急性心肌缺血大鼠心肌α辅肌动蛋白含量变化及其与心功能的关系  

Relationship between α-actinin and cardiac function in rats with myocardial ischemia-reperfusion

作　　者：陈唐葶[1] 周翔[1] 王立群[1] 金春华[1] 

机构地区：[1]南方医科大学医学基础实验教学中心,广东广州510515

出　　处：《南方医科大学学报》2011年第6期970-974,共5页Journal of Southern Medical University

基　　金：国家自然科学基金(30570707)~~

摘　　要：目的观察大鼠心肌缺血及再灌注过程中心肌细胞骨架蛋白α辅肌动蛋白(α-actinin)含量的变化及其与心功能的关系。方法 Wistar大鼠随机分为假手术组(sham),缺血30min组(I30min),缺血1h组(I1h),缺血1h再灌注2h组(IR),每组各8只。通过结扎大鼠冠状动脉左前降支建立急性心肌缺血及再灌注模型,记录左心室收缩压(LVSP)、左心室舒张末压(LVEDP)、左室内压上升最大速度(+dp/dtmax)、左室内压下降最大速度(-dp/dtmax)。采用免疫组化方法检测各组心肌中α-actinin含量和分布。ELISA法定量检测各组心肌组织磷酸肌醇3激酶(PI3K)和磷脂酶C(PLC)含量。急性分离大鼠心肌细胞,并用PI3K抑制剂(LY-29400)和PLC抑制剂(U-73122)处理细胞,观察其对心肌细胞收缩舒张能力及对α-actinin含量的影响。结果 (1)随缺血时间延长,大鼠LVSP、+dp/dtmax、-dp/dtmax下降,LVEDP升高;再灌注后LVSP、+dp/dtmax、-dp/dtmax回升,LVEDP回落,但不能恢复到缺血前水平。(2)免疫组化染色观察到随缺血时间延长,α-actinin出现点状、片状缺失,含量下降。(3)急性缺血过程中PI3K和PLC含量逐渐增加(P<0.05)。(4)应用LY-294002及U-73122后单个心肌细胞收缩幅度较缺血组明显增加(P<0.05)。(5)应用LY-294002及U-73122后心肌细胞α-actinin免疫荧光强度较缺血组增加(P<0.001)。结论心肌缺血时心肌细胞骨架蛋白α-actinin的含量减少可能与缺血后PI3K和PLC含量增加有关,并且α-actinin结构与含量变化可能是导致心肌功能障碍的原因之一。Objective To explore the relationship between α-actinin content and cardiac function in rats during myocardial ischemia-reperfusion. Methods Thirty-two rats were randomized equally into sham-operated group, 30 min ischemia group, 1 h ischemia group, and 1 h ischemia with 2 h reperfusion group. Acute myocardial ischemia was induced in the 3 ischemia groups by ligation of the left anterior descending coronary artery, and the cardiac functions were evaluated. The myocardial contents of α-actinin was measured by immunohistochemistry, and phospholipase C （PLC） and phosphatidylinositol-3-kinase （PI3K） contents were determined by ELISA after the operations. Results The left ventricular systolic pressure （LVSP）, ＋dp/dt max, and -dp/dt max tended to decrease during myocardial ischemia, and increased after reperfusion, and the left ventricular end-diastolic pressure （LVEDP） showed reverse changes. The levels of α-actinin decreased with prolonged ischemia, showing a significant difference in 1 h ischemia group from those in the other 3 groups. PI3K and PLC contents were significantly increased with prolonged myocardial ischemia. Stimulation by LY-294002 and U-73122 caused enhanced contraction of single cardiomyocytes, and also increased the fluorescence intensity of α-actinin in the cardiomyoctyes compared with that in 1 h ischemia group. Conclusions The cardiac dysfunction during acute ischemia-reperfusion in rats may be related with the changes of myocardial α-actinin content, which are probably a result of increased PI3K and PLC contents in the ischemic myocardium.

关 键 词：缺血再灌注 α辅肌动蛋白 磷酸肌醇3激酶 磷脂酶C 

分 类 号：R541[医药卫生—心血管疾病]