Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Botnar Research Centre, Oxford OX3 7LD, UK
Department of Zoology, University of Oxford, Botnar Research Centre, Oxford OX3 7LD, UK Department of Biology, Lund University, Lund, Sweden.
J R Soc Interface. 2014 Aug 6;11(97):20140330. doi: 10.1098/rsif.2014.0330.
In vitro mechanotransduction studies, uncovering the basic science of the response of cells to mechanical forces, are essential for progress in tissue engineering and its clinical application. Many varying investigations have described a multitude of cell responses; however, as the precise nature and magnitude of the stresses applied are infrequently reported and rarely validated, the experiments are often not comparable, limiting research progress. This paper provides physical and biological validation of a widely available fluid stimulation device, a see-saw rocker, as an in vitro model for cyclic fluid shear stress mechanotransduction. This allows linkage between precisely characterized stimuli and cell monolayer response in a convenient six-well plate format. Models of one well were discretized and analysed extensively using computational fluid dynamics to generate convergent, stable and consistent predictions of the cyclic fluid velocity vectors at a rocking frequency of 0.5 Hz, accounting for the free surface. Validation was provided by comparison with flow velocities measured experimentally using particle image velocimetry. Qualitative flow behaviour was matched and quantitative analysis showed agreement at representative locations and time points. Maximum shear stress of 0.22 Pa was estimated near the well edge, and time-average shear stress ranged between 0.029 and 0.068 Pa. Human tenocytes stimulated using the system showed significant increases in collagen and GAG secretion at 2 and 7 day time points. This in vitro model for mechanotransduction provides a versatile, flexible and inexpensive method for the fluid shear stress impact on biological cells to be studied.
体外机械转导研究揭示了细胞对机械力反应的基础科学，对于组织工程及其临床应用的进展至关重要。许多不同的研究描述了多种细胞反应；然而，由于施加的精确性质和幅度很少被报道，并且很少得到验证，因此实验往往不可比，限制了研究进展。本文为一种广泛可用的流体刺激装置——跷跷板摇床提供了物理和生物学验证，将其作为体外循环流体剪切力机械转导的模型。这允许在方便的六孔板格式中将精确表征的刺激与细胞单层反应联系起来。通过使用计算流体动力学对一个孔的模型进行广泛的离散化和分析，生成在 0.5 Hz 摇频下的循环流体速度矢量的收敛、稳定和一致预测，同时考虑自由表面。通过与使用粒子图像 velocimetry 实验测量的流速进行比较来提供验证。定性流动行为相匹配，定量分析在代表性位置和时间点上显示出一致性。在靠近井边缘处估计最大剪切应力为 0.22 Pa，时均剪切应力范围在 0.029 至 0.068 Pa 之间。使用该系统刺激的人腱细胞在 2 天和 7 天时间点显示出胶原蛋白和 GAG 分泌的显著增加。这种用于机械转导的体外模型提供了一种灵活、经济的方法，用于研究流体剪切力对生物细胞的影响。
