Tyler Bonin Biology
Amanda Smolinsky Associate Professor of Biology
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Abstract
Bone morphology is known to change in response to differing levels of strain, such as that generated during exercise. In general, increased strain levels on bone cause it to grow thicker. Muscle force is a large component of the strain experienced by bones. To better understand the interactions between muscle and bone, this experiment examines bone growth in the tibia of high-runner, mini-muscle (MM) mice. The high-runner lineage of mice was selectively bred for over 100 generations to increase voluntary wheel running. In one line of high-runner mice, dubbed “mini-muscle”, a mutation reduces calf muscle mass by half, creating an alternative biological solution for running long distances, while also reducing overall muscle force generated in the limbs and thus strain imposed upon the bones. The aim of this study is to determine if the MM phenotype affects bone morphology in the tibia. Micro-CT scans were analyzed to examine the cross-sectional properties of the tibia in sedentary MM and wild-type (non-MM and non-high runner) mice. Results show that the bone morphology of MM mice differs from wild-type mice because of the reduced muscle mass and, therefore, the magnitude of the force around the tibiae. Future studies will examine the effects of running exercise on MM bone morphology and whether proximal and distal limb bones respond to altered muscular force in different ways.
