Abstract | AIM: To determine whether hypoxia influences the phenotypic adaptation of skeletal muscle induced by mechanical overload. METHODS: Plantaris muscles of female rats were submitted to mechanical overload following synergist ablation. After 3 days of overload, rats were exposed to either hypobaric hypoxia (equivalent to 5500 m) or normoxia. Muscles were collected after 5, 12 and 56 days of overload (i.e. after 3, 9 and 53 days of hypoxia). We determined the myosin heavy chain (MHC) distribution, mRNA levels of myocyte-enriched calcineurin-integrating protein 1 (MCIP1) to indirectly assess calcineurin activity, the changes in oxidative capacity from the activities of citrate synthase (CS) and cytochrome c oxidase (COX), and the expression of regulators involved in mitochondrial biogenesis (Pgc-1α, NRF1 and Tfam) and degradation (BNIP-3). RESULTS: CONCLUSION:
Hypoxia is not a critical stimulus to modulate the fast-to-slow MHC transition associated with overload. Thus, the impairment of the fast-to-slow fibre shift often observed during post-natal development in hypoxia could be explained by the lower voluntary locomotor activity associated with hypoxia. Hypoxia alters mitochondrial oxidative capacity, but this adaptive response is similar in overloaded and control muscles.
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Authors | T Chaillou, N Koulmann, A Meunier, A Malgoyre, B Serrurier, M Beaudry, X Bigard |
Journal | Acta physiologica (Oxford, England)
(Acta Physiol (Oxf))
Vol. 209
Issue 4
Pg. 272-82
(Dec 2013)
ISSN: 1748-1716 [Electronic] England |
PMID | 23621297
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Copyright | © 2013 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd. |
Chemical References |
- Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha
- Ppargc1a protein, rat
- Transcription Factors
- Calcineurin
- Myosin Heavy Chains
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Topics |
- Adaptation, Physiological
(physiology)
- Animals
- Calcineurin
(metabolism)
- Female
- Hypoxia
(physiopathology)
- Models, Animal
- Muscle, Skeletal
(metabolism)
- Myosin Heavy Chains
(metabolism)
- Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha
- Phenotype
- Rats
- Rats, Wistar
- Stress, Mechanical
- Transcription Factors
(metabolism)
- Weight-Bearing
(physiology)
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