Effects of leucine on nonalcoholic fatty liver disease induced by high fat diet in rats

Objective To investigate the effects and mechanism of leucine on nonalcoholic fatty liver disease(NAFLD) induced by high fat diet in rats.Methods Forty male Sprague-Dawley rats fed with 60% high fat diet were randomly divided into 4 groups:one high-fat diet group and three leucine groups with 1.5%,3%,and 4.5% leucine in the high-fat diet,respectively.At the end of 16 weeks' treatment,the serum alanine aminotransferase(ALT),aspartate transferase(AST),total cholesterol(TC),triglycerides(TG),low density lipoprotein cholesterol(LDL-C),high density lipoprotein cholesterol(HDL-C),liver hepatic total anti-oxidation capacity(T-AOC),total superoxide dismutase(T-SOD),reduced glutathione hormone(GSH-Px),and malondialdehyde(MDA) were measured.The pathological changes in the livers of the rats were also observed.Results Obvious fatty degeneration of the livers was observed in the rats of the high-fat diet group.Serum levels of ALT,AST in leucine groups were signi-ficantly lower than those of the high-fat diet group.The serum TC in 3.0% and 4.5% leucine groups were 2.35±0.30 and 2.60±0.57 mmol/L,which were signifi-cantly lower than those of the high-fat diet group.Compared to those of the high-fat diet group,significantly higher T-SOD(285.99±53.53,272.47±65.02 vs.208.24±63.57 U/mg.prot,P<0.01) and GSH-PX(506.02±140.34,483.44±131.44 vs.209.50±80.38 U/mg.prot,P<0.01) were detected in the liver of the rats of 1.5% and 3.0% leucine groups,but significantly lower MDA(0.47±0.14 vs.1.04±0.43 nmol/mg.prot,P<0.01) was detected in 4.5% leucine group.Conclusion Leucine improves NAFLD induced by high fat diet in rats and the effect is related to improving lipid metabolism and antioxidant capacity.