Use of lactobacillus plantarum bile salt fermentation broth in preparation of liver injury treatment product

Abstract

The application belongs to the technical field of microorganisms, and provides application of Lactobacillus plantarum bile salt fermentation liquor in preparation of a product for treating liver injury, the classification name of Lactobacillus plantarum SSL1 is Lactobacillus plantarum, and the preservation number is CGMCC No.35102.The fermentation liquor has excellent biological characteristics and liver injury improvement capacity, and the tolerance to reverse intestinal environment is further enhanced, which lays a solid foundation for treating liver injury, can effectively reduce the activities of ALT, AST and GLDH in serum of liver injury mice, improve the activities of SOD and CAT in liver of liver injury mice, reduce the content of H2O2 in liver, and obviously improve the injury state of liver of the mice.

Description

Technical Field

[0001] This invention belongs to the field of microbial technology, and in particular relates to the application of Lactobacillus plantarum bile salt fermentation broth in the preparation of products for treating liver injury. Background Technology

[0002] The liver is the largest solid organ in an animal, playing vital roles in metabolic regulation, digestion, and nutrient storage. In livestock production, various factors, including drug abuse, poisoning, metabolic disorders, and infections, can cause liver damage in animals. Examples include mycotoxin poisoning (such as aflatoxin and ochratoxin) and the overuse of antiparasitic drugs and antibiotics. Liver damage is often manifested by significantly elevated activities of liver enzymes such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), and glutamate dehydrogenase (GLDH), decreased activities of superoxide dismutase (SOD) and catalase (CAT), and increased hydrogen peroxide (H2O2) content, resulting in significant oxidative stress and inflammatory damage, which can lead to death in severe cases. Liver damage affects animal production performance, reduces breeding efficiency and yield, and poses a serious threat to the development of the livestock industry. In daily human life and livestock farming, common liver injuries include those caused by drugs, metabolism, chemicals, and viruses. These types of liver injuries are characterized by oxidative stress and inflammation. Early stages often present with no obvious symptoms, but as the disease progresses, various abnormal liver functions will appear. In severe cases, it can further develop into liver fibrosis, liver failure, and even liver cancer. Current treatment for liver injury focuses on early intervention; however, due to delayed diagnosis, limited hepatocyte regeneration, and complications, the mortality rate of severe cases remains high.

[0003] D-GalN (D-GalN) inhibits the synthesis of hepatic ribonucleic acid and proteins, leading to oxidative stress, degeneration, and necrosis of hepatocytes. Combined with lipopolysaccharide (LPS), it can further activate the body's inflammatory response, inducing liver damage. Its pathogenesis closely matches that of various infection-induced liver injuries. Excessive acetaminophen (APAP) metabolized in the liver produces N-acetyl-p-benzoquinone imine, which depletes glutathione in hepatocytes, triggering oxidative stress, inflammatory cell infiltration, and inflammatory damage to the liver. Both of these models primarily involve oxidative stress and inflammatory damage in the liver, exhibiting typical pathological features and clear pathogenesis, and can reflect the pathological processes of most liver injuries in livestock production.

[0004] Lactic acid bacteria are a general term for a class of bacteria that can ferment carbohydrates to produce large amounts of lactic acid. They can colonize the intestines, inhibit the growth and reproduction of harmful bacteria, maintain the balance of the intestinal microecology, and stimulate the intestinal mucosal immune system, enhancing the activity of immune cells and thus improving the body's immune function. Among them, Lactobacillus plantarum can effectively alleviate intestinal inflammation and improve damage to tissues and organs such as the lungs, kidneys, and spleen. Bile salts are important components of the intestinal physiological environment, and the tolerance of lactic acid bacteria to high concentrations of bile salts is an important factor determining whether they can colonize the intestines and function normally.

