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Proliferation of satellite cells from soleus muscles of rats is altered by a period of unloading
Author(s) -
Salazar Jesus,
Brooks Susan V.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1250-b
Subject(s) - myod , myocyte , soleus muscle , population , skeletal muscle , biology , muscle atrophy , medicine , endocrinology , muscle hypertrophy , cell culture , myogenin , chemistry , andrology , myogenesis , genetics , environmental health
Unloading of skeletal muscle results in atrophy. With reloading, protein synthesis must increase to recover control muscle masses and new myonuclei must be added to growing myofibers. The source of the additional myonuclei is a resident population of muscle precursor cells, known as satellite cells. Our purpose was to investigate the effects of unloading on the ability of satellite cells to be activated and proliferate. Soleus muscles were unloaded by exposing rats to hind limb suspension (HS). Satellite cell cultures were established by plating approximately equal numbers of cells from soleus muscles of normally loaded control rats and from rats exposed to various periods of HS. Myoblasts were identified by staining cultures for expression of MyoD. While no differences between groups were observed for the number of myoblasts following 2 days in culture, there were significant differences between the groups for the numbers of myoblasts in cultures after 5 days. For cultures established from control muscles or muscles exposed to 3, 5, or 9 days of HS, modest increases in myoblast numbers between 2 and 5 days were observed. In contrast, for myoblasts from muscles of rats exposed to greater than 10 days of HS, proliferation between 2 and 5 days was dramatically enhanced by nearly ten‐fold compared with control cultures. Our findings indicate that the period of muscle unloading has profound effects on the proliferative response of satellite cells in culture. We conclude that the in vivo loading environment of a muscle may affect the ability of satellite cells to respond to the need for their activation and proliferation. Supported by NASA grant NNCO 4AA21A.