Salidroside improves high-fat diet-induced non-alcoholic steatohepatitis by regulating the gut microbiota–bile acid–farnesoid X receptor axis

BACKGROUND: Our previous studies found that salidroside can effectively treat non-alcoholic steatohepatitis (NASH). Here, we discuss the mechanism of salidroside in the treatment of NASH with a focus on the gut microbiota-bile acid-farnesoid X receptor axis. METHODS: A NASH mouse model was created by providing mice with a high-fat diet (HFD) for 14 weeks. Mice were randomly divided into the HFD group, HFD + salidroside treatment group, and HFD + obeticholic acid treatment group (n = 8 in each group) and were intragastrically administered corresponding drugs for 4 weeks. Hematoxylin-eosin staining was performed to evaluate the histopathological changes associated with the various treatments. In addition, liver triglyceride (TG) content, serum alanine aminotransferase (ALT) activity, serum inflammatory factors, gut microbiota diversity, and the bile acid profile were evaluated. Western blotting and RT-PCR were performed to detect the expressions of FXR and fibroblast growth factor 15 (FGF15). RESULTS: The HFD group displayed obvious signs of hepatic steatosis. The liver TG, serum ALT, and IL-1a, IL-12, MCP-1, KC, MIP-1a, and MIP-1β were significantly higher in the HFD group than the control group (P < 0.01). Intestinal bacteria and bile acid profiles changed significantly in the HFD group (P < 0.05). Further, the expressions of FXR and FGF15 decreased significantly in the HFD group (P < 0.05). After treatment with salidroside, liver steatosis, TG content, and serum inflammatory factors significantly improved and HFD-induced intestinal bacteria, bile acid disorder, and FXR deficiency were significantly alleviated (P < 0.05). CONCLUSION: Salidroside can improve NASH via the gut microbiota-bile acid-FXR axis.