Department of Aerospace Engineering and Applied Mechanics, Indian Institute of Engineering Science and Technology, Shibpur, Howrah, India.
Department of Restorative Dentistry, University of Washington, Seattle, WA, USA.
J Mech Behav Biomed Mater. 2024 Dec;160:106767. doi: 10.1016/j.jmbbm.2024.106767. Epub 2024 Oct 4.
The lacunar morphology and perilacunar tissue properties of osteocytes in bone can vary under different physiological and pathological conditions. How these alterations collectively change the overall micromechanics of osteocytes in the lacunar-canalicular system (LCS) of an osteon still requires special focus. Therefore, a Haversian canal and LCS-based osteon model was established to evaluate the changes in the hydrodynamic environment around osteocytes under physiological loading using fluid-structure interaction analysis, followed by a sub-modelled finite element analysis to assess the mechanical responses of osteocytes and their components. Osteocytes were modelled with detailed configurations, including cytoplasm, nucleus, and cytoskeleton, and parametric variations in lacunar equancy (L.Eq) and perilacunar elasticity (Pl.E) were considered within the osteon model. The study aimed to conduct a comparative study among osteon models with varying L. Eq and Pl. E to check the resulting differences in osteocyte mechanobiology. The results demonstrated that the average mechanical stimulation of each subcellular component of osteocytes increased with decreases in L. Eq and Pl. E, reflecting conditions typically seen in young, healthy bone as per previous literature. However, hydrodynamic responses, such as fluid flow and fluid shear stress on osteocytes, varied proportionally with the elasticity difference between the bone matrix and the perilacunar region during Pl. E variation. Additionally, the findings revealed that a minimal percentage of energy was used to transmit mechanical responses through microtubules from the cell membrane to the nucleus, and this energy percentage increased with higher L. Eq. The outcomes of the study could help to quantify how the osteocyte microenvironment and its mechanosensitivity within cortical bone changes with L. Eq and Pl. E alterations in different bone conditions, from young to aged and healthy to diseased.
在不同的生理和病理条件下，骨细胞的腔隙形态和腔周组织特性会发生变化。这些变化如何共同改变骨单位中腔隙-小管系统（LCS）中骨细胞的整体微力学特性仍需要特别关注。因此，建立了一个基于哈弗管和 LCS 的骨单位模型，通过流固耦合分析来评估生理负荷下骨细胞周围流体动力学环境的变化，然后进行子模型有限元分析来评估骨细胞及其成分的力学响应。骨细胞采用详细的配置建模，包括细胞质、细胞核和细胞骨架，并在骨单位模型中考虑了腔隙均等度（L.Eq）和腔周弹性（Pl.E）的参数变化。该研究旨在对具有不同 L.Eq 和 Pl.E 的骨单位模型进行比较研究，以检查骨细胞机械生物学方面的差异。结果表明，随着 L.Eq 和 Pl.E 的降低，骨细胞每个亚细胞成分的平均机械刺激增加，反映了先前文献中年轻、健康骨骼的典型情况。然而，流体动力学响应，如骨单位中流体流动和骨细胞上的流体剪切应力，与 Pl.E 变化期间骨基质和腔周区域之间的弹性差异成比例变化。此外，研究结果表明，通过细胞膜向细胞核传递机械响应的微管使用的能量百分比最小，并且该能量百分比随着更高的 L.Eq 而增加。该研究的结果可以帮助量化在不同骨条件下，从年轻到老年、健康到患病，骨单位中骨细胞微环境及其在皮质骨中的机械敏感性如何随着 L.Eq 和 Pl.E 的变化而变化。
