耐力训练对肌球蛋白重链的影响及MyoD、Myogenin的调控作用

The effect of endurance training on heavy chain myosin as well as the regulating function of MyoD and Myogenin

为了解耐力训练对肌球蛋白重链(MHC)组成及生肌调节因子MyoD和Myogenin表达的影响,探讨MyoD和Myogenin表达与MHC转换的关系,选用雄性SD大鼠20只,随机分成安静对照组(10只)和耐力训练组(10只)。耐力训练组进行跑台练习:跑台坡度10°,跑速20m/min,每天1次,每次1h,每周训练6d,28d后取浅层胫前肌。SDS-PAGE方法测定MHCⅠ、Ⅱa、Ⅱx、Ⅱb蛋白组成;RT-PCR测定MHCs及MyoD、Myogenin mRNA表达。结果:耐力训练没有改变MHCs蛋白表达,耐力训练后Ⅱx-MHC mRNA表达显著减少(P<0.05);耐力训练使MyoD、Myogenin mRNA均显著下降。结果说明耐力训练使快型MHC基因表达减少;快型MHCⅡx减少可能与MyoD表达下降有关,MyoD和Myogenin可能参与MHC表达的调节。

In order to gain an insight into the effect of endurance training on the composition of heavy chain myosin （HCM） and the expression of myogenic regulating factors MyoD and Myogenin, and to probe into the relation between the expression of MyoD and Myogenin and the conversion of HCM, the authors selected 20 male SD rats and randomly divided them into a resting control group （10 rats） and an endurance training group （10 rats）, put the rats in the endurance training group on a treadmill with a ＋ 10° slope for a running exercise at the speed of 20m/min once a day, 1 hour per time, 6 days a week, extracted the superficial layer of tibial anterior muscle of the rats in the two groups 28 days later, applied the SDS-PAGE method to measure the protein composition of HCM Ⅰ, Ⅱa, Ⅱx and lib, applied the RT-PCR method to measure HCMs and the expression of MyoD and Myogenin mRNA, and revealed the following findings： Endurance training did not change the protein expression of HCMs, after endurance training the expression of IIx - HCM mRNA was significantly reduced （P〈0.05）; endurance training lowered MyoD and Myogenin mRNA significantly, which indicate that endurance training reduce the gene expression of fast HCM, and that the reduction of fast HCM Ⅱx may relate to the reduction of the expression of MyoD, and that MyoD and Myogenin may play a role in the adjustment of the expression of HCM.