Lactobacillus paracasei Jlu-CH9 and application thereof

Abstract

The invention is applicable to the technical field of microorganisms, and provides a lactobacillus paracasei Jlu-CH9 and application thereof, the lactobacillus paracasei Jlu-CH9 is preserved in China General Microbiological Culture Collection Center on January 4, 2026, the preservation number is CGMCC No.37281, and the preservation address is No.3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The strain Jlu-CH9 obtained by separation has certain tolerance to acid and cholate, has no hemolysis phenomenon, and is sensitive to various antibiotics; the compound has good inhibitory activity on dipeptidyl peptidase IV and has a certain potential of reducing blood sugar. The compound has relatively good inhibitory activity on a plurality of pathogenic bacteria including salmonella typhimurium, staphylococcus aureus, escherichia coli, clostridium perfringens and pseudomonas aeruginosa; the traditional Chinese medicine composition has good prevention and treatment effects on a DSS-induced mouse colitis model, and can repair intestinal barriers, regulate immune balance, remodel intestinal flora homeostasis and relieve colonic atrophy.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of microorganisms, and particularly relates to a lactobacillus paracasei Jlu-CH9 and application thereof. BACKGROUND

[0002] In recent years, health intervention strategies based on intestinal microecological regulation have attracted much attention. Research shows that active probiotics and their metabolites in fermented foods have many aspects of promoting health, including regulating intestinal flora structure, enhancing intestinal barrier function, improving intestinal inflammation, assisting in regulating sugar and lipid metabolism, and inhibiting pathogenic bacteria colonization.

[0003] Isolation, identification and screening of probiotics from traditional fermented dairy products and evaluation of their functions are the key basis for realizing the transformation of probiotic resources "mining-function analysis-industrial application", which helps to obtain characteristic strains with strong adaptability and clear functions. SUMMARY

[0004] The purpose of the embodiment of the application is to provide a lactobacillus paracasei Jlu-CH9, which aims to solve the problems in the background art.

[0005] The embodiment of the application is achieved in that a lactobacillus paracasei Jlu-CH9 is preserved in the China General Microbiological Culture Collection Center on January 4, 2026, with a preservation number of CGMCC No.37281 and a preservation address of No.3, Beichen West Road, Chaoyang District, Beijing.

[0006] Another purpose of the embodiment of the application is to provide application of the lactobacillus paracasei Jlu-CH9 in preparation of a medicine for preventing and treating colitis.

[0007] Another purpose of the embodiment of the application is to provide application of the lactobacillus paracasei Jlu-CH9 in preparation of a medicine for assisting in reducing blood sugar.

[0008] Another purpose of the embodiment of the application is to provide application of the lactobacillus paracasei Jlu-CH9 in preparation of an antibacterial medicine, and the bacteria targeted by the antibacterial medicine are one of salmonella typhimurium, staphylococcus aureus, escherichia coli, clostridium perfringens and pseudomonas aeruginosa.

[0009] The strain Jlu-CH9 is isolated from a homemade cheese product in Inner Mongolia, has certain tolerance to acid and bile salt, has no hemolytic phenomenon, is sensitive to various antibiotics, has good dipeptidyl peptidase IV inhibitory activity, has certain hypoglycemic potential, has good inhibitory activity on various pathogenic bacteria such as Salmonella typhimurium, Staphylococcus aureus, Escherichia coli, Clostridium perfringens and Pseudomonas aeruginosa, has good prevention and treatment effect on a DSS-induced mouse colitis model, can repair intestinal barrier, regulate immune balance, reshape intestinal flora homeostasis and relieve colon atrophy. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 A colony morphology diagram provided by the embodiment of the present application; Figure 2 A gram staining microscopic examination result provided by the embodiment of the present application; Figure 3 A hemolytic result provided by the embodiment of the present application; Figure 4 A mouse weight detection result provided by the embodiment of the present application; Figure 5 A mouse mortality rate result provided by the embodiment of the present application; Figure 6 A mouse DAI score provided by the embodiment of the present application; Figure 7 A mouse colon length result provided by the embodiment of the present application; Figure 8 A mouse spleen index provided by the embodiment of the present application; Figure 9 An immune factor detection result provided by the embodiment of the present application, a is a relative expression amount of TNF-alpha, b is a relative expression amount of IL-1beta, c is a relative expression amount of IL-6, d is a relative expression amount of IL-10, e is a relative expression amount of IL-17A, and f is a relative expression amount of IL-22; Figure 10 A barrier function gene expression level provided by the embodiment of the present application, a is a relative expression amount of Muc2, b is a relative expression amount of Claudin-1, c is a relative expression amount of Occludin, and d is a relative expression amount of ZO-1; Figure 11 An intestinal flora genus level analysis result provided by the embodiment of the present application; In the drawings, statistical significance is determined by Tukey multiple comparison test after one-way analysis of variance (ANOVA), data is expressed by mean ± standard error, ns: P>0.05, *: P<0.05, **: P<0.01, ***: P<0.001, ****: P<0.0001. Detailed Implementation

[0011] 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.

