运动对大鼠心肌肌浆网钙调控蛋白基因表达的影响

Effects of Exercise on Gene Expression of Calcium Handling Protein in Normal Rat Heart

目的:观察长期耐力性训练和急性力竭训练对大鼠心肌肌浆网钙调控蛋白SERCA2、PLN和RyR2基因表达的影响,探讨心脏运动适应的分子机理。方法:4月龄雄性SD大鼠,分为安静对照组、急性运动组和长期运动组。运动组适应练习2周后,长期组进行16周耐力训练(20 m/min,跑60 min,坡度0,每周5次),急性组以20 m/min速度跑至力竭,训练后检测SERCA2、RyR2和PLN的mRNA表达水平。结论:16周耐力运动使心脏重量/体重比增加(P<0.05),提示长期耐力运动可能导致心肌肥大;16周耐力运动使心肌SR的SERCA2 mRNA表达水平增加,提示长期耐力训练提高了心肌肌浆网摄取钙离子的能力;16周耐力运动导致心肌SR的PLN mRNA表达水平增加,这可能是发生运动性心律徐缓的机制之一;16周耐力运动不能改变心肌SR的RyR2 mRNA表达水平,提示运动性心肌肥大与RyR2没有关联;急性力竭运动不能改变心肌SR的SERCA2、PLN和RyR2 mRNA的表达水平(P>0.05)。

Objective： The purpose of this study was to elucidate possible molecular mechanism of the exercise-induced adaptation effect of heart by observing the influence of exercise on the SERCA2,PLN and RyR2 gene expression of calcium handling protein in normal rat heart.Methods： 4 month-aged Sprague-Dawley rats were divided into three groups randomly,namely,sedentary control（SC）,acute exercise（AE） and chronic exercise（CE） group.The animals were familiarized to run on the treadmill for two weeks,after this acclimetion period,the CE rats run 60 min/day at 20m/min for 16 weeks＇ endurance training（slope 0,five times a week）.The AE rats ran till exhausted at the same speed.The SERCA,PLB,RyR2 were measured after the test.Results： The 16 weeks＇ endurance exercises led to the increase of the ration of the heart and body weight（GP〈0.05） which indicated that the long-time endurance exercises may lead to cardiac hypertrophy.16 weeke＇ endurance exercise induced changes in mRNAs level of SERCA2,indicating that the long-time endurance training increases the capacity of sarcoplasmic reticulum in the heart musle of rat to intake calcium.The endurance training increases the expression of PLB mRNAs of the SR of the heart muscle,which may be one of the causes of the exercise-induced bradycardia.While the endurance training did not change the RyR2 mRNA expression of SR of the heart muscle,which indicates the exercise-induced cardiac hypertrophy has no correlation with the RyR2.And acute exercise did not affect the mRNA expression level of SERCA,PLB and RyR2（P〉0.05）.