A high bile salt hydrolyzing active Lactobacillus plantarum for improving obesity and application thereof

Abstract

The present invention provides a plant lactobacillus with high bile salt hydrolysis activity for improving obesity and its application. The Lactobacillus plantarum Lp20 is deposited with CCTCC No.M 2024381 and deposited on March 4, 2024. Its hydrolysis ability for GDCA is higher than that of the current control WCFS1 of Lactobacillus plantarum, reaching 91.62%. The genome bsh1 in Lactobacillus plantarum Lp20 is seamlessly knocked out, and the wild-type and mutant strains are intervened in the control of obese mice. It is found that only the wild-type Lp20 can significantly reduce weight gain, improve liver fatty degeneration and reduce blood lipid elevation, etc., directly indicating that BSH is the key material basis for Lactobacillus plantarum to reduce fat and reduce weight. Thereby providing an efficient method for studying the influence of strains on host metabolites, in particular, an effective method for verifying that Bsh1 alleviates obesity, eliminating the influence of the parent bacterial cell background, proposing the possibility of using the Lactobacillus plantarum bsh1 gene in regulating the bile salt hydrolysis activity of Lactobacillus plantarum, and clarifying the importance of bile salt hydrolase in weight management and blood lipid reduction.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and particularly relates to a Lactobacillus plantarum with high bile salt hydrolyzing activity for improving obesity and an application thereof. Background Art

[0002] Obesity has become a major global health problem, with its prevalence increasing rapidly. A recent report from the World Obesity Federation predicts that by 2030, one billion people worldwide will be obese, indicating that global obesity figures have doubled since 2010. This upward trend underscores the urgent need for a global action plan on obesity. Traditional obesity treatments, such as medications like orlistat and metformin, or surgical interventions like gastric bypass and gastric banding, are limited by their side effects and long-term suitability. Emerging therapies, including biologic drugs and novel oral medications, such as GLP-1 agonists, show potential benefits in symptom management and reducing food intake. However, their efficacy, long-term safety, and cost-effectiveness remain to be further studied.

[0003] Probiotics offer a safe, effective, low-cost option with minimal side effects as a potential treatment for obesity. They work by modulating the gut microbiome, enhancing intestinal barrier integrity, and reducing inflammation. Studies on Lactobacillus strains, validated in animal models, have demonstrated potential anti-obesity effects through mechanisms such as reduced inflammation and gut microbiome modulation. Strains that produce bile salt hydrolase have shown significant efficacy in alleviating diet-induced hyperlipidemia and overweight obesity by regulating intestinal bile acid levels. Bile salt hydrolase plays a significant role in obesity treatment by affecting cholesterol metabolism and the enterohepatic circulation of bile acids, thereby impacting metabolic function and contributing to obesity alleviation. The activity of this enzyme can alter the proportion of bile acids bound to free bile acids, increasing cholesterol consumption and promoting the conversion of cholesterol to bile acids, which may help lower serum cholesterol levels and restore metabolic health. Summary of the Invention

[0004] In response to the problems existing in the prior art, the present invention aims to provide a Lactobacillus plantarum with high bile salt hydrolysis activity for improving obesity and its use. Lactobacillus plantarum Lp20, obtained by screening using qualitative and quantitative methods, has extremely high GDCA hydrolysis activity. This can improve bile salt hydrolase activity, thereby affecting cholesterol metabolism and the enterohepatic circulation of bile acids, thereby affecting metabolic function and achieving the purpose of improving obesity.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] The first aspect of the present invention provides a strain of Lactobacillus plantarum with high bile salt hydrolysis activity for improving obesity, wherein the Lactobacillus plantarum isLactiplantibacillus plantarum Lp20 was deposited in the China Center for Type Culture Collection with the deposit number CCTCC No. M 2024381 and the deposit date was March 4, 2024.

[0007] More preferably, the hydrolysis capacity of Lactobacillus plantarum Lp20 on glycodeoxycholic acid (GDCA) reaches 91.62%.

