Bone cell response to mechanical loading in a 3D trabecular bone scaffold : comparison of fluid shear stress and cyclic compressive strain

Abstract

[한글]

[영문]Mechanical loading is the critical factor that regulates the bone functional adaptation. The trabecular bone architecture is optimized by the bone remodeling resulting from the bone cell response to mechanical loading, and thus maintains the mechanical property of the bone tissue prevailing bone functional requirement. This study was conducted to come up with an effective system of mechanical loading to the bone functional adaptation, identifying the correlation between trabecular bone morphology and mechanically regulated bone cell response in a 3D trabecular bone scaffold. A custom made trabecular explant model was fabricated, and bone cells were loaded with oscillatory fluid flow induced shear stress and cyclic compressive strain in a 3D trabecular bone scaffold. The first result indicated that the fluid shear stress increased the alkaline phosphate activity as well as the mRNA levels of collagen type I and core binding factor I in accordance with the trabecular morphological feature, while the cyclic compressive strain increased the alkaline phosphate activity and mRNA level of collagen type I in the same condition, but to a lesser degree. The second result indicated that the fluid shear stress increased both the alkaline phosphate activity and the prostaglandin E2 release depending on bone volume fraction and bone surface as well as bone volume fraction and trabecular number, respectively, whereas the cyclic compressive strain increased only the alkaline phosphate activity depending on the magnitude of the strain. Based on the results that were obtained in the study, it is suggested that fluid shear stress produces different cellular mechanotransduction from the cyclic compressive strain, and that fluid shear stress may be a more potent mechanical stimulus compared to cyclic compressive strain for mechanically regulated bone adaptation in a 3D trabecular bone structure.