Abstract：
Different gravity fields have important effects on the structural morphology of bone. The fluid flow caused by loadings in the bone lacunar-canalicular system (LCS), converts mechanical signals into biological signals and regulates bone reconstruction by affecting effector cells, which ensures the efficient transport of signaling molecules, nutrients, and waste products. In this study, the fluid flow and mass transfer effects of bone lacunar-canalicular system at multi-scale were firstly investigated, and a three-dimensional axisymmetric fluid-solid coupled finite element model of the LCS within three continuous osteocytes was established. The changes in fluid pressure field, flow velocity field, and fluid shear force variation on the surface of osteocytes within the LCS were studied comparatively under different gravitational fields (0 G, 1 G, 5 G), frequencies (1 Hz, 1.5 Hz, 2 Hz) and forms of cyclic compressive loading. The results showed that different frequencies represented different exercise intensities, suggesting that high-intensity exercise may accelerate the fluid flow rate within the LCS and enhance osteocytes activity. Hypergravity enhanced the transport of solute molecules, nutrients, and signaling molecules within the LCS. Conversely, the mass transfer in the LCS may be inhibited under microgravity, which may cause bone loss and eventually lead to the onset of osteoporosis. This investigation provides theoretical guidance for rehabilitative training against osteoporosis.
摘要：
不同的重力场对骨的结构形态有重要影响。由骨腔隙-小管系统（LCS）中的载荷引起的流体流动，将机械信号转化为生物信号，并通过影响效应细胞来调节骨骼重建，确保信号分子的有效运输，营养素,和废品。在这项研究中,首先研究了骨腔隙-小管系统在多尺度下的流体流动和传质效应,建立了三个连续骨细胞内LCS的三维轴对称流固耦合有限元模型。流体压力场的变化，流速场,在不同重力场（0G，1G,5G),频率(1Hz,1.5Hz,2Hz）和循环压缩载荷的形式。结果表明，不同的频率代表不同的运动强度，表明高强度运动可以加速LCS内的流体流速并增强骨细胞活性。超重力增强了溶质分子的运输，营养素,和LCS内的信号分子。相反，在微重力下，LCS中的传质可能会受到抑制，这可能会导致骨质流失并最终导致骨质疏松症的发作。本研究为骨质疏松康复训练提供理论指导。