[0005] Microbially modified natural bile acid derivatives can also play a role in maintaining hepatic metabolic homeostasis and alleviating hepatic glucose and lipid metabolism disorders. Current research largely focuses on the individual application of *Lactobacillus plantarum* or bile acids; the related technologies and applications of combining the two to alleviate liver injury have not been fully developed. Therefore, in-depth research on the combined application of *Lactobacillus plantarum* and bile acids has significant research value and broad industrial application prospects for developing novel liver injury protective agents and expanding the application scope of probiotic and bile acid-related compositions. Summary of the Invention

[0006] The purpose of this invention is to provide the application of Lactobacillus plantarum bile salt fermentation broth in the preparation of products for treating liver injury, thereby addressing the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] On one hand, the present invention provides a *Lactobacillus plantarum* SSL1, which is classified as *Lactobacillus plantarum* and was deposited on July 4, 2025, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, with accession number CGMCCNo. 35102; the nucleotide sequence of the 16S rRNA of *Lactobacillus plantarum* SSL1 is shown in SEQ ID NO. 1.

[0009] On the other hand, the present invention provides a *Lactobacillus plantarum* bile salt fermentation broth, wherein the fermentation broth contains the aforementioned *Lactobacillus plantarum* SSL1, with a viable cell concentration ≥ 1×10⁻⁶. 9 CFU / mL.

[0010] On the other hand, the present invention provides the application of Lactobacillus plantarum SSL1 or Lactobacillus plantarum bile salt fermentation broth in the preparation of products for treating liver injury.

[0011] Compared with the prior art, the specific beneficial effects of the present invention are as follows:

[0012] The fermentation broth provided by this invention exhibits excellent biological properties and liver injury improvement capabilities, with further enhanced tolerance to adverse intestinal environments, laying a solid foundation for its treatment of liver injury. Animal experiments show that the fermentation broth can effectively reduce the activities of ALT, AST, and GLDH in the serum of mice with liver injury, increase the activities of SOD and CAT in the liver of mice with liver injury, reduce the content of H2O2 in the liver, and significantly improve the liver injury status of mice. This fermentation broth can be used directly to alleviate liver injury, and can also be applied to the research and development and production of related feeds, feed additives, foods, and health products, providing a new solution for the prevention and treatment of liver injury and the development of related functional products. Attached Figure Description

[0013] Figure 1 The growth curves and pH change curves of *Lactobacillus plantarum* SSL1 under different culture conditions from 0 to 12 h are shown in Example 2 of this invention; a is the growth curve of *Lactobacillus plantarum* SSL1 in the control group and the bile salt group; b is the pH change curve of the culture medium in the control group and the bile salt group.

[0014] Figure 2 The results of acid and bile salt tolerance tests of Lactobacillus plantarum SSL1 under different culture conditions provided in Example 2 of the present invention are shown in Figure a. The survival rate of Lactobacillus plantarum SSL1 in the control group and bile salt group in culture media with different pH values ​​is shown in Figure b. The survival rate of Lactobacillus plantarum SSL1 in the control group and bile salt group in culture media with different bile salt concentrations is shown in Figure b.

[0015] Figure 3 The antioxidant capacity test results of Lactobacillus plantarum SSL1 under different culture conditions provided in Example 2 of the present invention;

[0016] Figure 4 This is a mouse liver HE staining image provided in Example 3 of the present invention, wherein the graphic scale bar represents 100 μm;

[0017] Figure 5 The results of AST, ALT, and GLDH activities in mouse serum provided in Example 3 of the present invention; a) mouse serum AST activity; b) mouse serum ALT activity; c) mouse serum GLDH activity;

[0018] Figure 6 The table shows the SOD and CAT activities and H2O2 content of mouse liver provided in Example 3 of this invention; a) SOD activity of mouse liver tissue homogenate; b) CAT activity of mouse liver tissue homogenate; c) H2O2 content of mouse liver tissue homogenate.

[0019] Figure 7 This is a mouse liver HE staining image provided in Example 4 of the present invention, wherein the graphic scale bar represents 100 μm;

[0020] Figure 8 The results of AST, ALT, and GLDH activities in mouse serum provided in Example 4 of this invention; a) mouse serum AST activity; b) mouse serum ALT activity; c) mouse serum GLDH activity;

[0021] Figure 9 The table shows the SOD and CAT activities and H2O2 content of mouse liver provided in Example 4 of this invention; a) SOD activity of mouse liver tissue homogenate; b) CAT activity of mouse liver tissue homogenate; c) H2O2 content of mouse liver tissue homogenate.

