Phytobacterium plantarum ZKAW02 strain, fungicide and application thereof

Abstract

The invention relates to the technical field of probiotics and application thereof, in particular to a plant lactobacillus ZKAW02 strain, a fungicide and application of the fungicide. The invention relates to a plant lactobacillus ZKAW02 strain, which is classified and named as plant lactobacillus, the plant lactobacillus ZKAW02 strain is preserved in Guangdong Province Microbial Culture Collection Center on September 27, 2024, and the preservation number is GDMCC No: 65219. The invention further discloses a preparation method of the plant lactobacillus ZKAW02 strain. The plant lactobacillus ZKAW02 strain has the advantages that the plant lactobacillus ZKAW02 strain is named as plant lactobacillus, and the plant lactobacillus ZKAW02 strain is preserved in Guangdong Province Microbial Culture Collection Center on September 27, 2024. The lactobacillus plantarum ZKAW02 has the effects of remarkably reducing the cholesterol level, remarkably regulating the blood fat level of the liver and excrement and remarkably increasing the short-chain fatty acid level in the excrement of a high-fat rat, so that the expression level of lipid metabolism related signal channel genes is regulated, the intestinal flora homeostasis is regulated, the liver tissue damage is repaired, and the anti-tumor effect is achieved. The effects of regulating lipid metabolism and intestinal health are achieved.

Description

Technical Field

[0001] This invention relates to the field of probiotics and their application technology, and in particular to a strain of Lactobacillus plantarum ZKAW02, a bacterial agent, and their application. Background Technology

[0002] Hyperlipidemia is a significant risk factor for cardiovascular diseases such as atherosclerosis and coronary heart disease. Clinically, statins and dietary interventions are commonly used to control and lower blood lipid levels. However, most of these medications have side effects, such as headaches, drug-induced liver damage, gastrointestinal discomfort, sleep disturbances, memory loss, and allergic reactions. While dietary control can regulate blood lipid levels to some extent, its long-term effects are extremely limited. Therefore, finding a healthy and effective way to lower blood lipids is of great importance.

[0003] Studies have shown a close relationship between gut microbiota and host lipid metabolism. The structure of the gut microbiota, particularly changes in the abundance of certain specific bacterial groups, their metabolites, and the enzymes they produce, significantly impacts the host's lipid absorption and metabolism. Existing animal and clinical experiments have confirmed that some probiotics can lower blood lipids in vivo by improving gut microbiota structure and abundance, and regulating their metabolites.

[0004] Probiotics can provide a healthy non-drug treatment strategy or adjunctive therapy, reduce drug dosage and side effects, save medical resources, and are of great significance for improving the overall health level of society and promoting technological innovation and product upgrading in the health industry.

[0005] Due to the diverse origins of *Lactobacillus plantarum*, it exhibits both genetic and functional diversity, resulting in different strains possessing varying probiotic functions. Currently, while some research has begun to focus on the development and utilization of *Lactobacillus plantarum*, studies on its isolation, identification, probiotic characteristics, and metabolic mechanisms remain limited, which to some extent hinders its development and utilization. Therefore, it is necessary to further explore the probiotic functions of *Lactobacillus plantarum* based on its different origins, clarify its application prospects, and further enrich the quantity of probiotic *Lactobacillus plantarum* to enable it to play a greater role in human health. In conclusion, the research and application of probiotic *Lactobacillus plantarum* has broad development prospects. Summary of the Invention In order to solve the above-mentioned technical problems in the prior art, the present invention provides a strain of Lactobacillus plantarum ZKAW02, a bacterial agent and its application.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: The first aspect of the present invention is to provide a strain of *Lactobacillus plantarum* ZKAW02, classified and named *Lactobacillus plantarum*, which was deposited at the Guangdong Provincial Center for Microbial Culture Collection on September 27, 2024, with accession number GDMCC No: 65219; the full 16S rDNA sequence of the *Lactobacillus plantarum* strain is shown in SEQ ID No: 1.

[0007] The *Lactobacillus plantarum* ZKAW02 provided by this invention has been confirmed by animal experiments to have the effects of assisting in lowering blood lipids and promoting intestinal health. It can regulate the expression of genes in lipid metabolism-related signaling pathways, increase the content of short-chain fatty acids in feces, thereby reducing the levels of TC (serum total cholesterol) and TG (triglycerides) in the liver and feces, correcting intestinal flora imbalance, and restoring liver tissue damage and intestinal mucosal barrier function.

