Lack of myostatin impairs mechanical performance and ATP cost of contraction in exercising mouse gastrocnemius muscle in vivo.
Am J Physiol Endocrinol Metab
; 305(1): E33-40, 2013 Jul 01.
Article
in En
| MEDLINE
| ID: mdl-23632633
ABSTRACT
Although it is well established that the lack of myostatin (Mstn) promotes skeletal muscle hypertrophy, the corresponding changes regarding force generation have been studied mainly in vitro and remain conflicting. Furthermore, the metabolic underpinnings of these changes are very poorly documented. To clarify this issue, we have investigated strictly noninvasively in vivo the impact of the lack of Mstn on gastrocnemius muscle function and energetics in Mstn-targeted knockout (Mstn-/-) mice using ¹H-magnetic resonance (MR) imaging and ³¹P-MR spectroscopy during maximal repeated isometric contractions induced by transcutaneous electrostimulation. In Mstn-/- animals, although body weight, gastrocnemius muscle volume, and absolute force were larger (+38, +118, and +34%, respectively) compared with wild-type (Mstn+/+) mice, specific force (calculated from MR imaging measurements) was significantly lower (-36%), and resistance to fatigue was decreased. Besides, Mstn deficiency did not affect phosphorylated compound concentrations and intracellular pH at rest but caused a large increase in ATP cost of contraction (up to +206% compared with Mstn+/+) throughout the stimulation period. Further, Mstn deficiency limits the shift toward oxidative metabolism during muscle activity despite the fact that oxidative ATP synthesis capacity was not altered. Our data demonstrate in vivo that the absence of Mstn impairs both mechanical performance and energy cost of contraction in hypertrophic muscle. These findings must be kept in mind when considering Mstn as a potential therapeutic target for increasing muscle mass in patients suffering from muscle-wasting disorders.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Physical Conditioning, Animal
/
Muscle, Skeletal
/
Energy Metabolism
/
Myostatin
/
Muscle Contraction
Type of study:
Health_economic_evaluation
Limits:
Animals
Language:
En
Journal:
Am J Physiol Endocrinol Metab
Journal subject:
ENDOCRINOLOGIA
/
FISIOLOGIA
/
METABOLISMO
Year:
2013
Type:
Article
Affiliation country:
France