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

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.