination with a microscope objective lens as necessary. Is mentioned.

  Oxygen consumption measuring devices 760 and 860 measure and measure the oxygen consumption at the early blastocyst stage, blastocyst stage or expanded blastocyst stage of mammalian candidate embryos cultured in vitro from fertilized eggs The obtained oxygen consumption value is output to the fourth index information acquisition units 705 and 805. Although the oxygen consumption measuring devices 760 and 860 are not particularly limited, a device capable of measuring the oxygen consumption per single embryo as specifically described above can be used.

FIG. 9 is a schematic block diagram showing a functional configuration of the embryo sorting apparatus 900 when M is 3. As shown in FIG. The determination unit 970 is any three selected from the first index determination unit 606, the second index determination unit 607, the third index determination unit 608, and the fourth index determination unit 609 described with reference to FIG. M ₁ index determination unit 905, the M ₂ index determination unit 906 includes a second M ₃ index determination unit 907. Here, M ₁ , M ₂ , and M ₃ are integers selected from ₁ , ₂ , ₃ , and 4 in a mutually exclusive manner. In a preferred embodiment of the embryo sorting apparatus 900, M ₁ , M ₂ , and M ₃ are 2, 3, and 4, respectively.

FIG. 10 is a schematic block diagram showing a functional configuration of the embryo sorting apparatus 1000 when M is 2. The determination unit 1070 is any two selected from the first index determination unit 606, the second index determination unit 607, the third index determination unit 608, and the fourth index determination unit 609 described with reference to FIG. An M ₁ index determination unit 1004 and an M _2nd index determination unit 1005 are included. Here, M ₁ and M ₂ are integers selected from ₁ , ₂ , 3, and 4 in a mutually exclusive manner, and are preferably integers selected from 2, 3, and 4.

  FIG. 11 shows an embryo sorting apparatus 1100 and an embryo sorting system 1140, which are an embodiment in which the embryo sorting apparatus 700 and the embryo sorting system 740 shown in FIG. 7 are changed to M = 3.

  FIG. 12 shows an embryo sorting apparatus 1200 and an embryo sorting system 1240 according to an embodiment in which the embryo sorting apparatus 800 and the embryo sorting system 840 shown in FIG. 8 are changed to M = 3.

The embryo sorting apparatuses 1100 and 1200 are examples in the case of M ₁ = 2, M ₂ = 3, and M ₃ = 4 in the embryo sorting apparatus 900, but are not limited thereto.

  A method for sorting embryos with the embryo sorting apparatus of the present invention will be described with reference to the flowcharts shown in FIGS. In the following description, for the sake of convenience, the embryo discrimination devices 600, 900, and 1000 will be referred to as representative examples of the embryo discrimination device when M = 4, 3, and 2, respectively.

In the following description, M ₁ ... M _M means an integer selected from the group consisting of integers of 1... M (M is an integer of 2, 3, or 4) in a mutually exclusive manner.

FIG. 20 shows an outline of a method of selecting an embryo using the embryo discriminating apparatus 600, 900, 1000. Discriminator 670,970,1070 the first M ₁ index information, second M _M index information obtained for the candidate embryos, satisfies the corresponding index selection reference condition determines whether or not the (S2001). Next, the analysis unit 610,908,1006 analyzes whether the number of conditions determined to be satisfied in S2001 is N or more (S2002), and if it is N or more, it is an embryo to be selected Is output (S2003), and if it is less than N, a “bad” determination result indicating that it is not an embryo to be selected is output (S2004), and the process ends.

  FIG. 21 shows an outline of an embryo selection method using the embryo selection devices 700 and 1100 including the image extraction units 780 and 1180 shown in FIGS. In this method, the image extraction units 780 and 1180 extract predetermined images necessary for generating necessary information from the first to third index information from the acquired candidate embryo images (S2101). Next, predetermined information among the first to third index information generated based on the extracted predetermined image and / or fourth index information generated separately is acquired by the determination units 770 and 1170 (S2102) Is done. Subsequently, the above-described S2001 to S2004 are performed.

  FIG. 22 shows an outline of an embryo selection method using the embryo selection apparatus 800 or 1200 further including the image analysis units 890 and 1290 shown in FIGS. In this method, based on the predetermined image extracted in S2101 described above, predetermined information is generated from the first to third index information by the image analysis units 890 and 1290 and input to the determination units 870 and 1270. Subsequently, S2101 and S2001 to S2004 described above are performed.

The discrimination / analysis process of S2001 to S2004 shown in FIG. 20 can be roughly divided into two modes. In one manner, as shown in FIG. 13, by (here m which is an integer selected from 1 to M) a M _m index determination step executes from m = 1 to m = M, M-number After completing all the determinations regarding the satisfaction of the conditions (S1301), the analysis step S1302 is executed. This method is suitable when the determination step and the analysis step are performed after all necessary index information about the candidate embryo has been acquired. In the other format, as shown in FIGS. 14 to 19, the result of the “good” judgment is obtained when N conditions are satisfied without waiting for the completion of the determination about the satisfaction of all M conditions. When it is determined that N conditions cannot be satisfied, a “bad” result is output and the process is terminated. The latter mode is suitable for performing the discrimination process and the analysis process while acquiring necessary index information about the candidate embryos over time.

Therefore, an embryo selection method shown in the flowchart of FIG. 13 will be described. By a M _m index determination unit in the determination unit 670,970,1070, the M _m index the M _m index information of the obtained candidate embryos, to determine whether or not to satisfy a corresponding first M _m indicator selection criteria condition the determination process is performed in order from the first M ₁ index determination step until the M _M index determination step (S1301). Here, S1301 means that the M processes of the first index determination process, the second index determination process, the third index determination process, and the fourth index determination process are executed in an arbitrary order. Next, the analysis unit 610,908,1006 is to S1301 (the M ₁ index determination step, second M _M index determination step) determines conditions to satisfy in the analysis whether a N or more (S1302), N If the number is more than one, the result of “good” judgment indicating that the embryo should be selected is output (S1303), and if it is less than N, the result of “bad” judgment indicating that the embryo is not to be selected is output ( S1304) to finish the process.

Next, the method for selecting an embryo shown in the flowcharts of FIGS. In these methods, the M _m index determination step (where m is an integer selected from 1 to M) is sequentially executed from m = 1, and the M ₁ index determination step to the M _m index determination step If the number (x) of conditions determined to be satisfied among the m conditions determined is N (when x = N), the process does not proceed to the M _{m + 1} index determination step The result of the “good” determination is output and the process is terminated, and the number of conditions (x) determined to be satisfied is less than N, and it is assumed that from the M _{m + 1} index determination step to the M _M Even if the conditions determined in all processes up to the index determination process are satisfied, it is determined that a total of N conditions cannot be satisfied (when x <N and x + (Mm) <N) The result of “bad” is outputted to terminate the processing, and if none of them is satisfied (when x <N and N ≦ x + (Mm)), the process proceeds to the M _{m + 1} index determination step.