[0012] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0013] Example 1: Isolation, identification, and safety assessment of strain Jlu-CH9: 1.1 Isolation and purification of strains: Take an appropriate amount of sample (homemade cheese products from farmers in Inner Mongolia), crush it, place it in 100 mL of MRS broth, mix well, and incubate at 37°C with shaking for 24 h. Dilute the culture solution serially, inoculate it onto MRS solid medium, incubate at 37°C for 24 h, pick single colonies, incubate in MRS broth with shaking for 24 h, and repeat the purification process 5 times. Then, store it in a -80°C ultra-low temperature freezer using 50% (v / v) glycerol.

[0014] 1.2 Identification: After activation and culture, the frozen strain was sequenced by Shanghai Bioengineering Co., Ltd. Homology comparison of the predicted 16S rRNA sequence with the NCBI 16S database showed high similarity between the strain and the 16S rRNA sequences of four known *Lactobacillus paracasei* strains (BL23, W56, LOCK919, and TK-P4A). Further average nucleotide identity analysis showed that the ANI values ​​of this strain with *Lactobacillus paracasei* BL23, W56, LOCK919, TK-P4A, and L9 were 98.53, 98.55, 98.5%, 98.56, and 99.8%, respectively. Therefore, the strain was preliminarily identified as *Lactobacillus paracasei* and named *Lactobacillus paracasei*. paracasei) Jlu-CH9; This strain was deposited on January 4, 2026 at the China General Microbiological Culture Collection Center, located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, with accession number CGMCC No. 37281. Lactobacillus paracasei Jlu-CH9 was inoculated onto MRS agar medium and incubated at 37°C for 24 hours. The morphology of single colonies was observed and recorded, such as... Figure 1As shown, *Lactobacillus paracasei* Jlu-CH9 grew well on MRS agar medium, with round, raised, milky-white colonies that were smooth and had even edges. Gram staining of *Lactobacillus paracasei* Jlu-CH9 was performed, and the morphology of the stained bacteria was observed and recorded under a microscope. Figure 2 As shown, after Gram staining, the bacteria appear rod-shaped and purple under a microscope, which is consistent with the staining characteristics of Gram-positive bacteria.

[0015] 1.3 Safety assessment (hemolytic activity and antibiotic resistance assessments were performed separately): Hemolytic activity: The activated Jlu-CH9 strain was inoculated into Columbia blood agar medium and cultured at 37°C for 24 h. The presence of a hemolytic clear zone was observed. Antibiotic resistance: The susceptibility of the strain to common antibiotics was tested by the disk agar diffusion method. The test results were used to determine the drug susceptibility of the strain according to the standards of the National Committee for Clinical Laboratory Standards (NCCLS) in the United States. The results were expressed as sensitive (S), intermediate (I) and resistant (R). Hemolytic test results as follows Figure 3 As shown, the activated Jlu-CH9 strain was inoculated into Columbia blood agar medium and cultured at 37°C for 24 h. No hemolytic clear zone was observed, indicating no hemolysis. The strain was sensitive (S) to all five tested antibiotics: streptomycin, tetracycline, chloramphenicol, ampicillin, and clarithromycin, indicating that the tested strain had no antibiotic resistance.

[0016] Example 2: Key probiotic characteristics of Lactobacillus paracasei Jlu-CH9: 2.1 Acid resistance test: The Jlu-CH9 strain was inoculated into MRS broth liquid medium with pH adjusted to 2.5, 3.0, and 6.0. The strain's tolerance to acidic environment was tested at 37°C. The culture media with tolerance of 0h and 4h were diluted and spread. The survival rate was calculated based on the ratio of the number of colonies at 4h and 0h, thereby determining the strain's tolerance to acidic environment. In an acidic environment, when the pH was 2.5, 3.0 and 6.0, the survival rates of the Jlu-CH9 strain after 4 hours of cultivation were 0%, 63.7% and 314.4%, respectively, indicating that the strain also had tolerance in the extremely acidic environment of pH=3.0.

