Protective effect of MSCs by distinct administration time on renal ischemia-reperfusion injury in rats

Objective To observe the protection and distribution of bone marrow mesenchymal stem cells (MSCs) by distinct intravenous infusion time on renal ischemia reperfusion injury (IRI) in rats.Methods We used unilateral nephrectomy and contralateral vascular occlusion method to establish renal IRI model in rats.The experimental groups which received 2 × 106 MSCs infusion through the tail vein,were subsequently divided into 3 subgroups:2 h pre-reperfusion (PreOp,n =16),immediately after reperfusion (Op,n =16),6 h post-reperfusion (PostOp,n - 16).The control groups included sham operation group (n =16) and ischemia group (n =16).Chemotaxis of DAPI-labeled MSCs was detected 6 h after administration in the IR kidney.Renal function was detected at 6,24,and 48 h respectively after operation. Forty eight h after operation,the renal tissues were harvested to observe the pathological changes by HE staining and the tubular epithelial cell apoptosis via TUNEL assay.Results MSCs were found in the experimental groups after IR in the kidney,most in PostOp group.Twenty-four and 48 h after reperfusion,there was no significant difference in Cr and BUN between the experimental groups and sham operation group (P＞0.05),but the levels of Cr and BUN in the experimental groups were significantly lower than in the IR group (P＜ 0.05). As compared with IR group,the renal pathological injury was alleviated,the number of apoptotic cells was decreased in the experimental group,most significantly in PostOp group (P＜0.05).Conclusion MSCs can reduce the inflammatory response and inhibit renal tubular cell apoptosis in rat renal IRI.Post-reperfusion administration of MSCs leads to the best chemotaxis efficiency and protection. Key words: Rats; Bone marrow; Mesenchymal stem cells; Kidney; Reperfusion injury