| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Pulmonary Diseases, University Medical Center NijmegenMayo Medical School, Nijmegen, The Netherlands
2 Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN, USA
3 Department of Physiology & Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN, USA
4 Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN, USA; Department of Physiology & Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN, USA
* To whom correspondence should be addressed. E-mail: sieck.gary{at}mayo.edu.
Skeletal muscle fibers are multinucleated. Each myonucleus regulates gene products and protein expression in only a restricted portion of the muscle fiber, the myonuclear domain (MND). In the rat diaphragm muscle (DIAm), corticosteroid (CoS) treatment causes atrophy of fibers containing myosin heavy chain (MHC) MHC2X and/or MHC2B. We hypothesized that DIAm fiber MND size is maintained during CoS-induced atrophy. Adult male rats received methylprednisolone for 11 days at 1 (CoS-Low; n=8) or 8 mg/kg/day (CoS-High; n=8). Age-matched (CTL-AgeM; n=8), sham-operated (SHAMAgeM; n=8) and weight-matched (CTL-WtM; n=8) animals served as controls. In single DIAm fibers, cross-sectional area (CSA), MND size, and MHC expression were determined. Fiber CSA and MND size were similar in CTL-AgeM and SHAM-AgeM groups. Only fibers containing MHCSlow or MHC2A displayed smaller CSA in CTL-WtM vs. CTL-AgeM and SHAM-AgeM groups, and all fibers had reduced MND size. Thus, fibers containing MHCSlow and MHC2A maintain the number of myonuclei, whereas MHC2X or MHC2B fibers show loss of myonuclei during normal muscle growth. Both CoS groups displayed smaller CSA and MND size when compared to CTL-AgeM and SHAM-AgeM groups. However, when compared to CTL-WtM DIAm fibers, only fibers containing MHC2X or MHC2B displayed reduced CSA and MND size following CoS treatment. Thus, little, if any, loss of myonuclei was associated with CoS-induced atrophy of MHC2X or MHC2B DIAm fibers. In summary, MND size does not appear to be regulated during CoS-induced DIAm atrophy.
This article has been cited by other articles:
|
|
 |
|
  C. B. Mantilla, R. V. Sill, B. Aravamudan, W.-Z. Zhan, and G. C. Sieck Developmental effects on myonuclear domain size of rat diaphragm fibers J Appl Physiol, March 1, 2008; 104(3): 787 - 794. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Rehfeldt, C. B. Mantilla, G. C. Sieck, R. S. Hikida, F. W. Booth, F. Kadi, S. C. Bodine, and D. A. Lowe In response to Point:Counterpoint: "Satellite cell addition is/is not obligatory for skeletal muscle hypertrophy". J Appl Physiol, September 1, 2007; 103(3): 1104 - 1105. [Full Text] [PDF]
|
|
|
|
|
|
G. C. Sieck, W.-Z. Zhan, Y.-S. Han, and Y. S. Prakash Effect of denervation on ATP consumption rate of diaphragm muscle fibers J Appl Physiol, September 1, 2007; 103(3): 858 - 866. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. K. Powers, A. N. Kavazis, and J. M. McClung Oxidative stress and disuse muscle atrophy J Appl Physiol, June 1, 2007; 102(6): 2389 - 2397. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. M. McClung, A. N. Kavazis, K. C. DeRuisseau, D. J. Falk, M. A. Deering, Y. Lee, T. Sugiura, and S. K. Powers Caspase-3 Regulation of Diaphragm Myonuclear Domain during Mechanical Ventilation-induced Atrophy Am. J. Respir. Crit. Care Med., January 15, 2007; 175(2): 150 - 159. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Aravamudan, C. B. Mantilla, W.-Z. Zhan, and G. C. Sieck Denervation effects on myonuclear domain size of rat diaphragm fibers J Appl Physiol, May 1, 2006; 100(5): 1617 - 1622. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Zhong, R. R. Roy, B. Siengthai, and V. R. Edgerton Effects of inactivity on fiber size and myonuclear number in rat soleus muscle J Appl Physiol, October 1, 2005; 99(4): 1494 - 1499. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
