AIM: To observe the dynamic changes of expression of PKC? , TGF-? 1 and ?-SMA in glomeruli of diabetic rats induced by the alloxon and to invesitigate their roles in the diabetic nephropathy(DN). METHODS: Rats were randomly divided into four groups: normal control group (group A), diabetic group of one week (group B), diabetic group of one month (group C), diabetic group of two months (group D). Immunohistochemistry and Western blotting were used to detect the expression of PKC?, TGF-? 1 and ?-SMA in renal tissue of all groups. Blood glucose, triglycerides, cholesterol, creatinine and urine protein were analysed by chemical methods. The morphological changes of renal tissue were checked through microscopy. RESULTS: The expression of PKC? and TGF-? 1 in renal tissue of diabetic groups were increased comparing with those of nomal control group( P