The analysis of antioxidant expression during muscle atrophy induced by hindlimb suspension in mice.

Oxidative stress contributes to acceleration of muscle atrophy. However, it is still not completely understood what triggers the production of reactive oxygen species (ROS) during muscle atrophy. The objective of this study was to investigate redox balance during muscle atrophy. ROS generators and antioxidants were analyzed in atrophied soleus muscles after 2 weeks of hindlimb suspension (HLS) in mice. The HLS group showed an increase in lipid peroxidation, upregulated NOX1 and NOXO1, and downregulated mitochondrial complex I subunits NDUFS5 and NDUFV2. Additionally, HLS mice demonstrated a decrease in Prdx5 and MnSOD, but an increase in GPX2 and GPX3 in both mRNA and protein levels. As expected, MnSOD activity declined in the HLS group, while GPX activity was enhanced. These results suggest that redox imbalance occurs during muscle atrophy through NOX1 activation, mitochondrial complex I deficiency, and disturbance of antioxidants. Antioxidants altered by HLS may represent potential therapeutic targets for the protection against muscle atrophy.