FIG. 14 shows an example in which the threshold in the analysis process is set to N = 2 by the embryo sorting apparatus 600 (M = 4). S1401 is a first M ₁ index determination process of the first M ₁ index determination unit performs the S1402 and S1403 are the M ₂ index determination process of the first M ₂ index determination unit performs, S1404, S1405 and S1406 are the M ₃ index determination unit the first M ₃ index determination process is performed, indicating the S1407, S1408 and S1409 are the M ₄ index determination process of the first M ₄ index determination unit performs. The M ₁ index determination unit, the M ₂ index determination unit, the M ₃ index determination unit, the first M ₄ index determination unit, the first index determination unit 606 included in the determination unit 670, the second index determination unit 607, the The three index discriminating unit 608 and the fourth index discriminating unit 609 are mutually exclusive. S1410, S1412, and S1414 indicate steps in which the analysis unit 610 outputs the result of “good” determination. S1411, S1413, and S1415 indicate steps in which the analysis unit 610 outputs the result of the “defective” determination. If the M ₁ indicator selection criterion condition is satisfied at S1401 (x, m = 1,1, x <N and N ≦ x + (Mm)) proceeds to the S1402, if not satisfied (x, m = 0, 1, x <N and N ≦ x + (Mm)), the process proceeds to S1403. If the M ₂ indicator selection criterion condition is satisfied at S1402 (x, m = 2,2, x = N) to proceeds to S1410, if not satisfied (x, m = 1,2, x <N and If N ≦ x + (Mm)), the process proceeds to S1404. If the M ₃ indicator selection criterion condition is satisfied at S1404 (x, m = 2,3, x = N) , the process proceeds to S1410, if not satisfied (x, m = 1,3, x <N and If N ≦ x + (Mm)), the process proceeds to S1407. If the M ₄ indicator selection criterion condition is satisfied at S1407 (x, m = 2,4, x = N) , the process proceeds to S1410, if not satisfied (x, m = 1,4, x <N and If x + (Mm) <N), the process proceeds to S1411. If the M ₂ indicator selection criterion condition is satisfied at S1403 (x, m = 1,2, x <N and N ≦ x + (Mm)) proceeds to the S1405, if not satisfied (x, m = 0, 2, x <N and N ≦ x + (Mm)), the process proceeds to S1406. If the M ₃ indicator selection criterion condition is satisfied at S1405 (x, m = 2,3, x = N) , the process proceeds to S1412, if not satisfied (x, m = 1,3, x <N and If N ≦ x + (Mm)), the process proceeds to S1408. If the M ₄ indicator selection criterion condition is satisfied at S1408 (x, m = 2,4, x = N) , the process proceeds to S1412, if not satisfied (x, m = 1,4, x <N and If x + (Mm) <N), the process proceeds to S1413. If the M ₃ indicator selection criterion condition is satisfied at S1406 (x, m = 1,3, x = N) , the process proceeds to S1409, if not satisfied (x, m = 0,3, x <N and If x + (Mm) <N), proceed to S1415. If the M ₄ indicator selection criterion condition is satisfied at S1409 (x, m = 2,4, x = N) , the process proceeds to S1414, if not satisfied (x, m = 1,4, x <N and If x + (Mm) <N), proceed to S1415.

FIG. 15 shows an embodiment of the operation when the threshold value in the analysis step is set to N = 3 in the embryo sorting method using the embryo sorting apparatus 600 (M = 4). FIG. 16 shows an embodiment of the operation when the threshold in the analysis step is set to N = 4 in the embryo selection method using the embryo selection device 600 (M = 4). In Figure 15 and 16, similarly to FIG. 14, a is S1501 and 1601 a M ₁ index determination process of the first M ₁ index determination unit performs, S1502, S1503, S1602 is a M ₂ indicator is a M ₂ index determination unit performs the determination step, S1504, S1505, and S1506 and S1603 are the M ₃ index determination process of the first M ₃ index determination unit performs, S1507, S1508, S1509 and S1604 are the M ₄ index determination process of the first M ₄ index determination unit performs Indicates. S1510, S1512, S1514, and S1605 indicate steps in which the analysis unit 610 outputs the result of “good” determination. S1511, S1513, S1515, and S1606 are steps in which the analysis unit 610 outputs the result of the “defective” determination.

FIG. 17 shows an embodiment of the operation when the threshold in the analysis step is set to N = 2 in the embryo selection method using the embryo selection apparatus 900 (M = 3). FIG. 18 shows an embodiment of the operation when the threshold value in the analysis step is set to N = 3 in the embryo sorting method using the embryo sorting apparatus 900 (M = 3). In Figure 17 and 18, the the S1701 and S1801 are the M ₁ index determination process of the first M ₁ index determination unit 905 performs, S1702, S1703 and S1802 are the M ₂ index determination process of the first M ₂ index determination unit 906 performs, S1704, S1705 and S1803 shows a first M ₃ index determination process of the first M ₃ index determination unit 907 performs. S1706, S1708, and S1804 indicate steps in which the analysis unit 908 outputs the result of “good” determination. S1707, S1709, and S1805 indicate steps in which the analysis unit 908 outputs the result of “defect” determination.

FIG. 19 shows an embodiment of the operation when the threshold value in the analysis step is set to N = 2 in the embryo sorting method using the embryo sorting apparatus 1000 (M = 2). In Figure 19, S1901 shows a first M ₂ index determination process of the first M ₁ index determination step, S1902 has the M ₂ index determination unit 1005 performs the first M ₁ index determination unit 1004 performs. S1903 indicates a process in which the analysis unit 1006 outputs the result of the “good” determination. S1904 indicates a process in which the analysis unit 1006 outputs the result of the “defective” determination.

In FIGS. 23a to 23d, as an example, using the embryo sorting apparatus 900 (where M ₁ = 2, M ₂ = 3, and M ₃ = 4), the flowchart shown in FIG. 17 (M = 3, N = 2) A method for selecting a bovine embryo according to the above will be described specifically.

  When a plurality of candidate embryos are processed together, an address specifying each candidate embryo can be assigned. For example, when a candidate embryo is accommodated in each well of a multiwell plate having a plurality of wells (concave holes) arranged in a matrix, each candidate embryo can be specified by the coordinates (row, column) of the well. When one candidate embryo is accommodated in one well, individual management of the embryo is easy, but a plurality of candidate embryos may be accommodated in one well. In the latter case, each embryo in one well can be further distinguished by giving an ID number.

Each selection criterion condition and index information in the examples of FIGS. 23a to 23d are as follows.
Second indicator discrimination criteria: 2 cells at 31 hours after fertilization (at the end of the initial cleavage) and no fragmentation observed Third criteria selection criteria: 55 hours after fertilization (at the end of the third cleavage) In any one of 5 cells, 6 cells, 7 cells, and 8 cells, and no fragmentation is observed. 4th index selection criteria condition: 168 hours after fertilization (early blastocyst stage, blastocyst stage or expanded embryo) 2nd index information: oxygen consumption per single embryo at the blastocyst stage) is 0.91 × 10 ^-14 mol s ^-1 or more: Number of cells 31 hours after fertilization, and the presence or absence of fragmentation 3rd index information : Number of cells at 55 hours after fertilization and the presence or absence of fragmentation 4th index information: Oxygen consumption per single embryo at 168 hours after fertilization

  Information (row, column, ID number) for identifying individual candidate embryos is stored in the storage unit 901 (FIG. 23a). Whether the second index information acquired by the second index acquisition unit 902 satisfies the second index selection criterion condition is determined by the second index determination unit 905, and the second index information and the determination result are stored ( Figure 23b). O.K. indicates that the second index selection criterion condition is satisfied, and NG indicates that the condition is not satisfied. O.K. and NG may be replaced with numerical values such as 1 and 0, respectively. Next, the third index determination unit 906 determines whether the third index information acquired by the third index acquisition unit 903 satisfies the third index selection criterion condition, and stores the third index information and the determination result (FIG. 23c). A candidate embryo that satisfies the two conditions at the end of the third index discrimination step is concluded to be a non-defective product (the flowchart of FIG. 17 is followed in the order of S1701, S1702, and S1706), and the analysis result is stored in the storage unit 901. A candidate embryo that does not satisfy both conditions at the end of the third index discrimination step is concluded to be defective (following the flowchart of FIG. 17 in the order of S1701, S1703, and S1709), and the analysis result is stored in the storage unit 901. Next, for candidate embryos that satisfy one condition at the end of the third index determination step, whether or not the fourth index information acquired by the fourth index acquisition unit 904 further satisfies the fourth index selection criterion condition The discrimination by the fourth index discriminating unit 907 is performed, and the fourth index information and the discrimination result are stored (FIG. 23d). A candidate embryo that satisfies the two conditions is concluded as a non-defective product, a candidate embryo that satisfies only one condition is determined as a defective product, and the analysis result is stored in the storage unit 901.

