Protective Effect Of Limosilactobacillus Mucosae On Nonalcoholic Fatty Liver Disease And Its Safety Evaluation

Limosilactobacillus mucosae has a good ability to bind to intestinal epithelial cells,which is conducive to its colonization in the intestine and provides advantages for its probiotic function.Although L.mucosae has been allowed to be used in the food industry in the European Union,it has not yet been included in China’s list of strains that can be used in food.Previous research has shown that L.mucosae has good ability to regulate lipid metabolism,but the pathways through which different L.mucosae regulate lipid metabolism are still lacking in elucidation.Previous research suggested that the prevalence of NAFLD was greater than 25%globally.Obesity,dyslipidemia,hypertension,and diabetes are frequently associated with NAFLD.This article uses Nonalcoholic fatty liver disease(NAFLD)as a model and selects 12strains of L.mucosae from different sources based on the phylogenetic tree.Firstly,the protective effect of different sources of L.mucosae on NAFLD is evaluated,subsequently,the functional route of L.mucosae in alleviating NAFLD were explored,finally,safety evaluation was conducted on the L.mucosae with good protective effect.The main results are as follows:Firstly,starting from the phylogenetic tree of L.mucosae,12 strains of L.mucosae were selected for animal experiments.After 12 weeks of intervention in a high-fat diet induced mouse NAFLD model,3 strains of L.mucosae DCC1HL5,FZJTZ26M3,and GD16M9 with good protective effects on NAFLD were selected based on indicators such as body weight,liver and fat weight,pathological sections,glucose and insulin tolerance,and blood lipid levels.1 strain without protective effect was used as a control to explore the pathway of action of 3 strains of L.mucosae in alleviating NAFLD.The results showed that 3 strains of L.mucosae could regulate the gut microbiota of mice,increase the relative abundance of beneficial gut bacteria such as Lachnospiraceae NK4A136 group,Akkermansia and Roseburia,and reduce the relative abundance of NAFLD related genera such as Lachnospiraceae,Blautia,and Christensenellaceae,reducing serum endotoxin levels and slowing down inflammation in NAFLD mice by repairing the intestinal barrier.In addition,L.mucosae GD16M9 can regulate liver lipolysis and fatty acidsβ-Oxidation,L.mucosae DCC1HL5 and FZJTZ26M3 can restore leptin resistance in NAFLD mice,L.mucosae FZJTZ26M3 can also regulate lipid storage in white adipose tissue and differentiation of mouse adipocytes.Secondly,safety evaluations were conducted on 3 strains of L.mucosae DCC1HL5,FZJTZ26M3,and GD16M9,which have good protective effects on NAFLD,including phenotypes and genotypes,subacute oral toxicity tests,and their effects on immunosuppressed mice.The results showed that there were no virulence genes or gene islands with clear pathogenicity in L.mucosae DCC1HL5,FZJTZ26M3,and GD16M9,3 strains of bacteria are resistant to chloramphenicol,and DCC1HL5 also has resistance to kanamycin and tetracycline,but the possibility of horizontal transfer of their resistance genes is relatively low.In addition,L.mucosae DCC1HL5,FZJTZ26M3 and GD16M9 do not produce biogenic amine,and there isαhemolysis phenomenon.The results of the 28 days subacute oral toxicity test showed that10~9 CFU doses of L.mucosae DCC1HL5,FZJTZ26M3,and GD16M9 did not cause significant abnormalities in various aspects such as body weight,organ index and tissue structure,blood cell count and morphology distribution,fasting blood glucose and blood lipids,liver function indicators,and intestinal inflammation in normal and immunosuppressed mice.Therefore,L.mucosae DCC1HL5,FZJTZ26M3,and GD16M9 have the potential for safe application in functional foods that alleviate NAFLD.This research enriched the resources of probiotics and provided a reference for the future application of L.mucosae in China.