Knight M M, Toyoda T, Lee D A, Bader D L
IRC in Biomedical Materials and Medical Engineering Division, Department of Engineering, Queen Mary University of London, London, UK.
J Biomech. 2006;39(8):1547-51. doi: 10.1016/j.jbiomech.2005.04.006. Epub 2005 Jun 27.
In numerous cell types, the cytoskeleton has been widely implicated in mechanotransduction pathways involving stretch-activated ion channels, integrins and deformation of intracellular organelles. Studies have also demonstrated that the cytoskeleton can undergo remodelling in response to mechanical stimuli such as tensile strain or fluid flow. In articular chondrocytes, the mechanotransduction pathways are complex, inter-related and as yet, poorly understood. Furthermore, little is known of how the chondrocyte cytoskeleton responds to physiological mechanical loading. This study utilises the well-characterised chondrocyte-agarose model and an established confocal image-analysis technique to demonstrate that both static and cyclic, compressive strain and hydrostatic pressure all induce remodelling of actin microfilaments. This remodelling was characterised by a change from a uniform to a more punctate distribution of cortical actin around the cell periphery. For some loading regimes, this remodelling was reversed over a subsequent 1h unloaded period. This reversible remodelling of actin cytoskeleton may therefore represent a mechanism through which the chondrocyte alters its mechanical properties and mechanosensitivity in response to physiological mechanical loading.
在众多细胞类型中，细胞骨架广泛参与涉及拉伸激活离子通道、整合素和细胞内细胞器变形的机械转导途径。研究还表明，细胞骨架可响应诸如拉伸应变或流体流动等机械刺激而发生重塑。在关节软骨细胞中，机械转导途径复杂且相互关联，目前对此了解甚少。此外，关于软骨细胞骨架如何响应生理机械负荷知之甚少。本研究利用特征明确的软骨细胞 - 琼脂糖模型和成熟的共聚焦图像分析技术，证明静态和循环压缩应变以及静水压力均会诱导肌动蛋白微丝重塑。这种重塑的特征是细胞周边皮质肌动蛋白从均匀分布变为更点状分布。对于某些加载方式，这种重塑在随后1小时的卸载期内会逆转。因此，肌动蛋白细胞骨架的这种可逆重塑可能代表了软骨细胞响应生理机械负荷改变其力学性能和机械敏感性的一种机制。
