CN120617325B

CN120617325B - Composite probiotics for relieving acute lung injury and application thereof

Info

Publication number: CN120617325B
Application number: CN202511128404.3A
Authority: CN
Inventors: 李依璇; 侯瑞琪; 张雯; 王然; 侯佳瑶; 王心彤; 李子阳; 张怡然
Original assignee: Shaanxi Yiruikang Biotechnology Co ltd; Yiruikang Biotechnology Hainan Co ltd
Current assignee: Shaanxi Yiruikang Biotechnology Co ltd; Yiruikang Biotechnology Hainan Co ltd
Priority date: 2025-08-13
Filing date: 2025-08-13
Publication date: 2025-10-21
Anticipated expiration: 2045-08-13
Also published as: CN120617325A

Abstract

The invention provides a compound probiotics for relieving acute lung injury and application thereof, and in particular discloses application of the compound probiotics consisting of bifidobacterium animalis YRK-12 and lactobacillus rhamnosus LRa-Y8 in preparation of medicines for relieving acute lung injury, wherein the bifidobacterium animalis YRK-12 has a preservation number of CGMCC No.28597, and the lactobacillus rhamnosus LRa-Y8 has a preservation number of CGMCC No.34186. Experiments prove that the compound probiotics can obviously relieve acute lung injury induced by Lipopolysaccharide (LPS) through synergistic effect, and is particularly characterized by reducing the weight reduction rate of mice, improving pathological injury of lung tissues (maintaining the structural integrity of alveoli and reducing inflammatory cell infiltration), down-regulating the levels of proinflammatory factors (IL-1 beta, TNF-alpha and IL-6) in serum and lung tissues and up-regulating the level of anti-inflammatory factors (IL-4), thereby regulating lung immune balance through an intestinal-lung axis, and providing a safe and effective novel microecological regulation strategy for preventing and treating the acute lung injury.

Description

Composite probiotics for relieving acute lung injury and application thereof

Technical Field

The invention belongs to the technical field of microorganisms, and particularly relates to a compound probiotics for relieving acute lung injury and application thereof.

Background

Acute lung injury (Acute Lung Injury, ALI) is a clinically common respiratory critical condition, and is characterized by rapid onset and progression of the disease, and progressive exacerbation of hypoxic respiratory failure. The essence is acute respiratory distress syndrome (Acute Respiratory Distress Syndrome, ARDS) with minor clinical symptoms. Epidemiological studies have shown that ALI/ARDS has a morbidity as high as 57-78 cases/10 ten thousand people per year, and a mortality rate of 35% -46%, which not only seriously threatens patient lives, affects survival quality, but also brings a heavy burden to families and society. ALI can rapidly progress to ARDS and even cause death if not effectively intervened in time.

The central pathogenesis of the disease is an uncontrolled inflammatory response. During pathological processes, massive release of pro-inflammatory mediators triggers an inflammatory cascade effect, resulting in damage to pulmonary capillary endothelial cells and alveolar epithelial cells. Characteristic pathological changes include pulmonary edema, hyaline membrane formation and later pulmonary fibrosis, which are caused by abnormally increased permeability of pulmonary microvasculature, and are essentially caused by destruction of the pulmonary vascular endothelial barrier and the alveolar epithelial barrier due to inflammatory imbalance in the lung, ultimately leading to acute respiratory dysfunction.

Given that the inflammatory response is at the heart in ALI/ARDS development, targeted inhibition of the inflammatory cascade is a very potential control strategy. Gram-negative bacterial infection is a common inflammation trigger source, and outer membrane Lipopolysaccharide (LPS) is used as a key endotoxin component, so that excessive secretion of pro-inflammatory mediators can be strongly induced, and uncontrolled expansion of inflammation in the lung is driven. The LPS-induced animal or cell model can highly simulate the pathological damage characteristics and time course evolution of ALI, and is widely applied to preclinical screening of ALI control medicines.

