Expression of VEGF in kidney of diabetic rats

Abstract

Objective To investigate the expression of vascular endothelial growth factor (VEGF) in the kidney of diabetic rats and probe its relationship with the development of diabetic nephropathy (DN). Methods Diabetes mellitus was induced in SD rats by Streptozotocin. The renal tissues of rats were taken out at 2, 4, 8, 12, 16, 20 and 24 weeks after operation. The expression of VEGF was assessed by immunohistochemistry methods. VEGF mRNA in kidney was detected by RT-PCR at the same time points. The levels of VEGF mRNA and immunostaining were quantified by computer image analysis. The relationships of VEGF with the indices of renal damage, including renal/body weight, urinary protein excretion, glomerular volume and glomerular area, were analyzed. Results The expression of VEGF mRNA in diabetic kidney was significantly up-regulated after operation from 2 weeks to 24 weeks with the peak level at 20weeks, when compared with control at the same time-points. The positive results of VEGF staining in diabetic glomeruli was increasingly observed after operation from 2 weeks to 24 weeks, with the peak at 20 weeks. The positive results of VEGF staining in diabetic tubuli was increasingly seen from 2 weeks to 24 weeks, with the peak at 8 weeks. Conclusion VEGF level is increased continuously in the diabetic kidney of rat. The increased expression of VEGF is mainly located in the glomeruli at the early and middle stages, and is in the tubuli at the middle and late stages. VEGF expression in the diabetic kidney of rat is related to the development of renal changes.