力竭性跑台运动致大鼠心肌顿抑现象研究

The Establishment of Exercise-induced Myocardial Stunning Model of Rat with Repeated Exhaustive Exercise on Treadmills

目的:观察大鼠反复力竭性跑台运动后不同时相心电图、心肌梗死面积和超微结构等指标的变化情况;探讨运动性心肌顿抑现象存在的可能性。方法:成年雄性SD大鼠22只,随机分为A组(空白对照组,简称对照组,n=6)和B组(反复力竭性运动组,简称运动组,n=16)。根据运动后心电图是否出现异常将B组分为B1组(心电异常组)和B2组(心电正常组)。测定运动前、运动后即刻、10min、20min、30min、1h、1.5h、2h、3h、6h、12h、24h的心电图;并于运动后24h进行左室前壁心肌坏死面积分析;电镜观察部分大鼠心电异常时及运动后24h左室前壁心肌纤维超微结构变化情况。结果:B1组在运动后1～3h大鼠心电图出现J点下移,T波低平或倒置,S波加深,R波逐渐减小,ST-T弓背上抬,一过性的病理性Q波等异常变化,至运动后24h时上述变化基本恢复正常;B2组运动前、后大鼠心电图无明显变化;A组、B1组和B2组的心肌坏死区比率分别为17.9%±14.95%、29.1%±13.91%、21.3%±11.47%,两两比较组间差异无显著性;B1组心电出现明显异常时,心肌超微结构出现异常。而运动后24h时基本恢复正常。结论:反复力竭性跑台运动能诱发大鼠心脏心肌顿抑,证实存在着与临床缺氧缺血所致心肌顿抑相似的运动性心肌顿抑现象;心肌线粒体大面积损伤可能与心电图异常存在一定的关联性。

Objective：To verified the myocardial stunning phenomena caused by repeated exhaus- tive exercise on treadmills, and observed the changes of myocardial injury, electrocardiogram （ECG） and ultra structure of rats after exhaustive treadmill running. Methods： To select 22 SD class male rats, and are divided into 2 groups at random. A group is called control group and has 6 rats, B group is called training group and has 16 rats. According to normal or abnor- mal electrocardiogram after running, B group is divided B1 group called abnormal electrocardio- gram group and B2 group called normal electrocardiogram group. The change of electrocardio- gram on control, instant, 10 min, 20 min, 30 rain, 1 h, 1.5 h, 2 h, 3 h, 6 h, 12 h, 24 h is monitored. The area cellular necrosis in the parties anterior of left ventricle is analyzed on 24h after exer- cise and the histological changes of myocardial fiber are observed under Transmission Electron Microscope （TEM）. Results： Electrocardiogram between pre and after exercise were not sig- nificance difference in B2 group, and in B1 group, J point had downward shift, T wave shifted down and appeared inversion partially, and appeared pathologic Q wave in a few of rats with running. At the end of the drove, the phenomenon is gradually the same to the before. The my- ocardial necrosis percent of Control group,B2 group and B1 group are respectively 17.93%± 14.95%. 29.05 % ± 13.91% 21.34 % ± 11.47 %. There is no group difference each other. When the B1 of electrocardiogram was abnormal after running, under the electron-microscope, degeneration and swelling of mitochondria were found, but others had no significant change. and when 24h after running, under the electron-microscope, the degeneration and lyses of myo- fibrils, swelling of mitochondria vacuolar degeneration of carryon were found. Conclusions：Re- peated exhaustive treadmill running can efficiently induce the phenomenon of the myocardial stunning and the exercises-induced myocardial stunning exists. There is certain relationship between the changes of electrocardiogram and micro-damage of mitochondria.