缝隙连接蛋白43在脑心综合症中的作用研究

The effect of ventricular connexin 43 in cerebrocardial syndrome model rats

目的检测缝隙连接蛋白43(connexin43,Cx43)在脑心综合症模型大鼠心室肌中的表达及分布,以探讨其与脑缺血后心律失常的关系。方法用线栓法栓塞大鼠右侧大脑中动脉制备脑心综合症模型,检测心电图,电镜下观察心肌细胞的亚显微结构,采用Westernblot和免疫组织化学的方法,检测心室肌中Cx43表达和分布的改变。结果电镜显示脑缺血后,心肌组织闰盘内桥粒和缝隙连接结构及分布改变,与正常对照组相比,Western blot和免疫组织化学结果均显示脑缺血后2h心室肌中Cx43的表达水平明显降低,而缺血后24h心室肌中Cx43的表达增加(P<0·05)。心电图显示,发生心律失常之前10个心动周期的心电QT间期较脑未梗死前延长(P<0·01)。结论大鼠右侧局灶性脑缺血所引起的心律失常可能与心室肌Cx43蛋白表达异常并导致的QT间期延长有关。

Ahn To detect the expression and distribution of ventricular connexin43 （Cx43） in cerebrocardiac syndrome model rats and to probe the relationship between the expression of ventricular Cx43 and thearrhythmia caused by acute focal cerebral ischemia. Methods The cerebrocardiac syndrome model rats were induced by occluding right middle cerebral artery. The ECG was monitored. The microstructure of the myocardium was examined by electronic microscope. Then the ventricular tissue was taken 2 hours, 24 hours after cerebral ischemia. The expression and distribution of Cx43 of the ventricular tissue were detected by Western blot and immunohistochemistry. Results Changes of bridge corpuscle in intercalated disc and gap junction in myocardial tissue were detected under the electronic microscope after cerebral ischemia. According to the results of Western blot and immunohistochemistry, decreased amounts of Cx43 were found in the ventricle 2 hours after cerebral ischemia, while the expression of Cx43 increased in the ventricle 24 hours after cerebral ischemia compared with the control group. From the ECG, QT intervals of ten cardiac cycles before the arrhythmia caused by cerebral ischemia are remarkably longer than that before occluding right middle cerebral artery. Conclusion Abnormal expression of Cx43 protein in the ventricle after cerebral ischemia caused QT intervals prolongation which may be related with the arrhythmia resulted from acute focal cerebral ischemia.