Effects of soy isoflavone on hepatic steatosis in high fat-induced rats

Soy isoflavone has benefits for metabolic syndrome but the mechanism is not completely understood. This study was designed to determine the effects of soy isoflavone on hepatic fat accumulation in non-alcoholic fatty liver disease (NAFLD) rats induced by high fat diet (HFD). Sprague-Dawley rats were administrated with a normal fat diet (control), HFD (NAFLD model), HFD with 10 or 20 mg/kg soy isoflavone daily for 12 weeks. Hepatic and serum lipid contents, liver histopathological examination, serum alanine transaminase (ALT), protein and mRNA expression of sterol regulatory element binding protein (SREBP)-1c, fatty acid synthase (FAS), peroxisome proliferator-activated receptor (PPAR) alpha were assayed respectively. Our study found that soy isoflavone reduced HFD-induced lipid accumulation in liver, serum ALT and improved liver lobule structure. In addition, the expression of SREBP-lc and FAS was lower, whereas protein level of PPAR alpha was higher in two soy isoflavone groups than that of the HFD group. Collectively, these results demonstrate that soy isoflavone is capable of alleviating hepatic steatosis and delaying the progression of NAFLD via inhibiting lipogenesis and promoting fatty acid oxidation in liver.