Biology and Anatomy Department, Medical School, Shaheed Beheshti University of Medical Sciences, Tehran, Iran.
Tissue Cell. 2011 Dec;43(6):359-66. doi: 10.1016/j.tice.2011.07.004. Epub 2011 Aug 26.
It has been revealed that skeletal muscle cells have the potential to generate, sense and respond to biomechanical signals and that, mechanical force is one of the important factors influencing proliferation, differentiation, regeneration and homeostasis of skeletal muscle cells and myoblasts. The aim of this study was to illustrate the effect of cyclic uniaxial strain on myogenic differentiation of adipose-derived stem cells (ASCs). This study was designed to investigate this effect within 3 days in 4 groups: control (untreated), chemical, chemical-mechanical and mechanical based on exposure of ASCs to chemical growth factors for 3 days or to mechanical strain just on the 2nd day. Finally, cell orientation, muscle-related gene expression, myosin protein synthesis and the number of myosin-positive cells were examined to estimate the rate of differentiation. By studying the cells before and after exposure to uniaxial strain, it could be observed that by exerting the load, the cells were organized almost perpendicularly to strain direction. Real-time RT-PCR demonstrated that uniaxial strain had a significant effect on up-regulation of muscle-related genes in chemical-mechanical group (P < 0.001) as compared to mechanical or chemical groups. Immunocytochemistry confirmed the myosin-positive cells in treated groups and the numbers of these cells were enumerated by flow cytometry. These data suggest that uniaxial cyclic strain could affect ASCs and cause their myogenic differentiation and that the combination of chemical myogenic differentiation factors with mechanical signals promotes differentiation much more than differentiation by chemical myogenic differentiation factors or mechanical signals alone.
已经揭示，骨骼肌细胞具有产生、感知和响应生物力学信号的潜力，并且机械力是影响骨骼肌细胞和成肌细胞增殖、分化、再生和稳态的重要因素之一。本研究的目的是阐明循环单轴应变对脂肪来源干细胞（ASCs）成肌分化的影响。本研究旨在 4 组中研究这一影响：对照组（未处理）、化学组、化学机械组和机械组，基于 3 天内向 ASCs 暴露于化学生长因子或仅在第 2 天暴露于机械应变，分别进行处理。最后，通过检查细胞取向、肌肉相关基因表达、肌球蛋白蛋白合成和肌球蛋白阳性细胞的数量来评估分化率。通过研究暴露于单轴应变前后的细胞，可以观察到通过施加负荷，细胞几乎垂直于应变方向排列。实时 RT-PCR 表明，与机械组或化学组相比，单轴应变对化学机械组肌肉相关基因的上调有显著影响（P<0.001）。免疫细胞化学证实了处理组中的肌球蛋白阳性细胞，并且通过流式细胞术对这些细胞的数量进行了计数。这些数据表明，单轴循环应变可以影响 ASCs 并引起其成肌分化，并且化学成肌分化因子与机械信号的组合比单独使用化学成肌分化因子或机械信号更能促进分化。
