Abstract
The plasticity of the skeletal muscle allows it to adapt optimally to stimuli of the environment such as exercise, but also makes the skeletal muscle prone to deleterious conditions such as lack of activity and chronic diseases that are often associated. In end-stage renal disease, the muscle function, highly affected, can be improved by physical exercise performed during hemodialysis. This thesis highlights that whatever the sequence of exercises, combined rehabilitation improves limbs strength, walking speed and patients’ balance. The work in this thesis also shows the interest of the implementation of eccentric exercise at the patient bedside, which could allow an even more effective rehabilitation in the future that would also be accessible to the most deconditioned. At the same time, the development of effective therapeutic strategies requires the identification of the molecular mechanisms involved in the regulation of muscle protein balance. Numerous cellular signaling pathways regulate protein synthesis and degradation and eIF3f factor appears to be a major regulator of protein synthesis. In this thesis work, the study of the physiological functions of eIF3f in animals shows in vivo the impact of the level of expression of eIF3f on the regulation of muscle mass and protein synthesis at basal state and during hypoactivity. While its partial depletion decreases muscle mass and affects metabolism, its overexpression stimulates anabolism and helps to delay immobilization-induced muscle atrophy. Understanding the physiological roles of eIF3f in muscle function may possibly lead to the development of new therapies against muscle deconditioning.