[0017] 2.2 Bile salt tolerance test: The Jlu-CH9 strain was inoculated into MRS broth liquid medium containing 0.1%, 0.2%, and 0.3% (w / v) ox bile salts, respectively. The probiotics' tolerance to bile salts was tested at 37°C. The cultures that tolerated the strains for 0 h and 4 h were diluted and spread. The survival rate was calculated based on the ratio of the number of colonies at 4 h and 0 h, thereby determining the strain's tolerance to bile salts. When the bile salt concentrations were 1.0%, 2.0%, and 3.0%, the survival rates of the strains after four hours of incubation were 80.6%, 66.3%, and 53.3%, respectively. The strains still showed tolerance in a high concentration of 3% bile salts.

[0018] 2.3 In vitro digestion experiment: The Jlu-CH9 strain was washed twice with PBS buffer (pH 7.2) and then resuspended in PBS solution containing pepsin (3 mg / mL) (pH 3.0) and trypsin (1 mg / mL) (pH 7.0), with the initial concentration controlled within the range of 1×10⁻⁶. 8 CFU / mL, digestive tolerance was determined by the number of viable colonies after 0 and 4 h of pepsin culture at 37°C and 0 and 4 h of pancreatic digestion, respectively, simulating the time it takes for conventional food to pass through the stomach and small intestine. In experiments simulating gastric juice environment, the survival rate of Jlu-CH9 strain was 45.1% after four hours of cultivation, indicating that the strain could still survive in the presence of pepsin and in an environment with pH=3.0. In experiments simulating pancreatic juice environment, the survival rate of the strain was 174.2% after four hours of cultivation, indicating that the strain could survive well in pancreatic juice.

[0019] Example 3: In vitro detection of hypoglycemic activity of Lactobacillus paracasei Jlu-CH9 culture supernatant: 3.1 Assay of DPP-IV inhibitory activity: The inhibitory activity of Jlu-CH9 supernatant against dipeptidyl peptidase-IV (DPP-IV) was evaluated using an in vitro enzyme inhibition assay. DPP-IV was used as the reactive enzyme, and Gly-Pro-p-nitroanilide (Gly-Pro-pNA) was used as the chromogenic substrate. The absorbance change of the enzyme-catalyzed reaction products was measured colorimetrically to calculate the inhibition rate of the sample against DPP-IV. Four reaction systems were set up: experimental group (A, a mixture of Jlu-CH9 supernatant, DPP-IV enzyme solution, and substrate), background group (B, Jlu-CH9 supernatant and substrate, without DPP-IV enzyme solution), control group (C, DPP-IV enzyme solution and substrate, without sample), and blank control group (D, substrate only). Each reaction system was incubated at 37 ℃ for 1 h. After the reaction, the system was immediately placed in a boiling water bath to terminate enzyme activity. After cooling to room temperature, the enzyme activity was measured using a microplate reader at 405 nm. The absorbance values ​​of each group of reaction solutions were measured at a wavelength of nm. The inhibitory activity of the sample against DPP-IV was calculated using the following formula: ; Where A, B, C and D represent the absorbance values ​​of the experimental group, background group, control group and blank control group, respectively. The higher the inhibition rate, the stronger the inhibitory effect of Jlu-CH9 supernatant on DPP-IV. In vitro enzyme inhibition experiments showed that Jlu-CH9 supernatant exhibited a significant inhibitory effect on DPP-IV. Compared with the control group, the enzymatic activity of DPP-IV was significantly reduced after the addition of Jlu-CH9 supernatant, with an inhibition rate of over 50%. This indicates that Jlu-CH9 supernatant has strong DPP-IV inhibitory activity, and the metabolites of Jlu-CH9 have certain hypoglycemic potential.

