Modeling trabecular bone adaptation to local bending load regulated by mechanosensing osteocytes

Abstract

Cancellous bone has a complicated three-dimensional porous microstructure that consists of strut-like or plate-like trabeculae. The arrangement of the trabeculae is remodeled throughout the organism’s lifetime to functionally adapt to the surrounding mechanical environment. During bone remodeling, osteocytes buried in the bone matrix are believed to play a pivotal role as mechanosensory cells and help regulate the coupling of osteoclastic bone resorption and osteoblastic bone formation according to the mechanical stimuli. Previously, we constructed a mathematical model of trabecular bone remodeling incorporating cellular mechanosensing and intercellular signal transmission, in which osteocytes are assumed to sense the flow of interstitial fluid as a mechanical stimulus that regulates bone remodeling. Our remodeling simulation could describe the reorientation of a single strut-like trabecula under uniaxial loading. In the present study, to investigate the effects of a bending load on trabecular bone remodeling, we simulated the morphological change in a single trabecula under a cyclic bending load based on our mathematical model. The simulation results showed that the application of the bending load influences not only the formation of the plate-like trabecula but also the changes in trabecular topology. These results suggest the possibility that the characteristic trabecular morphology, such as the strut-like or plate-like form, is determined depending on the local mechanical environment.