Osteocytes are vital for regulating bone remodeling by sensing the flow-induced mechanical stimuli applied to their cell processes. In this mechanosensing mechanism, tethering elements (TEs) connecting the osteocyte process with the canalicular wall potentially amplify the strain on the osteocyte processes. The ultrastructure of the osteocyte processes and canaliculi can be visualized at a nanometer scale using high-resolution imaging via ultra-high voltage electron microscopy (UHVEM). Moreover, the irregular shapes of the osteocyte processes and the canaliculi, including the TEs in the canalicular space, should considerably influence the mechanical stimuli applied to the osteocytes. This study aims to characterize the roles of the ultrastructure of osteocyte processes and canaliculi in the mechanism of osteocyte mechanosensing. Thus, we constructed a high-resolution image-based model of an osteocyte process and a canaliculus using UHVEM tomography and investigated the distribution and magnitude of flow-induced local strain on the osteocyte process by performing fluid–structure interaction simulation. The analysis results reveal that local strain concentration in the osteocyte process was induced by a small number of TEs with high tension, which were inclined depending on the irregular shapes of osteocyte processes and canaliculi. Therefore, this study could provide meaningful insights into the effect of ultrastructure of osteocyte processes and canaliculi on the osteocyte mechanosensing mechanism.

骨细胞通过感知施加于其细胞过程的流动诱导的机械刺激，对于调节骨重塑至关重要。在这种机械传感机制中，连接骨细胞过程与小管壁的束缚元件 (TE) 可能会放大骨细胞过程的应变。可以通过超高压电子显微镜 (UHVEM) 使用高分辨率成像在纳米尺度上观察骨细胞过程和小管的超微结构。此外，骨细胞突起和小管的不规则形状，包括小管空间中的 TE，应显着影响施加于骨细胞的机械刺激。本研究旨在表征骨细胞过程和小管的超微结构在​​骨细胞机械传感机制中的作用。因此，我们使用 UHVEM 断层扫描构建了一个基于高分辨率图像的骨细胞过程和小管模型，并通过执行流体 - 结构相互作用模拟研究了流动诱导的骨细胞过程局部应变的分布和大小。分析结果表明，骨细胞过程中的局部应变集中是由少量高张力的TEs引起的，这些TEs根据骨细胞过程和小管的不规则形状而倾斜。因此，这项研究可以为骨细胞过程和小管的超微结构对骨细胞机械传感机制的影响提供有意义的见解。