[0022] In the attached figure, different letters (a, b, c) indicate significant differences between groups (P < 0.05), while the same letter indicates no significant differences (P > 0.05). Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0024] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0025] Example 1: Isolation and identification of Lactobacillus plantarum SSL1, including the following procedures:

[0026] (1) Isolation and Culture: Healthy adult dairy cows from a dairy farm in Changchun City, Jilin Province were selected. Fresh rumen fluid was collected using a rumen tube. After collection, the fluid was filtered under aseptic conditions. 1 mL of the filtered rumen fluid was then serially diluted 10-fold with sterile physiological saline. 10 mL of the diluted fluid was then used as the final product. -4 100 μL of gradient rumen fluid was spread onto MRS-CaCO3 solid medium and incubated at 37 ℃ for 24 h. Colony morphology was observed and recorded. Single colonies were picked from the plates for streak culture and incubated at 37 ℃ for 24 h. Single colonies were picked again for streak culture and this process was repeated 3-4 times until single colonies with consistent morphology were obtained. These colonies were named SSL1 and used for subsequent studies.

[0027] (2) Preservation: Select a single colony of purified SSL1 and inoculate it into MRS liquid medium. After culturing at 37 ℃ for 24 h, the bacterial solution is obtained. Take 1 mL of the bacterial solution and centrifuge it in a 1.5 mL centrifuge tube (3000 rpm, 5 min). Discard the supernatant. Take the bacterial sludge and add sterile physiological saline. Centrifuge (3000 rpm, 5 min) to wash it and obtain the washed bacterial cells. Repeat the above operation 3 times. Add sterile 50% glycerol to the obtained bacterial cells and store at -80℃.

[0028] (3) Homology analysis of 16S rRNA gene sequence: A single colony of purified SSL1 was picked and inoculated into MRS liquid medium. After culturing at 37 °C for 24 h, 1 mL of bacterial solution was sent to Jilin Kumei Biotechnology Co., Ltd. for 16S rRNA sequencing. The obtained gene sequence was compared with BLAST in the NCBI database to confirm that the strain was Lactobacillus plantarum and was finally named Lactobacillus plantarum SSL1. It was deposited on July 4, 2025, at the China General Microbiological Culture Collection Center, at No. 3, No. 1, Beichen West Road, Chaoyang District, Beijing, with accession number CGMCC No. 35102. The nucleotide sequence of the 16S rRNA of this strain is shown in SEQ ID NO. 1.

[0029] Example 2: Evaluation of the biological characteristics of Lactobacillus plantarum SSL1:

[0030] 1. Determination of growth curve and pH change curve:

[0031] Lactobacillus plantarum SSL1 was divided into a bile salt group (MRS medium supplemented with 0.05% ox bile salt, with a bile acid content ≥60%) and a control group (MRS medium) based on the different culture medium compositions. Both groups of Lactobacillus plantarum SSL1 were inoculated into MRS broth medium at a 6% inoculum size and incubated statically at 37 ℃. Samples were taken at 0, 2, 4, 6, 8, 10, 12, and 14 h of culture to measure the optical density (OD) at 600 nm. 600 (Value), and simultaneously detect the pH of the culture medium, and plot the growth curve and pH change curve accordingly, such as Figure 1 As shown;

[0032] Depend on Figure 1 As shown in Figure a, the cell density of *Lactobacillus plantarum* SSL1 in both groups exhibited an S-shaped curve trend with increasing culture time, consistent with bacterial growth patterns. In the initial culture stage, both the bile salt group and the control group were in the growth adaptation phase with little difference. With increasing culture time, the cell growth rate of the bile salt group was significantly higher than that of the control group, entering the logarithmic growth phase more quickly and proliferating rapidly. At 12 h of culture, the bile salt group entered the stationary phase, with OD... 600 The value was 1.793, while the OD value of the control group during the same period was 1.793. 600 The value was only 1.552; throughout the entire culture process, the growth trend of the bile salt group was consistently better than that of the control group; the trend of the growth curve showed that, compared with the control group, Lactobacillus plantarum SSL1 in the bile salt group grew more rapidly and had a stronger growth and reproduction capacity.

