延迟亚低温治疗对大鼠永久性大脑中动脉阻塞后凋亡相关蛋白表达的影响  

Effect of delayed mild hypothermia on the expression of apoptosis-regulating proteins after the permanent middle cerebral artery occlusion in rats

作　　者：吕佳宁[1] 韩锁成[2] 郭景春[3] 范薇[1] 

机构地区：[1]复旦大学附属中山医院神经内科,上海200032 [2]鄂尔多斯市中心医院神经内科,内蒙古鄂尔多斯017000 [3]复旦大学医学神经生物学国家重点实验室,上海200032

出　　处：《中风与神经疾病杂志》2008年第1期67-70,共4页Journal of Apoplexy and Nervous Diseases

摘　　要：目的研究延迟亚低温治疗对大鼠永久性脑缺血的神经保护作用以及作用机制。方法线栓法制备永久性大脑中动脉阻塞(pMCAO)模型,随机分为3组,每组10只。亚低温治疗组(HT组)分为HT2h组和HT6h组,前者在pMCAO后2h给予亚低温(33±0.5℃)治疗22h,后者在pMCAO后6h给予亚低温(33±0.5℃)治疗18h。缺血对照组(NT组)在pMCAO后放置于室温(25℃)。制备pMCAO模型过程中,应用激光多普勒血流监测仪监测局部大脑中动脉供血区脑血流量。持续监测直肠温度。各组大鼠均于pMCAO后24h灌注取脑制备冰冻切片,进行TUNEL染色以及Bcl-2、Bax、Caspase-3免疫组织化学染色。结果NT组有3只大鼠死亡,亚低温治疗组无大鼠死亡。与NT组比较,HT组皮层缺血半暗带区域凋亡细胞减少,Bcl-2蛋白表达增多,Bax蛋白表达减少,Bcl-2/Bax比值升高,Caspase-3蛋白表达显著减少(P<0.05)。与HT6h组比较,HT2h组皮层缺血半暗带区域凋亡细胞减少(P<0.05),但Bcl-2、Bax、Caspase-3蛋白表达以及Bcl-2/Bax比值均无显著性差异(P>0.05)。结论永久性脑缺血后延迟6h给予亚低温治疗18h仍然可以减少缺血后神经细胞凋亡。延迟亚低温治疗通过抑制Bcl-2基因家族蛋白介导的线粒体依赖性Caspase激活途径,抑制Caspase介导的细胞凋亡途径,从而发挥神经保护的作用。在脑缺血的治疗过程中,要尽早给予亚低温治疗,以保护更多的神经元和更好地促进神经功能的恢复。Objective To explore the neruoprotective effect of the delayed mild hypothermia on the permanent cerebral ischemia in rats and the pathway of neuroprotection by delayed mild hypothermia. Methods The intraluminal suture permanent middle cerebral artery occlusion （pMCAO） model in 30 male Sprague Dawley rats was used. Animals were randomly assigned to the 3 experimental groups. Mild hypothermia （33 ± 0.5℃ ） was achieved after 2h and 6h, which was maintained for 22h and 18h. Control group were raised in the room temperature （25℃）. Local cerebral blood flow was monitored in the cerebral cortex in the supply territory of the middle cerebral artery （MCA） by laser-Doppler floemetry. The rectal temperature was continually monitored. After 24 hours of pMCAO in all groups,the brain were removed and cut into sections for determination of the expression of Bcl-2, Bax, Caspase-3 using immunohistochemical staining and the apoptotic cells using TUNEL staining. Results 3 rats died in the mild hypothermic groups, and none in the control group. After 24 hours of pMCAO,the mild hypothermic groups showed significantly decreased apoptotic cells, increased Bcl-2 staining, decreased Bax and Capsase-3 staining and increased ratio of Bcl-2/Bax relative to control group（ P 〈0.05 ）. And there was a significant decrease in the apoptotic cells in HT2h group compared with HT6h group（ P 〈 0.05 ）, but there were no significant differences in the immunoreactivity of Bcl-2, Bax and Caspase-3 ,and the ratio of Bcl-2/Bax between HT2h group and HT6h group（P 〉0.05）. Conclusion The mild hypothermia could be delayed 6 hours after the induction of pMCAO and maintained 16h,which also could obtain optimal neuroprotection against ischemic cell death due to apoptosis. The delayed mild hypothermia produced a marked effect of neuroprotection by increasing the expression of Bcl-2, and decreasing the expression of Bax and Caspase-3 ,which decreased apoptosis of neurons in the penumbra region. Furthermore,we should begin the

关 键 词：亚低温 pMCAO 凋亡 

分 类 号：R454.5[医药卫生—治疗学] R743.3[医药卫生—临床医学]