Phenotypic response in the mouse tail musculoskeletal system associated with differences in tail use and mechanical loading milieus

• Published in: The FASEB journal 2017-04, Vol.31 (S1)
• Main Authors: Organ, Jason, Luger, Allison, Chavez, Lexy, Stachel, Alexandra, Adriaens, Dominique
• Format: Article
• Language: English
• ISSN: 0892-6638; 1530-6860
• DOI: 10.1096/fasebj.31.1_supplement.lb36

Abstract only For the last several years, our lab has utilized a fine‐wire mouse enclosure to model low‐impact exercise as a potential intervention to enhance musculoskeletal mechanical properties (e.g., bone strength and skeletal muscle contractile force). The model consists of two enclosures: a fine‐wire (climbing) enclosure that mimics a fine‐branch arboreal niche and requires mice to develop enhanced balancing and pedal grasping to move between nest sites, food, and water; and a parking deck (control) enclosure that prevents pedal grasping but is vertically stratified like the fine‐wire enclosure. We observed that mice raised in the fine‐wire enclosure laterally flex their tails to maintain balance above the substrate and/or coil their tails around the substrate in a semi‐prehensile manner in order to stabilize the body. We hypothesized that this differential use of the tail would result in musculoskeletal modifications in the tails of climbers vs. controls, of which some may be adaptive for improved prehension. To test this hypothesis, we raised female C57BL/6 mice from weaning to 4 months of age in these enclosures. At sacrifice, we imaged the intact tail with high resolution microcomputed tomography and examined the 3D anatomy and cross‐sectional geometry of select tail vertebrae. The CT images were reconstructed and analyzed using Amira (v. 6.2). Climbing (fine‐wire) mouse tail vertebrae showed a phenotypic response to differential mechanical loading imparted by habitual lateral tail flexion and occasional semi‐prehensility by thickened vertebral cortices. This would enhance bone bending strength, enhancing its prehensile ability to grasp. It is not clear whether this occurs through appositional bone growth or another modeling mechanism. It is also not yet clear what soft tissue adaptations may also occur. Support or Funding Information IUPUI Biomaterials and Biomechanics Research Center, Showalter Research Trust