反复力竭性运动后大鼠血清cTnI和心肌组织形态学的改变

Changes of serum cTnI and myocardium histomorphology after repeated exhaustive exercise in rats

目的:观察反复力竭性游泳运动后,不同时相大鼠血清心肌肌钙蛋白I(cTnI)与心肌组织形态学的动态改变,以评价过度运动后恢复期是否存在延迟性心肌损伤?方法:采用经典的Thomas的方法,通过力竭性游泳运动建立运动性心肌损伤实验动物模型。将无训练的87只Wistar雄性大鼠随机分为安静对照组和力竭性运动后即刻组、3 h组、6 h组、12 h组、24 h组、48 h组和96 h组。分别于末次运动结束后即刻、3、6、12、24、48和96 h,采血分离血清检测cTnI,并进行心肌组织的病理学检查。结果:①与安静对照组比较,力竭性运动后即刻、6 h和48 h大鼠血清cTnI的含量明显增加(P<0.05和P<0.01),其中运动后6 h和48 h分别达高峰,运动后3、12、24 h仍保持在较高水平,运动后96 h基本恢复运动前的水平。②经1周反复力竭性运动,光镜下可见运动后不同时相大鼠心肌细胞均有不同程度的损伤,运动后48 h最严重,96 h有所减轻。结论:长期过度运动和/或力竭性运动后,心肌组织发生病理性改变,且具有延迟性加重现象,即存在延迟性心肌损伤。

AIM： To study the dynamic changes of serum cTnI and myocardium histomorphology in different time periods after exhaustive exercise in rats in order to evaluate delayed-onset myocardial damage during recovery phase after exercise.METHODS： Animal models of exercise-induced myocardial injury were established according to Thomas＇s method.Healthy untrained 87 male Wistar rats were selected and randomly divided into one sedentary control group（n=10） and seven exhaustive exercise groups according to times of recovery phase after exercise（immediately after,3,6,12,24,48 and 96-h groups with 11 rats in each group）.Blood samples were obtained and cTnI in serum was measured.Changes of myocardial histopathology were examined immediately after,3,6,12,24,48 and 96 h after exercise.RESULTS： Compared with that in sedentary control group,the level of serum cTnI was significantly increased at immediately after,6 and 48 h after repeated exhaustive exercise（P〈0.05 and P〈0.01）,peaked at 6 h and 48 h,maintained the higher level at 3,12 and 24 h and basically recovered at 96 h post-exercise.After 1 week consecutive daily exhaustive exercise,myocardial injuries of different degrees were observed at immediately after,3,6,12,24,48 and 96 h after exhaustive exercise under light microscope.Myocardial injury was most severe at 48 h and was alleviated at 96 h post-exercise.CONCLUSION： After long-term excessive exercise and/or exhaustive exercise,the pathological changes in myocardium tissue occurred in a time-dependent manner.Similar to skeletal muscle,delayed-onset myocardial injury is also induced by exhaustive exercise.