Titre : | Inter-strain variation in muscle properties and responses to exercise (abstract : congrès international de Myologie, 2005) |
contenu dans : | |
Auteurs : | Congrès international de myologie 2005 (International Congress of Myology 2005; 9-13 mai 2005; Nantes, France) ; Mouisel E ; Millet G ; Betems A ; Billat V ; Melki J |
Type de document : | Article |
Année de publication : | 2005 |
Pages : | p. 100 |
Langues: | Anglais |
Mots-clés : | chaîne lourde de la myosine ; colloque ; étude transversale ; exercice musculaire ; expression génique ; fibre musculaire striée ; gène PAX7 ; masse musculaire ; métabolisme ; muscle squelettique ; myoblaste ; physiologie ; souris ; sport ; stress psychologique |
Résumé : |
Communication n° 323. Introduction : With the generation of mouse models of neuromuscular disorders, developing non-invasive methods to evaluate the physiological responses to stress represents an important goal. Moreover, the remarkable plasticity of skeletal muscle allows investigating the physical exercise as a therapeutical tool. Due to the variability of mouse motor performance within a given strain, the critical velocity (CV), a validated index of the aerobic capacity (Billat et al., 2004), is a valuable tool to evaluate muscular adaptations in response to an individualized physical training. Purpose : The goal of this study was to evaluate the effects of genetic background and individualized physical training on several muscle parameters. Methods : After a two-week individualized physical training on a treadmill, skeletal muscles of trained and sedentary mice from distinct genetic backgrounds (CD1, C57BL/6J and FVB/N) were collected, weighted and analysed. The myofiber number (soleus), cross-sectional area, the proportion of Pax7+ or CD34+ satellite cells (EDL), the expression of myosin heavy chain isoforms (MHC) and metabolic parameters were measured. Results : Comparison of physiological and muscle parameters revealed statistically significant differences between strains including CV, weight of skeletal muscles and number of myofibers in the entire soleus muscle. In contrast, no difference in the proportion of satellite cells expressing CD34 or Pax7 was observed on isolated myofibers. In response to physical training, a 15% increase of CV was observed in FVB strain (p=0.03), while no significant difference was observed in the other strains. Preliminary results revealed a muscle hypertrophy and a decrease of MHC-2b content in response to exercise. Analyses of other parameters are in progress. Conclusion : Our investigations should provide important informations on the physiological basis of improved muscle performance that could be used for therapeutics in neuromuscular disorders. Acknowledgements : This study was supported by the Association Française contre les Myopathies and the Fondation Bettencourt Schueller. |