[Effects of glucagon-like peptide-1 on liver oxidative stress, TNF-α and TGF-β1 in rats with non-alcoholic fatty liver disease].

OBJECTIVE: To investigate the effects of glucagon-like peptide-1 (GLP-1) on liver oxidative stress, TNF-α and TGF-β1 in rats with diet-induced non-alcoholic fatty liver disease (NAFLD). METHODS: Thirty male rats were randomly divided into 3 equal groups and fed for 16 weeks with normal diet (ND), high-fat diet (HFD), or high-fat diet with intraperitoneal injection of liraglutide (GLP-1, administered in the later 4 weeks). The rats were then sacrificed to obtain blood samples and liver tissues for analyzing the levels of blood aminotransferase (ALT), triglyceride (TG), and total-cholesterol (TC) using an automatic biochemical analyzer and the levels of superoxide dismutase (SOD), malondial-dehyde (MAD), free fatty acid (FFAs), TNF-α in the liver homogenates and TGF-β1 in serum by radioimmunoassay or ELISA. RESULTS: Compared with ND group, HFD group showed significantly increased body weight, liver index, serum levels of ALT, TG, TC, and TGF-β1, and TG, TC, MAD, FFAs, and TNF-α in the liver homogenates, with also significantly increased degree of hepatic steatosis and inflammation activity (P<0.05) and lowered level of SOD. All these changes were markedly ameliorated in GLP-1 group (P<0.05). CONCLUSION: Liraglutide can reduce high-fat diet-induced hepatic steatosis, improve oxidative stress and lipid peroxidation, and decrease TGF-β1 and TNF-α levels in serum and liver homogenates, suggesting its potential as a therapeutic agent for NAFLD.