Effects of total iridoid glycosides of Picrorhiza scrophulariiflora against non-alcoholic steatohepatitis rats induced by high-fat and high-sugar diet through regulation of lipid metabolism

OBJECTIVE: To investigate the therapeutic effect of total iridoid glycosides of Picrorhiza scrophulariiflora (TIGP) on non-alcoholic steatohepatitis (NASH). METHODS: SD rats were fed with high-fat and high-sugar diet for 8 weeks to establish NASH. TIGP were given orally at doses of 20, 40 and 80 mg/kg/d for 4 weeks. Triglycerides assay (TG), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), aspartate aminotransferase (AST), alanine aminotransferase (ALT), fasting plasma glucose (FPG), fasting insulin (FINS), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), chemokine-1 (MCP-1), leptin (LEP) in serum were tested. TG, TC, superoxide dismutase (SOD), malondialdehyde (MDA), and free fatty acid (FFA) in liver tissue were determined by colorimetric methods. Steatosis of hepatocytes and inflammation was performed by pathological examination. RESULTS: The results showed that TIGP significantly decreased TC, TG and FFA in liver tissue, increased SOD activity, decreased MDA content, decreased serum levels of TG, TC, HDL-C/LDL-C, ALT, AST, GLU, HOMA-IR, TNF-α and LEP, and in addition, improved steatosis of liver cells compared to NASH. CONCLUSION: TIGP had anti-fatty liver effect against NASH rats induced by high-fat and high-sugar diet. Its mechanism was related to the regulation of lipid metabolism and reduction of insulin resistance, through inhibition of oxidative stress and inflammation.