[0008] A second aspect of the present invention is to provide the use of the *Lactobacillus plantarum* strain ZKAW02 described in the first aspect in lowering cholesterol levels.

[0009] Preferably, the *Lactobacillus plantarum* strain ZKAW02 increases bile saline hydrolytic enzyme activity and cholesterol removal levels while lowering cholesterol levels. Experiments have shown that, compared to other *Lactobacillus plantarum* strains or other lactic acid bacteria strains, strain ZKAW02 exhibits higher bile saline hydrolysis and cholesterol removal capabilities relative to LGG (immunoglobulin G), with the diameter of the white precipitate ring and the cholesterol removal rate being 2.12 times and 1.64 times that of LGG, respectively.

[0010] A third aspect of the present invention is to provide the use of the *Lactobacillus plantarum* strain ZKAW02 described in the first aspect in regulating hepatic and fecal lipid levels.

[0011] Preferably, the regulation of liver lipid levels and fecal lipid levels involves lowering liver lipid levels and increasing fecal lipid levels, i.e., promoting lipid metabolism in the liver and excreting it through feces. More preferably, lowering liver lipid levels involves simultaneously reducing TC (total serum cholesterol) and TG (triglycerides) levels in the liver. Animal experiments have confirmed that *Lactobacillus plantarum* strain ZKAW02 can effectively regulate lipid metabolism balance in rats, restore lipid levels in hyperlipidemic rats, and achieve an auxiliary lipid-lowering effect.

[0012] A fourth aspect of the invention is to provide the use of the *Lactobacillus plantarum* strain described in the first aspect in upregulating intestinal short-chain fatty acid levels.

[0013] Preferably, the upregulation of intestinal short-chain fatty acid levels involves upregulating one or more of acetic acid, propionic acid, and butyric acid. Studies have confirmed that short-chain fatty acids (SCFAs) promote β-oxidation of fatty acids in the liver by activating transcription factors such as PPARα, inhibiting the synthesis and expression of key enzymes in fatty acid synthesis in the liver, and reducing the synthesis of triglycerides and cholesterol in the liver, thus lowering blood lipid levels. Furthermore, SCFAs can alter the intestinal environment and regulate the intestinal flora; in particular, butyric acid can promote the growth of beneficial bacteria in the intestine and affect cholesterol absorption, thereby lowering cholesterol levels. Besides affecting blood lipids, SCFAs also have the effects of protecting the intestinal barrier, reducing inflammation, inhibiting the growth of pathogenic bacteria, and enhancing immunity. Therefore, increasing the content of short-chain fatty acids not only helps lower blood lipids but also has health benefits.

[0014] The fifth aspect of the present invention is to provide the application of the Lactobacillus plantarum strain ZKAW02 described in the first aspect in regulating the expression levels of genes in lipid metabolism-related signaling pathways.

[0015] Preferably, the expression levels of genes regulating lipid metabolism-related signaling pathways are regulated at one or more of the following levels: SHP, CYP7A1, ABCG8, LXR, FXR, ABCG5, and NPC1L1. Studies have shown that FXR regulates bile acid and glucose-lipid metabolism; SHP participates in the cholesterol metabolism FXR / SHP / CYP7A1 pathway, negatively regulating bile acid metabolism; CYP7A1 is a key rate-limiting enzyme in the metabolism of cholesterol into bile acids; LXR participates in the absorption, transport, metabolism, and formation of cholesterol in the body; ABCG5 and ABCG8 mediate the secretion of sterols from liver cells into bile; and NPC1L1 is a cholesterol transporter protein, a key protein for cholesterol absorption in the small intestine.

[0016] The sixth aspect of the present invention is to provide the application of the Lactobacillus plantarum strain ZKAW02 described in the first aspect in improving the intestinal flora structure.

