Preconditioning with oxygen attenuates rat renal ischemia-reperfusion injury.

Abstract

BACKGROUND: Short time pretreatment with oxygen is reported to be protective against subsequent ischemia-reperfusion (IR) injury of heart and spinal cord in some animal models. The purpose of this study was to investigate the effects of pre-exposure to hyperoxic environment on rat renal IR injury for the first time. MATERIALS AND METHODS: The effects of 1 h/d pretreatment with oxygen (>or=95%) for 5 days on a right nephrectomized rat model of renal IR injury was investigated by comparing creatinine clearance, fractional excretion of sodium, plasma creatinine, blood urea nitrogen, and histological injury scores among three groups: IR (40 min ischemia-24 h reperfusion), sham (no IR), and hyperoxia (5 days intermittent pretreatment with oxygen + IR). RESULTS: Intermittent pretreatment with oxygen resulted in significant improvement of creatine clearance and fractional excretion of sodium (P <or= 0.05). Plasma creatinine above 175 micromol/L or blood urea nitrogen beyond 26 mmol/L was significantly less frequent in hyperoxia than IR group (P < 0.05). Jablonski histological injury score was also significantly lower in hyperoxia compared to IR group (P < 0.05) and hyperoxic preconditioning significantly reduced the frequency of massive proximal tubular necrosis (12.5% versus 75%, P < 0.05). CONCLUSIONS: The present findings demonstrate that intermittent pre-exposure to hyperoxic environment can reduce subsequent renal IR injury.