Agonist Muscle Adaptation Accompanied by Antagonist Muscle Atrophy in the Hindlimb of Mice Following Stretch-Shortening Contraction Training

Details

• Journal Article:
  BMC Musculoskeletal Disorders
• Personal Author:
  Rader, Erik P. ; Naimo, Marshall A. ; Ensey, James ; Baker, Brent A.
• Description:
  Background: The vast majority of dynamometer-based animal models for investigation of the response to chronic muscle contraction exposure has been limited to analysis of isometric, lengthening, or shortening contractions in isolation. An exception to this has been the utilization of a rat model to study stretch-shortening contractions (SSCs), a sequence of consecutive isometric, lengthening, and shortening contractions common during daily activity and resistance-type exercise. However, the availability of diverse genetic strains of rats is limited. Therefore, the purpose of the present study was to develop a dynamometer-based SSC training protocol to induce increased muscle mass and performance in plantarflexor muscles of mice. Methods: Young (3 months old) C57BL/6 mice were subjected to 1 month of plantarflexion SSC training. Hindlimb muscles were analyzed for muscle mass, quantitative morphology, myogenesis/myopathy relevant gene expression, and fiber type distribution. Results: The main aim of the research was achieved when training induced a 2-fold increase in plantarflexion peak torque output and a 19% increase in muscle mass for the agonist plantaris (PLT) muscle. In establishing this model, several outcomes emerged which raised the value of the model past that of being a mere recapitulation of the rat model. An increase in the number of muscle fibers per transverse muscle section accounted for the PLT muscle mass gain while the antagonist tibialis anterior (TA) muscle atrophied by 30% with preferential atrophy of type IIb and IIx fibers. These alterations were accompanied by distinct gene expression profiles. Conclusions: The findings confirm the development of a stretch-shortening contraction training model for the PLT muscle of mice and demonstrate that increased cross-sectional fiber number can occur following high-intensity SSC training. Furthermore, the TA muscle atrophy provides direct evidence for the concept of muscle imbalance in phasic non-weight bearing muscles, a concept largely characterized based on clinical observation of patients. The susceptibility to this imbalance is demonstrated to be selective for the type IIb and IIx muscle fiber types. Overall, the study highlights the importance of considering muscle fiber number modulation and the effect of training on surrounding muscles in exercise comprised of SSCs. Description provided by NIOSH
• Subjects:
  • Adaptation, Physiological
  • Air Movements
  • Air Pollutants, Occupational
  • Air Pollution, Indoor
  • Biomechanical Phenomena
  • Coal
  • Coal Mining
  • Cross-Sectional Studies
  • Dust
  • Engineering
  More +
• Keywords:
  • Muscles; Laboratory animals; Muscle contraction; Muscle physiology; Biomechanics;
  • Author Keywords: Stretch-shortening contractions; Plantarflexor muscles; Dorsiflexor muscles; C57BL6 mice; Myosin heavy chain; Muscle physiology; Biomechanics; Muscle fiber type
• Source:
  BMC Musculoskelet Disord 2017 Feb; 18:60
• ISSN:
  1471-2474
• Pubmed ID:
  28148306
• Pubmed Central ID:
  PMC5288976
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  15 pdf pages
• Volume:
  18
• NIOSHTIC Number:
  nn:20049333
• Contact Point Address:
  Erik P. Rader, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, MS L3014, 1095 Willowdale Rd, Morgantown, West Virginia 26505
• Email:
  WLZ4@cdc.gov
• Federal Fiscal Year:
  2017
• Peer Reviewed:
  True
• Download URL:
  https://stacks.cdc.gov/view/cdc/44399/cdc_44399_DS1.pdf
• File Type:
  [PDF - 5.35 MB]
• Collection(s):
  National Institute for Occupational Safety and Health ; CDC Public Access
• Main Document Checksum:
  urn:sha-512:aac960c45913cc030450cd4551a31187aafe637b569b034686cc1e25030fc59f68dd198b555611d8b043691f6a12f2442efcae964117c8005f45500a669b8d1f