[0020] Example 4: Evaluation of the antibacterial activity of Lactobacillus paracasei Jlu-CH9: After activating the frozen Salmonella typhimurium SL1344 (purchased from ATCC), Staphylococcus aureus USA300 (purchased from ATCC), Escherichia coli ATCC 25922 (purchased from ATCC), Clostridium perfringens ATCC 13124 (purchased from ATCC), and Pseudomonas aeruginosa PAO1 (purchased from ATCC), the concentration of the above pathogens was adjusted to 1×10⁻⁶. 8CFU / mL available; The aforementioned pathogenic bacteria were spread onto their respective solid culture medium plates to prepare pathogenic bacteria agar plates. Antimicrobial susceptibility plates soaked in Jlu-CH9 bacterial suspension were then placed in the center of the plates. The plates were incubated at 37°C for 24 hours. After incubation, the diameter of the inhibition zone was measured, and the results are shown in Table 1 (diameter: mm). Table 1

[0021] The results showed that the culture medium of Lactobacillus paracasei Jlu-CH9 strain had strong inhibitory activity on the growth of pathogens such as Salmonella typhimurium, Staphylococcus aureus, Escherichia coli, Clostridium perfringens, and Pseudomonas aeruginosa, with the most significant inhibitory effect on Salmonella typhimurium.

[0022] Example 5: Therapeutic effect of Lactobacillus paracasei Jlu-CH9 on a mouse model of colitis: 5.1 The main materials used in the experiment are shown in Table 2: Table 2

[0023] 5.2. Bacterial culture conditions and preparation of bacterial supernatant and bacterial sludge: Select a single colony of Jlu-CH9 and place it in 10 mL of LMRS liquid medium. After incubating at 37°C for 12 hours, obtain the bacterial suspension. Centrifuge the bacterial suspension at 5000 r / min for 10 min and take the supernatant as the bacterial suspension. Resuspend the precipitate in 10 mL of PBS to obtain the bacterial sludge solution as the bacterial suspension. 5.3 Animal Experiment Design: Fifty male C57BL / 6 mice (Liaoning Changsheng Biotechnology Co., Ltd.), aged 8-10 weeks, were randomly divided into five groups: a normal control group (Control) and a Jlu-CH9 bacterial sludge group (CH9) as the healthy group; and a model group (DSS), a Jlu-CH9 bacterial sludge + DSS group (DSS + CH9), and a mesalazine + DSS group (DSS + 5-ASA) as the disease group. After one week of acclimatization, the model was established under the following conditions: normal control group (10 days of sterilized water), Jlu-CH9 bacterial sludge group (10 days of Lactobacillus paracasei, 0.2 mL, 1.0 x 10⁻⁶ g / mL). 9The mice were divided into four groups: CFU / mL bacterial sludge dissolved in PBS, model group (3% DSS solution for the first 6 days + sterile water for the last 4 days), Jlu-CH9 bacterial sludge + DSS group (3% DSS solution for the first 6 days + Lactobacillus paracasei bacterial sludge dissolved in PBS for the last 4 days), and mesalazine + DSS group (3% DSS solution for the first 6 days + 100 mg / kg mesalazine for the last 4 days). During the modeling period, the mice were weighed at 9:00 AM every day and the percentage change relative to the initial body weight was calculated. After the modeling was completed, the mice were sacrificed and their intestinal tissue was collected to measure its length. The weight of the liver and spleen was also measured. The mice's serum and colon contents were collected. 5.4 Test Content: 5.4.1 The rate of change in mouse body weight is calculated using the following formula: ; 5.4.2 The mortality rate of mice is calculated using the following formula: ; 5.4.3 The Disease Activity Index (DAI) in mice is often used to comprehensively assess the severity of enteritis. The DAI is generally scored based on weight loss, fecal characteristics, and fecal bleeding. Each item is typically scored from 0 to 4, and the average score is taken. The scoring criteria are shown in Table 3. Table 3

[0024] 5.4.4 The spleen index of mice is calculated using the following formula: ; 5.4.5 Detection of mouse immune factors: Colon tissue was placed in a homogenizer, and RNA was extracted according to the instructions of the RNA extraction kit. The extracted RNA was then reverse transcribed into more stable cDNA using a reverse transcription kit, followed by real-time quantitative PCR. Primer information is shown in Table 4 below. Table 4 (Sequences are shown in SEQ ID No. 1-14)

[0025] 5.4.6. Intestinal barrier factor detection: The operation steps are the same as in 5.9, and the primer information is shown in Table 5 below: Table 5 (Sequences are shown in SEQ ID No. 15-24)