The current clinic mainly depends on mechanical ventilation and drug intervention (such as glucocorticoid and nitric oxide inhalation, etc.), but has obvious limitations that the mechanical ventilation is easy to cause secondary injury such as air pressure injury, the traditional drugs have side effects (such as immunosuppression of hormone) and drug resistance problems, and no specific therapy with high efficiency and safety exists. Recent studies have shown that intestinal flora is deeply involved in pulmonary immunomodulation via the "gut-lung axis". Specific probiotic strains show potential of anti-inflammatory, barrier repair and the like, but single strains have limited curative effects, and the synergistic intervention mechanism of the compound probiotics aiming at ALI is not clear.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a compound probiotics for relieving acute lung injury and application thereof, and the compound probiotics for relieving acute lung injury show clear synergistic effect in the aspects of reducing weight reduction rate, improving lung pathological injury, regulating inflammatory factor balance and the like after being compounded with bifidobacterium YRK-12 and lactobacillus rhamnosus LRa-Y8 for the first time, and solve the problem of limited curative effect of single probiotics.

The invention aims at realizing the following technical scheme:

The invention provides an application of composite probiotics in preparing medicines for relieving acute lung injury, wherein the composite probiotics consist of bifidobacterium animalis YRK-12 and lactobacillus rhamnosus LRa-Y8;

the bifidobacterium animalis YRK-12 is preserved in the China general microbiological culture Collection center, is classified and named as bifidobacterium animalis Bifidobacterium animalis, and has a preservation number of CGMCC No.28597 and a preservation date of 2023, 10 and 9;

The lactobacillus rhamnosus LRa-Y8 is preserved in China general microbiological culture Collection center, and is classified and named as lactobacillus rhamnosus Lacticaseibacillus rhamnosus, the preservation number is CGMCC No.34186, and the preservation date is 2025, 04 and 14.

Further, the content ratio of live bacteria of bifidobacterium animalis YRK-12 and lactobacillus rhamnosus LRa-Y8 in the composite probiotics is 1:5-5:1.

Further, the effective viable count of the composite probiotics in the medicine is not lower than 1 multiplied by 10 ¹⁰ CFU/mL.

Further, the acute lung injury is induced by lipopolysaccharide.

Further, the dosage form of the medicine is an oral preparation, including a tablet, a capsule, a granule or a suspension.

Furthermore, the medicine can reduce the weight reduction rate caused by acute lung injury, improve pathological injury of lung tissues, and regulate the level of inflammatory factors in serum and lung tissues.

Further, the improvement of pathological lesions in pulmonary tissue includes maintaining alveolar structural integrity, reducing alveolar spacer thickening and fusion, reducing inflammatory cell infiltration and interstitial edema.

Further, the regulation of inflammatory factor levels in serum and lung tissue includes down-regulating the expression of pro-inflammatory factors IL-1 beta, TNF-alpha, IL-6 and up-regulating the expression of anti-inflammatory factor IL-4.

Strain preservation information:

The bifidobacterium animalis is named YRK-12, is preserved in China general microbiological culture Collection center (CGMCC) at North Star Xila No. 1 and No. 3 in the Korean area of Beijing, is classified and named as bifidobacterium animalis Bifidobacterium animalis, and has a preservation number of CGMCC No.28597 and a preservation date of 2023, 10 and 9.

The strain is preserved in China general microbiological culture Collection center (CGMCC) with address of North Star Xila No. 1 and No.3 in the Korean area North Star of Beijing city, and classified and named as Lactobacillus rhamnosus Lacticaseibacillus rhamnosus with preservation number of CGMCC No.34186 and preservation date of 2025, 04 and 14 days.