[0033] Depend on Figure 1As shown in Figure b, the pH of the culture medium for both groups of *Lactobacillus plantarum* SSL1 decreased with increasing culture time, exhibiting an S-shaped curve trend. With prolonged culture time, the pH of the bile salt group decreased significantly faster than that of the control group, entering the logarithmic growth phase more quickly and proliferating rapidly. After 12 hours of culture, the bile salt group entered the stationary phase, with the pH of the culture medium in the control group being 4.11 and that in the bile salt group being 3.90. The trend of pH change in the culture medium showed that, compared with the control group, *Lactobacillus plantarum* SSL1 in the bile salt group grew more rapidly, and the pH change in the culture medium was more significant than that in the control group.

[0034] 2. Acid resistance test:

[0035] Lactobacillus plantarum SSL1 was divided into a bile salt group (MRS medium supplemented with 0.05% ox bile salt, with a bile acid content ≥60%) and a control group (MRS medium) based on the different culture medium compositions. The liquid culture medium was adjusted to pH = 2, pH = 3, pH = 4, and pH = 5 using 0.1 mol / L hydrochloric acid. Both groups of bacterial suspensions were inoculated into MRS liquid culture media at different pH values ​​at a 6% inoculum size and cultured at 37 ℃ for 12 h. A blank liquid culture medium was used as a control. OD was measured after 12 h. 600 The survival rate was calculated using the following formula: Survival rate (%) = OD of experimental group 600 / Control group OD 600 ×100%;

[0036] Depend on Figure 2 As shown in Figure a, the survival rate of Lactobacillus plantarum SSL1 in the bile salt group was higher than that in the control group at different pH levels, and the survival rate was higher than that in the control group under the culture conditions of pH = 4 and pH = 5, indicating that Lactobacillus plantarum SSL1 in the bile salt group has stronger acid resistance.

[0037] 3. Bile salt tolerance test:

[0038] Lactobacillus plantarum SSL1 was divided into a bile salt group (MRS medium supplemented with 0.05% ox bile salt, with a bile acid content ≥60%) and a control group (MRS medium) based on the different culture medium compositions. MRS liquid media containing 0.2%, 0.3%, 0.4%, and 0.5% bile salt were then prepared using ox bile salt. Both groups of bacterial suspensions were inoculated into MRS liquid media with different bile salt concentrations at a 6% inoculum rate and cultured at 37 ℃ for 12 h. A blank liquid medium was used as a control. OD was measured after 12 h. 600 The survival rate was calculated using the following formula: Survival rate (%) = OD of experimental group 600 / Control group OD 600 ×100%;

[0039] Depend on Figure 2 As shown in Figure b, the survival rate of Lactobacillus plantarum SSL1 in the bile salt group was higher than that in the control group at different bile salt concentrations, and the survival rate was significantly higher than that in the control group under the culture conditions of bile salt concentrations of 0.2% and 0.3%, indicating that Lactobacillus plantarum SSL1 in the bile salt group has a stronger bile salt tolerance.

[0040] 4. Antioxidant capacity experiment:

[0041] Lactobacillus plantarum SSL1 was divided into a bile salt group (MRS medium supplemented with 0.05% ox bile salt, with a bile acid content ≥60%) and a control group (MRS medium) based on the different culture medium compositions. Both groups of Lactobacillus plantarum SSL1 bacterial suspensions were inoculated into MRS broth medium at a 6% inoculum size and cultured at 37 ℃ for 12 h. The antioxidant capacity of the two fermentation broths was detected using a DPPH free radical scavenging kit. Figure 3 It can be seen that the DPPH free radical scavenging rate of Lactobacillus plantarum SSL1 in the bile salt group (87.54%) was significantly higher than that in the control group (76.55%), indicating that Lactobacillus plantarum SSL1 in the bile salt group has stronger antioxidant capacity.

[0042] In conclusion, compared with the absence of bile salts, the addition of a specific concentration of bile salts to MRS medium enables Lactobacillus plantarum SSL1 to exhibit superior growth and reproduction capabilities, gastrointestinal fluid tolerance potential, and antioxidant capacity, laying a solid foundation for subsequent verification of its in vivo therapeutic efficacy against liver injury.

