Short-term antioxidant diet prevents hyperfiltration in young male rat kidney subjected to ischemia/reperfusion injury

Abstract

Objectives: The process of transplantation is associated with exposure to both long and short cold and warm ischemic times that result in ischemia/reperfusion injury. Oxidative stress contributes to tissue fibrosis, renal dysfunction, and/or rejection. Treatments that scavenge oxygen free radicals and have antioxidant properties can ameliorate the damaging results in renal grafts following ischemia/reperfusion injury. The present study tests the hypothesis that an antioxidant-fortified diet given to rats before and after renal ischemia/reperfusion injury will reduce the kidney damage that results and improve renal function. Endothelial and inducible nitric oxide synthases may change with tissue injury, including ischemia/ reperfusion. Materials and Methods: Male Wistar rats were subjected to ischemia/reperfusion injury at 7 or 19 weeks of age with or without dietary antioxidant supplementation. One week later, glomerular filtration rate, mean arterial pressure and urinary nitric oxide were measured, and renal endothelial and inducible nitric oxide synthases examined. Results: The glomerular filtration rate was elevated more than two-fold above the normal range at 8 weeks in animals on the regular diet exposed to ischemia/reperfusion, while in the 8 week antioxidant-fortified diet group the glomerular filtration rate was normal. Also, in 8 week rats, levels of endothelial nitric oxide synthase protein in cortex were higher on the regular than on the antioxidant-fortified diet. Conclusion: Early after ischemia/reper-fusion injury renal endothelial nitric oxide synthase levels rise, possibly contributing to vascular dilation and hyperperfusion, and an antioxidant-fortified diet can ameliorate these changes in the younger age group.