High-intensity resistance training attenuates dexamethasone-induced muscle atrophy.
BACKGROUND
In this study we investigated the effects of high-intensity resistance training (RT) on dexamethasone (DEX)-induced muscle atrophy in flexor hallucis longus (FHL), tibialis anterior (TA), and soleus (SOL) muscles.


METHODS
Rats underwent either high-intensity RT or were kept sedentary. In the last 10 days they received either DEX (0.5 mg/kg/day, intraperitoneally) or saline.


RESULTS
DEX reduced body weight (-21%), food intake (-28%), FHL and TA muscle mass (-20% and -18%, respectively), and increased muscle-specific ring finger 1 (MuRF-1) protein level (+37% and +45.5%). RT attenuated FHL muscle atrophy through a combination of low increase in MuRF-1 protein level (-3.5%) and significant increases in mammalian target of rapamycin (mTOR) (+63%) and p70S6K (+46% and +49% for control and DEX, respectively) protein levels.


CONCLUSIONS
RT attenuated DEX-induced muscle atrophy through a combination of increases in mTOR and p70S6K protein levels and a low increase in MuRF-1 protein level.
Joint Graduate Program in Physiological Sciences, PIPGCF UFscar/UNESP, Federal University of Sao Carlos/Sao Paulo State University, Sao Carlos, São Paulo, Brazil.
André L O
AL
Krug
Joint Graduate Program in Physiological Sciences, PIPGCF UFscar/UNESP, Federal University of Sao Carlos/Sao Paulo State University, Sao Carlos, São Paulo, Brazil.
Anderson G
AG
Macedo
Department of Physical Education, Science Faculty, São Paulo State University, Avenida Eng. Luiz Edmundo Carrijo Coube, 14-01, Vargem Limpa, Bauru, São Paulo, Brazil.
Anderson S
AS
Zago
Department of Kinesiology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, Canada.
James W E
JW
Rush
Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, São Paulo, Brazil.
Carlos F
CF
Santos
Joint Graduate Program in Physiological Sciences, PIPGCF UFscar/UNESP, Federal University of Sao Carlos/Sao Paulo State University, Sao Carlos, São Paulo, Brazil.|Department of Physical Education, Science Faculty, São Paulo State University, Avenida Eng. Luiz Edmundo Carrijo Coube, 14-01, Vargem Limpa, Bauru, São Paulo, Brazil.
Sandra L
SL
Amaral
D000818:Animals; D015153:Blotting, Western; D001835:Body Weight / Q000187:drug effects; D003907:Dexamethasone / Q000009:adverse effects / Q000494:pharmacology*; D005247:Feeding Behavior / Q000187:drug effects; D005938:Glucocorticoids / Q000009:adverse effects / Q000494:pharmacology*; D009124:Muscle Proteins / Q000187:drug effects / Q000378:metabolism; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009133:Muscular Atrophy / Q000378:metabolism / Q000517:prevention & control*; D009929:Organ Size / Q000187:drug effects; D010805:Physical Conditioning, Animal / Q000379:methods*; D051381:Rats; D055070:Resistance Training / Q000379:methods*; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000187:drug effects / Q000378:metabolism; D058570:TOR Serine-Threonine Kinases / Q000187:drug effects / Q000378:metabolism; D000070584:Tripartite Motif Proteins; D044767:Ubiquitin-Protein Ligases / Q000187:drug effects / Q000378:metabolism
D005938:Glucocorticoids; D009124:Muscle Proteins; D000070584:Tripartite Motif Proteins; D003907:Dexamethasone; C499086:Trim63 protein, rat; D044767:Ubiquitin-Protein Ligases; C546845:mTOR protein, rat; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D058570:TOR Serine-Threonine Kinases
glucocorticoids; ladder climbing; muscle atrophy; resistance training; skeletal muscle