Dihydromyricetin ameliorated nonalcoholic steatohepatitis in mice by regulating the composition of serous lipids, bile acids and ileal microflora

Background Dihydromyricetin (DMY) is a natural flavonoid with anti-nonalcoholic steatohepatitis (NASH) activity. However, the effects of DMY on the composition of lipids and bile acids (BAs) in serum, and gut microbiota (GM) in ileum of mice with NASH are not clear. Methods After male C57BL/6 mice was fed with methionine and choline deficiency (MCD) diet and simultaneously administered with DMY (300 mg/kg/day) by gavage for 8 weeks, the pathological changes of liver tissue were observed by Oil Red O, hematoxylin eosin and Masson staining, the levels of serum alaninea minotransferase, aspartate aminotransferase and liver triglyceride, malonic dialdehyde were detected by the detection kits, the composition and contents of serum lipids and BAs were detected by Liquid Chromatograph-Mass Spectrometry, the mRNA levels of hepatic BAs homeostasis-related genes were detected by RT-qPCR, and microbiological diversity in ileum was analyzed by 16S rDNA sequencing. Results The results showed that the significant changes including 29 lipids, 4 BAs (23-nor-deoxycholic acid, ursodeoxycholic acid, 7-ketodeoxycholic acid and cholic acid), 2 BA transporters ( Mrp2 and Oatp1b2 ) and 8 GMs between MCD and DMY groups. Among them, DMY treatment significantly down-regulated 21 lipids, 4 BAs mentioned above, the ratio of Firmicutes/Bacteroidota and the abundance of Erysipelotrichaceae , Faecalibacuium, significantly up-regulated 8 lipids and 5 GMs ( Verrucomicrobiota , Bacteroidota, Actinobacteria , Akkermansiaceae and Akkermansia ). Conclusions The results suggested that DMY may alleviate MCD diet-induced NASH through decreasing the serum levels of toxic BAs which regulated by liver Oatp1b2 and Mrp2 , regulating the metabolism of related lipids, and up-regulating intestinal probiotics ( Actinobacteria and Verrucomicrobiota at the phylum level; Akkermansiaceae at the family level; Akkermansia at at the genus level) and inhibiting intestinal harmful bacteria ( Firmicutes at the phylum level; Erysipelotrichaceae at the family level; Faecalibaculum at the genus level).