| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Department of Physiology and Biophysics, University of California Irvine, Irvine, CA, USA
2 Brain Research Institute, University of California Los Angeles, Los Angeles, CA, USA
3 Department of Physiological Sciences, University of California Los Angeles, Los Angeles, CA, USA
4 Brain Research Institute, University of California Los Angeles, Los Angeles, CA, USA; Department of Physiological Sciences, University of California Los Angeles, Los Angeles, CA, USA
* To whom correspondence should be addressed. E-mail: kmbaldwi{at}uci.edu.
The goal of this study was to use the model of spinal cord isolation (SI), which blocks nearly all neuromuscular activity while leaving the motoneuron-muscle fiber connections intact, to characterize the cellular processes linked to marked muscle atrophy. Rats randomly assigned to normal control and SI groups were studied at 0, 2, 4, 8, and 15 days after SI surgery. The slow soleus muscle atrophied by ~50%, with the greatest degree of loss occurring during the first 8 days. Throughout the SI duration, muscle protein concentration was maintained at the control level, while myofibrillar protein concentration steadily decreased between 4 and 15 days of SI, and this was associated with a 50% decrease in myosin heavy chain (MHC) normalized to total protein. Actin relative to the total protein was maintained at the control level. Marked reductions occurred in total RNA and DNA content, and in total MHC and actin mRNA expressed relative to 18S ribosomal RNA. These findings suggest that two key factors contributing to the muscle atrophy in the SI model are 1) a reduction in ribosomal ribosomal RNA that is consistent with a reduction in protein translational capacity, and 2) insufficient mRNA substrate for translating key sarcomeric proteins comprising the myofibril fraction, such as MHC and actin. In addition, the marked selective depletion of MHC protein in the muscles of SI rats suggests that this protein is more vulnerable to inactivity than actin protein. This selective MHC loss could be a major contributor for the previously reported loss in the functional integrity of SI muscles. Collectively, these data are consistent with the involvement of pretranslational and translational processes in muscle atrophy due to SI.
This article has been cited by other articles:
|
|
 |
|
  J. M. Giger, P. W. Bodell, M. Zeng, K. M. Baldwin, and F. Haddad Rapid muscle atrophy response to unloading: pretranslational processes involving MHC and actin J Appl Physiol, October 1, 2009; 107(4): 1204 - 1212. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Choi, P.-J. I. Selpides, M. M. Nowell, and B. C. Rourke Functional overload in ground squirrel plantaris muscle fails to induce myosin isoform shifts Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2009; 297(3): R578 - R586. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. J. Kim, R. R. Roy, J. A. Kim, H. Zhong, F. Haddad, K. M. Baldwin, and V. R. Edgerton Gene expression during inactivity-induced muscle atrophy: effects of brief bouts of a forceful contraction countermeasure J Appl Physiol, October 1, 2008; 105(4): 1246 - 1254. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. M. Schneider, C. C. Hsieh, L. K. Sprod, S. D. Carter, and R. Hayward Cancer treatment-induced alterations in muscular fitness and quality of life: the role of exercise training Ann. Onc., December 1, 2007; 18(12): 1957 - 1962. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. D. Primeaux, M. Tong, and G. M. Holmes Effects of chronic spinal cord injury on body weight and body composition in rats fed a standard chow diet Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2007; 293(3): R1102 - R1109. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. M. Sacheck, J.-P. K. Hyatt, A. Raffaello, R. T. Jagoe, R. R. Roy, V. R. Edgerton, S. H. Lecker, and A. L. Goldberg Rapid disuse and denervation atrophy involve transcriptional changes similar to those of muscle wasting during systemic diseases FASEB J, January 1, 2007; 21(1): 140 - 155. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. V. Thompson, D. Durand, N. A. Fugere, and D. A. Ferrington Myosin and actin expression and oxidation in aging muscle J Appl Physiol, December 1, 2006; 101(6): 1581 - 1587. [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]
|
|
|
|
|
|
F. Haddad and G. R. Adams Aging-sensitive cellular and molecular mechanisms associated with skeletal muscle hypertrophy J Appl Physiol, April 1, 2006; 100(4): 1188 - 1203. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. J. Toth, P. A. Ades, M. M. LeWinter, R. P. Tracy, and A. Tchernof Skeletal muscle myofibrillar mRNA expression in heart failure: relationship to local and circulating hormones J Appl Physiol, January 1, 2006; 100(1): 35 - 41. [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]
|
|
|
|
 |
|
 M. J. Toth, D. E. Matthews, R. P. Tracy, and M. J. Previs Age-related differences in skeletal muscle protein synthesis: relation to markers of immune activation Am J Physiol Endocrinol Metab, May 1, 2005; 288(5): E883 - E891. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 O. Schakman, H. Gilson, V. de Coninck, P. Lause, J. Verniers, X. Havaux, J. M. Ketelslegers, and J. P. Thissen Insulin-Like Growth Factor-I Gene Transfer by Electroporation Prevents Skeletal Muscle Atrophy in Glucocorticoid-Treated Rats Endocrinology, April 1, 2005; 146(4): 1789 - 1797. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. J. Toth, D. E. Matthews, P. A. Ades, M. D. Tischler, P. Van Buren, M. Previs, and M. M. LeWinter Skeletal muscle myofibrillar protein metabolism in heart failure: relationship to immune activation and functional capacity Am J Physiol Endocrinol Metab, April 1, 2005; 288(4): E685 - E692. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Haddad, K. M. Baldwin, and P. A. Tesch Pretranslational markers of contractile protein expression in human skeletal muscle: effect of limb unloading plus resistance exercise J Appl Physiol, January 1, 2005; 98(1): 46 - 52. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. McClung, R. W. Thompson, L. L. Lowe, and J. A. Carson RhoA expression during recovery from skeletal muscle disuse J Appl Physiol, April 1, 2004; 96(4): 1341 - 1348. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Haddad, R. R. Roy, H. Zhong, V. R. Edgerton, and K. M. Baldwin Atrophy responses to muscle inactivity. II. Molecular markers of protein deficits J Appl Physiol, August 1, 2003; 95(2): 791 - 802. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
