运动训练对急性心肌梗死后心室重构中受磷蛋白和肌浆网钙泵表达的影响

Effect of exercise training on expression of SERCA2a and phospholamban during ventricular remodeling in rats with acute myocardial infarction

目的探讨急性心肌梗死(AMI)后运动训练对心室重构的影响及对肌浆网钙摄取的调控机制。方法 SD大鼠随机分为假手术组(Sham组)、心梗对照组(AMI-Sed组)和心梗+运动训练组(AMI-Ex组)。结扎前降支建立AMI模型,AMI-Ex组进行跑台训练。AMI后9周,测量血液动力学参数及胶原容积分数;提取肌浆网测量摄钙能力,心肌cAMP含量,PKA、SERCA2a、16Ser-PLB及17Thr-PLB蛋白表达量。结果与AMI-Sed组比较,AMI-Ex组RVWI、肺含水率、LVSP及+dp/dt max显著升高(P<0.05),LVEDP显著降低(P<0.05)。摄钙能力、PKA、SERCA2a及16Ser-PLB蛋白表达量显著提高(P<0.05)。结论 AMI后运动训练可改善心室重构及左室泵功能障碍。其机制可能与cAMP-PKA-16Ser-PLB-SERCA2a通路有关。

【Objective】 To investigate the effect of exercise training,started early after acute myocardial infarction（AMI）,on LV remodeling and dysfunction in rats,and to study the role of calcium uptake in myocardial sarcoplasmic reticulum（SR）.【Methods】 The AMI rat model was achieved by ligating coronary artery.The animals were randomized into sham group,AMI-Sed group and AMI-Ex group.After 9 weeks of treatment,hemodynamic changes,morphological parameters and collagen volume fraction（CVF） were assessed.Capacity of SR calcium uptake,the contents of cAMP and the expression of PKA,SERCA2a,16Ser-PLB and 17Thr-PLB were detected in the myocardial homogenate.【Results】 As compared with AMI-Sed group,exercise training deceased CVF and pulmonary congestion（P 0.05）.It also improved LVSP and ＋dp/dt max,but deceased LVEDP（P 0.05）.We also found that higher capacity of SR calcium uptake and SERCA2a expression in trained rats（P 0.05）,and this may associated with increases in content of cAMP and expression of PKA and 16Ser-PLB（P 0.05）.【Conclusions】 Early exercise training in rats after AMI has beneficial effect on LV remodeling and pump function.These can be explanted by the exercise induced improvement of Ca2＋ uptake,SERCA2a expression,and PLB phosphorylation status.These effects probably proceed through increases in levels of cAMP and PKA.