Relationship between peroxisome proliferator-activated receptor-γ and renal ischemia-reperfusion injury

The pathogenesis of ischemia-reperfusion (I/R) injury is known to involve cytokines and, in particular, surface adhesion molecules, the expression of which initiates inflammatory cell attachment. It has been suggested that peroxisome proliferator-activated receptor (PPAR)-γ is an important immunomodulatory factor as well as a regulator of fatty acid. In this study, we investigated the expression of PPAR-γ in a renal I/R injury rat model. The right kidney was harvested and the left renal artery and vein were clamped by means of a laparotomy. The kidney was reperfused following 90 min of ischemia. Rats were sacrificed at 0, 1.5, 3, 5, 12 and 24 h after reperfusion. PPAR-γ expression was analyzed by immunohistochemical staining using monoclonal antibody. PPAR-γ staining was weak in the endothelial cells, interstitial cells and collecting ducts in the normal kidney. From 1.5 to 5 h after reperfusion, PPAR-γ staining was strong. Twelve hours after reperfusion, necrosis had extended throughout the kidney, and nearly all the tubular epithelial cells were destroyed. However, 12 h after reperfusion, PPAR-γ staining was weak in the endothelial cells and its expression was moderate in the interstitial cells and collecting ducts. PPAR-γ was induced in the endothelial cells, including the mesangial cells, interstitial cells and collecting ducts in a rat model of renal I/R injury.