冠状动脉微栓塞致心肌细胞凋亡及心功能损伤的死亡受体途径研究  

Cardiomyocyte apoptosis and death receptor pathway in a rat model of coronary microembolization

作　　者：李浪[1] 苏强[1] 王炎 苏波[1] 戴日新[1] 陆永光[1] 巫相宏[1] 刘唐威[1] 

机构地区：[1]广西医科大学第一附属医院心内科广西心血管病研究所,南宁530021

出　　处：《中华心血管病杂志》2010年第4期363-368,共6页Chinese Journal of Cardiology

基　　金：国家自然科学基金资助项目（30760262/C030313）

摘　　要：目的探讨大鼠冠状动脉微栓塞（CME）致心肌细胞凋亡及心功能损伤的死亡受体凋亡途径激活的动态变化规律。方法100只大鼠随机分为CME组、假手术组（S组），每组50只大鼠；采用夹闭升主动脉后经左心室注射0．1ml、42μm微球（3X10。／ml，3000个）建立大鼠CME模型，注射生理盐水构建S组。每组大鼠按不同观察时间点随机分为0、3、6、12、24h组，大鼠各10只。应用心脏超声检测心功能。组织病理切片HE及HBFP染色进行梗死区域测量。TUNEL染色检测心肌细胞凋亡。以Western blot检测活化caspase-3及caspase-8的表达。结果CME组除0h时间点外，其余时间点的左室射血分数均较S组显著降低（P〈0．05），左室短轴缩短率和心排血量下降及左室舒张期末内径显著增加（均为P〈0．05）。CME组3、6、12、24h时间点均可见明显的心肌微梗死灶，但各时间点之间的微梗死面积比较差异无统计学意义（均为P〉0．05）。CME组各时间点的心肌细胞凋亡指数与S组比较均显著升高（均为P〈0．05），凋亡主要分布在微梗死区及其边缘区；CME组各时间点中，以6h的凋亡指数最高（P〈0．05），12h开始明显下降（P〈0．05）。Western blot结果显示，细胞凋亡过程中最主要的终末剪切酶caspase-3和死亡受体凋亡通路的关键蛋白caspase-8的表达均在3h开始升高，6h达高峰（均为P〈0．05），12h开始表达减少，24h已显著下降（P〈0．05）；与相应S组比较，除0h外，CME各时间点caspase-3、caspase-8的表达均显著升高（P〈0．05）。结论死亡受体凋亡途径的显著激活是CME致心肌细胞凋亡及心功能损伤的重要机制并具有明显的动态变化规律。Objective To investigate the dynamic changes of cardiomyocyte apoptosis and the role of death receptor apoptotic pathway in a rat model of coronary microembolization （CME）. Methods Adult rats were randomized to coronary microembolization （ CME group, n = 63 ） or sham-operated group （ S group, n=55）. CME model was established by aortic injection of 0. 1 ml microspheres（42 μm, 3 × 10^4/ml）into the left ventricle when the ascending aorta was temporarily clamped. S group received 0. 1 ml saline injection and survived rats were randomly examined at 0, 3, 6, 12 and 24 hour post CME （n = 10 each）. Heart function was evaluated by echocardiography. Myocardium sample was stained with hematoxylin-eosin and hematoxylin-basic fuchsin-picric acid to detect infarct areas. Cardiomyocyte apoptosis was detected with TUNEL staining. The expression of caspase-3 and caspase-8 was measured by Western blot analysis. Results Compared with S group, the left ventricular ejection fraction was significantly decreased and left ventricular end-diastolic diameter was significantly increased in CME group （ all P 〈 0. 05 ） except 0 hour CME group. The infarct sizes were similar in 3 hour, 6 hour, 12 hour, and 24 hour CME groups （P 〉0.05）. The apoptosis index （A1） in CME group were significantly higher at each time point compared to S group （P 〈 0.05 ） except 0 hour CME group and peaked at 6 hours. Apoptotic cardiomyocytes were found mainly in the myocardial microinfarcted area and border zones. The relative expression of caspase-3 and caspase-8 in CME group were both significantly increased at 3 hours and peaked at 6 hour post CME （P 〈 0. 05 ）. Conclusion Cardiomyocytes apoptosis was significantly increased after coronary microembolization via activating death receptor apoptotic pathway in this coronary microembolization model.

关 键 词：冠状血管 栓塞 细胞凋亡 超声心动描记术 

分 类 号：R543[医药卫生—心血管疾病]