Meeting Abstract
P2.192 Monday, Jan. 5 A cross-sectional analysis comparing woodchuck (Marmota monax) skeletons before and after hibernation DOHERTY, AH*; VINYARD, CJ; NEOUCOM; NEOUCOM ahdoherty@gmail.com
Long periods of inactivity in most mammals result in significant bone loss that may not be completely recoverable during an individuals lifetime regardless of changes in activity. Prolonged inactivity is the norm for hibernating animals, but it is unknown whether they suffer from adverse bone health after hibernation that affects their ultimate survival. We examined woodchuck (Marmota monax) skeletons using computed tomography (CT) to test the hypothesis that bone cross-sectional area and density is lost during hibernation due to prolonged inactivity. Museum specimens were grouped into pre- and post-hibernation samples based on the collection date, approximating time of death, from museum records. CT scans were taken at the diaphyses and distal metaphyses of the tibia and femur and through the midline of the fourth mandibular premolar. We analyzed scans using Image J and XCT540 to measure bone cross-sectional area, density, and biomechanical indices of pre- and post-hibernation specimens and compared the two groups using ANOVAs. Initial results from the size-adjusted diaphyses of the two long bones suggest that there is no significant loss of bone during hibernation. In fact, indications of bone formation were evident in that absolute values of femoral cortical diaphyseal area (p=0.014), femoral cortical density (p=0.047), and tibial cortical density (p=0.009) were significantly larger in the post-hibernation sample. Given that our sample included a percentage of yearlings, we speculate this absolute increase in bone parameters relates to continued growth during hibernation. While these results suggest woodchucks have derived mechanisms for maintaining bone health during hibernation, longitudinal studies are underway to identify which aspects of bone metabolism regulate the skeleton in hibernating woodchucks.