[0008] The second aspect of the present invention provides the use of the aforementioned Lactobacillus plantarum in the preparation of a weight loss and / or blood lipid lowering preparation.

[0009] More preferably, the preparation is a medicine or a biological preparation.

[0010] The third aspect of the present invention provides a plant lactobacillus bsh1 Application of a gene in regulating the bile salt hydrolysis activity of Lactobacillus plantarum, wherein the bsh1 The nucleotide sequence of the gene (Lp20_GM1654) is shown in SEQ ID NO. 1:

[0011] 。

[0012] The method of controlling comprises:

[0013] (1) By knockout bsh1 gene, thereby reducing the bile salt hydrolyzing activity of Lactobacillus plantarum; or,

[0014] (2) Through overexpression bsh1 gene, thereby improving the bile salt hydrolyzing activity of Lactobacillus plantarum.

[0015] A fourth aspect of the present invention provides a method for regulating the bile salt hydrolysis activity of Lactobacillus plantarum, the regulating method comprising:

[0016] (1) By knockout bsh1 gene, thereby reducing the bile salt hydrolyzing activity of Lactobacillus plantarum; or,

[0017] (2) Through overexpression bsh1 gene, thereby improving the bile salt hydrolysis activity of Lactobacillus plantarum;

[0018] described bsh1 The nucleotide sequence of the gene is shown in SEQ ID NO.1.

[0019] Further preferably, the pUC19E suicide vector is used for homologous recombination double exchange knockout of the bsh1 Gene, specifically including the following steps:

[0020] Two pairs of specific overlapping primers were designed and PCR was used to Lactiplantibacillus plantarum Lp20 genome amplified bsh1 The two homologous arms upstream and downstream of the gene were cloned and linked seamlessly with the linearized pUC19E vector using the homologous recombination method to construct the suicide plasmid pUCΔbsh1. The suicide plasmid pUCΔbsh1 was then transformed into the recipient Lactobacillus plantarum Lp20 by electroporation. The recombinant clones were screened using the ampicillin resistance gene of the vector, and the clones were continuously passaged in MRS medium to induce the second homologous recombination. The single clones that lost erythromycin resistance and GDCA hydrolysis ability were screened by double copying method. Finally, the results were verified by PCR amplification and DNA sequencing. bsh1 Gene knockout mutant Lactobacillus plantarum Lp20- Δbsh1 .

[0021] Further preferably, the two pairs of specific overlapping primers are:

[0022] The upstream primer sequence of Lp20_GM1654L is shown in SEQ ID NO.2:

[0023] 5' aaaacgacggccagtgaattcGATCATGTTGTTAAAACTCACTTACGATAA 3';

[0024] The downstream primer sequence of Lp20_GM1654L is shown in SEQ ID NO.3:

[0025] 5' ggaggattactatttAAGCCACTACTGTAATAGTTAAAATTGTTT 3';

[0026] The upstream primer sequence of Lp20_GM1654R is shown in SEQ ID NO.4:

[0027] 5' ggcttAAATAGTAATCCTCCTCGAAAATAATATTT 3';

[0028] The sequence of the downstream primer of Lp20_GM1654R is shown in SEQ ID NO.5:

[0029] 5' cttctgcaggtcgactctagaCGGCCGACCGTAATATTGG 3'.

[0030] The beneficial effects of the present invention compared to the prior art are:

[0031] 1. The present invention uses GDCA hydrolysis ability as a strain characteristic indicator to screen and obtain a strain of Lactobacillus plantarum Lp20 with the highest activity. Comparison shows that the GDCA hydrolysis ability of Lp20 is higher than that of the current standard strain of Lactobacillus plantarum Lactobacillus plantarum WCFS1. The Lactobacillus plantarum Lp20 is used to prepare a weight loss and / or lipid-lowering preparation, which can effectively play a role in weight loss and lipid reduction.

