Role of acid-sensing ion channel 1a in global cerebral ischemia-reperfusion injury in rats

Objective To investigate the role of acid-sensing ion channel 1a(ASIC1a) in global cerebral ischemia-reperfusion injury in rats.Methods Forty male SD rats weighing 250-300 g were randomly divided into 4 groups (n =10 each): sham operation group (group S),cerebral ischemia-reperfusion group (group I/R),solvent control group (group SC) and group PcTX1 (a ASIC1 a blocker,group P).Global cerebral ischemia-reperfusion was induced by four-vessel occlusion.PcTX1(500 ng/ml)6 μl or solvent 6 μl was injected into the crerbral ventricular at the begining of reperfusion in groups P and SC respectively.The rats were sacrificed at 24 h of reperfusion,and then the hippocampi were removed for determination of Caspase-3,Bcl-2 and Bax protein expression and microscopic examination.Results Compared with group S,the expression of Caspase-3,Bcl-2 and Bax protein was up-regulated in groups I/R,SC and P (P ＜ 0.05).Compared with group I/R,the expression of Caspase-3 and Bax was down-regulated,and the expression of Bcl-2 was up-regulated in group P ( P ＜ 0.05).There was no significant difference in Caspase-3,Bcl-2 and Bax protein expression between groups I/R and SC (P ＞ 0.05).The histopathologic damage was ameliorated in group P as compared with group I/R.Conclusion ASIC1a can induce global cerebral ischemia-reperfusion injury in rats by up-regulating Caspase-3 and Bax expression,and down-regulating Bcl-2 expression and inducing apoptosis. Key words: Sodium channels;  Reperfusion injury;  Brain