[0017] Preferably, the improvement of gut microbiota structure involves downregulating the relative abundance of Firmicutes and / or upregulating the relative abundance of Bacteroidetes. Studies have confirmed that the ratio of Firmicutes to Bacteroidetes is elevated in individuals with hyperlipidemia. Therefore, downregulating the relative abundance of Firmicutes and / or upregulating the relative abundance of Bacteroidetes has a positive effect on the recovery of hyperlipidemia levels. Alternatively, the improvement of gut microbiota structure involves upregulating one or more of Bifidobacterium, Trichophyton, and Ruminococcus. Numerous studies have confirmed that Bifidobacterium is the most important beneficial bacteria in the gut, while Trichophyton and Ruminococcus affect lipid metabolism by producing SCFAs, especially butyrate, thereby restoring beneficial gut microbiota and protecting intestinal epithelial cells and mucosal barrier function, thus having a health-promoting effect on gut health.

[0018] The seventh aspect of the present invention is to provide the use of the Lactobacillus plantarum strain ZKAW02 described in the first aspect in the recovery of liver tissue damage.

[0019] Preferably, the restoration of liver tissue damage involves improving the structural integrity of liver cells and / or reducing the number and size of liver fat vesicles.

[0020] The eighth aspect of the present invention is to provide the application of the Lactobacillus plantarum strain ZKAW02 described in the first aspect in upregulating intestinal mucosal barrier function.

[0021] Preferably, the upregulation of intestinal mucosal barrier function is to restore the integrity of colonic villi and / or restore the regularity of crypt structure arrangement.

[0022] The ninth aspect of the present invention is to provide the use of the Lactobacillus plantarum strain ZKAW02 described in the first aspect in its function of assisting in lowering blood lipids or improving intestinal health.

[0023] The tenth aspect of the present invention is to provide a *Lactobacillus plantarum* ZKAW02 bacterial agent, said bacterial agent being a bacterial solution containing the *Lactobacillus plantarum* ZKAW02 strain described in the first aspect; or, The bacterial agent is a solid bacterial agent, which is prepared using the Lactobacillus plantarum ZKAW02 strain described in the first aspect, with the addition of a physiologically acceptable solid carrier and / or adjuvants.

[0024] Preferably, the solid carrier or additive can be selected from commonly used carriers and additives such as microcrystalline cellulose, sodium carboxymethyl cellulose, ethyl cellulose, cellulose acetate titanate, hydroxypropyl cellulose, and sugars.

[0025] The eleventh aspect of the present invention is to provide a food, dietary supplement, health product, medical formula food, and pharmaceutical containing the *Lactobacillus plantarum* ZKAW02 strain described in the first aspect.

[0026] The twelfth aspect of the present invention is to provide a food, dietary supplement, health product, medical formula food and pharmaceutical containing the *Lactobacillus plantarum* ZKAW02 bacterial agent described in the tenth aspect.

[0027] Compared with the prior art, the present invention has the following technical effects: The strain of *Lactobacillus plantarum* used in this invention is named ZKAW02. In vitro cell experiments and rat animal experiments have shown that *Lactobacillus plantarum* ZKAW02 can significantly reduce cholesterol levels, significantly regulate liver and fecal blood lipid levels, and significantly upregulate the level of short-chain fatty acids in the feces of hyperlipidemic rats. This can regulate the expression level of lipid metabolism-related signaling pathway genes, regulate intestinal flora homeostasis, repair liver tissue damage, and has the effect of regulating lipid metabolism and intestinal health. The *Lactobacillus plantarum* ZKAW02 provided by this invention has excellent bile salt hydrolase and cholesterol removal activity, and can significantly downregulate the content of TC and TG in rat liver and upregulate the content of TG in feces. The *Lactobacillus plantarum* ZKAW02 provided by this invention can significantly upregulate the mRNA expression of gene SHP and significantly downregulate the mRNA expression of genes CYP7A1, ABCG8 and FXR, thereby achieving the effect of lowering blood lipids. The *Lactobacillus plantarum* ZKAW02 provided by this invention can effectively correct the intestinal flora imbalance in high-fat rats, significantly downregulate the abundance of Firmicutes, significantly upregulate the abundance of Bacteroidetes, Bifidobacterium, Trichophyton, and Ruminococcus, and significantly increase the content of propionic acid and butyric acid in feces, thus having the health benefits of lowering blood lipids and promoting intestinal health. The *Lactobacillus plantarum* ZKAW02 provided by this invention can effectively restore liver tissue damage and intestinal mucosal barrier function in hyperlipidemic rats, prevent tissue and organ lesions, and increase intestinal defense and protection. The *Lactobacillus plantarum* ZKAW02 provided by this invention is naturally derived and has significant effects in regulating lipid metabolism and intestinal health. It also has certain safety advantages compared to traditional drugs currently used to assist in lowering blood lipids. Attached Figure Description