[0032] 2. The present invention utilizes the principle of double exchange by homologous recombination in prokaryotes to construct a BSH scarless knockout mutant of Lactobacillus plantarum Lp20. Furthermore, the obese mouse model confirms that BSH plays a key role in the fat-reducing function of probiotics, and establishes the relationship between probiotic bile salt hydrolase and improved host metabolic function. This provides data support for the reference of high-throughput screening targets for fat-reducing probiotics, and also proposes a new basis for effective probiotic intervention in alleviating obesity symptoms.

[0033] Culture deposit information:

[0034] Lactobacillus plantarum Lp20 was isolated from dried plums, a fermented food product, in Shuanglang, Dali, Yunnan Province, in July 2019. After purification and identification, it was deposited in the China Center for Type Culture Collection (CCTCC) at Wuhan University, Wuhan, China. The deposit date was March 4, 2024. The deposit number is CCTCC NO: M 2024381. The taxonomic name is Lactobacillus plantarum. Lactiplantibacillus plantarum Lp20.

[0035] The control strains used in the present invention are:

[0036] Plantarum Lactobacillus WCFS1 was originally deposited by de Vos WM et al. in 2003 and the genome was uploaded to the NCBI database with genome Taxonomy ID: 220668. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention will be further described below with reference to the accompanying drawings and examples:

[0038] Figure 1 The results of screening for Lactobacillus plantarum strains with high GDCA hydrolysis ability described in Example 1 are shown; wherein, A: Lactobacillus plantarum WCFS1 streaked on a GDCA plate; B: Lactobacillus plantarum Lp20 streaked on a GDCA plate; C: GDCA hydrolysis rates of 28 Lactobacillus plantarum strains with positive precipitation zones.

[0039] Figure 2 The results of the construction of wild-type Lactobacillus plantarum Lp20 and BSH-inactivated mutants are shown; A: double-exchange mutants were screened by bile salt and antibiotic plates after continuous passage of single-exchange clones; B: the precipitation zone of wild-type Lactobacillus plantarum Lp20-derived mutants disappeared; C: wild-type bsh1 The construct was transformed into the expression vector pNZ11 and the hydrolytic activity of the mutant was restored.

[0040] Figure 3 The results of intervention with the wild-type strain of Lactobacillus plantarum Lp20 on reducing the body weight of obese mice are shown; wherein, A: animal experiment design; B: changes in body weight during the modeling and intervention periods of mice, and the weight gain of each group before and after the strain intervention.

[0041] Figure 4 The results show that Bsh1 activity of Lactobacillus plantarum Lp20 reduces body fat content and adipose tissue content; A: body composition analysis of mice in each group at the end of the intervention period (lean meat mass ratio to fat mass ratio); B: epididymal adipose tissue content (mass / body weight); C: inguinal adipose tissue content (mass / body weight); D: mesenteric fat content (mass / body weight).

[0042] Figure 5The results of the intervention with the wild-type strain of Lactobacillus plantarum Lp20 on reducing serum cholesterol and transaminase levels are shown; wherein, A: serum total cholesterol content; B: high-density lipoprotein cholesterol; C: low-density lipoprotein cholesterol; D: aspartate aminotransferase; E: alanine aminotransferase.

[0043] Figure 6 The histological sections and HE staining analysis of the livers of mice in each group are shown (scale bar: 100 μm); A: low-fat control group; B: high-fat control group; C: Lactobacillus plantarum Lp20 wild-type strain intervention group; D: Lactobacillus plantarum Lp20- Δ bsh1 Mutant strain intervention group. DETAILED DESCRIPTION

[0044] The examples are provided to better illustrate the present invention, but are not intended to limit the present invention to the examples. Therefore, non-essential improvements and adjustments to the embodiments made by those skilled in the art based on the above-mentioned invention still fall within the scope of protection of the present invention.

[0045] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0046] The present invention will be described in detail below through examples. It should be understood that the following examples are only used to further explain and illustrate the content of the present invention in detail, and are not intended to limit the present invention.