[0026] 5.4.7 Extraction and sequencing of the metagenomic genome of gut microbiota from fecal samples: Immediately after euthanizing the mice, intestinal tissue was removed, and colonic and cecal contents were collected. These contents were placed in sterile cryovials, flash-frozen with liquid ammonia for 5 minutes, and then stored at -80°C in a biological freezer for analysis. High-throughput analysis of the colonic microbiota was performed. (1) Extraction and detection of sample DNA: Select the appropriate commercially available extraction kit according to the sample type to extract total DNA from microbial samples from various sources, and use Qubit (Invitrogen, USA) to quantify the DNA; (2) PCR amplification and sequencing library construction: Using the DNA genome as a template, the 16S rDNA gene spanning the V3-V4 region was amplified by PCR. The forward primer was 341F (5'-CCTACGGGNGGCWGCAG-3') (as shown in SEQ ID No. 25), and the reverse primer was 805R (5'-GACTACHVGGGTATCTAATCC-3') (as shown in SEQ ID No. 26). The amplified fragment was then used to construct a library. (3) PCR product quantification: PCR products were purified by AMPure XT beads (Beckman Coulter Genomics, Danvers, MA, USA) and quantified by Qubit (Invitrogen, USA); (4) Library pooling and sequencing: The purified PCR products were evaluated using an Agilent 2100 bioanalyzer (Agilent, USA) and Illumina (Kapa Biosciences, Woburn, MA, USA) library quantification kit. The concentration of qualified libraries should be above 2 nM. The qualified sequencing libraries (index sequences must not be reproducible) were serially diluted and mixed according to the required sequencing volume. They were then denatured into single strands by NaOH and sequenced. 2×250bp paired-end sequencing was performed using a NovaSeq 6000 sequencer with the NovaSeq 6000 SP Reagent Kit (500 cycles). Bioinformatics analysis was performed using the Lianchuan Bio Microbial Amplicon System.

[0027] 5.5 Analysis of Experimental Results: 5.5.1. Weight measurement results, mortality rate, DAI index, and intestinal length: During the experiment, the weight of the mice was recorded daily, and the results were as follows: Figure 4As shown, after drinking 3% DSS solution, the weight of mice began to decrease significantly from the fifth day until the end of the experiment, indicating that drinking 3% DSS solution would lead to weight loss in mice. At the beginning of the modeling, there was no significant difference in the weight of mice among the groups. At the end of the experiment, compared with the DSS group, the DSS+CH9 group and the DSS+5-ASA group could significantly alleviate the weight loss of mice caused by DSS. Furthermore, mice began to die on the fourth day after successful model establishment, with a mortality rate as follows: Figure 5 As shown, at the experimental endpoint, the mortality rate in the DSS group reached 40%, while the mortality rate in the treated mice decreased significantly, with the mortality rates in the DSS+CH9 group and the DSS+5-ASA group being 10%. This indicates that Jlu-CH9 has a better therapeutic effect. Further analysis of DAI scores, such as Figure 6 As shown, at the experimental endpoint, compared with the DSS group, the DAI scores of both the DSS+CH9 group and the DSS+5-ASA group were lower, indicating that probiotics and mesalazine intervention have a certain alleviating effect on intestinal inflammation. like Figure 7 As shown, after successful modeling, the intestinal length of the DSS group was significantly shorter than that of the Control group, and after Jlu-CH9 treatment, the colon length of the DSS+CH9 group was significantly increased compared with the DSS group. 5.5.2 Spleen Index: Spleen index results as follows Figure 8 As shown, compared with the DSS group, the spleen index of both the DSS+CH9 group and the DSS+5-ASA group was significantly decreased. This indicates that Jlu-CH9 can improve the spleen index of mice. As the spleen is an immune organ in the body, this further illustrates that Jlu-CH9 may alleviate the inflammatory response by protecting the body's immune system.

[0028] 5.5.3 Changes in inflammatory factors: Inflammatory cytokines play a crucial role in the pathogenesis of colitis, controlling the development of inflammatory responses. TNF-α is one of the important inflammatory cytokines in the body; its expression promotes the secretion of chemokines, attracts leukocytes to sites of tissue damage, and activates the body's immune function. Other related pro-inflammatory cytokines include IL-1β, IL-6, and IL-17A; anti-inflammatory cytokines include IL-10 and IL-22. The expression of genes related to inflammatory factors in mouse colon tissue was detected, and the results are as follows: Figure 9As shown, the results indicated that after drinking 3% DSS solution, the relative expression levels of pro-inflammatory factors TNF-α, IL-1β, IL-6, and IL-17A in mice were significantly increased. Compared with the DSS group, the relative expression levels of TNF-α, IL-1β, IL-6, and IL-17A in the DSS+CH9 group and the DSS+5-ASA group were significantly decreased. At the same time, compared with the DSS group, the relative expression levels of anti-inflammatory factors IL-10 and IL-22 in the DSS+CH9 group and the DSS+5-ASA group were significantly increased. These results suggest that Jlu-CH9 has a certain ameliorative effect on intestinal immune response, thereby alleviating intestinal inflammation in mice to some extent.