  A preferred embodiment of the hardware configuration of the embryo sorting system of the present invention is schematically shown in FIG. The embryo sorting apparatus includes a computer 2401 having a central processing unit (CPU) and a hard disk drive (HDD). The imaging apparatus includes a charge coupled device (CCD) 2404 and an objective lens 2405 that can observe an embryo. A culture vessel 2407 for culturing an embryo is installed on the stage 2408. It is preferable to further include a position control mechanism 2409 for controlling the relative position between the imaging device (2404, 2405) and the stage 2408 to position the imaging position in the culture vessel 2407 by the imaging device. The imaging device (2404, 2405) may be position-controlled so that a single candidate embryo is included in the field of view by the objective lens 2405 at the time of imaging, or position-controlled so that a plurality of candidate embryos are included. Also good. An imaging device (2404, 2405), an oxygen consumption measuring device 2406, a display interface 2402, and an input interface 2403 are connected to the computer 2401.

  Each function of the embryo sorting apparatus of the present invention can also be realized by a program code of software that realizes the function. In this case, a storage medium in which the program code is recorded is provided to the system or apparatus of the present invention, and the computer (or CPU or MPU) of the system or apparatus reads the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the function, and the program code itself and the storage medium storing the program code constitute the present invention. As a storage medium for supplying such a program code, for example, a flexible disk, CD-ROM, DVD-ROM, hard disk, optical disk, magneto-optical disk, CD-R, magnetic tape, nonvolatile memory card, ROM Etc. are used.

  Further, an OS (operating system) running on the computer may perform part or all of the actual processing based on an instruction of the program code, and the above functions may be realized by the processing. Further, after the program code read from the storage medium is written in the memory on the computer, the computer CPU or the like performs part or all of the actual processing based on the instruction of the program code. The function may be realized by.

  In addition, by distributing the program code of software that realizes the above functions via a network, the program code is stored in a storage means such as a hard disk or memory of a system or apparatus, or a storage medium such as a CD-RW or CD-R, The function may be realized by the computer (or CPU or MPU) of the system or apparatus reading and executing the program code stored in the storage means or the storage medium.

  Hereinafter, the present invention will be described more specifically based on examples. However, embodiments of the present invention, materials and instruments used are not limited to the specific examples shown in the examples.

<Experiment 1: Relationship between the index of the present invention and the conception rate>
<Materials and methods>
<Culture container>
In this experiment, a cell container 3 consisting of 25 microwells 4 at the center of a 35 mm culture dish having a bottom wall 2 and a side wall 1 standing on the outer periphery thereof, and an annular shape surrounding the periphery of the cell container 3 The culture vessel 10 shown in FIGS. 1a to 1f in which the inner wall 5 was formed was used. The diameter r of each microwell 4 constituting the cell accommodating portion 3 is 270 μm, and the depth L is 150 μm. The 25 microwells 4 are arranged in 5 rows and 5 columns so that the distance a between the wells is 150 μm. The bottom surface 6 of each microwell is inclined so as to descend from the outer peripheral portion toward the center to form a conical surface, and an angle α formed between the center line of the cone and the generatrix is 83 °. The annular inner wall is 7mm in diameter and 1.5mm in height. The inner wall 5 has a diameter d of 7 mm and a height of 1.5 mm, and was used to form a culture liquid droplet.

  The culture vessel was made of polystyrene, and one produced by a normal injection molding method was used.

<Oocyte collection and in vitro maturation (IVM)>
The collection and in vitro maturation of bovine cumulus-oocyte complexes (COCs) are described in Imai et al. (Imai K, Tagawa M, Yoshioka H, Matoba S, Narita M, Inaba Y, Aikawa Y, Ohtake M, Kobayashi S (2006) The efficiency of embryo production by ovum pick-up and in vitro fertilization in cattle. J Reprod Dev 52 (suppl): 19-29). The ovaries collected from Japanese Black heifers or Holsteins were washed with physiological saline supplemented with 50 μg / ml gentamicin (Sigma Chemical, St Louis, MO, USA) It was kept at 20 ° C. for about 20 hours in physiological saline. COCs were aspirated from follicles (2-6 mm in diameter) using a 5 mL syringe with a 19 gauge needle and used for in vitro maturation. As an in vitro maturation medium, 25 mM Heptes buffered TCM199 (M199; Gibco BRL, Grand Island, NY, USA) supplemented with 5% calf serum (CS; Gibco BRL) was used. COCs in _{2 in} vitro maturation medium coated with paraffin oil in 35% mm Petri dishes (Nunclon Multidishes; Nalge Nunc International, Roskide, Denmark) under saturated humidity 5% CO ₂ /95% air Washed twice.

<In vitro fertilization (IVF)>
In vitro fertilization was performed according to the procedure described in the above-mentioned Imai et al. Specifically, a frozen Japanese Black bull sperm sample in a 0.5 ml straw was thawed in a 37 ° C. water bath for 30 seconds and then 2100 × g in 3 ml of 90% Percoll solution. For 10 minutes. The pellet formed by centrifugation was treated with 6 ml of sperm washing solution (10 mM hypotaurine (Sigma), 2 U / mL heparin (Novo-Heparin Injection 1000; Aventis Pharma Ltd., Tokyo, Japan), 10 mg / ml bovine Brackett and Oliphant solution (BO solution) supplemented with serum albumin (BSA, crystallized and lyophilized; Sigma) (Reference: Brackett BG, Oliphant G (1975) Capacitation of rabbit spermatozoa in vitro. Biol Reprod 12: 260-274))) and centrifuged to give a final concentration of 3 × 10 ⁶ sperm / ml. A 100 μL droplet of this suspension was formed on a 35-mm dish and coated with paraffin oil to give a fertilization droplet. COCs are separated from the in vitro maturation medium, washed with BO solution supplemented with 10 mg / ml BSA, added to the fertilization droplets to contain 20 COCs per droplet, and saturated humidity The cells were cultured at 38.5 ° C. for 6 hours under 5% CO ₂ /95% air.

<Pretreatment of culture vessel>
2 ml of ethanol was added to the culture vessel 10 for sterilization. After 30 minutes, ethanol was removed from the culture container, dried in air on a heating plate, and ultraviolet sterilized for 10 minutes. After sterilization, 125 μl CR1aa medium containing 5% CS was added to the area surrounded by the annular inner wall 5 and covered with paraffin oil. Bubbles in the microwell 4 were driven out by hitting the container from the outside. Culture vessels were preincubated for at least 3 hours before use.

<In vitro culture (IVC)>
In vitro culture was performed at 38.5 ° C. for 168 hours in 125 μl CR1aa medium supplemented with 5% CS under saturated humidity of 5% CO ₂ /5% O ₂ /90% N ₂ . In this test system, the culture density is 5 μl per embryo. Fujita et al. (Fujita T, Umeki H, Shimura H, Kugumiya K, Shiga K (2006) Effect of group culture and embryo-culture conditioned medium) that this culture density is most advantageous for development up to the blastocyst stage. reported on on development of bovine embryos. J Reprod Dev 52: 137-142). After fertilization, the cells considered zygotes were completely separated from cumulus cells and sperm by gently pipetting with a fine glass pipette in a pre-incubated in vitro culture medium. Twenty-five zygotes were arranged so that one zygote was placed in one microwell 4 in a droplet in the microwell 4 of the culture vessel.