[0047] Example 1: Screening of Lactobacillus plantarum Lp20

[0048] In this example, 28 strains of Lactobacillus plantarum isolated and identified from traditional Chinese fermented foods in our laboratory were screened by bile salt activity identification. The specific method is as follows:

[0049] 1. Strains and culture conditions

[0050] The strain used in this example was passaged three times and then inoculated into MRS liquid culture medium at a 1% (v / v) inoculum. The culture was cultured to the middle of the stationary phase and used for physiological experiments.

[0051] 2. Qualitative screening of BSH expression strains by bile salt plate precipitation method

[0052] For qualitative determination of in vitro bile salt hydrolase (BSH) activity, a single bile salt substrate is added to MRS solid plates supplemented with 0.05% (w / v) cysteine ​​hydrochloride. The substrate is 0.1% (w / v) GDCA. Activated bacterial cells are streaked onto the plate surface and anaerobically cultured for at least 48 hours to observe whether the colonies form a visible halo-like precipitate within the plate.

[0053] 3. Quantitative evaluation of the ability of strains to hydrolyze bile salts by ninhydrin colorimetry

[0054] Viable bacterial cells in the stationary phase were collected by centrifugation, washed with sodium phosphate buffer, and resuspended to an OD600 of 5. 50 μL of the bacterial suspension was mixed with an equal volume of 20 mM bile salt substrate and incubated at 37°C for 60 min. The reaction was then terminated with 100 μL of trichloroacetic acid. 100 μL of the supernatant was collected by centrifugation and mixed with 900 μL of ninhydrin. After a boiling water bath, the cells were immediately removed and placed on ice to protect the color. The OD570 value was measured, and the concentration of amino acids generated by the decomposition of 5 mM bound bile salt substrate was calculated based on the standard curve. The amount of bile salt substrate hydrolysis was then calculated using the following formula:

[0055]

[0056] 5—The initial concentration of bile salt substrate in the reaction system is 5 mM;

[0057] C ——The concentration of amino acids after substrate hydrolysis.

[0058] In this example, ninhydrin used to determine the bile salt hydrolysis rate was purchased from Shanghai Yuanye Biotechnology, and bile salt GDCA was purchased from Sigma Aldrich.

[0059] like Figure 1 The results show that Lactobacillus plantarum Lp20 can generate obvious hydrolysis apertures in glycodeoxycholic acid (GDCA) plates, indicating that it may have extremely high GDCA hydrolysis ability. Further qualitative determination of the hydrolysis activity showed that the bile salt hydrolysis rate of Lp20 was significantly higher than that of the control strain Lactobacillus plantarum WCFS1, that is, the GDCA hydrolysis rate reached 91.62%.

[0060] Example 2: Study on the gene for bile salt hydrolase activity of Lactobacillus plantarum Lp20

[0061] In this example, the genome of Lactobacillus plantarum Lp20 obtained by screening in Example 1 was sequenced, assembled and annotated, and then identified and verified. bsh1 It is a key gene that provides bile salt hydrolase activity of Lactobacillus plantarum Lp20.

[0062] bsh1 Knockout mutant Lactobacillus plantarum Lp. plantarum Lp20- Δbsh1 Build:

[0063] 1. Strains and culture conditions

[0064] Lactobacillus plantarum was activated and cultured using MRS medium at 37°C. After two subcultures and activations during the stationary phase, the strain was used for various experiments. Lactococcus lactis NZ9000 was cultured at 30°C in M17 medium supplemented with 0.5% (w / v) glucose. Luria Bertani (LB) medium was used to resuscitate and culture Escherichia coli DH5α and its derivatives at 37°C with shaking. Antibiotics and working concentrations were as follows: E. coli (ampicillin 50-100 μg / mL); Lactobacillus (ampicillin 500 μg / mL or erythromycin 10 μg / mL); and L. lactis (chloramphenicol 10 μg / mL).

