Expression and significance of thrombospondin-1 and vascular endothelial growth factor in process of renal interstitial fibrosis

Objective To elucidate the association of renal tubulointerstitial expression of TSP-1(thrombospondin-1) and VEGF(vascular endothelial growth factor) with renal disease in the patients with chronic nephropathy and to evaluate the role of TSP-1 and VEGF in the genesis of chronic renal interstitial fibrosis.Methods The expression of TSP-1,VEGF,CD34, TGF-β1,α-SMA,and type IV collagen in renal tissue were investigated with immunohistochemistry assay and computer image analysis system in 53 patients with chronic kidney disease.According to the score of the renal interstitial pathology injury,fifty-three patients were divided into four groups: 5 patients in none injury group(the normal control group),18 patients in light injury group,19 patients in middle injury group,11patients in severe injury group.Results TSP-1 was not detected in normal control group,TGF-β1,α-SMA and type IV collagen were rarely detected in normal control group,and the expression increased gradually in other groups with the degree of renal interstitial pathological injury(P0.01).A significant positive correlation was found between the expression of TSP-1,VEGF,CD34,TGF-β1,α-SMA,and type IV collagen and the degree of renal tubulointerstitial pathological injury(r=0.86,0.674,0.779,0.784 respectively).The expression of VEGF and CD34 was the strongest in tubular epithelial cells and peritubular capillaries respectively in normal control group,and decreased gradually with the degree of renal interstitial pathological injury(P≤0.01),and a significant negative correlation was found between the expression of VEGF and CD34 and the degree of renal tubulointerstitial pathological injury(r=-0.715,-0.672,respectively).Conclusion TSP-1 increased with the degree of the renal interstitial pathological injury.VEGF and CD34 both decreased gradually with the degree of renal interstitial pathological injury.The expression of TSP-1 was significantly positive correlated with the degree of renal interstitial pathological injury.The expression of VEGF was negatively correlated with the degree of the renal interstitial pathological injury.The disturbance of TSP1 and /or VEGF decreased sums of peritubular capillaries and the degradation of ECM.