The compound probiotics provided by the invention have the following remarkable beneficial effects in relieving acute lung injury:

1. the experimental result shows that the remission effect of the two strains is obviously better than that of a single strain (YRK-12 or LRa-Y8) and other compound combinations (such as YRK-12+BB12+LRa-Y8), the synergistic effect is obvious in the aspects of reducing weight reduction rate, improving lung pathological injury, regulating inflammatory factor balance and the like, and the problem of limited curative effect of a single probiotics is solved.

2. The multi-target point release lung injury is realized by targeting and controlling the intestinal-lung axis, and the compound probiotics can release acute lung injury from multiple layers:

a metabolic layer, namely remarkably reversing the rapid weight reduction induced by LPS and maintaining the metabolic steady state of the organism;

The histopathological layer can effectively protect the structural integrity of alveoli, reduce the thickening of alveolar spaces, inflammatory cell infiltration and interstitial edema, and inhibit the formation of transparent membranes;

the immunoregulation level is that the level of pro-inflammatory factors (IL-1 beta, TNF-alpha and IL-6) in serum and lung tissues is obviously reduced, the level of anti-inflammatory factors (IL-4) is up-regulated, the pulmonary immune balance is rebuilt, and the inflammatory cascade amplification effect is blocked.

3. The safety is high, no obvious side effect is caused, the strain is probiotics (YRK-12) or commercial safe strain (LRa-Y8) from human intestinal tracts, the oral administration can play a role, the immunosuppression side effect of traditional medicines (such as glucocorticoid) and the secondary injury risk of mechanical ventilation are avoided, and the method is suitable for long-term or early intervention.

4. The invention provides a novel microecological strategy for acute lung injury, firstly defines the synergistic action mechanism of YRK-12 and LRa-Y8, breaks through the curative bottleneck of the existing acute lung injury treatment means, provides a safe and efficient new microecological regulation scheme for clinically preventing and treating acute lung injury/acute respiratory distress syndrome (ALI/ARDS), and has important clinical conversion value.

Drawings

The invention is further illustrated by the following examples in conjunction with the accompanying drawings:

figure 1 shows the effect of different probiotics/complex probiotics on the weight of acute lung injury in mice caused by LPS;

FIG. 2 shows the effect of different probiotics/complex probiotics on the lung pathology of acute lung injury in mice caused by LPS, wherein (A) is the lung tissue pathology;

FIG. 3 shows the effect of different probiotics/complex probiotics on serum inflammatory factors of acute lung injury in mice caused by LPS, wherein (A) the level of inflammatory factor IL-1 beta, (B) the level of inflammatory factor IL-4;

FIG. 4 shows the effect of different probiotics/complex probiotics on inflammatory factors of acute lung injury lung tissue of mice caused by LPS, wherein (A) the level of inflammatory factor IL-1 beta, (B) the level of inflammatory factor IL-6, and (C) the level of inflammatory factor TNF-alpha.

Detailed Description

The examples are presented for better illustration of the invention, but the invention is not limited to the examples. Those skilled in the art will appreciate that various modifications and adaptations of the embodiments described above are possible in light of the above teachings and are intended to be within the scope of the invention.

The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.

The present invention will be described in detail by examples. It should be understood that the following examples are illustrative only of the present invention and are not intended to limit the present invention.

In the following examples, LPS was purchased from Beijing Soy Co.Ltd, L8880. Bifidobacterium animalis YRK-12 and Lactobacillus rhamnosus LRa-Y8 are provided by Shaanxi Yi Ruikang biotechnology Co., ltd, and the strain is deposited in China general microbiological culture Collection center (China Committee) and is derived from human intestinal tracts. BB-12 strain is derived from Hansen company of Danish. Mice/ration/litter daily ration were purchased from the biological technologies company, ltd.

The improved MRS culture medium comprises peptone 10 g, yeast extract 5g, glucose 20g, beef extract 10 g, K ₂HPO₄ 2g, diammonium citrate 2g, mgSO ₄·7H₂O 0.58 g,MnSO₄·4H₂ O0.25 g, anhydrous sodium acetate 5g, tween 80 1 mL, cysteine hydrochloride 0.5 g, distilled water to a volume of 1L, and adjusting pH to 6.5,121 ^o C for sterilization 15 min.