[0028] Figure 1 Comparison of bile salt hydrolase activity of Lactobacillus plantarum: (a) Lactobacillus plantarum ZKAW04, (b) Lactobacillus casei, (c) Lactobacillus rhamnosus, (d) Bifidobacterium animalis subsp. lactis ZKAW01, (e) Lactobacillus rhamnosus LGG, (f) Lactobacillus plantarum ZKAW02; Figure 2 Comparison of TC levels in rat livers in the Lactobacillus plantarum ZKAW02 intervention group, model group, blank control group, and positive drug group: Control group is blank control group, Model group is model group, ZKAW02 group is ZKAW02 intervention group, and Simvastain group is positive drug group; Figure 3 Comparison of TG levels in the livers of rats in the Lactobacillus plantarum ZKAW02 intervention group, model group, blank control group, and positive drug group: Control group is blank control group, Model group is model group, ZKAW02 group is ZKAW02 intervention group, and Simvastain group is positive drug group; Figure 4Comparison of TG levels in rat feces in the Lactobacillus plantarum ZKAW02 intervention group, model group, blank control group, and positive drug group: Control group is blank control group, Model group is model group, ZKAW02 group is ZKAW02 intervention group, and Simvastain group is positive drug group; Figure 5 Comparison of short-chain fatty acid (propionic acid) levels in rat feces of the Lactobacillus plantarum ZKAW02 intervention group, model group, blank control group, and positive drug group: Control group is blank control group, Model group is model group, ZKAW02 group is ZKAW02 intervention group, and Simvastain group is positive drug group; Figure 6 Comparison of short-chain fatty acid (butyric acid) levels in rat feces of the Lactobacillus plantarum ZKAW02 intervention group, model group, blank control group, and positive drug group: Control group is blank control group, Model group is model group, ZKAW02 group is ZKAW02 intervention group, and Simvastain group is positive drug group; Figure 7 A comparison of the expression levels of lipid metabolism-related signaling pathway genes (SHP) in the livers of rats in the Lactobacillus plantarum ZKAW02 intervention group, model group, blank control group, and positive drug group; Figure 8 A comparison of the expression levels of the lipid metabolism-related signaling pathway gene (CYP7a1) in the liver of rats in the Lactobacillus plantarum ZKAW02 intervention group, model group, blank control group, and positive drug group; Figure 9 A comparison of the expression levels of lipid metabolism-related signaling pathway genes (FXR) in the livers of rats in the Lactobacillus plantarum ZKAW02 intervention group, model group, blank control group, and positive drug group; Figure 10 A comparison of the expression levels of the lipid metabolism-related signaling pathway gene (ABCG8) in the colon of rats in the Lactobacillus plantarum ZKAW02 intervention group, model group, blank control group, and positive drug group; Figure 11 A comparison of the relative abundance of Firmicutes in the intestines of rats in the Lactobacillus plantarum ZKAW02 intervention group, model group, blank control group, and positive drug group: Control group is blank control group, Model group is model group, ZKAW02 group is ZKAW02 intervention group, and Simvastain group is positive drug group; Figure 12A comparison of the relative abundance of Bacteroidetes in the intestines of rats in the Lactobacillus plantarum ZKAW02 intervention group, model group, blank control group, and positive drug group: Control group is blank control group, Model group is model group, ZKAW02 group is ZKAW02 intervention group, and Simvastain group is positive drug group; Figure 13 A comparison of the relative abundance of Bifidobacterium spp. in the intestines of rats in the Lactobacillus plantarum ZKAW02 intervention group, model group, blank control group, and positive drug group: Control group is blank control group, Model group is model group, ZKAW02 group is ZKAW02 intervention group, and Simvastain group is positive drug group; Figure 14 A comparison of the relative abundance of *Trichophyton* spp. in the rat gut of the *Lactobacillus plantarum* ZKAW02 intervention group, model group, blank control group, and positive drug group: Control group is blank control group, Model group is model group, ZKAW02 group is ZKAW02 intervention group, and Simvastain group is positive drug group. Figure 15 A comparison of the relative abundance of Ruminococcus spp. in the rat intestine of the Lactobacillus plantarum ZKAW02 intervention group, model group, blank control group and positive drug group: Control is blank control group, Model is model group, ZKAW02 is ZKAW02 intervention group and Simvastain is positive drug group; Figure 16 Comparative images of rat liver tissue morphology in the Lactobacillus plantarum ZKAW02 intervention group, model group, blank control group and positive drug group; Figure 17 Comparative images of rat colon tissue morphology in the Lactobacillus plantarum ZKAW02 intervention group, model group, blank control group, and positive drug group. Detailed Implementation

[0029] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0030] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.

