Abstract
Fluid shear stress caused by mechanical loading plays an important role in regulation of bone remodeling. Osteocyte is exposed to the fluid flow inside bones, and therefore considered to be the most promising cell that provides a cellular basis for mechanosensing. In order to determine the role of osteocyte, functional responses to fluid shear stress were investigated in osteocyte-like cell line MLO-Y4 culture. A tapered cone was rotated on the medium-filled culture plate, generating continuous laminar fluid flow over the cells. The application of fluid shear stress reoriented the cells so that they aligned with the direction of fluid flow, which indicated the induction of cytoskeletal reorganization. Additionally, nitric oxide (NO) release and expression of cyclooxygenase-2 (COX-2), the key enzyme for prostaglandins production, were enhanced in the fluid-sheared cells. These findings may reveal the mechanism by which osteocyte senses mechanical loading and regulates osteoclast and/or osteoblast functions.
