Abstract: 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-a 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-a levels in serum and liver homogenates, suggesting its potential as a therapeutic agent for NAFLD.