584 Effect of Rescue and Prophylaxis with L-Arginine on Apoptotic Cell Death in Neonatal Rats

Abstract

Hypoxic ischemic brain damage presents significant mortality and morbidity rates in newborns. Various animal models of hypoxia-ischemia have made important contribution to the trial of pathogenesis and new treatment modalities. Seven day old rat hypoxia-ischemia model can be used to evaluate the effect of different agents. The complex role of nitric oxide and its antagonists in neonatal hypoxic ischemia has been widely known. However effects of L-arginine, an NO precursor, on apoptotic cell death in neonatal hypoxia-ichemia animal models have not been studied before. The aim of this study is to investigate the effects of the pre and post treaatment of L-arginine on apoptotic cell death in hypoxia-ischemia neonatal rat model. Seven-day-old rats were administered L-arginine intraperitoneally before and after hypoxic ischemia inflicted through right cartotid artery ligation and the exposed to 8 % oxygen. Apoptotic cell death was shown by Tunnel method after there-day recovery. Right hippocampal and striatal apoptotic cell death percentage in L-arginine post-treated group were significantly lower than those of vehicle groups, but no change was found in cortex. L-arginine pretreatment was found to have no effect on apoptotic cell death in the three brain regions. As a result, nitric oxide may play an important dual role in apoptotic cell death in neonatal hypoxicischemic brain injury. Pre-treatnent of L-arginine, a an NO precursor has not been proven to reduce apoptotic celll death, while early treatment after hypoxic ischemia has antiapoptotic effect on neurons in neonatal rat model.