The Morphological Measurements with a Micro CT and the Stress Analyses of the Adaptive Remodeling by Applied Mechanical Stimuli in Rat Caudal Vertebrae

Abstract

To observe the remodeling process in bone adapted to mechanical stimuli, a microcomputed tomography (micro CT) system with a high spatial resolution was utilized. The rat fifth caudal vertebrae (C5) were subjected to daily axial or offset loads. Morphological alterations of C5 were measured periodically and non-invasively with the micro CT between daily mechanical stimuli for 14 days. The finite element (FE) models were built from the binary cross-sectional images of cortex and trabecular bone architecture of C5. Von Mises stresses were calculated by applying the contact pressures from the rigid-body spring model (RBSM) analyses to the FE-models as boundary conditions. The transformations of cortex and the increases of the cortical area were observed in the loaded rats. FE-analyses in the offset loaded rat indicated that von Mises stress distributed uniformly under the analytical offset loaded condition. This fact suggests that the C5 would adapt to the offset loads applied externally by morphological alterations.