Regulatory Effects Of Lactobacillus Plantarum H6 On Intestinal Flora And Metabolites In Hypercholesterolemia Mice

Cholesterol levels in the human body play an important role in normal cells and function,and excessive cholesterol levels can cause lipid metabolism disorders and increase the risk of complications such as cardiovascular disease,non-alcoholic steatohepatitis,and obesity.This study evaluated the cholesterol-lowering effect of active,inactivated,and supersound lysate Lactobacillus plantarumH6 on hypercholesterolemia mice.The mechanism of the cholesterol-lowering effect ofH6 was elaborated by analyzing the regulatory effects ofH6 on fecal flora and metabolites in hypercholesterolemia mice.A total of 88 male C57BL/6 mice were randomly divided into 10 groups:normal diet group(ND,blank control group),high cholesterol diet group(HCD),normal diet＿high cholesterol diet group(HCD＿ND,control group),Simvastatin group(Sim),activeH6 group(aH6),inactivatedH6 group(iH6),and supersound lysateH6 group(sH6),HCD＿ND fecal microbiota transplantation group(FMT1),Sim fecal microbiota transplantation group(FMT2),and aH6 fecal microbiota transplantation group(FMT3).The intragastric concentration was 1×10~9 cfu/ml for 8 weeks.The insulin tolerance of mice was measured during the experiment.After the experiment,serum and liver were collected to measure physical and chemical indicators.Mouse feces were collected for 16S r RNA amplicon sequencing analysis and non-targeted metabolomics analysis.The results show that aH6 could significantly improve serum TC,TG,LDL-C,ALT,and AST levels,reduce liver weight and TC,TG content,and regulate insulin resistance in hypercholesterolemia mice.iH6 could significantly improve serum TC and ALT levels,reduce liver weight and TC content and regulate insulin resistance in hypercholesterolemia mice.sH6can significantly improve serum TC,LDL-C,and ALT levels,reduce liver weight and TC,TG content,improve glucose tolerance,and all can improve liver degeneration in mice.FMT3 can also improve blood lipid and liver state of hypercholesterolemia mice,significantly improve serum TC,TG,LDL-C,ALT,and AST levels,reduce liver weight and TC,TG content,improve liver steatosis,and regulate glucose tolerance and insulin tolerance of hypercholesterolemia mice.The a/i/sH6 and FMT3 groups were enough to significantly improve the reduction in species richness and community uniformity induced by the high cholesterol diet,and regulate theαandβdiversity of intestinal microorganisms.In addition,the a/i/sH6 and FMT3 groups significantly reduced the F/B ratio.The linear discriminant analysis showed that the dominant genera of bacteria in the aH6 group were Lactobacillus、Coriobacteriaceae＿UCG-002;The dominant bacterial genera in iH6 were norank＿f＿＿Oscillospiraceae,Muribaculu,unclassified＿o＿＿Bacteroidales and Ruminococcus.The dominant genus of bacteria in the sH6group was norank＿f＿＿Muribaculaceae.The dominant bacterial genera in FMT3 were norank＿f＿＿Muribaculaceae,unclassified＿f＿＿Ruminococcaceae、unclassified＿c＿＿Bacilli and Intestinimonas.In both analyses,the abundance of norank＿f＿＿Muribaculaceae increased significantly in the a/i/sH6 groups compared with the HCD＿ND group.The abundance of Enterorhabdus,Muribaculum,unclassified＿c＿＿Bacilli,Coriobacteriaceae＿UCG-002 and norank＿f＿＿Paracaedibacteraceae increased in FMT3 compared with FMT1 in fecal transplantation.Compared with HCD＿ND,a/i/sH6 group increased the contents of Vitamins,Cofactors and amino acids related to the metabolism of intestinal flora,while a/i/sH6 and FMT3groups decreased the relative contents of primary bile acid cholic acid.The KEGG pathway analysis showed that the regulation of hypercholesterolemia in mice of the a/i/sH6 group might be related to such pathways as Vitamin digestion and absorption,m TOR signaling pathway,PI3K-Akt signaling pathway,and Secondary BA biosynthesis,and it might be related to Bile secretion and Secondary BA biosynthesis Pathway in fecal microbiota transplantation.Pearson correlation analysis showed that norank＿f＿＿Muribaculaceae and Lactobacillus had a significantly negative correlation with TC,TG,LDL,ALT,AST,liver TC,liver TG and liver weight.Redundancy analysis(RDA)showed a positive correlation between Vitamins and Cofactors,Amino acids,and a/i/sH6 dominant bacteria,and significant positive correlations between Turicibacter,Romboutsia and Faecalibaculum with most BAs.In a word,a/i/sH6 and FMT3,to varying degrees,can effectively improve hypercholesterolemia induced by a high-cholesterol diet in mice,which is partly due to the regulation of the structure and metabolites of the intestinal flora related to lipid metabolism.