Abstract: Objective: To investigate the effects of ferulic acid (FA) on the streptozocin (STZ) -induced kidney injury in diabetic rats and its possible mechanisms.Methods: Diabetes was induced in male SD rats by an injection of STZ (40 mg/kg,i.v.). After 72 hours, blood glucose levels were detected and blood glucose levels exceeded 16.7 mmol/L were diagnosed as diabetic model rats. Diabetic model rats were randomly divided into model group and FA group, ten animal in each group. Another 10 healthy male SD rats were treated as control group. The rats in FA group were treated with FA (100 mg/kg, i.g.,qd) from the 5th week since the diabetic rats model was successfully established and lasted for 8 weeks. The levels of blood glucose, body weight, organ coefficient of kidney, blood urea nitrogen and creatinine were tested. HE staining was employed to observe the pathological changes of the renal tissue. Immunohistochemistry was employed to determine the protein of nephrin and podocin.Results: Compared to control group, the levels of blood glucose, organ coefficient of kidney, blood urea nitrogen(BUN) and serum creatinine(sCr) were increased significantly. Renal cells from model group rats showed atrophied and disordered after HE staining and interstitial proliferation were also appeared in renal tissue of the model group. Meantime, the levels of nephrin and podocin protein were obviously decreased. These changes were significantly attenuated in the model group treated with FA.Conclusion: FA can evidently ameliorate renal damage in rats with diabetic nephropathy induced by STZ, which might be related to increase the level of nephrin and podocin protein.

Key words: ferulic acid, diabetic nephropathy, rat, podocytes, nephrin, podocin