Abstract
If myonuclear loss initiates muscle wasting, it should precede the loss of muscle mass. As aging affects muscle plasticity, the time-course of muscle atrophy during disuse may differ between young and old animals. To investigate this, gastrocnemius muscles of 5- and 25-month-old rats were exposed to 1, 2, or 4 weeks of denervation, whereas the contralateral gastrocnemius muscles served as controls. Muscle fibers of each type responded similarly to 4 weeks of denervation. For both ages most of the atrophy (36%; P < 0.001) occurred in the first 2 weeks. In young-adult muscles, the myonuclear number remained constant, but in old muscles it decreased to below control level after 4 weeks of denervation (P < 0.05). Despite this differential response, myonuclear domain size decreased similarly at both ages (P < 0.001). In both young-adult and old rats, denervation-induced atrophy was not preceded by a loss of myonuclei. © 2011 Wiley Periodicals, Inc.
Original language | English |
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Pages (from-to) | 212-222 |
Journal | Muscle and Nerve |
Volume | 43 |
Issue number | 2 |
DOIs | |
Publication status | Published - 2011 |