[0065] 2. Construction and transformation of suicide vectors

[0066] (1) Design specific primers from Lp. plantarum Amplification of the Lp20 genome bsh1 The two homology arms Lp20_GM1654L and Lp20_GM1654R required for gene knockout on both sides, the primer sequences are:

[0067] The upstream primer sequence of Lp20_GM1654L is shown in SEQ ID NO.2:

[0068] 5' aaaacgacggccagtgaattcGATCATGTTGTTAAAACTCACTTACGATAA 3';

[0069] The downstream primer sequence of Lp20_GM1654L is shown in SEQ ID NO.3:

[0070] 5' ggaggattactatttAAGCCACTACTGTAATAGTTAAAATTGTTT 3';

[0071] The upstream primer sequence of Lp20_GM1654R is shown in SEQ ID NO.4:

[0072] 5' ggcttAAATAGTAATCCTCCTCGAAAATAATATTT 3';

[0073] The sequence of the downstream primer of Lp20_GM1654R is shown in SEQ ID NO.5:

[0074] 5' cttctgcaggtcgactctagaCGGCCGACCGTAATATTGG 3'.

[0075] The homology arms at both ends were amplified separately, and the PCR procedure was as follows:

[0076] Pre-denaturation at 98°C for 5 min, denaturation at 98°C for 30 s, annealing at 60°C for 30 s, extension at 72°C for 30 s, and final extension at 72°C for 10 min were performed for a total of 30 cycles.

[0077] Since the homologous segments of the vector and homology arms were introduced into the primer sequence, after the homology arm PCR products were recovered, the homology arms were connected and circularized with the homology segments of the linear vector pUC19E using a seamless cloning kit.

[0078] (2) Mass replication of recombinant plasmids

[0079] Take Escherichia coli DH5α competent cells, thaw on ice, aspirate 40 μl competent cells and mix with 5 μl ligation product, ice bath for 30 min, heat shock at 42 °C for 90 s, immediately ice bath for 2 min, add 1 ml fresh LB medium, and recover and culture at 37 °C for 1.5 h. Then, take an appropriate amount of bacterial liquid and spread it on LB plate containing ampicillin (100 μg / ml). After culturing for 24 h, pick single colonies, identify recombinants, and extract recombinant plasmid pUC19E-bsh1.

[0080] (3) Preparation of competent cells of Lactobacillus plantarum and plasmid transformation

[0081] Lactobacillus plantarum was cultured in MRSS (MRS supplemented with 0.3 M sucrose and 1% glycine) medium and grown to OD 600 =0.4-0.6, take 10 mL of bacterial solution and centrifuge at 6000 rpm, 4 ℃ for 10 min to collect the bacteria; add 2 ml of Washing buffer (0.3 M sucrose, 1 mM MgCl2) to resuspend, centrifuge under the same conditions and discard the supernatant, repeat twice; add 2 ml of 30% PEG-1500 to resuspend the bacteria, centrifuge at 6000 rpm, 4 ℃ for 10 min, discard the supernatant; finally, resuspend the bacteria in 200 μl of 30% PEG-1500 and aliquot 40 μl for use.

[0082] 150 ng of recombinant pUC19E-bsh1 plasmid was taken and Lp. plantarum The competent Lp20 cells were mixed in a 2 mm electroporation cuvette and kept at an ice bath temperature throughout the process. TMPlasmids were introduced into competent cells using an electroporator at 1.5 kV, 25 μF, and 400 Ω. Immediately after electroporation, 1 ml of MRSSM recovery medium (MRS supplemented with 0.3 M sucrose and 0.1 M MgCl2) was added and cultured at 37°C for 2 h. An appropriate amount of the bacterial culture was spread onto MRS plates containing erythromycin (10 μg / ml) and cultured at 37°C for 48 h to screen for recombinants that had undergone homologous recombination of the plasmid to the genomic homologous arm.

[0083] (4) Single-crossover screening and acquisition of double-crossover mutants

[0084] The Lactobacillus plantarum that had undergone one homologous recombination was serially passaged in MRS liquid medium, with an inoculum size of 1% per generation and cultured at 37°C for 12 h.

