全脑缺血再灌注损伤大鼠海马神经元凋亡调节蛋白Bcl-2和Bax的表达

背景:脑缺血再灌注对中枢神经系统的影响,除了急性期的细胞坏死,还有迟发性的神经元凋亡.目的:观察大鼠全脑缺血不同再灌注阶段海马神经元凋亡率、坏死率及凋亡调节蛋白Bcl-2和Bax的表达情况,并探讨其对全脑缺血再灌注损伤的调节作用.设计:随机对照实验.单位:首都医科大学附属北京天坛医院的神经外科和麻醉科.材料:实验于2003-01/2004-01在首都医科大学附属北京神经外科研究所完成.选择清洁级成年雄性健康Wistar大鼠33只,随机分5组,缺血再灌注24 h组7只、缺血再灌注48 h组7只、缺血再灌注72 h组7只、缺血再灌注7 d组7只和假手术对照组5只.干预:制备大鼠全脑缺血再灌注模型.分别于再灌注24,48,72 h和7 d取脑海马组织,用流式细胞仪检测细胞凋亡率,坏死率,Bcl-2和Bax蛋白在大鼠脑海马神经元中的表达情况.主要观察指标:①流式细胞仪检测各组大鼠脑海马组织细胞凋亡率和坏死率.②Bcl-2和Bax蛋白表达百分率.结果:33只大鼠全部进入结果分析.①缺血再灌注7 d组海马神经元的凋亡率最高(24.59±0.97)%],坏死率峰值出现在缺血再灌注24 h组(16.67±1.04)%],明显高于假手术对照组(1.28±0.50)%,(0.90±0.38)%](P＜0.01).②假手术对照组Bcl-2表达极低(1.07±0.27)%],但Bax有高表达(46.09±5.37)%].③Bcl-2蛋白峰值出现在缺血再灌注后48 h(14.41±0.67)%],而Bax蛋白峰值出现在缺血再灌注之后72 h(77.38±1.52)%].结论:全脑缺血再灌注损伤后海马神经元凋亡率逐渐增高,凋亡调控基因Bcl-2和Bax表达异常增高,提示Bcl-2和Bax蛋白参与了全脑缺血再灌注损伤的凋亡调节.

Expression of Bcl-2 and Bax apoptosis-regulating proteins in hippocampal neurons in rats with global cerebral ischemia-reperfusion injury

BACKGROUND: Cerebral ischemia and reperfusion affects not only cellular necrosis at acute stage, but also delayed neuronal apoptosis in central neural system.OBJECTIVE: To observe apoptosis rate, necrosis rate and expression of Bcl-2 and Bax apoptpsis-regulating proteins in hippocampal neurons at various reperfusion stages of complete cerebral ischemia in rats so as to probe into the regulation of injury induced by complete cerebral ischemia and reperfusion.DESIGN: Randomized control experiment.SETTING: Department of Neurosurgery and Department of Anesthesiology in Beijing Tiantan Hospital Affiliated to Capital University of Medical Sciences.MATERIALS: The experiment was performed in Beijing Institute of Neurosurgery Affiliated to Capital University of Medical Sciences from January 2003 to January 2004. Totally 33 healthy adult male Wistar rats of clean grade were employed, randomized in 5 groups, named ischemia +reperfusion 24 hours group (24 hours group) (7 rats), ischemia + reperfusion 48 hours group (48 hours group) (7 rats), ischemia + reperfusion 72hours group (72 hours group) (7 rats), ischemia + reperfusion 7 days group (7 days group) (7 rats) and sham-operation control (control) (5 rats).INTERVENTIONS: Model of complete cerebral ischemia and reperfusion was prepared in rat. Cerebral hippocampal tissues were collected in 24, 48,72 hours and 7 days after reperfusion successively. The flow cytometer was used to determine cellular apoptosis rate and necrosis rate and expression of Bcl-2 and Bax proteins in cerebral hippocampal neurons in rats.percentages of Bcl-2 and Bax proteins.hippocampal neurons in 7 days group was the highest (24.59±0.97) %].The peak value of necrosis rate presented in 24 hours group (16.67±1.04)%], which was remarkably higher than the control (1.28±0.50)%,low (1.07±0.27)%], but high expression of Bax presented (46.09±5.37)%].and reperfusion (14.41±0.67)%] and the peak value of Bax protein presented in 72 hours after ischemia and reperfusion (77.38±1.52)%].CONCLUSION: Hippocampal neuronal apoptosis rate is increased gradually and expression of Bcl-2 and Bax apoptosis-regulating genes was increased abnormally after injury induced by complete cerebral ischemia and reperfusion, which suggests that Bcl-1 and Bax proteins are involved in apoptosis regulation in the injury induced by complete cerebral ischemia and reperfusion.