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Title: Differential regulation of apoptosis in slow and fast twitch muscles of aged female F344BN rats

Age-related muscle atrophy is characterized by decreases in muscle mass and is thought be mediated, at least in part, by increases in myocyte apoptosis. Recent data has demonstrated that the degree of muscle loss with aging may differ between males and females while other work has suggested that apoptosis as indicated by DNA fragmentation may be regulated differently in fast- and slow-twitch muscles. Herein, we investigate how aging affects the regulation of muscle apoptosis in the fast-twitch extensor digitorum longus (EDL) and slow-twitch soleus muscles of young (6-month), aged (26-month), and very aged (30-month) female Fischer 344/NNiaHSD × Brown Norway/BiNia (F344BN) rats. Tissue sections were stained with hydroethidium for ROS and protein extract was subjected to immunoblotting for assessing apoptotic markers. Our data suggest that decreases in muscle mass were associated with increased DNA fragmentation (TUNEL positive) and increases in reactive oxygen species (ROS) as determined by hydroethidium staining in both the EDL and soleus. Similar to our previous work using aged male animals, we observed that the time course and magnitude of changes in Bax, Bcl-2, caspase-3, caspase-9, and cleavage of α-fodrin protein were regulated differently between muscles. As a result, These data suggest that aging in the femalemore » F344BN rat is associated with decreases in muscle mass, elevations in ROS level, increased muscle cell DNA fragmentation, and alterations in cell membrane integrity and that apoptotic mechanisms may differ between fiber types.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Marshall Univ., Huntington, WV (United States)
Publication Date:
OSTI Identifier:
1225665
Report Number(s):
MarshallU--30
Journal ID: ISSN 0161-9152
Grant/Contract Number:
SC0005162
Type:
Accepted Manuscript
Journal Name:
Age
Additional Journal Information:
Journal Volume: 37; Journal Issue: 2; Journal ID: ISSN 0161-9152
Publisher:
Springer
Research Org:
Marshall Univ., Huntington, WV (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Contributing Orgs:
Marshall University
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES aging; female; skeletal muscle; apoptosis; ROS; caspase