EXAMPLE 1 preparation for microorganism culture

(1) Preparation of bifidobacterium animalis YRK-12

A probiotic is obtained by separating human intestinal flora, and identified as bifidobacterium animalis Bifidobacterium animalis, which is named as bifidobacterium animalis YRK-12, and is preserved in China general microbiological culture Collection center with the preservation number of CGMCC No.28597 and the preservation date of 2023, 10 and 9.

After the isolated bifidobacterium animalis YRK-12 was passaged twice in the modified MRS broth, it was inoculated in the modified MRS broth at an inoculum size of 10% and cultured for 24 hours under conditions of 37.+ -. 1 ^o C and 0% oxygen concentration. The supernatant was removed by centrifugation (4000 rpm,10 min). After washing the cells twice with PBS, the cells were resuspended in 0.9% physiological saline and the concentration of the cells was adjusted to 1X 10 ¹⁰ CFU/mL at the time of gastric lavage.

(2) Preparation of bifidobacterium animalis BB12

After two passages of bifidobacterium animalis BB-12 in the modified MRS liquid medium, the bifidobacterium animalis BB-12 was inoculated in the modified MRS liquid medium according to an inoculum size of 10%, and cultured for 24 hours under the conditions of 37+/-1 ^o C and an oxygen concentration of 0%. After removing the supernatant by centrifugation (4000 rpm,10 min), the cells were washed twice with PBS, resuspended in 0.9% physiological saline and the cell suspension concentration was adjusted to 1X 10 ¹⁰ CFU/mL during lavage.

(3) Preparation of Lactobacillus rhamnosus LRa-Y8 strain

The lactobacillus rhamnosus LRa-Y8 is preserved in China general microbiological culture Collection center (CGMCC) with the preservation number of CGMCC NO.34186 and the preservation date of 2025, 04 and 14.

After two passages of lactobacillus rhamnosus LRa-Y8 in the modified MRS liquid medium, it was inoculated in the modified MRS liquid medium at an inoculum size of 10% and cultured for 24 hours under the conditions of 37±1 ^o C and 0% oxygen concentration. After removing the supernatant by centrifugation (4000 rpm,10 min), the cells were washed twice with PBS, resuspended in 0.9% physiological saline and the cell suspension concentration was adjusted to 1X 10 ¹⁰ CFU/mL during lavage.

Example 2

The embodiment provides a compound probiotic for alleviating acute lung injury, which consists of bifidobacterium animalis YRK-12 and lactobacillus rhamnosus LRa-Y8.

The preparation method of the composite probiotics comprises the steps of mixing bifidobacterium animalis YRK-12 and lactobacillus rhamnosus LRa-Y8 bacterial suspension prepared in the embodiment 1 in a ratio of 1:1, so that the total concentration of thalli of two bacteria in the microbial inoculum is adjusted to be 1X 10 ¹⁰ CFU/mL.

Test example Effect of Complex probiotics on acute Lung injury

To explore the impact of different composite probiotic combinations on acute lung injury, the present test example conducted the following animal experiments:

48 male C57BL/6J mice (purchased from Fukang Biotechnology Co., ltd., beijing) aged for 8 weeks were randomly divided into 8 groups after one week of adaptive feeding, a blank control group, an LPS treatment group, an LPS+animal bifidobacterium YRK-12 intervention group, an LPS+animal bifidobacterium BB12 intervention group, an LPS+rhamnose cheese bacteria LRa-Y8 intervention group, an LPS+animal bifidobacterium YRK-12+rhamnose cheese bacteria LRa-Y8 intervention group, an LPS+animal bifidobacterium BB12+rhamnose cheese bacteria LRa-Y8 intervention group, and an LPS+animal bifidobacterium YRK-12+animal bifidobacterium BB12+rhamnose cheese bacteria LRa-Y8 intervention group. The composite probiotics group is continuously irrigated for 28 days, the amount of the irrigated bacteria is 1 multiplied by 10 ¹⁰ CFU, and the volume of the irrigated bacteria is 100 mu L. Mice from the blank and LPS treated groups were perfused with the same volume of saline. The light/dark cycle is 12 hours per day, and the water can be drunk and eaten freely.

