Schizandrin A supplementation improves nonalcoholic fatty liver disease in mice fed a high-fat and high-cholesterol diet

Abstract

We hypothesized that schizandrin (SCH) A, a lignan found in the fruits of the Schisandra genus, would exert protective effects against high-fat and high-cholesterol (HFHC) diet-induced nonalcoholic fatty liver disease (NAFLD) via regulation of lipid metabolism and oxidative stress. To test our hypothesis, male C57BL/6J mice were fed an HFHC diet with or without SCH A for 15 weeks. There were no significant differences in food intake, body weight, fat mass, and plasma total cholesterol level between the 2 groups. However, supplementation of SCH A significantly decreased levels of plasma free fatty acid and triglyceride, whereas plasma high-density lipoprotein cholesterol level was increased in the SCH A-supplemented mice. Moreover, hepatic free fatty acid, triglyceride, and cholesterol content, as well as hepatic lipid droplet accumulation, were markedly lower in the SCH A group in contrast to the control group. Activity of hepatic enzymes involved in fatty acid and triglyceride synthesis was significantly decreased by SCH A supplementation, whereas SCH A markedly increased hepatic β-oxidation and fatty acid oxidation-related gene expression as well as fecal excretion of free fatty acid and triglyceride. SCH A also significantly increased expression of genes involved in cholesterol homeostasis (biliary cholesterol excretion and cholesterol efflux to high-density lipoprotein) in the liver. Moreover, SCH A significantly decreased hepatic lipid peroxidation, which was accompanied by increased hepatic antioxidant enzymes activity. These results suggest that SCH A could alleviate HFHC diet-induced NAFLD by regulating hepatic lipid metabolism and oxidative stress as well as fecal lipid excretion.

Keywords: Antioxidant activity; High-fat and high-cholesterol diet; Lipid metabolism; Nonalcohol fatty liver disease; Schizandrin A.