[0031] Example 1: Information on *Lactobacillus plantarum* used in this invention The *Lactobacillus paraplantarum* used in this invention, which has the effects of regulating lipid metabolism and intestinal health, was screened by the inventor from milk residue collected in Tibet and named ZKAW02. It was deposited at the Guangdong Provincial Center for Microbial Culture Collection on September 27, 2024, with the accession number GDMCC No. 65219 and the microbial classification name *Lactobacillus paraplantarum*.

[0032] 1. Morphological characteristics On MRS solid medium, the colonies are milky white, with a raised center, round or nearly round shape, 1-2 mm in diameter, and smooth edges; the bacteria are short rods or clubs, and exist singly.

[0033] 2. Identification of 16S rDNA of the strain The strain ZKAW02 was frozen and sent to Shanghai Sangon Biotech Co., Ltd. for 16S rDNA nucleotide sequence determination. BLAST comparison results showed that strain ZKAW02 had more than 99.5% homology with *Lactobacillus paraplantarum*, therefore it was identified as *Lactobacillus plantarum* and named *Lactobacillus plantarum* ZKAW02.

[0034] Example 2: Function of *Lactobacillus plantarum* used in this invention 1. In vitro bile salt hydrolysis function Add 0.3% sodium deoxytaurocholate (TDCA), 0.2% sodium thioglycolate (THIO), 0.37 g / L CaCl2, and 1.6% agar to MRS liquid medium. After sterilization at 121℃ for 15 min, pour the solution into sterile Petri dishes, allow it to solidify and dry, then place it in an anaerobic bag for 48 h. Add 10 μL of bacterial suspension to each plate, using *Lactobacillus rhamnosus* LGG as a control. After the suspension dries, place the plate back into the anaerobic bag and incubate at 37℃ for 72 h. Observe the presence and size of any white precipitate around the filter paper.

[0035] The results are as follows Figure 1 As shown, Lactobacillus rhamnosus LGG and Lactobacillus plantarum ZKAW02 have significant bile salt hydrolase activity, with Lactobacillus plantarum ZKAW02 exhibiting the strongest activity. The white precipitate ring has a diameter of 32 mm, which is 2.12 times that of Lactobacillus rhamnosus LGG.

[0036] 2. In vitro cholesterol removal activity Prepare MRS medium containing 0.1 g / L cholesterol: Weigh 0.1 g cholesterol, 0.1 g sucrose ester, and 1 g Tween 80. Add 5 mL of glacial acetic acid and boil to dissolve. Add this solution to the boiled MRS medium and bring the final volume to 1000 mL. Adjust the pH to 6.2 ± 0.2 with 4 mol / L NaOH and autoclave at 121℃ for 15 min. Activate the test strains with a 2% (v / v) inoculum and anaerobic culture at 37℃ for 18–24 h. Subculture three times before use. Centrifuge at 8000 rpm, 4℃ for 5 min to harvest the bacterial cells and resuspend them in sterile physiological saline to achieve a concentration of 5 × 10⁻⁶. 8 CFU / mL (OD = approximately 0.5). The bacterial suspension was inoculated into cholesterol micelle-MRS medium at a 2% (v / v) inoculum and incubated at 37°C for 48 h. The culture was then centrifuged at 4000 rpm for 5 min at 4°C to obtain the fermentation supernatant for later use. A blank cholesterol micelle-MRS medium was used as a negative control.

[0037] The cholesterol content in the supernatant was determined according to the second method of GB 5009.128-2016, and the results are shown in Table 1.

[0038] Table 1 Cholesterol Removal Rate

[0039] As shown in Table 1, Lactobacillus rhamnosus LGG and Lactobacillus plantarum ZKAW02 have high activity in removing cholesterol, with Lactobacillus plantarum ZKAW02 showing the strongest activity, which is 1.64 times that of Lactobacillus rhamnosus LGG.