[0043] Example 3: Evaluation of the therapeutic effect of Lactobacillus plantarum SSL1 on APAP-induced liver injury in mice, including the following procedures:

[0044] (1) Using APAP (acetaminophen) as an inducer of liver injury, 20 male C57BL / 6 mice aged 7 weeks were selected for the experiment and purchased from Liaoning Changsheng Biotechnology Co., Ltd. (SCXK (Liaoning) 2023-0002); they were randomly divided into blank control group, fermentation broth control group, APAP model group and APAP + fermentation broth group, and were acclimatized for 7 days;

[0045] (2) Before the experiment officially began, the mice were weighed and their weight was recorded. After the adaptive feeding was completed, the mice in the fermentation broth control group and the APAP+ fermentation broth group were continuously gavaged for 7 days (the concentration of Lactobacillus plantarum SSL1 in the fermentation broth was ≥ 1×10). 9 Two hours after the last administration, the APAP model group and the APAP+fermentation broth group were treated with 300 mg / kg APAP, while the blank control group and the fermentation broth control group were injected with an equal volume of physiological saline intraperitoneally.

[0046] (3) After 12 h, mouse blood and liver samples were collected. The blood samples were centrifuged at 4 ℃, and the upper serum was taken to determine the activities of AST, ALT and GLDH.

[0047] (4) A portion of the right lobe of the liver was cut off, fixed in 4% paraformaldehyde, and stained with hematoxylin and eosin (HE).

[0048] (5) Take an appropriate amount of liver tissue sample, prepare a 10% liver tissue homogenate, and determine the SOD, CAT activity and H2O2 content.

[0049] HE staining results are as follows Figure 4 As shown, in the blank control group, hepatocytes were arranged neatly in a radial pattern without degeneration, necrosis, or inflammatory infiltration; in the APAP model group, hepatocytes were arranged randomly, the normal radial structure was destroyed, large areas of necrosis appeared around the central vein, and aggregated inflammatory cells could be observed in some areas, indicating inflammatory infiltration; compared with the APAP model group, the APAP + fermentation broth group had a more intact liver lobule structure, a reduced necrosis area centered on the central vein, no obvious inflammatory infiltration, and a significantly reduced degree of liver damage.

[0050] Liver function test results as follows Figure 5 As shown, compared with the blank control group, the activities of AST, ALT and GLDH in the APAP model group mice were significantly increased (p < 0.05), indicating that the mice suffered liver damage; compared with the APAP model group, the activities of AST, ALT and GLDH in the APAP + fermentation broth group mice were significantly decreased (p < 0.05), indicating that the fermentation broth can treat APAP-induced liver damage.

[0051] Results of oxidative stress indicators as follows Figure 6 As shown, compared with the blank control group, the activities of CAT and SOD in the liver of mice in the APAP model group were significantly reduced, while the content of H2O2 was increased (p < 0.05), indicating that the liver of mice was under oxidative stress. Compared with the APAP model group, the activities of CAT and SOD in the liver of mice in the APAP + fermentation broth group were significantly increased, while the content of H2O2 was decreased (p < 0.05), indicating that the fermentation broth can alleviate the oxidative stress caused by APAP-induced liver injury.

[0052] Example 4: Evaluation of the therapeutic effect of Lactobacillus plantarum SSL1 on D-GalN and LPS-induced liver injury in mice, including the following procedures:

[0053] (1) Using D-GalN (D-galactosamine) and LPS (lipopolysaccharide) as inducers of liver injury, 20 male C57BL / 6 mice aged 7 weeks were selected for the experiment and purchased from Liaoning Changsheng Biotechnology Co., Ltd. (SCXK (Liaoning) 2023-0002). They were randomly divided into blank control group, fermentation broth control group, model group, and D-GalN+LPS+fermentation broth group and were acclimatized for 7 days.

[0054] (2) Before the experiment officially began, the mice were weighed and their weight was recorded. After the adaptive feeding was completed, the mice in the fermentation broth control group and the D-GalN+LPS+fermentation broth group were continuously administered bacteria for 7 days (the concentration of Lactobacillus plantarum SSL1 in the fermentation broth was ≥ 1×10). 9 Two hours after the last administration, the D-GalN+LPS model group and the D-GalN+LPS+fermentation broth group were given D-GalN (700 mg / kg) and LPS (10 μg / kg) by intraperitoneal injection, while the blank control group and the fermentation broth control group were given an equal volume of physiological saline by intraperitoneal injection.

