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Satellite cell regulation of muscle mass is altered at old age.
- Source :
-
Journal of applied physiology (Bethesda, Md. : 1985) [J Appl Physiol (1985)] 2004 Sep; Vol. 97 (3), pp. 1082-90. Date of Electronic Publication: 2004 Apr 30. - Publication Year :
- 2004
-
Abstract
- Muscle mass is decreased with advancing age, likely due to altered regulation of muscle fiber size. This study was designed to investigate cellular mechanisms contributing to this process. Analysis of male Fischer 344 X Brown Norway rats at 6, 20, and 32 mo of age demonstrated that, even though significant atrophy had occurred in soleus muscle by old age, myofiber nuclear number did not change, resulting in a decreased myonuclear domain. Also, the number of centrally located nuclei was significantly elevated in soleus muscle of 32-mo-old rats, correlating with an increase in gene expression of MyoD and myogenin. Whereas total 5'-bromo-2'deoxyuridine (BrdU)-positive nuclei were decreased at older ages, BrdU-positive myofiber nuclei were increased. These results suggest that, with age, loss of muscle mass is accompanied by increased myofiber nuclear density that involves fusion of proliferative satellite cells, resembling ongoing regeneration. Interestingly, centrally located myofiber nuclei were not BrdU labeled. Rats were subjected to hindlimb suspension (HS) for 7 or 14 days and intermittent reloading during HS for 1 h each day (IR) to investigate how aging affects the response of soleus muscle to disuse and an atrophy-reducing intervention. After 14 days of HS, soleus muscle size was decreased to a similar extent at all three ages. However, myofiber nuclear number and the total number of BrdU-positive nuclei decreased with HS only in the young rats. IR was associated with an attenuation of atrophy in soleus muscles of 6- and 20- but not 32-mo-old rats. Furthermore, IR was associated with an increase in BrdU-positive myofiber nuclei only in young rats. These data indicate that altered satellite cell function with age contributes to the impaired response of soleus muscle to an intervention that attenuates muscle atrophy in young animals during imposed disuse.
- Subjects :
- Adaptation, Physiological
Animals
Female
Hindlimb Suspension adverse effects
Hindlimb Suspension methods
Muscular Atrophy etiology
Organ Size
Rats
Rats, Inbred F344
Recovery of Function
Aging metabolism
Muscle, Skeletal pathology
Muscle, Skeletal physiopathology
Muscular Atrophy pathology
Muscular Atrophy physiopathology
Satellite Cells, Skeletal Muscle cytology
Satellite Cells, Skeletal Muscle metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 8750-7587
- Volume :
- 97
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Journal of applied physiology (Bethesda, Md. : 1985)
- Publication Type :
- Academic Journal
- Accession number :
- 15121742
- Full Text :
- https://doi.org/10.1152/japplphysiol.00006.2004