Tracer transport in the lacunar-canalicular system of cyclically loaded osteonal bone

摘要

In bone tissue, osteocytes are encased in a clcified matrix and connected via narrow canalicular channels to one another and to blood vessels in the osteonal canals. It has been suggested that diffusion between the blood vessels and these bone cells may be insufficient to obtain nutrients and dispose of waste products appropriately. The stress-induced fluid flow in the lacunar-canalicular system has been proposed to be the mechanism that increases the efficiency of transport between the blood supply and bone cells (Piekarski and Munro, 1977; Kufahl and Saha, 1990). Knothe Tate el al. (1998) have used tracer methods to experimentally confirm the existence of stress-induced transport within bone tissue. However, little is known about the mechanism of this enhanced transport. The model presented here proposes that the relatively large fluid space surrounding the osteocy in a lacuna produces a mixing process that creates a concentration difference between the inward and outward lacunar flow that is wital for net transport during cyclic loading.