<Measurement of oxygen consumption per single embryo>
The oxygen consumption by individual embryos was measured non-invasively using the SECM system (HV-405; Hokuto Denko Co., Ltd.) (Abe H, Hoshi H (2003) Evaluation of bovine embryos produced in high performance serum-free media. J Reprod Dev 49: 193-202 and Shiku H, Shiraishi T, Ohya H, Matsue T, Abe H, Hoshi H, Kobayashi M (2001) Oxygen consumption of single bovine embryos probed by scanning electrochemical microscopy. Anal Chem 73: 3751 -3758). Transfer embryos one by one into a plate filled with 5 ml of embryo respiration assay medium-2 (ERAM-2; manufactured by Functional Peptide Institute, Inc.) Allowed to settle. The plate was placed on a heating plate on a microscope stage, and the temperature of the ERAM-2 solution was maintained at 38.5 ° C. The oxygen consumption was measured by the method described in Shiku H et al. The XYZ stage and potentiostat were controlled by computer. Voltammetry of a Pt-microdisk electrode (Hokuto Denko Co., Ltd.) in ERAM-2 solution shows a current-potential curve. No response from other electrochemically active species was observed near the surface of the embryo. The oxygen consumption rate of the embryo was calculated using software. This software calculates the difference in oxygen consumption (ΔC) between the bulk solution and the embryo sample surface and the oxygen consumption rate (F, unit: mol s ^-1 ) of one embryo sample from the spherical diffusion theory (Shiku H above) Et al.). The electrodes were scanned twice before and after, and the average value of ΔC was estimated for each embryo sample.

<Evaluation of embryo morphology using Time-lapse cinematography TLC>
The cleavage state and embryo morphology were described by Somfai T et al. (Somfai T, Inaba Y, Aikawa Y, Ohtake M, Kobayashi S, Konishi K, Imai K (2009) Relationship Between the Length of Cell Cycles, Cleavage Pattern and Developmental Competence. J Reprod Dev 56: 200-207) in Bovine Embryos Generated by In Vitro Fertilization or Parthenogenesis. Embryos were cultured at 38.5 ° C. under saturated humidity 5% CO ₂ /5% O ₂ /90% N ₂ . The occurrence was monitored using a real-time Culture Cell Monitoring System (CCM-M1.4Z; Astec Corporation). During the 168-hour culture period, 673 photographs of the embryo were taken at 15-minute intervals using a 4x plain objective. The accumulated images were analyzed using CCM-M1.4 software (Astech Co., Ltd.).

<Synchronous cycle and embryo transfer>
The sexual cycle of the recipient Japanese black / Holstein hybrid was synchronized with 3 ml prostaglandin F _2α . One embryo on the 7th day after fertilization selected based on the index described later was transplanted to the synchronized luteal uterine horn of the recipient on the 7th to 8th day after estrus. All recipients were similarly fed and managed to observe estrus behavior at least twice a day in the morning and evening.

<Conception diagnosis>
On the 30th and 60th day after embryo transfer, a conception diagnosis was performed using an ultrasonic examination method (HS101V; Honda Electronics Co., Ltd.). The conception was confirmed by observing the fetus in the uterus and observing the heartbeat of the fetus.

<Indicators>
The following indicators were used. The following indicators 1 and 2 are conventionally used for selection of embryos.

Indicator 1: The morphological quality after 168 hours of fertilization is Code 1.
Indicator 2: The blastocyst has reached 168 hours after fertilization.
Index 3: 2 cells at 31 hours after fertilization (at the end of the initial cleavage), and no fragmentation is observed.
Index 4: One of 5 cells, 6 cells, 7 cells, and 8 cells at 55 hours after fertilization (at the end of the third cleavage), and no fragmentation is observed.
Indicator 5: Oxygen consumption per single embryo after 168 hours of fertilization (early blastocyst stage, blastocyst stage or extended blastocyst stage) is 0.91 × 10 ^-14 mol s ^-1 or more.

  In Code 1, `` Code 1 '' for morphological quality means Robertson I, Nelson RE (1998) Certification and identification of the embryo.In: DA Stringfellow and SM Seidel, Editors, Manual of the international embryo transfer society, IETS, Savoy , As defined in Illinois 103-116. Specifically, at a time point after 168 hours of fertilization, an embryo having normal development and no morphological abnormality (eg, egg cell irregularity or degeneration) is evaluated as having a morphological quality of Code 1.

<Result>
The following table shows the relationship between the number of transplanted embryos satisfying the above indices and the conception rate. The presence or absence of conception is the result of observation 60 days after embryo transfer.

  Indexes 1 and 2 have been established as selection indexes for transplanted embryos, but the conception rate was 50% or less even when transplanted embryos satisfying them alone or in combination were used. It can be seen that the conventional judgment index based only on the morphology of the embryo after 168 hours of fertilization is not necessarily sufficient for selecting transplanted embryos having a high conception rate.

The conception rate of transplanted embryos satisfying one of the indicators 3, 4, and 5 was 63.6% at the highest.
Even for transplanted embryos that satisfy one or both of indicators 1 and 2 and one of indicators 3, 4, and 5, the conception rate was less than 70%.

  Surprisingly, however, it was confirmed that the conception rate of transplanted embryos satisfying a combination of at least two of indicators 3, 4, and 5 was 70% or 80%.

  From the above results, it was concluded that a particularly high conception rate can be achieved by combining at least two of the indicators 3, 4, and 5 as a selection indicator for transplanted embryos.

<Experiment 2: Preliminary study>
From the results of the preliminary examination conducted before Experiment 1, the above indicators 3 to 5 were predicted to be useful as factors for predicting embryos with a high conception rate. The preliminary examination procedure and results are shown below.
The embryo used in this experiment is a bovine (Bos taurus) embryo.

<Candidate for prediction index>
The following indicators were used as predictor candidates.

31 hours after fertilization (at the end of the initial cleavage): Number of blastomeres, uniformity of blastomeres, presence or absence of fragmentation.
55 hours after fertilization (at the end of the third cleavage): Number of blastomeres, uniformity of blastomeres, presence or absence of fragmentation.
168 hours after fertilization (early blastocyst stage, blastocyst stage or extended blastocyst stage): blastocyst stage (whether or not it reaches the extended blastocyst), oxygen consumption.

<Evaluation method>
Total embryo cell number, inner cell mass (ICM) cell number, trophectoderm (TE) cell number, ICM cell rate, zona pellucida hatching rate, conception rate at the time of embryo transfer Is known to show a positive correlation.

  It is known that there is a negative correlation between the rate of embryo positive cells in embryos and the conception rate at the time of embryo transfer.

  Therefore, we investigated the correlation between the above index and the total number of embryo cells, ICM cells, TE cells, ICM cell rate, apoptosis positive cell rate, embryo zona pellucida escape rate, and is it useful as a predictor? I confirmed it.

  The procedure for in vitro culture to obtain an embryo, the method for observing the cleavage state, and the procedure for measuring oxygen consumption are the same as in Experiment 1.

  The number of cells, apoptosis-positive cell rate, zona pellucida escape rate, and blastomere heterogeneity were measured by the following procedure.

<Measurement of cell number>
The cell distribution in the embryo was analyzed by Thouas et al. (Thouas GA, Korfiatis NA, French AJ, Jones GM, Trounson AO (2001) Simplified technique for differential staining of inner cell mass and trophectoderm cells of mouse and bovine blastocysts. Reprod Biomed Online 3: 25-29.) According to the procedure of ICM and TE, evaluation was performed.

