Heat‐Stress effects on the myosin heavy chain phenotype of rat soleus fibers during the early stages of regeneration |
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| Authors: | Yasuharu Oishi PhD Roland R Roy PhD Tomonori Ogata PhD Yoshinobu Ohira PhD |
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| Institution: | 1. Laboratory of Muscle Physiology, Faculty of Education, Kumamoto University, Kumamoto, Japan;2. Department of Integrative Biology and Physiology and Brain Research Institute, University of California Los Angeles, Los Angeles, California, USA;3. Faculty of Human Environmental Studies, Hiroshima‐Shudo University, Hiroshima, Japan;4. Research Center for Adipocyte & Muscle Science, Doshisha University, Kyotanabe City, Kyoto, Japan |
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| Abstract: | Introduction: We investigated heat‐stress effects on the adult myosin heavy chain (MyHC) profile of soleus muscle fibers at an early stage of regeneration. Methods: Regenerating fibers in adult rats were analyzed 2, 4, or 6 days after bupivacaine injection. Rats were heat stressed by immersion in water (42 ± 1°C) for 30 minutes 24 hours after bupivacaine injection and every other day thereafter. Results: No adult MyHC isoforms were observed after 2 days, whereas some fibers expressed only fast MyHC after 4 days. Heat stress increased fast and slow MyHC in regenerating fibers after 6 days. Regenerating fibers expressing only slow MyHC were observed only in heat‐stressed muscles. Bupivacaine injection increased the number of Pax7+ and MyoD+ satellite cells in regenerating fibers, more so in heat‐stressed rats. Conclusion: The results indicate that heat stress accelerates fast‐to‐slow MyHC phenotype conversion in regenerating fibers via activation of satellite cells. Muscle Nerve 52 : 1047–1056, 2015 |
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| Keywords: | fiber regeneration heat stress myosin heavy chain rat soleus satellite cell |
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