Abstract
We investigated the ameliorative effect of mussel polysaccharide α-D-glucan (MP-A) on non-alcoholic fatty liver disease (NAFLD) and further investigated its action mechanism based on serum metabolomics. The results showed that MP-A improved the hepatic steatosis in the rat NAFLD model induced by high-fat diet (HFD) significantly. MP-A could improve the metabolic disorders in NAFLD models. Four metabolites, ursodeoxycholic acid (UDCA), indole-3-propionic acid (IPA), indole-3-carbinol (I3C) and glycine ursodeoxycholic acid (GUDCA), mainly produced by intestinal flora and absorbed into the blood were screened out through serum metabolomics techniques and analysis. Compared with the normal group, the levels of these four metabolites were reduced in the HFD group but increased through the MP-A intervention. The four metabolites significantly reduced the intracellular lipid droplet accumulation and triglyceride (TG) content in sodium oleate-induced HepG2 cells. Meanwhile, they upregulated the intracellular farnesoid X receptor (FXR) protein expression and downregulated the sterol regulatory element-binding protein-1C (SREBP-1C) and fatty acid synthase (FAS) proteins expression. These results suggested that MP-A might improve NAFLD by affecting the metabolites of intestinal flora, UDCA, IPA, I3C and GUDCA, which then regulated the FXR-SREBP-1C-FAS signaling pathway and liver lipid metabolism.