[0040] Example 3: Animal experiments with Lactobacillus plantarum ZKAW02 Twenty-four male SD rats (130-150 g) were used in the experiment. After 7 days of acclimatization, they were randomly divided into two groups according to their body weight. Four rats were given a normal diet as the blank control group, and 20 rats were given a model diet as the model control group. Body weight was measured weekly. After one week of feeding the model diet, blood was collected from the tails of both the blank and model control groups without fasting to measure serum TC, TG, LDL-C, and HDL-C levels. Based on TC levels, the model group was randomly divided into four subgroups. There were no significant differences in TC, TG, LDL-C, and HDL-C between the blank and model control groups after grouping.

[0041] The four groups included a blank control group, a model group, a probiotic (ZKAW02) intervention group, and a positive control group. The control group consisted of normal rats fed a normal diet and administered 1 mL of sterile saline by gavage; the model group consisted of hyperlipidemic rats fed a high-cholesterol diet and administered 1 mL of sterile saline by gavage; the probiotic intervention group consisted of rats fed a high-cholesterol diet and administered 1 mL of the corresponding bacterial suspension (3 × 10⁻⁶) by gavage. 9 (CFU / ml); the positive control group was fed a high-cholesterol diet and administered 1 mL of simvastatin by gavage for 30 days. The entire experimental period lasted 35 days, during which the rats had free access to water and food. After the experiment, the rats were euthanized by cervical dislocation, and their feces were collected. The liver, jejunum, colon, and other tissues were dissected for relevant index testing.

[0042] 1. Liver and feces TC and TG The results are as follows Figures 2-4 As shown, compared with the blank control group, the TC and TG levels in the liver of rats in the model group were significantly higher than those in the blank control group. Compared with the model group, the TC and TG levels in the probiotic intervention group and the positive drug group were significantly lower than those in the model group. This indicates that ZKAW02 has a significant effect on reducing TC and TG in hyperlipidemic rats, and there was no significant difference in the effect between the probiotic intervention group and the positive drug group.

[0043] Compared with the model group, the probiotic intervention group showed a significant increase in fecal TG content, indicating that ZKAW02 can promote the excretion of triglycerides in hyperlipidemic rats and achieve an auxiliary lipid-lowering effect.

[0044] 2. Changes in short-chain fatty acids in feces This invention employs high-performance liquid chromatography (HPLC) to detect short-chain fatty acids (propionic acid and butyric acid) in feces. The results are shown below. Figures 5-6 Compared with the blank control group, the levels of propionic acid and butyric acid in the feces of rats in the model group were significantly reduced. Compared with the model group, the levels of propionic acid and butyric acid in the probiotic intervention group and the positive drug group were significantly increased, and there was no significant difference between the probiotic group and the positive drug group. This indicates that ZKAW02 can significantly increase the level of short-chain fatty acids in the intestine of high-fat rats, and has the effects of enhancing the intestinal mucosal barrier, reducing inflammation, and assisting in lowering blood lipids.

[0045] 3. Expression of genes in lipid metabolism-related signaling pathways The results are as follows Figures 7-10As shown in the figure, compared with the blank control group, a high-fat diet significantly downregulated the mRNA expression of SHP in the rat liver, while the probiotic intervention group significantly upregulated the mRNA expression of SHP compared with the model group. Compared with the blank control group, a high-fat diet significantly upregulated the mRNA expression of ABCG8 in the rat colon, while the probiotic intervention group significantly downregulated the mRNA expression of ABCG8 compared with the model group. Compared with the model group, the probiotic intervention group significantly downregulated the mRNA expression of CYP7a1 and FXR in the rat liver, and there was no significant difference compared with the positive drug group. This indicates that ZKAW02 can restore glucose and lipid metabolism and cholesterol metabolism to normal levels.

[0046] 4. Changes in gut microbiota Total DNA was extracted from the feces of rats in each group, amplified using primers for the 16S rDNA V3+V4 region, sequenced, and the data were collected and analyzed. The results are as follows: Figures 11-15 As shown in the figure, at the phylum level, compared with the blank control group, the relative abundance of Firmicutes and the relative abundance of Bacteroidetes were significantly increased in the intestines of high-fat rats in the model group. Compared with the model group, the relative abundance of Firmicutes was significantly downregulated and the relative abundance of Bacteroidetes was significantly upregulated in the probiotic intervention group. At the genus level, compared with the blank control group, the relative abundance of Bifidobacterium, Trichophyton, and Ruminococcus was significantly decreased in the intestines of high-fat rats in the model group, while the relative abundance of Bifidobacterium, Trichophyton, and Ruminococcus was significantly increased in the probiotic intervention group. This indicates that ZKAW02 achieves the effects of reducing hyperlipidemia and promoting intestinal health by regulating the intestinal flora structure, increasing the abundance of beneficial bacteria, and reducing the abundance of harmful bacteria.

