Effect of tripterygium combined irbesartan on nephrin and podocin expression in the podocyte of diabetic nephropathy rats

Objective To observe the effect of tripterygium and irbesartan on nephrin and podocin expression in the podocyte of diabetic nephropathy rats. Methods Fifty SD rats(weight 200-260 g) were randomly divided into control group(group C) and model group. Rats in model group were then divided into diabetic nephropathy group (group DN), Irbesartan group ( group I) , Tripterygium group ( group T) and combined treatment group(group T+ I ) after being given streptozotocin (STZ) (60 mg/kg) by a single intraperitoneal injection to establish animal model of diabetes. After 8 weeks, blood and Urine index were measured. The renal cortical tissues were obtained and used for HE staining to determine pathological changes. The expression of nephrin and podocin in renal cortices were semiquantitatively measured with RT-PCR. Results Compared to group DN, the mRNA expressions of nephrin and podocin were higher in the cortex of renal in group (T+ I) compared to group DN (0.507±0.024 vs 0.276±0.015, P<0.01 and 0.533±0.024 vs 0.463±0.022, P<0.01). The expressions of nephrin and podocin protein were higher in the cortex of renal in group (T+ I) compared to group DN (0.738±0.029 vs 0.199±0.012, P<0.01 and 0.811±0.032 vs 0.227±0.014, P<0.01). HE and Masson staining showed that the glomerular volume became bigger, messegium increased, mesangial cells proliferation, basement-membrane thickening and lymphocytes and mononuclear cell infiltration in group DN, which reduced in Irbesartan group and Tripterygium group, and further reducing in combined treatment group. Conclusions Tripterygium combined irbesartan play a protective role on the podocytes in diabetic nephropathy rats. The mechanism may be partly through the up-regulated expression of nephrin and podocin in kidney. Key words: Tripterygium; Irbesartan; Diabetic nephropathy