[Effects of ginsenoside Rb_1 on liver FXR pathway and liver and fecal bile acid profiles in rats induced by high-fat diet based on targeted metabolomics].

A targeted metabolomics study was conducted on the bile acid profiles in the liver and feces of rats induced by a high-fat diet and intervened by ginsenoside Rb_1, along with the detection of FXR pathway gene expression in the liver, to explore and clarify its mechanism of action. The content of biochemical indicators in the serum were detected using an automatic biochemical analyzer. Hematoxylin and eosin(HE) staining and oil red O staining were used to detect pathological changes and lipid deposition in the liver. RT-PCR was used to detect the mRNA expression of FXR, small heterodimer partner(SHP), cholesterol 7 alpha-hydroxylase(CYP7A1), and sterol regulatory element-binding protein-1c(SREBP-1c) in the liver. Targeted bile acid metabolomics technology was employed to analyze changes in bile acid profiles in liver tissue and feces, and a correlation analysis was performed between key genes such as FXR, SHP, CYP7A1, SREBP-1c and differential bile acid metabolites. The results showed that ginsenoside Rb_1 significantly reduced the levels of total cholesterol(TC), triglycerides(TG), low-density lipoprotein cholesterol(LDL-C), and high-density lipoprotein cholesterol(HDL-C) in the serum, alleviated the large fat vacuoles and lipid deposition in the liver, increased the expression of FXR mRNA in the liver, and decreased the expression of SREBP-1c mRNA. The expression of CYP7A1 and SHP mRNA was increased, but the differences were not statistically significant. Targeted bile acid metabolomics showed that ginsenoside Rb_1 could restore the levels of 9 bile acids in the liver and 8 bile acids in the feces. Ginsenoside Rb_1 also increased the percentage of taurocholic acid(TCA) in the liver(56.78%) and the percentage of 12-ketolithocholic acid(12-KLCA) in the feces(26.10%). Pathway enrichment analysis revealed two pathways involved in bile acid metabolism: primary bile acid biosynthesis and taurine and hypotaurine metabolism. Correlation analysis showed that FXR, SHP, CYP7A1, and SREBP-1c were positively correlated with multiple differential bile acids. These results suggest that ginsenoside Rb_1 may intervene in lipid metabolism disorders induced by a high-fat diet by regulating the FXR pathway and modulating bile acid profiles in the liver and feces.