[0047] 5. Liver tissue morphology Rat livers were collected and fixed in 4% neutral formaldehyde solution for 12 hours. After dehydration, clearing, paraffin embedding, and embedding, 3μm sections were prepared. Hematoxylin and eosin (HE) staining was performed, and pathological changes were observed under a microscope. The liver tissue morphology is as follows: Figure 16 As shown in the figure, compared with the blank control group, the livers of rats in the model group showed more vacuolar morphology and hepatocytes were filled with lipids. Compared with the model group, the liver morphology of the probiotic intervention group was improved, and the number and size of lipid vesicles were reduced. Moreover, the improvement effect of the probiotic intervention group was better than that of the positive drug. This indicates that ZKAW02 can alleviate liver tissue lesions in hyperlipidemic rats.

[0048] 6. Colonic tissue morphology Rat colons were collected and fixed in 4% neutral formaldehyde solution for 12 hours. After dehydration, clearing, paraffin embedding, and embedding, 3μm sections were prepared. Hematoxylin and eosin (HE) staining was performed, and pathological changes were observed under a microscope. The colon tissue morphology is as follows: Figure 17As shown in the figure, compared with the blank control group, the model group rats showed some atrophy of colonic villi, changes in crypt structure, and disordered arrangement, indicating that the intestinal barrier defense function of the model group rats was reduced. Compared with the model group, the atrophy of colonic villi in the probiotic intervention group rats was significantly improved, and the crypt structure and arrangement tended to be normal, indicating that ZKAW02 can restore the intestinal mucosal barrier damage induced by a high-fat diet and increase intestinal defense function.

[0049] 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, improvements, etc., 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 plantarum* ZKAW02, classified and named *Lactobacillus plantarum*, characterized by, The *Lactobacillus plantarum* strain ZKAW02 was deposited at the Guangdong Provincial Center for Microbial Culture Collection on September 27, 2024, with accession number GDMCC No: 65219; the full 16S rDNA sequence of the *Lactobacillus plantarum* strain is shown in SEQ ID No:

1.

2. The application of the Lactobacillus plantarum strain ZKAW02 as described in claim 1 in lowering cholesterol levels.

3. The application of the *Lactobacillus plantarum* strain ZKAW02 as described in claim 1 in regulating liver lipid levels and fecal lipid levels.

4. The application of the Lactobacillus plantarum ZKAW02 strain according to claim 1 in upregulating intestinal short-chain fatty acid levels.

5. The application of the Lactobacillus plantarum ZKAW02 strain according to claim 1 in regulating the gene expression levels of lipid metabolism-related signaling pathways.

6. The application of the Lactobacillus plantarum ZKAW02 strain according to claim 1 in improving the intestinal flora structure.

7. The application of the Lactobacillus plantarum strain ZKAW02 according to claim 1 in the recovery of liver tissue damage.

8. The application of the Lactobacillus plantarum ZKAW02 strain according to claim 1 in upregulating intestinal mucosal barrier function.

9. The use of the Lactobacillus plantarum strain ZKAW02 as described in claim 1 in assisting in lowering blood lipids or improving intestinal health.

10. A *Lactobacillus plantarum* ZKAW02 inoculant, characterized in that, The bacterial agent is a bacterial solution containing the *Lactobacillus plantarum* ZKAW02 strain as described in claim 1; or, The bacterial agent is a solid bacterial agent, which is prepared by adding a physiologically acceptable solid carrier and / or adjuvants to the Lactobacillus plantarum ZKAW02 strain as described in claim 1.

11. A food, dietary supplement, health product, food for medical use, and pharmaceutical containing the *Lactobacillus plantarum* ZKAW02 strain as described in claim 1.

12. A food, dietary supplement, health product, medical formula food, and pharmaceutical containing the *Lactobacillus plantarum* ZKAW02 bacterial agent as described in claim 10.

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