The effect of neutrophil elastase inhibitor on acute tubular necrosis after renal ischemia-reperfusion injury

In renal transplantation, ischemia-reperfusion (I/R) injury is a major cause of renal dysfunction. Activated neutrophils are reported to be closely involved in I/R injury after renal transplantation. Neutrophil elastase, a protease released from activated neutrophils, damages tubular endothelial cells. We investigated the beneficial effect of neutrophil elastase inhibitor (ONO-5046.Na) on renal I/R injury in rats. The study was conducted using 10 male Lewis rats (270-320 g) that were intravenously administered ONO-5046.Na (30 mg/kg before ischemia and after reperfusion) (group A) and control rats (group B) in a 90-min renal warm I/R injury model. Neutrophil elastase expression was analyzed using immunohistochemical staining, and the degree of renal dysfunction was evaluated using H&E staining and blood biochemistry. Neutrophil elastase was detected in tubular endothelial cells. The necrotic area extended to and encompassed nearly all the ischemic kidney within 12 h after reperfusion. The necrotic area and the grade of neutrophil elastase staining were significantly reduced in group A compared to group B. Significant differences in blood urea nitrogen and serum creatinine levels were observed. Survival rates over a 14-day period were examined. No rats survived for more than 4 days in group B. However, 2 of the 10 rats (20%) in group A survived for a 14-day period. To conclude, ONO-5046.Na inhibits neutrophil elastase and reduces acute tubular necrosis. Thus, it is a potent therapeutic agent for the control of renal I/R injury in renal transplantation.