Abstract:The effects of gamma-aminobutyric acid (γ-aminobutyric acid, GABA) on oxidative stress, liver function, hepatic steatosis and lipid metabolism-related gene expression were studied in the liver of high-fat diet fed mice. 50 C57BL / 6 male mice were randomly divided into five groups: normal group (normal diet), high fat diet group (high fat diet), and three GABA groups (0.2%, 0.12% and 0.06 % GABA in drinking water, respectively). After 18 weeks, reactive oxygen species (ROS) levels, antioxidant enzyme activities, contents of lipid and glycogen in liver and plasma activities of alanine aminotransferase and aspartate aminotransferase were measured. In addition, the morphological features of liver tissue were observed and the expressions of SREBP-1c, FAS, ACC1, PPARα, Cpt1a and the PGC-1α in liver were measured by using of RT-PCR. The results showed that in high-fat diet fed mice, liver weight, liver index, triglyceride and cholesterol contents in liver increased significantly with damaged liver function; 0.2%, 0.12% and 0.06% GABA treatments can significantly reduce liver weight and liver index; 0.2%, 0.12% GABA treatments significantly inhibited hepatic steatosis and improved liver function. Compared with that of in normal group, high fat diet treatment significantly reduced antioxidant enzyme activities and increased ROS and malondialdehyde (MDA) contents; 0.2% and 0.12% GABA treatments significantly alleviated oxidative stress. In liver of high-fat diet fed mice, expressions of PPARα, Cpt1a PGC-1α were significantly reduced, while, expressions of SREBP-1c, FAS and ACC1 were remarkably increased, but both 0.2% and 0.12% GABA supplements can significantly alleviate the gene expression changes that high fat caused. Thus, high-fat diet treatment led to oxidative stress in liver, steatosis and damaged liver function. Meanwhile, a certain dose of GABA can improve redox status and fat metabolisms, thereby preventing the occurrence of fatty liver.
