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Cold exposure increases slow‐type myosin heavy chain 1 ( MyHC1 ) composition of soleus muscle in rats
Author(s) -
Mizunoya Wataru,
Iwamoto Yohei,
Sato Yusuke,
Tatsumi Ryuichi,
Ikeuchi Yoshihide
Publication year - 2014
Publication title -
animal science journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.606
H-Index - 38
eISSN - 1740-0929
pISSN - 1344-3941
DOI - 10.1111/asj.12143
Subject(s) - ucp3 , myosin , soleus muscle , chemistry , endocrinology , medicine , skeletal muscle , uncoupling protein , myoglobin , gene isoform , fiber type , biochemistry , biology , adipose tissue , gene , brown adipose tissue
The aim of this study was to examine the effects of cold exposure on rat skeletal muscle fiber type, according to myosin heavy chain ( MyHC ) isoform and metabolism‐related factors. M ale W istar rats (7 weeks old) were housed individually at 4 ± 2°C as a cold‐exposed group or at room temperature (22 ± 2°C) as a control group for 4 weeks. We found that cold exposure significantly increased the slow‐type MyHC1 content in the soleus muscle (a typical slow‐type fiber), while the intermediate‐type MyHC2A content was significantly decreased. In contrast to soleus, MyHC composition of extensor digitorum longus ( EDL , a typical fast‐type fiber) and gastrocnemius (a mix of slow‐type and fast‐type fibers) muscle did not change from cold exposure. Cold exposure increased mRNA expression of mitochondrial uncoupling protein 3 ( UCP3 ) in both the soleus and EDL . Cold exposure also increased mRNA expression of myoglobin, peroxisome proliferator‐activated receptor gamma coactivator 1α ( PGC1 α) and forkhead box O 1 ( FOXO1 ) in the soleus. Upregulation of UCP3 and PGC1 α proteins were observed with W estern blotting in the gastrocnemius. Thus, cold exposure increased metabolism‐related factors in all muscle types that were tested, but MyHC isoforms changed only in the soleus.