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目的:探明低强度周期性应力调控骨骼肌细胞增殖分化的分子机制。方法:采用Flexercell Strain Unit系统对C2C12成肌细胞加载5%牵张应力,观察细胞增殖和分化情况,检测成肌细胞分化标志基因myogenin等的表达情况,荧光报告系统检测NFkappa B的活性,microRNA特异性荧光定量PCR检测miR146a在增殖和分化条件下表达差异。结果:在5%周期性牵张应力作用下,成肌细胞分化受到抑制;无论增殖条件还是分化条件下,低强度拉伸均可以导致miR146a升高,但在分化条件下更为明显(P<0.05);分化条件下组成性的NFkappa B的活性低于其在增殖条件下的活性(P<0.05)。结论:低强度应力抑制骨骼肌细胞分化,可能是通过miR146a的升高从而抑制NFkappaB的活性引起的。
Objective: To explore the molecular mechanism of low intensity periodic stress regulating proliferation and differentiation of skeletal muscle cells. Methods: C2C12 myoblasts were loaded with Flexercell Strain Unit system at 5% stretch stress to observe the proliferation and differentiation of myoblasts. Myofibroblast differentiation marker gene myogenin was detected by fluorescent reporter system. The NF-κB activity was detected by fluorescence reporter system. Fluorescent quantitative PCR was used to detect miR146a expression in proliferation and differentiation conditions. Results: Myoblast differentiation was inhibited by 5% cyclic stretch stress. MiR146a was increased by low-intensity stretching under both proliferative and differentiation conditions, but more significantly under differentiation conditions (P < 0.05). The activity of constitutive NFkappa B under differentiation was lower than that under proliferation condition (P <0.05). Conclusion: Low-intensity stress can inhibit the differentiation of skeletal muscle cells, which may be caused by the increase of miR146a and the inhibition of NFkappaB activity.