The significance of oxidative stress in diabetic nephropathy and the intervention study by pioglitazone

Objective To observe levels of oxidative stress in kidneys of diabetic rats.and to investigate roles of oxidative stress in diabetic nephropathy and the intervention effects of pioglitazone.Methods The diabetic model was induced by streptozotocin.24 rats were randomly divided into three groups,8 rats in each group,normal control group(NC group),diabetic group(DM group),diabetic group treated with pioglitazone(3 mg·kg-1·d-1,DT group).12 weeks later,serum glucose,total cholesterol(TC),triglyceride(TG),blood insulin,blood C-peptide,blood urea nitrogen(BUN),serum creatinine(Scr),ratio of kidney weight to body weight(KW/BW),and 24-hour urinary protein were measured.The activities of antioxidant enzymes in renal cortex,including Cu-Zn superoxide dismutase(Cu-ZnSOD),catalase(CAT)and malondialdehyde(MDA)were measured by chromatometry.Results Compared with NC group,there were significant differences in the levels of serum glucose,TC,TG,BUN,Scr,KW/BW and 24-hour urinary protein both in DM group and DT group.The activities of Cu-Zn SOD and CAT were much lower in DM group than those in NC group(P0.01),while the level of MDA was much higher(P0.01).There were no marked differences in the levels of serum glucose,TC,TG,BUN and Scr between DT group and DM group(P0.05).Compared with DM group,KW/BW and 24-hour urinary protein in DT group decreased obviously(P0.05),the activities of Cu-Zn SOD and CAT increased significantly,but the level of MDA decreased in DT group(P0.05).Conclusion The increase of oxidative stress in kidneys of diabetic rats played an important role in pathogenesis of diabetic nephropathy and pioglitazone treatment may have protected kidneys from oxidative injury by antioxidation.