GPX1 and chronic obstructive pulmonary disease: In cultured COPD myotubes (Fig. 7 E–H), the expression level of Mn SOD [133.5 a.u. (121.5–166.0) versus 148.5 a.u. (121.0–162.0); P = 0.878], Cu/Zn SOD [102.5 a.u. (67.0–135.5) versus 91.5 a.u. (61.0–239.0); P = 0.959], catalase [3054.0 a.u. (1565.0–3534.5) versus 2813.0 a.u. (1951.0–4535.0); P = 0.463] and GPx1 [126.0 a.u. (85.0–256.3) versus 211.0 a.u. (141.0–336.0); P = 0.336] was similar to that in healthy individual myotubes.