周期性张应力对C2C12成肌细胞增殖的影响

Effect of cyclic stretch on the proliferation of C2C12 myoblasts

背景:在力学刺激下,肌肉组织发生改建,其中的成肌过程是一个多阶段的发育过程,细胞外基质的许多信号参与了成肌过程,其中力学信号是肌肉形成和再生的重要外界因子。目前国内外有许多关于周期性张应力刺激成肌细胞凋亡和增殖的报道,但是力学刺激在成肌作用中的具体机制目前还明确。目的:探讨周期性张应力对C2C12成肌细胞增殖的作用及影响机制。方法:采用FX4000T应力加载系统对体外培养的C2C12成肌细胞施加10%的周期性张应力,分别作用6,12,24 h。结果与结论:MTT结果显示,随着加力时间的延长C2C12成肌细胞的增殖情况及S期的细胞周期率逐渐增加,在应力作用12 h时增殖效果最明显(P<0.05),随后开始降低。Western blot检测显示,C2C12成肌细胞中核转录因子κB蛋白的表达随加力时间增加而不断减少,加力24 h时表达量又开始上升。结果提示,周期性张应力可以诱导C2C12成肌细胞增殖,能够改变其细胞周期,核转录因子κB可能也参与了此调节过程。

BACKGROUND：Mechanical stimulation triggers a muscle tissue remodeling, during which, myoblast process is a multi-stage development process. Many signals in extracellular matrix are involved in myoblast process, and mechanical signals are considered as important external factors for muscle formation and regeneration. Numerous studies concerning cyclic tensile stress effects on myoblast proliferation and apoptosis have been reported, but the specific mechanism underlying the mechanical stimulation in muscle formation is stil unclear. OBJECTIVE：To study the effects of cyclic stretch on proliferation of C2C12 myoblasts and its mechanism. METHODS：C2C12 myoblasts were cultured in vitro under 10%cyclic stretch for 6, 12 and 24 hours. RESULTS AND CONCLUSION：The results of 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide assay showed that with the time of cyclic stretch, the proliferation of C2C12 myoblasts and the rate of S-phase fraction were gradual y increased and peaked at 12 hours （P〈0.05）, and then decreased. Western blot assay showed that the expression of nuclear transcription factorκB protein was decreased with time, which was inversely correlated to the proliferation of C2C12 myoblasts, but increased at 24 hours under the cyclic stretch. These findings indicate that the cyclic stretch can induce C2C12 myoblasts proliferation and alter the cellcycle. Nuclear transcription factorκB may be involved in this process.