Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1, Yamada-Oka, Suita, Osaka 565-0871, Japan.
Acta Biomater. 2013 Jul;9(7):7227-35. doi: 10.1016/j.actbio.2013.03.015. Epub 2013 Mar 20.
Bone tissue geometry shows a highly anisotropic architecture, which is derived from its genetic regulation and mechanical environment. Osteoblasts are responsible not only for bone formation, through the secretion of collagen type I, but also for sensing the mechanical stimuli due to bone surface strain. Mechanotransduction by osteoblasts is therefore considered one of the regulators of anisotropic bone tissue morphogenesis. The orientation of osteoblasts and the secreted collagen matrix was successfully regulated by applying a continuous mechanical stress on osteoblasts for a long period. Under a continuous cyclic stretch of 4% magnitude at a rate of 2 cycles min(-1), osteoblasts reoriented their actin stress fibers in the direction that minimizes the strain applied to them. Extended culture of up to 2weeks resulted in the formation of collagen fibers in the extracellular spaces, and the preferred orientation of these fibers was parallel to the direction of cell elongation. To the best of our knowledge, this is the first report to establish anisotropic bone matrix architecture following the alignment of osteoblasts under mechanical stimuli for long-term cultivation.
骨组织的几何结构呈现出高度各向异性的特点，这是由其遗传调控和力学环境决定的。成骨细胞不仅负责通过分泌 I 型胶原来进行骨形成，还负责感知由于骨表面应变引起的机械刺激。因此，成骨细胞的机械转导被认为是调节各向异性骨组织形态发生的因素之一。通过对成骨细胞施加长期连续的机械应力，可以成功地调节成骨细胞的取向和分泌的胶原基质。在幅度为 4%、频率为 2 个循环/分钟的连续循环拉伸下，成骨细胞将肌动蛋白应力纤维定向排列在使施加给它们的应变最小的方向上。延长培养时间长达 2 周会导致细胞外空间中胶原纤维的形成，这些纤维的优选取向与细胞伸长的方向平行。据我们所知，这是第一个在机械刺激下通过长期培养使成骨细胞排列一致来构建各向异性骨基质结构的报道。
