Dexamethasone attenuates neutrophil infiltration in the rat kidney in ischemia/reperfusion injury: the possible role of nitroxyl

Neutrophil infiltration to the tissue, which is one of the important pathogenetic factors in ischemia/reperfusion injury, can be inhibited by glucocorticoids. The purpose of the present study was to clarify the mechanisms by which glucocorticoids inhibit neutrophil infiltration in renal ischemia/reperfusion injury in rats. Pretreatment with dexamethasone significantly attenuated the enhanced neutrophil infiltration and expression of intercellular adhesion molecule-1 induced by renal ischemia/reperfusion. Treatment with nitroxyl anion releaser known as Angeli’s salt abolished the beneficial effect of dexamethasone in renal ischemia/reperfusion. Renal dysfunction and tubular damage induced by renal ischemia/reperfusion were not ameliorated by pretreatment with dexamthasone. These results indicate that the attenuation by dexamethasone of neutrophil infiltration and intercellular adhesion molecule-1 expression during renal ischemia/reperfusion may be mediated by the suppressed production of nitroxyl anion. Thus, neutrophil infiltration in renal ischemia/reperfusion injury may be mediated, at least in part, by the enhanced production of nitroxyl anion.