  In this method, embryonic cells were stained for 40 seconds with 100 μg / ml propidium iodide fluorochrome containing an osmotic solution of 0.2% (v / v) Triton X-100 ionic surfactant. The embryos were then immobilized by incubating for 5 minutes in a second solution containing Hoechst 33342 at a concentration of 25 μg / ml in 99.5% ethanol. The number of embryo cells after staining and fixation was observed with an epifluorescence microscope (IX-71; Olympus Corporation, Tokyo). Blue nuclei indicate ICM cells and pink-red nuclei indicate TE cells. The total number of ICM cells and TE cells is the total number of cells.

<Measurement of apoptosis positive cell rate>
Yamanaka et al. (Yamanaka K, Sugimura S, Wakai T, Kawahara M, Sato E (2009) Difference in sensitivity to culture condition between in vitro fertilized and somatic cell nuclear transfer embryos in pigs. J Reprod Dev 55: 299-304) According to the procedure, apoptosis positive cells were detected by TUNEL assay.

  Embryos were washed 3 times in PBS supplemented with 0.1% polyvinylpyrrolidone (Sigma), 2% (w / v) paraformaldehyde (Sigma) and 0.2% (v / v) Triton-X (Sigma) PBS ( The solution was fixed in a phosphate buffer solution at room temperature for 40 hours. Apoptosis-positive cells were detected using a commercially available kit (ApopTag; Chemicon, Temecula, CA, USA). As a positive control sample, an embryo treated with DNase I (10 IU / mL, Sigma) was used.

  After washing with 0.1% PVA (polyvinyl alcohol) PBS for 10 minutes, the embryos were incubated in the above buffer for 20 minutes at room temperature. It was then incubated for 2 hours at 37 ° C. with a 70% (v / v) reaction buffer containing 30% (v / v) terminal deoxynucleotidyl transferase and digoxigenin-11-dUTP in a humid chamber. The reaction was stopped by adding 3% (v / v) stop / wash buffer (Chemicon) for 10 minutes at 37 ° C. After washing 4 times with PBS containing 0.2% (v / v) Triton-X for 2 minutes each time, the mixture was incubated with horseradish peroxidase-conjugated anti-digoxigenin antibody for 1 hour at room temperature. After washing 4 times with 0.2% Triton-X and 0.1% PVA PBS, the embryos were stained with a solution containing 10 μg / mL of propiodium iodide in PBS for 1 hour at room temperature. All samples were observed with an epifluorescence microscope. The number of apoptotic positive nuclei in the embryo and the number of all nuclei were counted. TUNEL positive cells are indicated by yellow to green.

<Escape rate of zona pellucida>
Percentage of embryos that have completely escaped from the zona pellucida. Judgment is made by visual observation of an enlarged image of the embryo.

<Nonuniformity of blast ball>
Visually observe the enlarged image of the embryo to determine the nonuniformity of the size of the blastomere.

<Result>
Relationship between each predictor (indicator) and total embryo cell number, ICM cell number, TE cell number, ratio of ICM cell number to total cell number (ICM%), apoptosis positive cell rate, embryo zona pellucida escape rate The results of multiple regression analysis are summarized below.

  Logistic analysis analyzed the relationship between predictors and total cell count, ICM cell count, TE cell, ICM%, apoptosis positive cell rate, and success or failure of zona pellucida escape. The analysis conformed to Applied Logistic Regression Analysis, 2nd ed (Menard 2002). Dependent variables are total cell number (continuous variable), ICM cell number (continuous variable), TE cell number (continuous variable), ICM% (continuous variable), apoptosis positive cell rate (continuous variable), success or failure of zona pellucida escape (name) Variable: “1” for composition and “0” for failure. Number of blastomeres at Day 1 (nominal variable: 2 for cells, “1” for others, “0” for others), blastomere heterogeneity (nominal variable: heterogeneity is “1”, uniform ”0”), presence / absence of fragmentation (nominal variable: “1” for fragmentation, “0” for none), number of blastomeres at Day2 (3-4 cells) (nominal variable: 3-4 1 for cells, 0 for others), number of blastomeres (5-8 cells) (nominal variable: 5-8 cells for “1” and others for “0”) “ie 3-4 cells Is "1,0", 5-8 cells are "0,1",> 8 cells are "0,0"], uniformity of blastomeres (same name variable as Day1), presence of fragmentation (Day1 Nominal variable), success or failure of reaching the expanded blastocyst on Day 7 (nominal variable: “1” for growth, “0” for failure), oxygen consumption (continuous variable). If the 95% confidence interval did not include 1, it was considered statistically significant.

  Table 2 shows that the presence or absence of fragmentation after 55 hours of fertilization, blastocyst stage after 168 hours and oxygen consumption have a significant correlation with the total cell number. Therefore, in order to select embryos with a large total number of cells, it is effective to select embryos that have expanded blastocysts with high oxygen consumption and did not have fragmentation after 55 hours. It was estimated.

  Table 3 shows that the presence or absence of fragmentation after 55 hours of fertilization, blastocyst stage after 168 hours and oxygen consumption have a significant correlation with the number of ICM cells. Therefore, in order to select embryos with a large number of ICM cells, it is effective to select embryos with extended blastocysts with high oxygen consumption and no fragmentation at 55 hours. It was estimated.

  Table 4 shows that the number of blastomeres after 31 hours of fertilization, the presence or absence of fragmentation after 55 hours of fertilization, the blastocyst stage after 168 hours and oxygen consumption have a significant correlation with the number of TE cells. Therefore, in order to select embryos with a large number of TE cells, the oxygen consumption in the expanded blastocyst is high, the developmental stage at 31 hours after fertilization is 2 cells, and at 55 hours after It was estimated that selecting embryos that did not have fragmentation was effective.

  Table 5 shows that the number of blastomeres 31 hours after fertilization has a significant correlation with the ICM cell rate (ICM%). From this, it was presumed that selecting embryos whose development stage was 2 cells at 31 hours later was effective in selecting embryos with high ICM%.

  Table 6 shows that the number of blastomeres at 55 hours after fertilization and the presence or absence of fragmentation have a significant correlation with the percentage of apoptosis-positive cells. Therefore, in order to select embryos with a low apoptosis-positive cell rate, it is effective to select embryos that are in the 5-8 cell stage at 55 hours after fertilization and have no fragmentation. It was estimated.

  Table 7 shows that the number of blastomeres after 31 hours of fertilization and the presence or absence of fragmentation, and the blastocyst stage and oxygen consumption after 168 hours have a significant correlation with the ability to escape from the zona pellucida. Therefore, in order to select embryos with high ability to escape from the zona pellucida, oxygen consumption is high in the expanded blastocyst, and at the time of 31 hours after fertilization, it is in the 2-cell stage and has no fragmentation. It was presumed that it would be effective to select embryos.

  Examples of measurement results are shown in FIGS.

  FIG. 2 shows the relationship between the number of cells and oxygen consumption.

  Fig. 3 shows the relationship between the first cleavage pattern after 31 hours of fertilization and the rate of apoptosis positive cells (Fig. 3 (a)), the relationship between the presence of fragmentation and the rate of apoptosis positive cells after 55 hours of fertilization (Fig. 3 ( b)), the relationship between the number of blastomeres 55 hours after fertilization and the rate of apoptosis positive cells (Fig. 3 (c)), the relationship between the oxygen consumption after 168 hours of fertilization and the rate of apoptosis positive cells (Fig. 3 (d)) ).

