急性心肌缺血时连接蛋白43降解对传导速度影响的研究

Impacts of connexin 43 degradation on conduction velocity during acute myocardial ischemia

目的 :探讨急性短时间缺血时心肌细胞连接蛋白 4 3(Cx4 3)的降解对缺血心肌电传导速度的影响。方法 :16只犬随机分为正常对照组 (n =4 )和缺血组 (n =12 ) ,缺血组结扎冠状动脉 1h造成急性心肌缺血 ,测定缺血区心肌电传导速度 ,应用激光共聚焦显微镜技术和荧光免疫组织化学方法对缺血心肌Cx4 3含量进行定量检测。结果 :(1)急性心肌缺血时Cx4 3迅速降解 ,心肌电传导速度明显下降 ;(2 )缺血区各局部传导速度与该部位Cx4 3像素密度呈明显正相关 ;(3)出现持久传导阻滞的区域其Cx4 3降解程度均大于 5 0 %。结论 :急性短时间 (1h)缺血时Cx4 3的降解已经开始对心肌传导速度产生明显的影响 ,而局部心肌Cx4 3的严重降解将导致该区域出现持久传导阻滞。

AIM: To study the impacts of the myocardial connexin 43 degradation on conduction velocity during acute myocardial ischemia. METHODS: Studies were carried out in 16 dogs which were randomly divided into control group( n= 4) and ischemia group( n= 12). The acute myocardial ischemia was induced by ligation of the left anterior descending coronary artery. The conduction velocity of ischemic myocardium was determined. The content of Cx43 of the ischemic myocardium was examined by laser confocal microscopy with a double-label immunohistochemistry technique. RESULTS: (1)The Cx43 degraded rapidly during acute myocardial ischemia, and the conduction velocity of ischemic myocardium declined greatly; (2)The conduction velocity correlated positively with the Cx43 pixel density in each small region of ischemic myocardium; (3) The Cx43 pixel density decreased over 50% in the region which occuring permanent conduction block. CONCLUSION: These data suggest the degradation of Cx43 decreases the conduction velocity greatly during acute short time myocardial ischemia, and severe degradation of Cx43 would lead to permanent conduction block.