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Time‐course of changes in the myonuclear domain during denervation in young‐adult and old rat gastrocnemius muscle
Author(s) -
van der Meer Sander F.T.,
Jaspers Richard T.,
Jones David A.,
Degens Hans
Publication year - 2011
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.21822
Subject(s) - denervation , atrophy , gastrocnemius muscle , muscle atrophy , amyotrophy , medicine , endocrinology , anatomy , wasting , skeletal muscle
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. Muscle Nerve 43: 212–222, 2011