  In FIG. 3 (a), NC indicates an embryo having the same size of two blastomeres and no fragmentation. MF indicates an embryo with 2 blastomeres but multiple fragmentation within the follicular cavity. UB represents an embryo in which the size of the two blastomeres is not uniform. PT represents an embryo with a blastomere of 2 but with a protrusion. 3C indicates an embryo divided directly from the 1-cell stage into 3 or 4 cells. The same applies to FIG. 4 (a) and FIG.

  Figure 4 shows the relationship between the first cleavage pattern 31 hours after fertilization and zona pellucida escape (Figure 4 (a)), the relationship between the blastocyst stage 168 hours after fertilization and zona pellucida escape (Figure 4 (b)), Fig. 4 (c) shows the relationship between oxygen consumption and zona pellucida escape after 168 hours of fertilization.

The results in Fig. 4 (c) show that embryos have low ability to escape the zona pellucida when the oxygen consumption per embryo after 168 hours of fertilization is 0.9 x 10 ^-14 mol s ^-1 or less (32.6%) On the other hand, when it exceeds 0.9 × 10 ⁻¹⁴ mol s ⁻¹ , it is suggested that the zona pellucida escape ability is remarkably high (87.4%).

  FIG. 5 shows the relationship between the first cleavage pattern 31 hours after fertilization and oxygen consumption. There was no significant difference in oxygen consumption due to the difference in the first cleavage pattern. This suggests that it may not be possible to efficiently select embryos that are cytogenetically normal (without chromosomal aberrations) simply by measuring oxygen consumption.

<Experiment 3: Preliminary study on the first cleavage time>
<Number of chromosomes>
After tracking the development process with a real-time cell culture observation device, the oxygen consumption of the embryo that reached the blastocyst (early blastocyst or expanded blastocyst) was analyzed by SECM. The embryo used in this experiment is a bovine (Bos taurus) embryo. Chromosome analysis was performed according to Somfai et al. (2010). After measuring the oxygen consumption, the cells were cultured in CR1aa supplemented with 100 ng / ml vinblastine 5% CS for 17 hours, and the cell cycle was stopped at the mitotic phase (M phase). After the embryo was treated with 0.4 ml of 1% sodium citrate, 0.02 ml of methanol acetate (1: 1) was injected into the same solution to fix the embryo. Ten minutes later, the embryo was placed on a slide glass. A small amount (1 μl) of acetic acid was added dropwise to the embryo and then re-fixed with ethanol acetate (1: 3). Chromosome samples were air-dried and stained with 2% Giemsa solution for 10 minutes. Chromosome specimens were observed with an optical microscope. The number of chromosomes was analyzed with NIH ImageJ (v.1.40). Embryos with 60 chromosomes (58 autosomes, 2 sex chromosomes) in all analyzed cells were normal, and the rest were abnormal embryos. The factors (parameters) involved in the number of staining were analyzed by logistic regression analysis from the results of time lapse and oxygen consumption. As a result, there was a significant correlation between the end time of the first cleavage and the number of blastomeres and the number of blastomeres at the end of the third cleavage (Table 8).

  The percentage of normal embryos that were cleaved after 27.25 hours was 16.7%, which was significantly lower than the percentage of normal embryos that were cleaved within 27 hours (55.0-72.4%) (Table 9). And FIG. 25).

<Gene expression>
After tracking the development process with a real-time cell culture observation device, the oxygen consumption of the embryo that reached the blastocyst (early blastocyst or expanded blastocyst) was analyzed by SECM. The embryo used in this experiment is a bovine (Bos taurus) embryo. After measuring oxygen consumption, embryos were placed one by one in 50 μl RNA extract (Arcturus) and cultured at 42 ° C. for 30 minutes. Total RNA was extracted using PicoPure RNA Isolation Kit (Arcturus) according to the manufacturer's instructions. RevaTra Ace qPCR RT Kit (Toyobo Bio) was used for reverse transcription to cDNA. Quantitative real-time RT-PCR was performed using StepOnePlus ^™ . The reaction conditions for real-time PCR are as follows. 1 cycle at 95 ° C for 20 seconds, 43 cycles at 95 ° C for 3 seconds, 60 ° C for 10 seconds and 72 ° C for 20 seconds. Using H2AFZ (SEQ ID NO: 15) as an internal standard, the relative gene expression of each gene (AKR1B1, IGF2R, IFN-tau, PLAC8 and CDX2) was calculated. From the results of time lapse and oxygen consumption, the factors (parameters) involved in each gene expression were analyzed by multiple regression analysis. As a result, the end time of the first cleavage and the number of blastomeres showed a significant correlation with IGF2R gene (SEQ ID NO: 13) expression and IFN-tau gene (SEQ ID NO: 14) expression (Tables 10 and 11). As the end time of the first cleavage increased, the expression levels of IGF2 and IFN-tau (relative expression levels when the expression level of H2AFZ was 1) decreased (Table 12 and FIG. 26).

  Table 13 shows the GeneBank Accession number of each gene, the sequence of a primer set consisting of a forward primer and a reverse primer used for PCR amplification of each gene using cDNA as a template, and the amplified fragment size of each primer set.

<Experiment 4: Relationship between four indicators and conception rate>
Cumulus cell ovary complexes (COCs) were collected from Japanese black cattle by transvaginal oocyte aspiration (OPU), and subjected to in vitro fertilization (IVF) after in vitro maturation culture (IVM) for 22 hours. In vitro fertilization was monitored by a real-time cell culture observation device, and oxygen consumption of embryos that reached blastocysts (early blastocysts or expanded blastocysts) was analyzed by SECM. Embryos were selected according to the following indicators and transferred to temporary parents. The presence or absence of conception was confirmed by ultrasonic diagnosis at 30 and 60 days after embryo transfer.

ステージ：BL=胚盤胞，ExBL=拡張胚盤胞
Code: Robertson I, Nelson RE (1998) Certification and identification of the embryo. In: D.A. Stringfellow and S.M. Seidel, Editors, Manual of the international embryo transfer society, IETS, Savoy, Illinois 103-116.での定義に従う。具体的にはCode1は生存細胞が全体の85%以上，Code2は生存細胞が全体の50%以上の胚盤胞もしくは拡張胚盤胞を指す。「Code1-2」は「Code1もしくは2」を意味する。
指標#1：受精から第一卵割完了までの時間が27時間であること。
指標#2：受精31時間後（初期卵割終了時）において2細胞であり、且つ、フラグメンテーションが観察されないこと。
指標#3：受精55時間後（第三卵割終了時）において6細胞、7細胞、8細胞のいずれかであり、且つ、フラグメンテーションが観察されないこと。
指標#4：受精168時間後（初期胚盤胞期、胚盤胞期又は拡張胚盤胞期）の、単一胚あたりの酸素消費量が0.91×10^-14 mol s^-1以上であること。

Stage: BL = blastocyst, ExBL = expanded blastocyst
Code: Robertson I, Nelson RE (1998) Certification and identification of the embryo. In: DA Stringfellow and SM Seidel, Editors, Manual of the international embryo transfer society, IETS, Savoy, Illinois 103-116. Specifically, Code1 refers to blastocysts or expanded blastocysts that have more than 85% of viable cells, and Code2 has more than 50% of viable cells. “Code1-2” means “Code1 or 2”.
Indicator # 1: The time from fertilization to the completion of the first cleavage is 27 hours.
Index # 2: 2 cells at 31 hours after fertilization (at the end of initial cleavage), and no fragmentation is observed.
Index # 3: Either 6 cells, 7 cells, or 8 cells at 55 hours after fertilization (at the end of the third cleavage), and no fragmentation is observed.
Indicator # 4: Oxygen consumption per single embryo after 168 hours of fertilization (early blastocyst stage, blastocyst stage or extended blastocyst stage) is 0.91 × 10 ^-14 mol s ^-1 or more .

