Naloxone Inhibited Cell Apoptosis By Regulating XIAP/Caspase-9Expression In The Cerebral Ischemia/Reperfusion Injury In Rats

ObjectiveIn recent years, studies have shown that the apoptosis program occurred in3-8hours after cerebral ischemia/reperfusion (I/R), and if ischemia could be recovered timely, some brain cells might return to normal activity.Further, once the apoptosis program is activated, a series of apoptosis molecular in this pathway will be changed by the positive feedback or negative feedback, and increased the apoptosis; based recent advances in the understanding of molecular pathways, several new strategies are currently emerging, x-linked inhibitor of apoptosis protein(XIAP) can inhibit the neuronal apoptosis by regulating the expression of start molecular casepase-9and effector molecular caspase-3in ischemia during brain injury. Numbers of studies have validated that Naloxone can inhibit nerve cells apoptosis effectively after the cerebral ischemia/reperfusion. But, it is still unclear whether Naloxone could inhibit the brain cell apoptosis after the cerebral ischemia/reperfusion by regulating XIAP/caspase-9expressions.So, in this study, our aims to explore the hypothesis that Naloxone inhibited the apoptosis in cerebral ischemia/reperfusion injury in rats by regulating XIAP/caspase-9expressions.MethodsI/R middle cerebral artery occlusion(MACO) SD rats model were constructed based on Zea Longa, and two groups which were namely natrium chloride (NS) group and Naloxone group were then randomly divided into by the way of treatment.XIAP Caspase-9mRNA and protein expressions were detected by real time RT-PCR and Western bloting.And the nerve cells apoptosis was analysed by Tunel stain.ResultsInfarct zone gradually increase from0h,6h,24h to72h after cerebral ischemia/reperfusion, the brain cell apoptosis significantly decreased in the Naloxone treatment compared with the NS treatment by Tunel stain. Both the NS group and the Naloxone group, XIAP mRNA and protein level was down-regulated in Oh, but up-regulated in6h after I/R. Furthermore,there were significantly different in6h、24h、and72h (F=1072.778p<0.001),but was no difference in0h(p>0.05) between the NS group and Naloxone group. Moreover, caspase-9mRNA and protein expressions were enhanced both NS group and Naloxone group from Oh to6h after I/R, caspase-9expressions gradually increased,but no difference between NS group and Naloxone group (both p>0.05);after6h, the expressions begun to decline in the Naloxone group, on the contrary, to increase in the NS group, there was significantly different in them (F=172.5P=0.016)ConclusionNaloxone treatment could inhibit brain cell apoptosis and protect ischemic neuronal activity after cerebral ischemia/reperfusion injury, and this protocol suggested that Naloxone would up-regulate XIAP expression and sequentialy inhibit Caspase-9expression in I/R models.