运动性心肌肥大大鼠心肌肌肉生长抑制素表达的变化

目的:观察运动性心肌肥大大鼠心肌组织肌肉生长抑制素(myostatin,MSTN)表达的变化。方法:16周龄雄性SD大鼠随机分为对照组和运动组,每组10只。运动组进行持续8周跑台训练,每周5次,每次60分钟,跑速26米/分钟。测定两组大鼠心重并计算心系数,HE染色观察心肌细胞横截面积,分别采用real-time PCR技术和western blot方法测定心肌MSTN mRNA和蛋白表达,放免法测定血浆MSTN水平。结果:运动组大鼠心脏重量和心系数显著高于对照组(P<0.05),心肌细胞横截面积增大。运动组大鼠血浆MSTN水平、心肌MSTN mRNA和蛋白表达显著低于对照组(P<0.05)。结论:运动性心肌肥大时,大鼠心肌MSTN mRNA和蛋白表达被抑制,可能通过解除其对心肌生长的负调控作用,促进心肌细胞对运动产生适应性肥大。

Alteration of the Myostatin Expression in Myocardium of Rats with Exercise-induced Cardiac Hypertrophy

Objective To observe the alteration of the myostatin(MSTN) expression in myocardium of rats with exercise-induced cardiac hypertrophy.Methods Male 16-week-old SD rats were randomly divided into control group(n = 10) and treadmill running group(n = 10).Rats in running group ran on treadmill 60 min at the speed of 26 m/min,5 days/week for 8 weeks.Heart weight and the ratio of heart weight/body weight was measured,the cross section area of cardiac tissue was observed using the HE stain,the mRNA and protein expression of MSTN were detected by real-time PCR and western bolt,respectively,and plasma MSTN level was detected by radioimmunoassay.Results The heart weight and the heart weight/body weight ratio increased significantly in running group(P < 0.05) and the cardiac cell cross section area enlarged markedly.Compared with the control group,plasma ir-MSTN content and myocardium MSTN mRNA and protein level of rats in running group decreased significantly(all P < 0.05).Conclusion The expression of myocardial MSTN mRNA and protein level of rats was inhibited in exercise-induced cardiac hypertrophy,which probably caused by abolishing the negative regulation on myocardium.