小鼠与大鼠急性力竭运动方法的建立及其对心肌超微结构的影响

Establishment of mouse and rat acute exhaustive exercise models and their effects on myocardial ultrastructures

目的研究小鼠与大鼠急性力竭运动的方法及急性力竭运动对心肌超微结构的影响。方法健康雄性8月龄C57/black小鼠及SD大鼠各10只,分别分为对照组和力竭运动组。小鼠进行为期2周的适应性训练,即在平板跑台上跑步训练,1次/d,10 min/次,运动速度为15～20 m/min;大鼠进行为期1周的适应性训练后,在平板跑台上跑步1次/d,15 min/次,运动速度为20 m/min。适应性运动训练后进行一次性力竭运动,小鼠力竭运动速度为20～25 m/min,大鼠力竭运动速度为25～30 m/min,动物在跑台上持续跑步直至出现顽固拒跑及力竭体征时停止跑步,并立即将动物麻醉后开胸取左心室心尖部心肌,2%戊二醛固定、树脂包埋、制作超薄切片,以透射电子显微镜观察心肌超微结构的变化。结果小鼠经2周适应性训练后,一次性跑步平均时间(3.6±2.2)h、跑步距离达(4 561±2 174)m时可造成明显的力竭;心肌超微结构变化表现为心肌细胞水肿、线粒体嵴肿胀甚至溶解,出现部分线粒体异常高密度颗粒样结构及溶酶体增多。大鼠经过1周适应性训练后,一次性跑步平均时间(2.3±0.4)h、跑步距离达(6 947±1 052)m时可造成明显的力竭;心肌超微结构变化表现为心肌细胞水肿,肌丝排列紊乱,线粒体密度增加,线粒体嵴断裂、溶解、甚至空泡化。结论小鼠及大鼠一次性急性力竭运动可致心肌细胞水肿与线粒体损伤。

Objective To explore the methods of acute exhaustive exercise in mice and rats,and investigate the effects of acute exhaustive exercise on myocardium ultrastructures. MethodsTen healthy C57/black mice and 10 healthy SD rats aged 8 months were divided into control group and exhaustive exercise group respectively.Before acute exhaustive exercise,mice were subjected to adaptive training(treadmill running,1 time/d,10 min/time,15 to 20 m/min) for 2 weeks,and SD rats received adaptive training(treadmill running,1 time/d,15 min/time,20 m/min) for 1 week.Animals in exhaustive exercise group underwent exhaustive running for one time(20 to 25 m/min for mice and 25 to 30 m/min for rats) until they stubbornly refused to exercise with signs of exhaustion.Left ventricular muscles were then obtained for ultrastructure observations with transmission electron microscope. ResultsAfter adaptive training in mice for 2 weeks,exhaustion occurred after continuous running for(4 561±2 174) m within(3.6±2.2) h,and the ultrastructures were characterized by myocardial edema,mitochondria cristae swelling and lysis,abnormal high density structures in some mitochondria and increased lysosomes.After adaptive training in rats for 1 week,exhaustion occurred after continuous running for(6 947±1 052) m within(2.3±0.4) h,and the ultrastructures were characterized by myocardial edema,chaotic myofilament arrangement,increased mitochondria density and mitochondria cristae rupture,lysis and vacuolization. ConclusionAcute exhaustive exercise can induce myocardial edema and mitochondrial damage in mice and rats.