1. Rate of change in body weight

The weight loss ratio of each group of mice was calculated by recording the weight of each group of mice before molding and before sacrifice, and the weight change ratio was calculated as = (weight before sacrifice-weight before modeling)/weight before modeling. The weight change of mice after molding is obvious.

2. H & E staining

Samples of large leaves of lung tissue were fixed with 4% neutral buffered formalin for 24 hours, gradient ethanol dehydrated (70% → 80% → 90% → 95% → 100%), xylene transparent, paraffin embedded and 4 μm thick sections were prepared. The sections were dewaxed with xylene, hydrated with gradient ethanol (100%. Fwdarw.95%. Fwdarw.85%. Fwdarw.70%), stained with Hematoxylin (Hematoxylin) for 5 min, rinsed with running water, differentiated with 1% ethanol hydrochloride for 3 seconds, removed of nonspecific staining, blue-returning with saturated lithium carbonate solution for 30 seconds, restoration of nuclear blue, counterstaining with 0.5% Eosin (Eosin) solution for 2 min, again dehydrated with gradient ethanol, transparent with xylene, and sealed with neutral gum. Finally, pathological changes of lung tissues (such as inflammatory infiltration, alveolar structure destruction, edema and the like) are observed under an optical microscope.

3. Serum inflammatory factor assay

Serum IL-1 beta and IL-4 levels were detected using an ELISA kit from Emblica Biotechnology Co (EnzymeCore Biotechnology), the procedure was as follows, serum samples were centrifuged at 4 ^o C for 10 min at 3000 Xg and the supernatant was taken for 10-fold dilution, 7.8-500 pg/mL of a 7-point concentration gradient standard curve was prepared simultaneously using standard dilutions, 100. Mu.L of standard or diluted samples were added to an antibody pre-coated 96 well plate, incubated at 37 ^o C for 90 min, 100. Mu.L/well biotinylated detection antibody (37 ^o C for 60 min), horseradish peroxidase-labeled streptavidin (37 ^o C for 30 min) and TMB substrate solution (37 ^o C for 15 min) were sequentially added after washing, washing 3 times with PBS between each step, and finally the reaction was stopped by adding 50. Mu.L/Kong Zhongzhi of solution, and OD was measured at 450 nm wavelength in an ELISA apparatus for 10 min. All samples are provided with 3 complex holes, the standard curve fitting requirement R ² is more than or equal to 0.99, and the concentration calculation is carried out by taking the complex Kong Junzhi.

4. Tissue inflammatory factor determination

Detection of inflammatory factors (TNF- α, IL-1β, IL-6) in lung tissue was performed using an enzyme-linked immunosorbent assay (EnzymeCore) ELISA kit. Fresh or frozen lung tissue (30 mg) was homogenized in ice-bath in PBS-Triton X-100 buffer containing protease inhibitor, and the supernatant was collected after centrifugation at 4 ^o C for 15 min at 12,000Xg. The total protein concentration of the tissue is determined by BCA method (BSA standard curve 0-2000. Mu.g/mL, R ². Gtoreq.0.99). In ELISA detection, tissue supernatant is diluted according to a dilution ratio of 1:5 determined by a pre-experiment, and is synchronously added into a pre-coating plate with 7.8-500 pg/mL standard substance, and is incubated for 90 minutes at 37 and ^o C, a biotinylated antibody (60 minutes) and HRP-streptavidin (30 minutes) are reacted in sequence, TMB is developed for 15 minutes in a dark place and then is stopped, and OD value is measured at 450 and nm. The standard curve was fitted with four parameters (R ². Gtoreq.0.99), and the final concentration was converted to pg/mg protein by the formula [ ELISA concentration (pg/mL) x dilution ]/[ BCA protein concentration (μg/mL) x 1000] x 10 ⁶ to eliminate tissue sampling differences.