1: Side wall, 2: Bottom wall, 3: Cell housing, 4: Microwell, 5: Inner wall, 6: Bottom of microwell, 10: Culture vessel, 600, 700, 800, 900, 1000, 1100, 1200: Embryo sorting device, 740, 840, 1140, 1240: Embryo sorting system, 670, 770, 870, 970, 1070, 1170, 1270: Discrimination unit, 610, 710, 810, 908, 1006, 1108, 1208: Analysis unit, 606, 706, 806: First indicator discriminator, 607, 707, 807: Second indicator discriminator, 608, 708, 808: Third indicator discriminator, 609, 709, 809: Fourth indicator discriminator, 750, 850, 1150, 1250 imaging device, 760, 860, 1160, 1260: oxygen consumption measuring device, S2001: discrimination process, S2002: analysis process

Claims (20)

A method of selecting mammalian embryos cultured in vitro from fertilized eggs ,
Morphology at the stage after the first cleavage and before the second cleavage;
Morphology at the stage after the third cleavage and before the fourth cleavage; and oxygen consumption at the early blastocyst stage, blastocyst stage or extended blastocyst stage ;
Comprising the step of selecting the embryo as an index,
The embryo selected in the above process has the following conditions:
2 cells and no fragmentation at the stage after the first cleavage and before the second cleavage (condition a);
Be 5 cells, 6 cells, 7 cells or 8 cells and have no fragmentation after the third cleavage and before the fourth cleavage (condition b); and
Oxygen consumption at the early blastocyst stage, blastocyst stage or extended blastocyst stage is the oxygen consumption of the embryo at the early blastocyst stage, blastocyst stage or extended blastocyst stage and the embryo escapes Based on the correlation with the probability of reaching the blastocyst, the oxygen consumption is confirmed to be 50% or more (condition c);
Wherein said method is an embryo . In the process
Time from fertilization to completion of the first cleavage;
2. The method of claim 1, wherein the embryos are selected using as an index. The embryo selected in the above step is further subjected to the following conditions:
Correlation between the time from fertilization to completion of the first cleavage and the time from embryo fertilization to completion of the first cleavage and the probability that the embryo has a normal number of chromosomes at the blastocyst stage Based on the relationship, the time has been confirmed that the probability is 40% or more (condition d1), the time from fertilization to completion of the first cleavage is The relative expression level is 0.45 based on the correlation between the time until the split is completed and the relative expression level of the gene IGF2R at the blastocyst stage of the embryo, where the expression level of the gene H2AFZ is 1. And the time from fertilization to completion of the first cleavage is the time from fertilization to completion of the first cleavage. Based on the correlation with the relative expression level of the gene IFN-tau at the blastocyst stage of the embryo, with the expression level of the gene H2AFZ as 1. It Relative expression level that satisfies at least one condition may become 0.2 or more it is time has been confirmed (condition d3), it is selected from (condition d);
3. The method of claim 2, wherein the method satisfies the following. The mammal is a cow,
In condition d, the time from fertilization to completion of the first cleavage is 27 hours or less
The method of claim 3. A method for producing an embryo from a fertilized egg of a non-human mammal by in vitro culture ,
Morphology at the stage after the first cleavage and before the second cleavage;
Morphology at the stage after the third cleavage and before the fourth cleavage; and oxygen consumption at the early blastocyst stage, blastocyst stage or extended blastocyst stage ;
Selecting embryos as an index containing the sorting step,
The embryo selected in the above process has the following conditions:
2 cells and no fragmentation at the stage after the first cleavage and before the second cleavage (condition a);
Be 5 cells, 6 cells, 7 cells or 8 cells and have no fragmentation after the third cleavage and before the fourth cleavage (condition b); and
Oxygen consumption at the early blastocyst stage, blastocyst stage or extended blastocyst stage is the oxygen consumption of the embryo at the early blastocyst stage, blastocyst stage or extended blastocyst stage and the embryo escapes Based on the correlation with the probability of reaching the blastocyst, the oxygen consumption is confirmed to be 50% or more (condition c);
Wherein said method is an embryo . In the process
Time from fertilization to completion of the first cleavage;
6. The method of claim 5, wherein the embryo is selected using as an index. The embryo selected in the above step is further subjected to the following conditions:
Correlation between the time from fertilization to completion of the first cleavage and the time from embryo fertilization to completion of the first cleavage and the probability that the embryo has a normal number of chromosomes at the blastocyst stage Based on the relationship, the time has been confirmed that the probability is 40% or more (condition d1), the time from fertilization to completion of the first cleavage is The relative expression level is 0.45 based on the correlation between the time until the split is completed and the relative expression level of the gene IGF2R at the blastocyst stage of the embryo, where the expression level of the gene H2AFZ is 1. And the time from fertilization to completion of the first cleavage is the time from fertilization to completion of the first cleavage. Based on the correlation with the relative expression level of the gene IFN-tau at the blastocyst stage of the embryo, with the expression level of the gene H2AFZ as 1. It Relative expression level that satisfies at least one condition may become 0.2 or more it is time has been confirmed (condition d3), it is selected from (condition d);
7. The method of claim 6, wherein the embryo satisfies the following conditions. The non-human mammal is a cow;
In condition d, the time from fertilization to completion of the first cleavage is 27 hours or less
8. The method of claim 7. The mammal is a non-human mammal, and the embryo selected by the method according to any one of claims 1 to 4 or the embryo produced by the method according to any one of claims 5 to 8 is transplanted into a female individual for conception. A method for producing a non-human mammal individual, comprising An embryo sorting apparatus for sorting a mammalian candidate embryo cultured in vitro from a fertilized egg,
Including a determination unit and an analysis unit,
The determining portion is
The climate Hohai, second index information on the form of the first cleavage after and second egg percent previous stage, the second indicator selection criteria regarding the form in after the first cleavage and second egg percent prior to step A second index discriminating unit for discriminating whether or not the condition is satisfied,
The third index information regarding the morphology of the candidate embryo after the third cleavage and before the fourth cleavage is the third index selection criterion condition regarding the morphology after the third cleavage and before the fourth cleavage The third index discriminating unit for discriminating whether or not the condition is satisfied, and the fourth index information regarding the oxygen consumption in the early blastocyst stage, blastocyst stage or expanded blastocyst stage of the candidate embryo, A fourth index discriminating unit that discriminates whether or not the fourth index selection criterion condition regarding oxygen consumption at the blastocyst stage, blastocyst stage or expanded blastocyst stage is satisfied
It includes,
The analysis unit analyzes candidate embryos that satisfy all of the conditions determined by the determination unit as embryos to be selected ,
The second index selection criterion condition is a condition that, in the stage after the first cleavage and before the second cleavage, is 2 cells and does not have fragmentation (condition a),
The third index selection criterion condition is 5 cells, 6 cells, 7 cells, or 8 cells after the third cleavage and before the fourth cleavage and has no fragmentation (Condition b), And the condition
The fourth index selection criterion condition is that the oxygen consumption in the early blastocyst stage, blastocyst stage or extended blastocyst stage is the embryo in the early blastocyst stage, blastocyst stage or extended blastocyst stage Based on the correlation between the amount of oxygen consumed and the probability that the embryo reaches the escaped blastocyst, the probability is that the probability is 50% or more (condition c). The embryo sorting apparatus characterized by the above-mentioned conditions . The discrimination unit is
Determine whether or not the first index information regarding the time from fertilization to completion of the first cleavage satisfies the first index selection criterion condition regarding the time from fertilization to completion of the first cleavage 1st index discriminating unit
Further includes
The embryo sorting apparatus according to claim 10. The first index selection criterion condition is