[0085] After 20 passages, the clone method ( Figure 2 Middle A) Screening for Lactobacillus plantarum that has undergone two homologous recombination events: Fresh bacterial culture was diluted and plated onto MRS solid plates. Approximately 150 CFU of a single colony should grow on the plate containing GDCA and erythromycin. The colony was then replicated onto an MRS plate containing GDCA and erythromycin and incubated at 37°C for 48 hours. The original plate and the replicated plate were compared. Colonies that had lost erythromycin resistance and the hydrolysis precipitation zone on the GDCA plate were identified as Lactobacillus plantarum that had undergone two homologous recombination events. This single colony was verified by PCR and sequencing.

[0086] For the qualitative and quantitative detection methods of BSH of mutants, refer to Example 1.

[0087] 3. Replenish the strain to confirm that bsh1 provides the strain with bile salt hydrolysis ability

[0088] The vector construction method uses double enzyme digestion of PCR product and expression vector, in which the amplified Lp. plantarum Lp20 bsh1 The primers for the genes are:

[0089] NcoI-bsh1: 5' catgCCATGGGGTGTACTGCCATAACTTATCAATCTTA 3';

[0090] SacI-bsh1: 5'cGAGCCTTAGTTAACTGCATAGTATTGTGCTTCTG3'.

[0091] After double digestion with NcoI and SacI, Lp20 was further ligated using T4 ligase. bsh1 The sequence was constructed into a pNZ8048 derivative vector (replacing the inducible p nis The promoter is a constitutive promoter p 11)pNZ11, the vector named pNZ11bsh1 was electroporated into Lactococcus lactis L. lactis NZ9000 was used to replicate the plasmid in large quantities. The empty vector pNZ11 and the recombinant plasmid pNZ11bsh1 were electroporated into bsh1 knockout mutants to obtain Lp. plantarum Lp20- Δbsh1 Derivatized empty load control Lp. plantarum Lp20- Δbsh1 - Overexpression complementation strains Lp. plantarum Lp20- Δbsh1 ＋ .

[0092] For the qualitative and quantitative detection methods of BSH of the recombinant strain, refer to Example 1.

[0093] Depend on Figure 2 Middle B shows the wild type Lp. plantarum The precipitation circle disappeared after Lp20 mutant was transformed with empty vector. Figure 2 Middle C shows the wild type bsh1 The hydrolysis activity of the mutant was restored after transformation into the expression vector pNZ11. bsh1 Yes Lp. plantarum Lp20 is the gene for the major bile salt hydrolase activity.

[0094] Example 3: Study on the Weight Loss and Lipid-Lowering Efficacy of Lactobacillus plantarum Lp20

[0095] This example establishes an obese mouse model to explore the relationship between Lactobacillus plantarum Lp20 bile salt hydrolase and improved host metabolic function, hoping to provide new evidence for the effective intervention of probiotics for alleviating obesity symptoms. The specific animal experiments are as follows:

[0096] 1. Strains and pretreatment

[0097] The strains used for gavage in this example were obtained by screening in Example 1. Lp. plantarum Lp20 wild type and the one constructed in Example 2 Lp. plantarum Lp20- Δbsh1 The culture conditions were the same as those described in the previous example. The bacterial liquid at the initial stage of stabilization was centrifuged and the culture supernatant was discarded. The cells were washed with PBS and resuspended to 5×10 9 CFU / mL was used for oral administration of experimental animals.

[0098] 2. Experimental Animal Grouping and High-Fat Diet Induction of Obesity

[0099] Eight-week-old C57BL / 6J male mice were placed in an environment of 21±3°C with a 12-hour light / dark cycle, and the mice had free access to food and water. The body weight and the remaining weight of the food were measured when the bedding and food were changed every week, and the average daily energy intake of each group of mice was calculated by the mass difference. After 7 days of adaptation, the experimental mice were randomly divided into 4 groups (n=6) and the diet pattern was changed: including a low-fat diet group LFD+PBS, and the other 3 groups were a high-fat control group HFD+PBS, a wild-type strain intervention group HFD+Lp20-WT, and a mutant strain intervention group HFD+Lp20- Δbsh1 The mice were fed a high-fat diet for 12 weeks to induce obesity. Subsequently, the wild-type and mutant strains were resuspended in 200 μL of bacterial suspension and gavage was performed on the mice (dose: 1×10 9 CFU) were administered orally to low-fat and high-fat control groups with equal volumes of PBS solution for 8 weeks. Before sacrifice, the animals were fasted for 12 hours with or without water. After weighing, the mice were anesthetized, bled, and sacrificed by cervical dislocation. Adipose tissue and organs were then collected for analysis.

