Meeting Abstract
Bone is a dynamic tissue functioning to maintain mineral homeostasis, and provide mechanical support for the body. In the absence of mechanical stimuli (i.e., disuse), net resorption of bone occurs. Uniquely, bone can be influenced by intrinsic (e.g. genetics) as well as extrinsic (e.g. mechanical loading) factors. Bone remodeling requires increased oxygenation and blood flow. Nutrient vessels account for 50-70% of long bone blood supply in amniotes, therefore foramina may serve as good proxies for metabolic intensity. To consider the separate and combined influences of genetics and mechanical loading, we used mice from 4 replicate lines selectively bred for high levels of voluntary wheel running (HR) from generations 11, consisting of males and females, and generation 71, consisting of female mice trained for over 12 consecutive weeks and untrained counterparts. We hypothesized that foramen area would be greater in more metabolically active mice. To evaluate this, femoral foramen area (total), cortical thickness of diaphysis, length, volume, moment of inertia, and polar moment were measured via micro-computed tomography. Expected differences are: sex-specific within generation 11 as females run more than males, selection-specific within generations 11 and 71 as HR have higher voluntary metabolic activity than controls, training-specific within generation 71 as training yields greater endurance capacity and affects bone properties, and long-term selective effects as continued selection for wheel running increases morphological and anatomical differences between selected and control lines.
