Effect of Benazepril on Expressions of Transforming Growth Factor-β_1 and Smad4 in Kidney Tissue of Diabetic Rats

Objective:To investigate the effect of Benazepril on expressions of TGF-β_1 and Smad4 in kidney tissue of diabetic rats.Methods:Healthy male Wistar rats were divided randomly into three groups:normal control group,Strepotozocin induced diabetes group and group of Strepotozocin-induced diabetes treated with Benazepril.The rats in the three groups were sacrificed eight weeks after the treatment.The mean arterial pressure,plasma glucose,BUN,Ccr and 24-hour urine albumin excresion rate (UAER) were measured.The levels of TGF-β_1 and Smad4 mRNA were examined by RT-PCR.The localization and expressions of TGF-β_1 and Smad4 protein were observed with immunohistochemistry and colour pathological image analysis system.Results:Compared with normal control group,the mean arterial pressure,plasma glucose,BUN,Scr,24-houe urinary protein were significantly increased in diabetic group and the group also shown markedly accumulated glomerular extracellular matrix and mesangial expansion on PAS staining sections.The level of TGF-β_1 and Smad4 mRNA were up regulated and so were the expressions of TGF-β_1 and Smad4 protein. After Benazepril administration, all the above changes improved greatly (P0.01).Conclusions:TGF-β/Smad signaling pathway is activated in diabetic nephropathy.Benazepril administration could delay the process of renal damage in diabetes.