The Effects Of Endothelial Progenitor Cells Induced By Ischemic Preconditioning On The Renal Of Ischemia Reperfusion Injury Of Rats

BACKGROUD:It is known that renal ischemia/reperfusion injury (IRI) in the Department of Urology of the most commonclinical phenomenon, including retain the nephron of the kidney cancer surgery,kidney stone surgery and kidney transplant. Study found that it can cause microvascular endothelial cells dysfunction (ECD) in peritubular capillaries (PTC), leading to renal tubular epithelial cell structure and function change, which is theimportant pathologic basis of kidney IRI. Ischemic preconditioning (IPC) as a body can develop tolerance to ischemia is an important means,which could protect the kidney from renal IRI, but the mechanism remains unclear up to the present.AIM:In IPC group,15minutes pre-ischemia was performed,10minutes after pre-ischemia45minutes occlusion was performed. The homing of EPCs and the expression level of VEGF,SDF-1in the renal tissues were detected.To explore the role of EPCs in the kidney of rats IPC, as well as possible mechanisms.METHODS:While the right kidneys were removed in75male SD rats,all animals were randomly divided into3groups:sham operation group(sham),ischemia/reperfusion group(I/R) and ischemic preconditioning group(IPC).45minutes ischemia was induced by clamping renal unilateral pedicles followed by reperfusion in I/R group.15minutes pre-ischemia was performed,10minutes after pre-ischemia45minutes occlusion was performed in IPC group.Serum creatinine(Scr),blood urea nitrogen(BUN),kidney morphology and apoptosis were observed at different time points following reperfusion (3h,24h,3d,7d,14d; n=5).The expression level of CD34and flk-1in the renal tissues were detected by immunohistochemistry analysis.The expression of vascular endothelial growth factor(VEGF) and stromal cell-derived factor-1(SDF-1) were evaluated by the method of western blotting.RESULTS:Compared with I/R group,acute tubulointerstilial injury was significantly relieved in IPC group,and the levels of Scr and BUN were also significantly decreased.At72h following reperfusion,apoptosis of tubular epithelial cells were also decreased in IPC group[(17.6±4.45)%vs(63.8±6.10)%, P<0.01].The homing of EPCs were increased significantly in IPC group,massively accumulated in the renal medullary interstitium,and the expression level of VEGF,SDF-1in the kidney were markedly increased compared with I/R group (P<0.05)CONCLUSION:IPC attenuates both morphologic and functional injuries induced by renal I/R.This protective effect may be related to the homing of EPCs and VEGF,SDF-1paracrine mechanism.