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目的:探讨力竭运动后不同时相大鼠心肌线粒体转录因子A(mtTFA)表达的变化特点。方法:90只健康成年雄性SD大鼠,分为一次力竭游泳运动组(n=40)、2周反复力竭游泳运动组(n=40)及安静对照组(n=10),分别于力竭运动后0、6、12及24小时取材,应用免疫荧光技术和图像分析方法研究大鼠心肌mtTFA含量的变化。结果:在一次力竭和反复力竭运动后,大鼠心肌各部位mtTFA表达含量均显著低于对照组(P<0.01)。一次力竭运动后,大鼠心肌室间隔、右心室mtTFA含量在运动后12小时达到最低(P<0.01),左心室mtTFA含量在运动后24小时达到最低;反复力竭运动后,室间隔、右心室mtTFA含量在运动后12小时达到最低(P<0.01),而左心室mtTFA含量在运动后6小时达到最低。结论:一次力竭运动和反复力竭运动可导致mtTFA表达明显降低,直接影响心肌纤维线粒体的氧化能力和能量产生,可能是运动性心肌微损伤和心律失常发生的诱导因素和重要机制之一。此外,上述改变在运动后24小时出现不同程度的回升也提示急性大强度运动后心肌mtTFA的改变是可恢复性的,有别于病理性心肌损伤。
Objective: To investigate the changes of mitochondrial transcription factor A (mtTFA) expression in myocardium at different phases after exhaustive exercise. Methods: Ninety healthy adult male Sprague-Dawley rats were divided into three groups: one exhaustive swimming group (n = 40), two exhaustive swimming groups (n = 40) and quiet control group (n = 10) The rats were drawn at 0, 6, 12 and 24 hours after exhaustive exercise. The changes of mtTFA in myocardium of rats were studied by immunofluorescence and image analysis. Results: After exhaustive exhaustion and repeated exhaustive exercise, mtTFA expression levels in various parts of myocardium in rats were significantly lower than those in control group (P <0.01). After exhaustive exercise, the content of mtTFA in ventricular septum and right ventricle of rats was the lowest at 12 hours after exercise (P <0.01), and the content of mtTFA in left ventricle reached its lowest at 24 hours after exercise. After repetitive exhaustive exercise, Right ventricular mtTFA content reached the lowest 12 hours after exercise (P <0.01), while left ventricular mtTFA content reached the lowest 6 hours after exercise. CONCLUSION: A single exhaustive exercise and repeated exhaustive exercise can significantly reduce the expression of mtTFA, which may directly affect the oxidative capacity and energy production of mitochondria in myocardial fibers. It may be one of the most important inducing factors and mechanisms of myocardial micro-injury and arrhythmia. In addition, these changes in the 24 hours after exercise showed varying degrees of recovery also prompted changes in myocardial mtTFA after acute high-intensity exercise is recoverable, different from the pathological myocardial injury.