Effects of Selection for High Voluntary Running on Nutrient Foramen Dimensions

Event Center A & B

Genetic composition is the blueprint from which bone is built, affecting over 50% of overall bone mineral content in adult mammals. However, stress from mechanical loading causes micro-fractures in bones, triggering dynamic bone remodeling by shifting the balance of absorption and formation to net formation. This remodeling is limited by supply of blood through the nutrient artery, which supplies 50-70% of total blood volume in long bones. The nutrient artery is limited in size by the nutrient foramen that it penetrates. Because genetic and environmental factors can independently affect the structure of bone, we used mice from lines that have been selectively bred for high levels of voluntary wheel running (High Runner, or HR lines) to determine whether a difference in nutrient foramen size in long bones was present in mice selectively bred for increased voluntary running (11th and 72nd generations). Femoral foramen, cortical thickness of the diaphysis, length, volume, moment of inertia, and polar moment were measured via micro-computed tomography. We use the data to test the effects of selection (HR vs control), exercise (wheel access vs sedentary), and potential interactions between them (HR vs control with wheel access).