持续和间歇有氧运动对心梗大鼠心肌Myostatin及其受体表达的影响

Effects of Continuous and Interval Aerobic Exercise on Expressions of Myostatin and Its Receptor in Infarcted heart

目的:探讨持续和间歇有氧运动对心肌梗死(MI)大鼠心功能及心肌肌肉抑制素(Myostatin)及其受体表达的影响。方法:3月龄雄性Sprague-Dawley大鼠,随机分为安静对照组(A组)、MI组(B组)、MI+持续有氧运动组(C组)和MI+间歇有氧运动组(D组),每组12只。其中,C组和D组大鼠于术后1周开始进行跑台适应性训练(10～15m/min,30min/天,共5天)。之后C组以16m/min(50%～60%VO2max)运动60min/天,5天/周,共8周;D组以10 m/min(40%～50%VO2max)运动10 min,再以25 m/min(85%～90%VO2max)运动7min和以15m/min(50%～60%VO2max)运动3min,依次交替进行运动60min/天,5天/周,共8周。训练结束后,通过心电图和血流动力学等指标测定心功能变化;采用RT-PCR法检测心肌ActRIIB的基因表达,采用Western Blot法检测心肌α-actin、α-myosin、Myostatin和ActRIIB的蛋白表达,采用荧光免疫组化法观察分析心肌Myostatin和ActRIIB表达。结果:MI后心功能和心肌α-actin及α-myosin表达显著降低,Myostatin和ActRIIB表达显著升高;持续和间歇有氧运动可显著提升MI大鼠心功能和心肌α-actin及α-myosin表达,降低Myostatin和ActRIIB表达,且间歇有氧运动效果优于持续有氧运动。结论:间歇有氧运动有效提升MI大鼠心功能和心肌α-actin和α-myosin的表达,且优于持续有氧运动干预效果;间歇有氧运动有效降低MI大鼠心肌Myostatin和ActRIIB的表达,且优于持续有氧运动干预效果,并与MI心脏心功能提升关系密切。

Objectives： To discuss the influence of continuous and interval aerobic exercise on myocardial myostatin, ActRIIB and myocardial function in myocardial infarction （MI） rats. Methods ： 3-month-old male Sprague-Dawley rats were randomly divided into ： sedentary control group （A）, sedentary MI group （B）, MI with continuous aerobic exercise group （C） and MI with aerobic interval training group （D）. The MI model in rats were established by ligation of left anterior descending （LAD） coronary artery. After a 5 day＇s adaptability training （10 15m/min, 30min/d）, rats in Group C were subjected to 8 week treadmill training at the speed of 16m/rain for 60rain/d, 5d/wk and rats in Group D warmed up at the speed of 10m/min on the treadmill for 10min at first, and then ran at the speed of 25m/min for 7rain, 15m/min for 3min, sequentially alternating, 60min/d, 5d/wk, total 8 weeks. Hemodynamic measurement and electrocardiogram were performed to evaluate the cardiac function after 8 weeks training. Then the hearts were picked out and expression levels of myostatin, ActRIIB, a-actin and a myosin were detected by RT-PCR, Western Blot or immunofluorescence. Results：Compared to control rats, the MI rats were found to have impaired cardiac function and decreased the expression levels of α-actin and a-myosin, increased the expression levels of Myostatin and ActRIIB. Continuous and aerobic interval training both can increase the expressions of α-actin and α-myosin and decrease the expressions of Myostatin and ActRIIB significantly, but the latter is better. Conclusion：Both continuous and aerobic interval training can effectively promote myocardial function, which related to increasing the expression levels of α actin and α-myosin and decreasing the levels of Myostatin and ActRIIB, and aerobic interval training has a better effect.