Comparative analysis of effects of melatonin,vitamin E and glutathione on oxidative stress in alloxan-induced diabetic rats

Objective To investigate the effects of melatonin(MLT),vitamin E(VE) and glutathione(GSH) on oxidative stress in liver,kidney and pancreas tissue of diabetic rats.Methods Alloxan(200?mg·kg~(-1) i.p.)-induced diabetic rats were treated with MLT(2?mg·kg~(-1) i.p.) or VE(100?mg·kg~(-1) i.p.) or GSH(100?mg·kg~(-1) i.p.) for 14 days.Lipid peroxidation(MDA),nitric oxide(NO) levels and superoxide dismutase(SOD),glutathione peroxidase(GSH-Px) activity in liver,kidney and pancreas tissue were measured.Results MDA and NO levels and GSH-Px activity were significantly increased and SOD activity was significantly decreased in liver,kidney and pancreas in alloxan-induced diabetic rats compared with normal rats.In rats treated with MLT,VE or GSH,MDA and NO levels were decreased significantly,and elevated GSH-Px activity reversed significantly,while SOD activity increased significantly,but GSH had no effect on liver SOD activity.The antioxidant effects of MLT were greater than that of VE and GSH in kidney and pancreas whereas VE was more potent than MLT and GSH in liver.Conclusion MLT prevents the development and progression of diabetes,as well as its complications by enhancing antioxidative function and reducing oxidative stress in diabetic rats. Moreover,MLT may be a more powerful antioxidant than VE and GSH.