Correlation between the time from fertilization to completion of the first cleavage and the time from embryo fertilization to completion of the first cleavage and the probability that the embryo has a normal number of chromosomes at the blastocyst stage Based on the relationship, the time has been confirmed that the probability is 40% or more (condition d1), the time from fertilization to completion of the first cleavage is The relative expression level is 0.45 based on the correlation between the time until the split is completed and the relative expression level of the gene IGF2R at the blastocyst stage of the embryo, where the expression level of the gene H2AFZ is 1. And the time from fertilization to completion of the first cleavage is the time from fertilization to completion of the first cleavage. Based on the correlation with the relative expression level of the gene IFN-tau at the blastocyst stage of the embryo, with the expression level of the gene H2AFZ as 1. The relative expression level is at least one condition is satisfied (Condition d), the condition that it be 0.2 or more selected from (condition d3), it is time has been confirmed
The embryo sorting apparatus according to claim 11. The embryo selection apparatus according to any one of claims 10 to 12 , further comprising an image extraction unit,
When the determination unit includes the first index determination unit, the image extraction unit, from the image of the candidate embryo, a threshold value for the time from fertilization to completion of the first cleavage in the first index selection criterion condition Including a first image extraction unit that extracts an image at the time of the above or an image capable of confirming the completion time of the first cleavage, and the first index determination unit is an image extracted by the first image extraction unit To determine the information generated based on the first index information,
When the determination unit includes the second index determination unit, the image extraction unit extracts, from the candidate embryo image, an image at a stage after the first cleavage and before the second cleavage. Including an extraction unit, the second index determination unit determines the information generated based on the image extracted by the second image extraction unit as the second index information,
When the determination unit includes the third index determination unit, the image extraction unit extracts, from the candidate embryo image, an image at a stage after the third cleavage and before the fourth cleavage, The embryo sorting apparatus including an image extracting unit, wherein the third index discriminating unit discriminates information generated based on the image extracted by the third image extracting unit as the third index information. An embryo selection system for selecting candidate mammalian embryos cultured in vitro from fertilized eggs,
The embryo sorting apparatus of claim 13 ,
An imaging device that images the candidate embryo and outputs the captured image to the image extraction unit;
When the discriminating unit includes the fourth index discriminating unit, the oxygen consumption at the early blastocyst stage, blastocyst stage or extended blastocyst stage of the candidate embryo is measured, and the measured oxygen consumption The embryo sorting system further comprising an oxygen consumption measuring device that outputs a quantity value to the fourth index determining unit. A program for causing a computer to execute an embryo selection method for selecting a mammalian candidate embryo cultured in vitro from a fertilized egg, the method including a discrimination step and an analysis step,
The determining step,
The climate Hohai, second index information on the form of the first cleavage after and second egg percent previous stage, the second indicator selection criteria regarding the form in after the first cleavage and second egg percent prior to step A second index determination step for determining whether or not the condition is satisfied,
The third index information regarding the morphology of the candidate embryo after the third cleavage and before the fourth cleavage is the third index selection criterion condition regarding the morphology after the third cleavage and before the fourth cleavage The third index determination step for determining whether or not the condition is satisfied, and the fourth index information regarding oxygen consumption in the early blastocyst stage, blastocyst stage or expanded blastocyst stage of the candidate embryo, board blastocyst stage, as a fourth indicator determination Engineering for determining whether to satisfy the fourth index selection criteria condition regarding oxygen consumption at blastocyst stage or expansion blastocyst stage
It includes,
Said analysis step, the candidate embryos that satisfies all of the determination conditions in the determination step, see contains an analysis step of analyzing to be embryo to be sorted,
The second index selection criterion condition is a condition that, in the stage after the first cleavage and before the second cleavage, is 2 cells and does not have fragmentation (condition a),
The third index selection criterion condition is 5 cells, 6 cells, 7 cells, or 8 cells after the third cleavage and before the fourth cleavage and has no fragmentation (Condition b), And the condition
The fourth index selection criterion condition is that the oxygen consumption in the early blastocyst stage, blastocyst stage or extended blastocyst stage is the embryo in the early blastocyst stage, blastocyst stage or extended blastocyst stage Based on the correlation between the amount of oxygen consumed and the probability that the embryo will reach the escaped blastocyst, the condition that the probability is confirmed to be 50% or more (condition c) The program. The discrimination step is
Determine whether or not the first index information regarding the time from fertilization to completion of the first cleavage satisfies the first index selection criterion condition regarding the time from fertilization to completion of the first cleavage First index discrimination process
Further includes
The program of claim 15. The first index selection criterion condition is
Correlation between the time from fertilization to completion of the first cleavage and the time from embryo fertilization to completion of the first cleavage and the probability that the embryo has a normal number of chromosomes at the blastocyst stage Based on the relationship, the time has been confirmed that the probability is 40% or more (condition d1), the time from fertilization to completion of the first cleavage is The relative expression level is 0.45 based on the correlation between the time until the split is completed and the relative expression level of the gene IGF2R at the blastocyst stage of the embryo, where the expression level of the gene H2AFZ is 1. And the time from fertilization to completion of the first cleavage is the time from fertilization to completion of the first cleavage. Based on the correlation with the relative expression level of the gene IFN-tau at the blastocyst stage of the embryo, with the expression level of the gene H2AFZ as 1. It Relative expression level that satisfies at least one condition to be a 0.2 or more selected from (condition d3), it is time has been confirmed (condition d), with the proviso that,
The program of claim 16. A method of culturing an embryo from a fertilized egg of a mammal by in vitro culture,
Morphology at the stage after the first cleavage and before the second cleavage;
The form after the third cleavage and before the fourth cleavage; and
Oxygen consumption at the early, blastocyst or expanded blastocyst stage;
Including a sorting step of sorting embryos using as an index,
The embryo selected in the above process has the following conditions:
2 cells and no fragmentation at the stage after the first cleavage and before the second cleavage (condition a);
Be 5 cells, 6 cells, 7 cells or 8 cells and have no fragmentation after the third cleavage and before the fourth cleavage (condition b); and
Oxygen consumption at the early blastocyst stage, blastocyst stage or extended blastocyst stage is the oxygen consumption of the embryo at the early blastocyst stage, blastocyst stage or extended blastocyst stage and the embryo escapes Based on the correlation with the probability of reaching the blastocyst, the oxygen consumption is confirmed to be 50% or more (condition c);
Is an embryo that satisfies
Said method. In the process
Time from fertilization to completion of the first cleavage;
19. The method of claim 18, wherein the embryo is selected using as an index. The embryo selected in the above step is further subjected to the following conditions:
Correlation between the time from fertilization to completion of the first cleavage and the time from embryo fertilization to completion of the first cleavage and the probability that the embryo has a normal number of chromosomes at the blastocyst stage Based on the relationship, the time has been confirmed that the probability is 40% or more (condition d1), the time from fertilization to completion of the first cleavage is The relative expression level is 0.45 based on the correlation between the time until the split is completed and the relative expression level of the gene IGF2R at the blastocyst stage of the embryo, where the expression level of the gene H2AFZ is 1. And the time from fertilization to completion of the first cleavage is the time from fertilization to completion of the first cleavage. Based on the correlation with the relative expression level of the gene IFN-tau at the blastocyst stage of the embryo, with the expression level of the gene H2AFZ as 1. It Relative expression level that satisfies at least one condition may become 0.2 or more it is time has been confirmed (condition d3), it is selected from (condition d);
20. The method of claim 19, wherein the embryo satisfies the following.

Images