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Dynamics of nuclei of muscle fibers and connective tissue cells in normal and denervated rat muscles
Author(s) -
Schmalbruch H.,
Lewis D.M.
Publication year - 2000
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/(sici)1097-4598(200004)23:4<617::aid-mus22>3.0.co;2-y
Subject(s) - denervation , connective tissue , anatomy , soleus muscle , extensor digitorum longus muscle , atrophy , extensor digitorum muscle , biology , chemistry , muscle spindle , medicine , myocyte , mitosis , endocrinology , skeletal muscle , microbiology and biotechnology , genetics , afferent
The mitotic activity in muscles of growing rats and the effect of denervation were studied by means of continuous infusion of 5‐bromo‐2‐deoxyuridine (BRDU). Denervated muscles after 10 weeks contained 20 to 60% fewer muscle nuclei than normal; BRDU labeled about 25% of the nuclei of normal soleus and extensor digitorum longus (EDL) and of denervated EDL muscles but only 5% in the denervated soleus muscle. Labeled nuclei persisted in denervated but not in normal muscles. After the main growth period, the turnover of myonuclei was at most 1 to 2% per week. The behavior of connective tissue nuclei was similar to that in muscle fibers. Infusion of BRDU had no effect on contractile properties. It is suggested that the exceptionally rapid atrophy of the denervated rat soleus associated with loss of satellite cells was due to loss of myonuclei and differentiation and fusion of satellite cells. The cause may possibly be that the phase of postdenervation fibrillation is shorter than in other muscles. © 2000 John Wiley & Sons, Inc. Muscle Nerve 23: 617–626, 2000.