Effects of amiodarone on connexin43 expression during myocardial ischemia-reperfusion in rats / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effects of amiodarone on connexin43 (Cx43) expression during myocardial ischemia-reperfusion (I/R) in rats.Methods Adult male Sprague-Dawley rats,weighing 250-300 g,were randomly divided into 3 groups (n =12 each) using a random number tableshame operation group (group S),I/R group and amiodarone group (group AM).Myocardial ischemia was induced by occlusion of anterior descending branch of left coronary artery for 30 min followed by 120 min of reperfusion in I/R and AM groups.Amiodarone 5.0 mg/kg was injected intravenously at 10 min before ischemia followed by infusion at a rate of 0.15 mg· kg-1 · min 1 until the end of reperfusion.Arrhythmia was recorded during reperfusion and scored.At the end of reperfusion,blood samples were taken from the femoral artery for determination of the serum levels of cardiac troponin Ⅰ (cTnI) and creatine kinase isoenzyme-MB (CK-MB).Then the animals were sacrificed and myocardial specimens were removed for determination of the expression of Cx43 protein (by immuno-histochemistry) and mRNA (by RT-PCR) in myocardial tissues.Results Compared with group S,the arrhythmia score and serum levels of CK-MB and cTnl were significantly increased,and the expression of Cx43 protein and mRNA was downregulated in I/R and AM groups (P ＜ 0.05).Compared with group I/R,the arrhythmia score and serum levels of CK-MB and cTnI were significantly decreased,and the expression of Cx43 protein and mRNA was up-regulated in group AM (P ＜ 0.05).Myocardial Cx43 was unevenly distributed in group I/R,while evenly distributed in S and AM groups.Conclusion The mechanism by which amiodarone protects myocardium against I/R-induced arrhythmia is related to inhibition of redistribution of Cx43 and up-regulation of Cx43 expression in rats.