Effects of melatonin on oxidation,antioxidation in nonalcoholic steatohepatitis rats fed with high fat diet

AIM:To investigate the effects of melatonin on hepatic morphology,lipid and the system of oxidation and antioxidation in nonalcoholic steatohepatitis rats.METHODS:Fifty male Wistar rats were divided into 5 groups with 10 for each randomly.The melatonin in low dose,moderate dose,high dose group and model group were fed with high fat diet while the control group with common diet for 12 wk.Meltatonin(contain≤1% dehydrated alcohol)was intraperitoneally injected to the rats in various melatonin groups(2.5 mg·kg~(-1)d~(-1),5.0 mg·kg~(-1)·d~(-1),and 10.0 mg·kg~(-1)·d~(-1) respectively)and equal dose of saline(contain 1% dehydrated alcohol)to control and model groups once a day.Histopathological changes in liver were observed.The level of serum aspartate aminotransferase(AST),alanine aminotransferase(ALT),liver tissues homogenates triglyceride(TG),total cholesterol(TC),superoxide dismutase(SOD),malondialdehyde(MDA)and GSH-peroxidase(GSH-PX)were measured by biochemical methods.RESULTS:Comparing with control group,the model group developed mid- die-heavy steatosis with significant increase on level of serum ALT,AST,liver tissue homogenates TC and MDA (P＜0.05),simultaneously with decrease on tissue homogenates SOD and GSH-PX(P＜0.05).Comparing with model group,the Level of serum ALT,AST,liver tissue homogenates TC decreased and pathological changes in liver was improved in melatonin-treated groups;the decrease of MDA(P＜0.01)and the increase of GSH-PX, SOD(P＜0.01,0.02＜P＜0.05)was correlated with the increase of melatonin dose.CONCLUSION:Mela- tonin can significantly improve morphology,antioxidase activity and depress lipid peroxidation of fatty liver,pre- senting the protective and therapeutic effects for nonalcoholic steatohepatitis.