Relationship Between Gut Microbiota And Nonalcoholic Fatty Liver Induced By High-Fat Diet In Mice

Objective:To explore the relationship between gut microbiota and non-alcoholic fatty liver induced by high-fat diet in mice.Method:1.C57 BL mice were used as experimental subjects and randomly divided into two groups: normal diet group and high-fat diet group.Non-alcoholic fatty liver disease(NAFLD)model was established by high-fat diet intervention for 12 weeks.Fresh liver specimens were used for HE and oil red O staining to observe liver pathological damage and lipid accumulation in mice.2.The serum lipopolysaccharide binding protein(LBP)and insulin levels were detected by ELISA,and the blood glucose and blood lipid levels of the mice were detected by automatic biochemical analyzer.3.High-throughput sequencing method for 16 SrRNA V4-V5 region gene sequencing and bioinformatics analysis of intestinal fecal bacteria: After taking fresh fecal samples from mice,extract the total DNA,and amplify and purify 16 SrDNA by PCR.The library was constructed and sequenced using HiSeq 2500 PE250.The sequencing results were characterized by species and functions.Finally,the results were analyzed by bioinformatics,such as cluster analysis,diversity analysis and community structure analysis.4.To analyze the correlation between intestinal flora and non-alcoholic fatty liver related indicators: to find the species with different levels of portal and genus,and perform Spearman correlation analysis with NAFLD-related serum metabolic indicators.Result:1.Compared with the normal diet group,the normal liver structure of the mice in the high-fat diet group was destroyed,the hepatic lobule structure was disordered,the liver inflammatory cells were infiltrated,and there was significant lipid accumulation.2.Compared with the normal diet group,serum LBP levels in the high-fat diet group were significantly increased,and the difference between the two groups was statistically significant(P<0.01).The serum HOMA-IR index of the high-fat diet group was significantly higher than that of the normal diet group,and the difference was statistically significant(P <0.05).The fasting blood glucose,serum total cholesterol(TC),high-density lipoprotein(HDL-C)and low-density lipoprotein(LDL-C)concentrations in the high-fat diet group were significantly higher than those in the normal diet group(P <0.05).3.Compared with the normal diet group,the diversity of gut microbiota in the high-fat diet group increased.At the level of the portal,the abundance of Proteobacteria and Tenericutes in the intestinal tract of the high-fat diet group increased significantly.(P<0.05);At the genus level,the abundance of Lactobacillus,Streptococcus,Allobaculum and Bifidobacterium in the intestinal tract of the high-fat diet group was significantly lower(P<0.05).The abundance of Odoribacter was significantly increased(P<0.05).4.Petococcus was positively correlated with serum LBP,HDL-C,LDL-C,TC t(P<0.05).Odoribacter was positively correlated with serum HDL-C,LDL-C,TC(P<0.05).Faecalitalea and Desulfovibrio were positively correlated with serum LBP,HDL-C(P<0.05).Bifidobacteria and Allobaculum were negatively correlated with serum LBP,HDL-C,TC and other lipid indexes(P<0.05).Conclusion:The results of this study showed that high fat diet induced NAFLD in mice was associated with changes in intestinal microbial structure,suggesting that high-fat diet may induce the pathogenesis of NAFLD by regulating the gut microbiota of mice.