线粒体ATP敏感性钾通道在局灶性脑缺血再灌注损伤大鼠神经元凋亡中的作用  

Role of mito-KATP in neurocyte apoptosis induced by focal cerebral ischemia-reperfusion injury in rats

作　　者：张小霓[1] 李德龙[2] 林财珠[1] 林新[1] 陈百红[1] 王良山[1] 杨锡馨[1] 

机构地区：[1]福建医科大学附属第一医院麻醉科,福州市350005 [2]福建省立医院麻醉科

出　　处：《中华麻醉学杂志》2007年第9期831-834,共4页Chinese Journal of Anesthesiology

基　　金：福建省自然科学基金资助项目（Z0516038）

摘　　要：目的探讨线粒体ATP敏感性钾通道（mito-KATP）在局灶性脑缺血再灌注损伤大鼠神经元凋亡中的作用及其机制。方法清洁级雄性SD大鼠32只,体重250～280 g,线栓法制备大鼠右侧大脑局灶性脑缺血再灌注损伤模型。随机分为4组（n=8）：假手术组（S组）经股静脉注射生理盐水0.6 ml,45 min后右颈内动脉置入线栓10 mm（不足以造成栓塞缺血）,2 h后拔出线栓;缺血再灌注组（IR组）经股静脉注射生理盐水0.6 ml,45 min后行线栓法缺血2 h再灌注24 h;二氮嗪组（Dz组）经股静脉注射生理盐水0.3 ml,15 min后静脉注射二氮嗪5 mg/kg（0.3 ml）,30 min后行线栓法缺血2 h再灌注24 h;格列苯脲＋二氮嗪组（Gl＋Dz组）经股静脉注射格列苯脲1 mg/kg（0.3 ml）,15 min后静脉注射二氮嗪5 mg/kg（0.3ml）,30 min后行线栓法缺血2 h再灌注24 h。分别于缺血2 h、再灌注2、24h时行Longa神经功能缺失评分,评分后处死大鼠,提取脑组织,观察病理学,计数凋亡神经元,计算凋亡指数（AI）,测定bcl-2 mRNA和caspase-3 mRNA的表达。结果与S组比较,IR组、Dz组和Gl＋Dz组凋亡神经元增多,AI升高,bcl-2 mRNA和caspase-3 mRNA表达上调;与IR组和Gl＋Dz组比较,Dz组凋亡神经元减少,AI降低,bcl-2 mRNA表达上调,caspase-3 mRNA表达下调（P〈0.05）;IR组与Gl＋Dz组差异无统计学意义（P〉0.05）。结论开放mito-K_（ATP）可减少局灶性脑缺血再灌注损伤大鼠神经元凋亡,产生脑保护作用,其机制与上调bcl-2 mRNA表达,下调caspase-3 mRNA表达有关。Objective To investigate the role of mitochondrial ATP-sensitive potassium channel （mito-KATP） in neurocyte apoptosis induced by focal cerebral ischemia-reperfusion injury （I/R） and the possible mechanism. Methods Thirty-two male SD rats weighing 250-280 g were randomly allocated into 4 groups （ n = 8 each）： group Ⅰ sham operation （S）; group Ⅱ I/R; group m diazoxide preconditioning （DZ） and group Ⅳ glibenclamide ＋ DZ （GL ＋ DZ ）. Focal cerebral ischemia-reperfusion injury was induced by 2 h right middle cerebral artery occlusion followed by 24 h reperfusion according Longa EZ, et al in group Ⅱ -Ⅳ . In group m diazoxide 5.0 mg/kg was given iv 30 min before I/R; while in group Ⅳ glibenclamide 1.0 mg/kg was given 15 min before DZ preconditioning. The animals were killed at 24 h of reperfusion and right brain was removed. Neurocyte apoptosis was detected by TUNEL staining. Apoptotic index （AI） was calculated. The expression of bcl-2 and caspase-3 mRNA in neurocytes was determined by RT-PCR. Results （ 1 ） The number of apoptotic neurocytes was significantly increased and AI was higher and the expression of bcl-2 and caspase-3 mRNA was up-regulated in group Ⅱ , m and Ⅳ as compared to sham operation group （ Ⅰ ）. （2） The number of apoptotic neurocytes was significantly reduced and AI lower and the bcl-2 mRNA expression was significantly up-regulated but caspase-3 mRNA expression down-regulated in DZ group （m） as compared to I/R and GL＋ DZ group （ Ⅱ , Ⅳ ）. （3） There was no significant difference in apoptotic neurocyte count, AI and expression of bcl-2 and caspase-3 mRNA between I/R and GL ＋ DZ group. Conclusion Opening mito-KArP can attenuate neurocyte apoptosis induced by focal cerebral I/R by up-regulating bcl-2 mRNA expression and down-regulating caspase-3 mRNA expression.

关 键 词：钾通道 腺苷三磷酸酶 脑 再灌注损伤 神经元 细胞凋亡 

分 类 号：R686[医药卫生—骨科学]