[0055] (3) Six hours later, mouse blood and liver samples were collected. The blood samples were centrifuged at 4 °C, and the upper serum was taken to determine the activities of AST, ALT and GLDH.

[0056] (4) A portion of the right lobe of the liver was cut off, fixed in 4% paraformaldehyde, and stained with hematoxylin and eosin (HE).

[0057] (5) Take an appropriate amount of liver tissue sample, prepare a 10% liver tissue homogenate, and determine the SOD, CAT activity and H2O2 content.

[0058] HE staining results are as follows Figure 7 As shown, in the blank control group, hepatocytes were arranged neatly in a radial pattern without degeneration, necrosis, or inflammatory infiltration. In the D-GalN+LPS model group, hepatocytes were arranged randomly, the normal radial structure was destroyed, and large areas of necrosis appeared around the central vein. In some areas, obvious inflammatory cell aggregation foci were visible, forming focal inflammation. Inflammatory cells were seen accumulating along the vascular endothelium around multiple central veins or hepatic veins, and some invaded the vessel wall or surrounding liver parenchyma. Compared with the D-GalN+LPS model group, the D-GalN+LPS+fermentation broth group had a more intact liver lobule structure, a reduced necrosis area centered on the central vein, and only scattered, small amounts of inflammatory cells were seen distributed in the sinusoids and perivascular areas without obvious inflammatory infiltration. Only a very small number of inflammatory cells were seen adhering to the wall around the central vein or hepatic vein, indicating a significant reduction in the degree of liver damage.

[0059] Liver function test results as follows Figure 8As shown, compared with the blank control group, the activities of AST, ALT and GLDH in mice in the D-GalN+LPS model group were significantly increased (p < 0.05), indicating that the mice suffered liver damage; compared with the D-GalN+LPS model group, the activities of AST, ALT and GLDH in mice in the D-GalN+LPS+fermentation broth group were significantly decreased (p < 0.05), indicating that the fermentation broth can treat liver damage induced by the combined effects of D-GalN and LPS.

[0060] Results of oxidative stress indicators as follows Figure 9 As shown, compared with the blank control group, the CAT and SOD activities of mice in the D-GalN+LPS model group were significantly reduced, while the H2O2 content was increased (p < 0.05), indicating that the liver of mice was under oxidative stress. Compared with the D-GalN+LPS model group, the CAT and SOD activities of mice in the D-GalN+LPS+fermentation broth group were significantly increased, while the H2O2 content was decreased (p < 0.05), indicating that the fermentation broth can alleviate the oxidative stress caused by liver damage induced by the combined effects of D-GalN and LPS.

[0061] In summary, the in vitro biological characteristics studies show that adding a specific concentration of bile salts to the culture medium can enhance the growth and reproduction capacity, gastrointestinal fluid tolerance potential, and antioxidant capacity of Lactobacillus plantarum SSL1. In animal models, gavage administration of the fermentation broth showed significant therapeutic effects on liver injury caused by APAP or the combination of D-GalN and LPS.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A type of Lactobacillus plantarum SSL1, characterized in that, The *Lactobacillus plantarum* SSL1 is classified as *Lactobacillus plantarum* and was deposited on July 4, 2025, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, with accession number CGMCCNo. 35102. The nucleotide sequence of the 16S rRNA of *Lactobacillus plantarum* SSL1 is shown in SEQ ID NO.

1.

2. A fermentation broth containing bile salts from *Lactobacillus plantarum*, characterized in that, The fermentation broth contains *Lactobacillus plantarum* SSL1 as described in claim 1, with a viable cell concentration ≥ 1 × 10⁻⁶. 9 CFU / mL; The preparation method of the fermentation broth includes the following steps: inoculating Lactobacillus plantarum SSL1 into MRS liquid medium containing 0.05% ox bile salt and culturing at 37 ℃ for 48 h to obtain the broth; The ox bile salts contain ≥60% cholic acid.

3. The use of *Lactobacillus plantarum* SSL1 as described in claim 1 or *Lactobacillus plantarum* bile salt fermentation broth as described in claim 2 in the preparation of drugs for treating liver injury, characterized in that... The liver injury described is characterized by oxidative stress and inflammatory damage caused by the combination of D-galactosamine and lipopolysaccharide or by acetaminophen.

Images