力竭运动对大鼠心脏传导系统ICAM-1的影响

Effect of Exhaustive Exercise on ICAM-1 in Cardiac Conduction System

目的:探讨力竭运动后不同时相心脏窦房结、房室结和浦肯野氏纤维炎性因子细胞间粘附分子-1(ICAM-1)基因和蛋白水平的表达特点,为运动性心肌损伤与心律失常发生机制的阐明提供实验依据。方法:100只健康成年雄性SD大鼠随机分为10组,每组10只,分别为一次力竭运动组(4组,n=40)、反复力竭运动组(4组,n=40)、一次力竭安静对照组(n=10)和反复力竭安静对照组(n=10)。分别于力竭运动后0、4、12及24小时取材,进行免疫荧光组化及实时荧光定量PCR分析。应用激光显微切割技术定位并收集窦房结、房室结和浦肯野氏纤维细胞,研究细胞炎性因子ICAM-1的m RNA和蛋白表达的变化。结果:一次力竭运动后心脏窦房结ICAM-1 m RNA和蛋白表达在运动后12小时达峰值,显著高于对照组(P<0.05),浦肯野氏纤维在运动后24小时达峰值,显著高于对照组(P<0.01)。反复力竭运动后心脏窦房结ICAM-1 m RNA和蛋白表达在运动后即刻和12小时出现两次峰值,显著高于对照组(P<0.01),浦肯野氏纤维ICAM-1蛋白表达12小时达峰值,显著高于对照组(P<0.01)。结论:力竭运动后心脏传导系统不同部位ICAM-1 m RNA和蛋白表达的时相规律各异,但心脏窦房结炎性因子增高幅度较大,是运动性心肌损伤与心律失常的机制之一。

Objective In this study the gene and protein expression characters of intercellular cell adhesion molecule-1（ICAM-1） in sinoatrial node,atrioventricular node,and Purkinje＇s fiber at different time-phrase after exhaustive exercise was investigated in order to clarify the mechanism of exercise-induced cardiac arrhythmia. Method 100 healthy adult male SD rats were divided into 4 groups of acute exhaustive swimming,4 groups of 2-week repeated exhaustive swimming,and their 2 respective control groups. Rats were sacrificed at 0,4,12,and 24 hours after exhaustive swimming. The electrocardiogram of each group was obtained before sacrifice. The sinoatrial node,atrioventricular node,and Purkinje＇s fiber cells were spotted and collected by Laser Micro Dissection. The m RNA and protein expression of ICAM-1 in the sinoatrial node,atrioventricular node,and Purkinje＇s fiber cells were analyzed by real-time fluorescent quantitative PCR,immunochemistry and image analysis. Results Compared to the control group,（1）the expression of m RNA and protein of ICAM-1 in sinoatrial node and atrioventricular node increased greatly 12 hours after acute exhaustive swimming（P〈0.05）,and the expression of m RNA and protein of ICAM-1 in Purkinje＇s fiber increased greatly 24 hours after acute exhaustive swimming（P〈0.01）;（2）the expression of m RNA and protein of ICAM-1 in sinoatrial node increased greatly immediately and 12 hours after repeated exhaustive swimming（〈 0.01）;（3）the expression of m RNA and protein of ICAM-1 in Purkinje＇s fiber increased greatly 12 hours after repeated exhaustive swimming（P〈0.01）. Conclusion There were differences in the expression of m RNA and protein of ICAM-1 in different parts of cardiac conduction system at different timephrase after acute and repeated exhaustive swimming,especially in sinoatrial node,which could be one of the mechanisms of exercise induced-cardiac injure and arrhythmia.