Mouse Hind Limb Skeletal Muscle Functional Adaptation in a Simulated Fine Branch Arboreal Habitat. Issue 3 (8th February 2018)

• Record Type: Journal Article
• Authors: Rupert, Joseph E.; Joll, J. Ethan; Elkhatib, Wiaam Y.; Organ, Jason M.
• Other Names: Hartstone‐Rose Dr. Adam guestEditor.; Santana Dr. Sharlene guestEditor.; Marchi Dr. Damiano guestEditor.; Laitman Dr. Jeffrey T. guestEditor.
• Is Part Of: Anatomical record. Volume 301:Issue 3(2018)
• Page Start: 434
• Page End: 440
• Publication Date: 2018-02-08
• Subjects: climbing -- specific force -- fatigue -- ex vivo contractility; Anatomy -- Periodicals; Evolution (Biology) -- Periodicals; Morphology -- Periodicals; 571.3
• DOI: 10.1002/ar.23744
• Languages: English
• ISSNs: 1932-8486

Abstract

ABSTRACT: The musculoskeletal system is remarkably plastic during growth. The purpose of this study was to examine the muscular plasticity in functional and structural properties in a model known to result in significant developmental plasticity of the postcranial skeleton. Fifteen weanling C57BL/6 mice were raised to 16 weeks of age in one of two enclosures: a climbing enclosure that simulates a fine branch arboreal habitat and is traversed by steel wires crossing at 45° relative to horizontal at multiple intersections, and a control enclosure that resembles a parking deck with no wires but the same volume of habitable space. At killing, ex vivo contractility properties of the soleus (SOL) and extensor digitorum longus (EDL) muscles were examined. Our results demonstrate that EDL muscles of climbing mice contracted with higher specific forces and were comprised of muscle fibers with slower myosin heavy chain isoforms. EDL muscles also fatigued at a higher rate in climbing mice compared to controls. SOL muscle function is not affected by the climbing environment. Likewise, mass and architecture of both EDL and SOL muscles were not different between climbing and control mice. Our data demonstrate that functional adaptation does not require concomitant architectural adaptation in order to increase contractile force. Anat Rec, 301:434–440, 2018. © 2018 Wiley Periodicals, Inc.