Oxidative stress and disuse muscle atrophy: cause or consequence?

PURPOSE OF REVIEW: This review will discuss the evidence both for and against the concept that reactive oxygen species (ROS) play an important role in the regulation of inactivity-induced skeletal muscle atrophy. RECENT
FINDINGS: It is well established that prolonged skeletal muscle inactivity causes muscle fiber atrophy and a decrease in muscle force production. This disuse-induced muscle atrophy is the consequence of a loss in muscle protein resulting from increased protein degradation and decreased protein synthesis. Recent studies suggest that oxidative stress can influence cell-signaling pathways that regulate both muscle protein breakdown and synthesis during prolonged periods of disuse. Specifically, it is feasible that increased ROS production in muscle fibers can promote increased proteolysis and also depress protein synthesis during periods of skeletal muscle inactivity.
SUMMARY: Although it is established that oxidants can participate in the regulation of protein turnover in cells, there remains debate as to whether oxidative stress is required for disuse skeletal muscle atrophy. Nonetheless, based on emerging evidence we conclude that increased ROS production in skeletal muscles significantly contributes to inactivity-induced muscle atrophy.