有氧训练大鼠腓肠肌组织微小RNA-133a和肌细胞增强因子2的表达

Effect of aerobic exercise on the expression of microRNA-133a and myocyte enhancer factor 2 in the gastrocnemius

背景:研究表明微小RNA-133a、肌细胞增强因子2和成肌分化抗原可调解骨骼肌的分化与重塑。目的:观察有氧训练对腓肠肌微小RNA-133a、肌细胞增强因子2和成肌分化抗原表达的影响。方法:将SD大鼠随机分为对照组和有氧训练组,有氧训练组采用大鼠跑台运动模型,而对照组不进行运动训练。训练4,6周后采集各组大鼠腓肠肌组织,并称取腓肠肌的质量,实时定量PCR检测骨骼肌中肌球蛋白、微小RNA-133a、肌细胞增强因子2与成肌分化抗原mRNA的表达,并采用免疫组织化学的方法检测腓肠肌Ⅱ型肌纤截面积的改变。结果与结论:训练4,6周,有氧训练组大鼠腓肠肌的相对质量以及肌球蛋白重链-Ⅱa的表达水平较对照组显著增加(P<0.05或P<0.01),Ⅱ型肌纤维横截面积即显著增大(P<0.05),其微小RNA-133a和肌细胞增强因子2mRNA的表达较对照组显著升高(P<0.05,P<0.01),而成肌分化抗原mRNA的表达在各组间差异均无显著性意义。证实,有氧训练可上调大鼠腓肠肌组织微小RNA-133a、肌细胞增强因子2mRNA的表达。

BACKGROUND： Studies have demonstrated that mircoRNA-133a, myocyte enhancer factor 2, and myogenic differentiation antigen can regulate the development and remodeling of skeletal muscle. OBJECTIVE： To investigate the effect of aerobic exercise on the expression of mircoRNA-133a, myocyte enhancer factor 2, and myogenic differentiation antigen in the gastrocnemius. METHODS： Forty male SD rats were randomized into control and training group. The treadmill training was performed in the training group, and no training was in the control group. After training for 4 and 6 weeks, myosin, microRNA-133a, myocyte enhancer factor 2, myoblast differentiation antigen mRNA expressions in the gastrocnemius were detected using quantitative real-time PCR, and the changes in cross-section area of type Ⅱ muscle fiber was detected using immunohistochemistry method. RESULTS AND CONCLUSION： After the continuous treadmill training for 4 and 6 weeks, the relative weight of gastrocnemius and the contents of myosin heavy chain II a mRNAs increased significantly compared with the control group （P 〈 0.05 or P 〈 0.01）. Simultaneously, the cross-sectional area of type Ⅱ muscle fibers increased （P﹤0.05）. The expressions of mircoRNA-133a and myocyte enhancer factor 2 increased significantly （P 〈 0.05 and P 〈 0.01） in training groups after 4 and 6 weeks of aerobic exercise, while the expression of myogenic differentiation antigen maintained the same levels. It is indicated that aerobic exercise elevates the expressional levels of mircoRNA-133a and myocyte enhancer factor 2.