Abstract:Objective To determine whether local gradient fluid shear stress (FSS) causes a specific distribution of intracellular calcium ion concentration, which ultimately determines the direction of cell migration. Methods Numerical simulations were performed using COMSOL software. The method of staining intracellular calcium ion for RAW264.7 osteoclast precursors was established. After applying gradient FSS on the cells, the distribution and dynamic changes of intracellular calcium ion concentration and cell migration parameters were analyzed. Results Osteoclast precursors tended to migrate towards regions with lower FSS, and oscillatory flow regulated the distribution of intracellular calcium ions along the direction of cell migration. After blocking phospholipase C (PLC), mechanosensitive cation-selective channels (MSCC), endoplasmic reticulum (ER), and removing extracellular calcium, the migration speed of cells towards the low FSS direction was significantly reduced, but the migration speed along the liquid flow direction was significantly enhanced. Meanwhile, the calcium ion distribution along the liquid flow direction was significantly increased. Conclusions Osteoclast precursors can sense the FSS gradient, resulting in a specific distribution of intracellular calcium ions along the direction of migration. This ultimately leads to the migration of osteoclast precursors towards regions with lower FSS. This study provides important basic data for ultimately elucidating the cellular and molecular mechanisms of bone tissue remodeling under dynamic external forces.