Role of Leptin in Diabetic Nephropathy of Rats

Objective To study the relationship between leptin and diabetic nephropathy(DN).Methods Seventy Wistar rats were randomly divided into two groups:30 in the normal control(NC)group and 40 in the diabetic mellitus(DM)group.The rats in DM group were injected intraperitoneally with low dose streptozotocin(STZ,30mg/kg)after 2-month fed with high calorie diet,while the animals of NC group were injected intraperitoneally with the same volume citric acid buffer after 2-month normal diet.Before and after treatment 1,2,3 and 6 months,6 rats in each group were sacrificed and blood samples were obtained to measure the levels of leptin,fasting blood insulin(FINS),cholesterol(Cho),triglyceride(Tri),etc.The kidney samples were used for analyzing morphologically.Results Volume of glomerule of DM group was bigger than NC group at month one after injection with STZ(P0.01).The difference was more significant at month two.However,the volume of glomerule of DM group was smaller than NC group at months 3 and 6(P0.01).Glomerular basement membrane(GBM)was thicker in DM group than in NC group at months 3 and 6(P0.01);the level of leptin of DM group was much higher than NC group after high calorie diet given for two months(P0.01),but decreased after injected with STZ,then it increased continually during the whole experiment.Conclusion leptin may be one of the facilitative facts in the pathogenesis of DN.