[0100] This experiment has passed the experimental animal ethics review of China Agricultural University (approval number: AW81503202-5-2).

[0101] 3. Body composition analysis and adipose tissue analysis

[0102] After fasting for 12 hours, mice were deprived of food and water, and their fat and lean body composition was analyzed using a nuclear magnetic resonance (NMR) body composition analyzer. At sacrifice, inguinal white adipose tissue, mesenteric fat, and epididymal white adipose tissue were isolated and weighed. The ratio of adipose tissue weight to fasting body weight was used to represent the content of each adipose tissue in the mouse.

[0103] 4. Blood component analysis

[0104] Serum total cholesterol, total triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, alanine aminotransferase, and aspartate aminotransferase were detected using an automatic biochemical analyzer.

[0105] 5. Liver Histological Analysis

[0106] Liver tissue samples were obtained at the time of mouse sacrifice. Equal portions of the largest lobe of the liver were fixed in 4% paraformaldehyde. The fixed samples were dehydrated in successive stages and embedded in liquid paraffin until completely solidified. 5 μm sections were then prepared and stained with hematoxylin and eosin (HE). The sections were then examined under a light microscope, using consistent imaging conditions for fields of view with the same magnification.

[0107] The wild-type and mutant strains were used to intervene in high-fat diet-induced obese mice. Figure 3The results showed that the wild type with BSH activity could reduce the weight of mice by 7.34% compared with the mutant group and 12.13% compared with the obese control group. The weight change before and after the intervention was significantly reduced, effectively controlling weight gain. Figure 4 As shown in the results, the body fat content of mice gavaged with the wild-type strain was 13.86% lower than that of the mutant strain group. The analysis found that the mesenteric fat content and inguinal fat content of the mice were significantly reduced, and there was no significant difference in lean meat content between the intervention group and the control group. This indicates that the activity of bile salt hydrolase Bsh1 contributes to Lp. plantarum Lp20 has the function of reducing body weight and body fat content.

[0108] like Figure 5 、 Figure 6 As shown, in obese mice treated with wild-type Lp20, liver steatosis was significantly improved, serum transaminase levels were significantly reduced, and restored to the level of low-fat diet control. Among them, serum alanine aminotransferase and aspartate aminotransferase were significantly lower than those in the high-fat control group and mutant group; HE and PAS staining showed that the number of lipid droplets in liver tissue and cells was significantly reduced, and the liver index was significantly reduced, while the liver lipid content in the mutant group was still close to that of the high-fat control group. The above results suggest that wild-type Lp20 with bile salt hydrolase activity Lp. plantarum Lp20 can reduce liver lipid accumulation caused by a high-fat diet and reverse liver damage and fatty degeneration.

[0109] Finally, it should be noted that the above is only used to illustrate the technical solution of the present invention and is not limiting. Although the present invention is described in detail with reference to the preferred arrangement scheme, ordinary technicians in this field should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A strain of Lactobacillus plantarum with high bile salt hydrolysis activity for improving obesity, characterized in that: The plant lactobacillus is Lactiplantibacillus plantarum Lp20 is deposited in the China Center for Type Culture Collection with the deposit number CCTCC No. M 2024381 and the deposit date is March 4, 2024.

2. Use of the plant lactobacillus as claimed in claim 1 in the preparation of a weight loss and / or blood lipid lowering preparation.

3. The use according to claim 2, characterized in that: The preparation is a medicine or a biological preparation.

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