Endogenous mechanisms exist to limit inflammation. One such molecule is netrin. This study examined the impact of ischemia-reperfusion (I/R) on netrin expression and the role of netrin in preventing renal inflammation and injury. All three isoforms of netrin (1, 3 and 4) are expressed in normal kidney. I/R significantly down regulated netrin-1 and -4 mRNA expression whereas expression of netrin-3 was moderately upregulated at 24 hours after reperfusion. The netrin receptor UNC5B mRNA increased at 3 hours and but decreased at later time points. Expression of a second netrin receptor, DCC, was not altered significantly. I/R was associated with dramatic changes in netrin-1 protein abundance and localization. Netrin-1 protein levels increased between 3 and 24 hours after reperfusion. Immunolocalization showed an interstitial distribution of netrin-1 in sham operated kidneys which colocalized with Von Willebrand Factor suggesting the presence of netrin-1 in peritubular capillaries. After I/R, interstitial netrin-1 expression decreased and netrin-1 appeared in tubular epithelial cells. By 72 hours after reperfusion, netrin-1 reappeared in the interstitium while tubular epithelial staining decreased significantly. Down regulation of netrin-1 in the interstitium corresponded with increased MCP-1 and IL-6 expression and infiltration of leukocytes into the reperfused kidney. Administration of recombinant netrin-1 significantly improved kidney function (Creatinine: 1.3±0.07 vs. 0.75±0.16 mg/dl, P0.05 at 24 hours) and reduced tubular damage and leukocyte infiltration in the outer medulla. These results suggest that down regulation of netrin-1 in vascular endothelial cells may promote endothelial cell activation and infiltration of leukocytes into the kidney thereby enhancing tubular injury.