The structure of a bone tissue is capable of adapting to mechanical loading through the process of bone remodeling, which is regulated by osteoblasts and osteoclasts. Fluid flow within trabecular porosity under cyclic loading is one of the factors stimulating the biological response of osteoblasts and osteoclasts. However, the relation between loading directions and interstitial fluid flow was seldom studied. In the present study, a finite element model based on micro-computed tomographic reconstructions is built by using a mouse femur. Results from the fluid–solid coupling numerical simulation indicate that the loading in different directions generates a distinct distribution of von Mises stress in the bone matrix and a fluid shear stress (FSS) in the bone marrow. The loading along the physiological direction leads to a more uniform distribution of solid stress and produces an FSS level beneficial to the biological response of osteoblasts and osteoclasts compared with those along the non-physiological direction. There was a minimum threshold line of wall FSS with a specific solid stress at the bone surface, suggesting that the wall FSS is mainly induced by the solid strain. These results may offer fundamental data in understanding the mechanical environment around osteoblasts and osteoclasts and the cellular and molecular mechanisms of mechanical loading-induced bone remodeling.

骨组织的结构能够通过成骨细胞和破骨细胞调节的骨重塑过程适应机械负荷。循环载荷下小梁孔隙内的流体流动是刺激成骨细胞和破骨细胞生物学反应的因素之一。但是，很少研究加载方向与间隙流体流动之间的关系。在本研究中，通过使用小鼠股骨建立基于微计算机断层摄影术重建的有限元模型。流固耦合数值模拟的结果表明，不同方向的载荷会在骨基质中产生冯·米塞斯应力的独特分布，并在骨髓中产生流体剪切应力（FSS）。与沿着非生理方向的那些相比，沿着生理方向的载荷导致固体应力的分布更加均匀，并产生有益于成骨细胞和破骨细胞的生物学反应的FSS水平。在骨骼表面存在一个壁FSS的最小阈值线，并具有特定的固体应力，这表明壁FSS主要是由固体应变引起的。这些结果可能为了解成骨细胞和破骨细胞周围的机械环境以及机械负荷诱导的骨重塑的细胞和分子机制提供基础数据。在骨骼表面存在一个壁FSS的最小阈值线，并具有特定的固体应力，这表明壁FSS主要是由固体应变引起的。这些结果可能为了解成骨细胞和破骨细胞周围的机械环境以及机械负荷诱导的骨重塑的细胞和分子机制提供基础数据。在骨骼表面存在一个壁FSS的最小阈值线，并具有特定的固体应力，这表明壁FSS主要是由固体应变引起的。这些结果可能为了解成骨细胞和破骨细胞周围的机械环境以及机械负荷诱导的骨重塑的细胞和分子机制提供基础数据。