Animal test results:

(1) Influence of Complex probiotics on weight change in mice

As can be seen from the results shown in FIG. 1, mice showed a sharp decrease in body weight after LPS intraperitoneal injection, and the rate of body weight decrease was 17.13%. Through probiotic intervention treatment, each treatment group shows weight loss alleviation, especially YRK-12+lra-Y8 group has more remarkable effect on alleviating weight loss, better effect than YRK-12 and LRa-Y8 groups alone, and shows synergy.

Interestingly, YRK-12+lra-y8+bb12 groups had less effect on weight loss than the single and double bacteria formulations. The results show that YRK-12+LRa-Y8 compounding can most effectively reverse LPS-induced weight loss and maintain metabolic homeostasis.

(2) Influence of composite probiotics on lung tissue pathology of mice

As shown in fig. 2, the alveolar structure of the blank group is complete and clear, the alveolar space is uniform and has no thickening, the bronchial epithelial cells are closely arranged, the inflammatory cell infiltration congestion or edema phenomenon is avoided, and the lung tissue is in a normal physiological state. The lung tissue of LPS treatment group shows typical acute injury pathological changes, such as serious destruction of alveolar structure, diffuse thickening and fusion of alveolar space, extensive congestion of capillary vessels, exudation of a large number of neutrophils and other immune cells, local alveolar collapse, and formation of transparent membrane and interstitial edema.

Single bacterial intervention group:

Group YRK-12 with reduced alveolar septum thickening, reduced inflammatory cell infiltration by about 30%, but still visible local hyperemia foci;

BB12 group had limited improvement compared to LPS group, reduced inflammatory exudation, and still significant alveolar fusion area;

LRa-Y8 group, edema reduced, but neutrophil infiltration was still evident.

Double bacteria compound group:

Inflammatory cell infiltration is reduced, alveolar structure part is restored, and interval is thickened occasionally in BB12+LRa-Y8 group;

YRK-12+LRa-Y8 group, the synergistic protective effect is remarkable. The alveolus structure is basically complete, the phenomenon of interval thickening and congestion is very little, inflammatory cell infiltration is reduced, and no transparent membrane is formed or interstitial edema exists.

It can be seen that YRK-12+lra-Y8 formulations are significantly better than single bacteria and other formulations in maintaining alveolar structural integrity to inhibit inflammatory exudation. Furthermore, we found that the effect of the YRK-12+BB12+LRa-Y8 combination was not very pronounced.

(3) Influence of composite probiotics on serum inflammatory factors of mice

As shown in fig. 3, the level of proinflammatory factor IL-1β was significantly elevated in the LPS model group, reflecting a strong inflammatory response. The IL-1 beta fraction of the monobacterium group is reduced. The YRK-12+LRa-Y8 double-bacteria compound group has obviously reduced IL-1 beta and shows synergistic anti-inflammatory effect, and BB12+LRa-Y8 is also obviously reduced but weaker than YRK-12+LRa-Y8 group. The IL-4 level of the anti-inflammatory factor IL-4 LPS model group is obviously inhibited, which indicates that the immunoregulation is unbalanced. The single bacterial group IL-4 is slightly promoted. The YRK-12+LRa-Y8 group IL-4 was significantly elevated, approaching the blank group (P < 0.05), whereas the BB12+LRa-Y8 group IL-4 was significantly elevated compared to LPS, but significantly lower than the YRK-12+LRa-Y8 group (P < 0.05). In addition, the YRK-12+BB12+LRa-Y8 three-bacterium compound set has the effect of inhibiting serum pro-inflammatory factors, is superior to BB12 and LRa-Y8 single bacteria and BB12+LRa-Y8 compound set, but is not as good as YRK-12 single bacteria and YRK-12+LRa-Y8 compound set.

