Osteocytes direct bone adaptation to mechanical loading (e.g., exercise), but the ways in which osteocytes detect loading remain unclear. We recently showed that osteocytes develop repairable plasma membrane disruptions (PMD) in response to treadmill-running exercise, and that these PMD initiate mechanotransduction. As treadmill running is a non-voluntary activity for rodents, our current goal was to determine whether osteocytes develop PMD with voluntary wheel running as a better model of physiological exercise. Male and female Hsd:ICR mice from lines selectively bred (>75 generations) to demonstrate high voluntary wheel running (“High Runners”) or non-selected control lines (“Control”) were studied (n=9 to 12 mice per sex per line, 4 lines each). At 12 weeks of age, half of the animals within each group were provided access to running wheels for 6 days while remaining mice had no wheel access. Tibias were collected at sacrifice and bone mineral density was analyzed by DXA. Osteocyte PMD were quantified by immunochemistry for intracellular albumin. Groups were compared with 3-factor ANOVA.
