运动预处理对压力超负荷诱导的大鼠病理性心肌肥厚的影响

Exercise Preconditioning Improving the Pathological Cardiac Hypertrophy in Pressure Over-loaded Rats

目的:探究运动预处理(EP)对压力超负荷引起的大鼠病理性心肌肥厚和心力衰竭(心衰)的影响。方法:雄性6周龄SPF级SD大鼠60只分为Sham组、主动脉缩窄(TAC)组和运动预处理+主动脉缩窄(EP+TAC)组,每组20只。分别在TAC术后4周和8周时行超声心功能评价、病理检查以及心衰标志物检测来探讨EP的作用。结果:超声心动图和病理检测提示两个手术组的检测指标相比Sham组均有明显变化,而且两手术组间比较,EP+TAC组的各项指标均优于TAC组,特别是在术后8周时,左心室射血分数增加15%,心脏重量指数减少15.7%和左心室重量指数减少20%(P<0.05),差异有统计学意义。从心衰标志物心钠肽和脑钠肽信使核糖核酸(mRNA)和蛋白表达来看,与Sham组比较,TAC组在两个时间点表达量均明显升高,EP+TAC组的变化在TAC术后4周时不明显,但在术后8周时升高明显。与TAC组相比,EP+TAC组的mRNA表达量在术后4周时分别下降47%和62%,术后8周时减少44.0%和28.1%(P<0.05);蛋白表达量术后4周时下降42.3%和48.0%,术后8周时下降21.5%、38.3%(P<0.01),在术后8周时两手术组心衰标志物表达量差异较术后4周时减小。结论:EP能改善压力超负荷诱导大鼠病理性心肌肥厚,且在早期的保护作用明显,能够延缓心衰的进程,为进一步探究作用机制提供模型基础。

Objective： To explore the effect of exercise preconditioning （EP） on pathological cardiac hypertrophy and heart failure （HF） in pressure over-loaded experimental rats. Methods：A total of 60 SD rats at the age of 6 weeks were randomly divided into 3 groups, n=20 in each group. Sham-operation group, Transverse aortic constriction （TAC） group and EP ＋ TAC group. The cardiac function and structure were evaluated by echocardiography, patholgical changes and HF biomarkers were examined for EP effect at 4 and 8 weeks after TAC. Results：Compared with Sham-operation group, the cardiac function and structure had obvious changes in the other 2 groups. Compared with TAC group, the ejection fraction in EP＋ TAC group increased 15%, the heart weight index and left ventricular weight index decrease 15.7%and 20%respectively at 8 weeks after TAC, all P〈0.05. Compared with Sham-operation group, the mRNA and protein expressions of ANP and BNP increased in TAC group at 4 and 8 weeks after TAC, increased in EP＋TAC group at 8 week after TAC. Compared with TAC group, the mRNA expressions of ANP and BNP in EP＋TAC group decreased 47%and 62%at 4 weeks after TAC, decreased 44%and 28.1%at 8 weeks after TAC, all P〈0.05;the protein expression of ANP and BNP in EP＋TAC group decreased 22.3%and 48%at 4 weeks after TAC, decreased 21.5%and 38.3%at 8 weeks after TAC, all P〈0.01. Conclusion： EP may improve cardiac pathological hypertrophy in pressure over-loaded rats at the early stage, and delay the heart failure process.