酸敏感离子通道1a在大鼠全脑缺血再灌注损伤中的作用

目的 探讨酸敏感离子通道1a(ASIC1a)在大鼠全脑缺血再灌注损伤中的作用.方法成年雄性SD大鼠40只,体重250～ 300 g,采用随机数字表法,将大鼠随机分为4组(n=10):假手术组(S组)、全脑缺血再灌注组(I/R组)、ASIC1a特异性阻断剂PcTX1组(P组)和溶剂对照组(SC组).采用改良的Pulsinelli四血管阻断法制备大鼠全脑缺血再灌注损伤模型.P组和SC组于再灌注即刻分别经侧脑室注射PcTX1 (500 ng/ml)6μl和双蒸水6μl.再灌注24h时处死大鼠,取海马组织,采用Western blot法测定Caspase-3的表达,采用免疫组织化学法检测海马CA1区Bcl-2、Bax的表达水平,并观察海马病理学结果.结果 与S组比较,I/R组、P组和SC组海马Caspase-3、Bcl-2和Bax表达上调(P＜0.05)；与I/R组比较,P组海马Caspase-3和Bax表达下调,Bcl-2表达上调(P＜0.05),SC组差异无统计学意义(P＞0.05).P组海马病理学损伤较I/R组减轻.结论 ASIC1a激活后可能通过上调脑组织Caspase-3和Bax的表达,下调Bcl-2的表达,诱发细胞凋亡,从而导致大鼠全脑缺血再灌注损伤.

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.