[0029] 5.5.4 Intestinal barrier function: Barrier protein gene expression results as follows Figure 10 As shown, compared with the DSS group, the relative expression levels of Muc2, Occludin, Claudin-1 and ZO-1 in the DSS+CH9 group and the DSS+5-ASA group were significantly increased, indicating that Jlu-CH9 and mesalazine have a certain restorative effect on the barrier function of mice with enteritis.

[0030] 5.5.5 Analysis of Gut Microbiota Results: The results of species analysis of gut microbiota at the genus level are as follows: Figure 11 As shown, within the disease group, compared with the DSS group, the abundance of Lachnospiraceae_NK4A136_group (Knockmansia, Lactobacillus), Lactobacillus, UCG-005, Ruminococcus, and Monoglobus in the DSS+CH9 and DSS+5-ASA groups increased to varying degrees. This indicates that Jlu-CH9 and mesalazine can increase the abundance of probiotics in the intestines of mice with enteritis, thereby... The presence of pathogenic bacteria such as Ligilactobacillus, Alloprevotella, Streptococcus, Candidatus Saccharimonas, and Escherichia-Shigella was reduced to varying degrees, indicating that Jlu-CH9 and mesalazine can reduce the abundance of pathogenic bacteria in the intestines of mice with enteritis and improve the species distribution of the intestinal flora. Lactobacillus is a typical probiotic that plays a significant role in improving inflammatory bowel disease and maintaining intestinal homeostasis. Studies have shown that the metabolites of Lactobacillus can directly or indirectly regulate immune responses, induce the secretion of anti-inflammatory factors IL-10 and TGF-β, and inhibit the NF-κB pathway, thereby reducing the levels of pro-inflammatory factors TNF-α, IL-1β, and IL-6. In the embodiments of this invention, the abundance of Lactobacillus in the DSS+CH9 group and the DSS+5-ASA group increased by 6.64 and 13.71 times, respectively, compared with the DSS group, which can prove that Lactobacillus was significantly increased in the intestine of mice with enteritis, thus indicating that Jlu-CH9 and mesalazine have good regulatory effects. In the healthy group, the abundance of Lactobacillus in the CH9 group was 2.66 times that of the Control group, indicating that Jlu-CH9 can increase the abundance of Lactobacillus in healthy mice, making the intestinal flora of mice healthier. Akkermansia, especially Akkermansia muciniphila (Akkermansia muciniphila), is considered an important next-generation probiotic. Akkermansia can improve intestinal barrier function by degrading mucin in intestinal mucus, thereby stimulating intestinal epithelial cells to accelerate the synthesis and secretion of tight junction proteins such as ZO-1, Occludin, and Claudin-1. On the other hand, Akkermansia can also inhibit the NF-κB pathway by regulating Treg cell differentiation, inhibiting excessive Th17 cell activation, and upregulating anti-inflammatory factors such as IL-10 and TGF-β. In the embodiments of this invention... The abundance of Akkermansia in the DSS+CH9 group and the DSS+5-ASA group increased by 1.54 and 2.78 times, respectively, compared with the DSS group, demonstrating a significant increase in Akkermansia in the intestines of mice with enteritis. This indicates that Jlu-CH9 and mesalazine can improve the intestinal barrier function of mice with enteritis. In the healthy group, the Akkermansia abundance in the CH9 group was 1.69 times that in the Control group, indicating that under healthy conditions, Jlu-CH9 can also enhance the intestinal barrier function and has a certain preventive effect on intestinal diseases.

[0031] The above description is merely 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 strain of Lactobacillus paracasei Jlu-CH9, characterized in that, It was deposited on January 4, 2026, at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 37281, located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing.

2. The use of Lactobacillus paracasei Jlu-CH9 as described in claim 1 in the preparation of drugs for the prevention and treatment of colitis.

3. The use of Lactobacillus paracasei Jlu-CH9 as described in claim 1 in the preparation of adjunctive hypoglycemic drugs.

4. The use of *Lactobacillus paracasei* Jlu-CH9 as described in claim 1 in the preparation of antibacterial drugs, characterized in that... The antibacterial drug targets one of the following bacteria: Salmonella Typhimurium, Staphylococcus aureus, Escherichia coli, Clostridium perfringens, and Pseudomonas aeruginosa.

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