The result shows that YRK-12+LRa-Y8 compound can synergistically inhibit the pro-inflammatory factor and activate the anti-inflammatory factor, reestablish the immune balance and show the optimal anti-inflammatory effect.

(4) Influence of composite probiotics on mouse lung tissue inflammatory factors

Further examined the inflammatory factor (TNF-alpha, IL-1 beta, IL-6) content of lung tissue, as shown in figure 4, the levels of TNF-alpha, IL-1 beta, IL-6 in the model group mice were all significantly increased compared with the blank group, showing acute inflammatory response, and conforming to the core pathological characteristics of acute lung injury. The YRK-12+LRa-Y8 group shows the strongest synergistic inhibition effect in inhibiting inflammation, and TNF-alpha, IL-1 beta and IL-6 show better inhibition effect compared with single bacteria YRK-12 and LRa-Y8, and are also better than the compounding effect of BB12+LRa-Y8. Likewise, the YRK-12+BB12+LRa-Y8 three-strain complex does not show a stronger synergistic effect. It can be seen that YRK-12 and LRa-Y8 are compounded to block inflammatory cascade amplification by synergistically down-regulating core pro-inflammatory factors (TNF- α, IL-1β, IL-6) of lung tissue, and the effect is significantly better than that of single bacteria and bb12+lra-Y8, which proves that the two have unique synergistic mechanisms in regulating and controlling the intestinal-lung axis and repairing the lung barrier.

Finally, it should be noted that the above only illustrates the technical solution of the present invention and is not limiting, and although the present invention has been described in detail with reference to the preferred arrangement, it should be understood by those skilled in the art that modifications and equivalents may be made to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A use of a composite probiotic in the preparation of a drug for alleviating acute lung injury, characterized in that the composite probiotic consists of Bifidobacterium animalis YRK-12 and Lactobacillus rhamnosus LRa-Y8;

Bifidobacterium animalis YRK-12 was deposited in the General Microbiology Center of China National Committee for the Administration of Microbiological Cultures, and was classified as Bifidobacterium animalis with a deposit number of CGMCC NO.28597 and a deposit date of October 9, 2023.

Lactobacillus rhamnosus LRa-Y8 was deposited in the General Microbiology Center of China National Microbiological Culture Association, classified as Lacticaseibacillus rhamnosus , with a deposit number of CGMCC NO.34186 and a deposit date of April 14, 2025.

The ratio of the live bacteria content of Bifidobacterium animalis YRK-12 and Lactobacillus rhamnosus LRa-Y8 in the composite probiotic is 1:1;

The effective viable bacterial count of the composite probiotics in the medicine is not less than 1×10 ¹⁰ CFU/mL.

2. The method according to claim 1, wherein the acute lung injury is induced by lipopolysaccharide.

3. The use according to claim 1, characterized in that the dosage form of the drug is an oral preparation, including tablets, capsules, granules or suspensions.

4. The use according to claim 1 is characterized in that the drug can reduce the weight loss rate caused by acute lung injury, improve lung tissue pathological damage, and regulate the levels of inflammatory factors in serum and lung tissue.

5. The use according to claim 4, characterized in that the improvement of lung tissue pathological damage includes: maintaining the integrity of alveolar structure, reducing alveolar septal thickening and fusion, and reducing inflammatory cell infiltration and interstitial edema.

6. The use according to claim 4, characterized in that the regulation of the levels of inflammatory factors in serum and lung tissue comprises: downregulating the expression of pro-inflammatory factors IL-1β, TNF-α, and IL-6, and upregulating the expression of anti-inflammatory factor IL-4.