Neutralizing mitochondrial ROS does not rescue muscle atrophy induced by hindlimb unloading in female mice.

Excess reactive oxygen species (ROS) induced by physical inactivity is associated with muscle atrophy and muscle weakness. However, the role of mitochondrial ROS on disuse-induced muscle atrophy is not fully understood. The purpose of this study was to utilize a genetic strategy to examine the effect of neutralizing mitochondrial ROS on disuse-induced skeletal muscle atrophy. This was accomplished by placing wildtype (WT) and mitochondrial-targeted catalase expressing (MCAT) littermate mice on 7-days of hindlimb unloading. After assessment of body weight and composition, muscles were analyzed for individual muscle mass, force generating capacity, fiber-type, cross-sectional area, and mitochondrial phenotyping including H2O2 production. Despite a successful attenuation of mitochondrial ROS, MCAT mice were not protected from muscle atrophy. No differences were observed in body composition, lean mass, individual muscle masses, force-generating capacity, and muscle fiber cross-sectional area. These data suggest that neutralizing mitochondrial ROS is insufficient to suppress disuse-induced loss of skeletal muscle mass and contractile function.