Expression levels of protein breakdown markers after H₂O₂ treatment.

<p>Variation of MuRF1 (A), atrogin-1 (B), FoxO1 (C), FoxO3 (E) and myostatin (F) RNA expression in COPD myotubes after H₂O₂ treatment. (D) Variation of FoxO1 protein expression relative to tubulin expression in COPD myotubes after H₂O₂ treatment, and representative Western blots showing expression levels of FoxO1 and tubulin in cultured COPD myotubes derived from 12 COPD patients (1–12), with or without H₂O₂ treatment. (n.s.) indicates statistically non-significant, and (*) indicates statistical significance at P≤0.05. The medians are indicated.</p

Diameter of COPD and healthy subject myotubes after H₂O₂ treatment.

<p>Representative images of COPD myotubes (A) or healthy subject myotubes (C) with or without H₂O₂ treatment, showing fluorescence double-labelling using an anti-troponin T antibody (green) and Hoechst (blue). Bar = 200 μm. Analysis of the variation of the myotube diameter after H₂O₂ treatment of the COPD myotubes (B) or the healthy subject myotubes (D). (**) indicates statistical significance at P<0.01. (n.s.) indicates statistically non-significant. The medians are indicated.</p

Oxidative stress status after H₂O₂ treatment.

<p>(A) The variation of ROS production in COPD myotubes is represented after H₂O₂ treatment. (B) Representative Western blots showing levels of protein carbonylation with or without H₂O₂ treatment, for the myotubes cultures derived from 12 COPD patients (1–12). Coomassie blue-stained gels are also presented for loading control. (C) Variation of protein carbonylation relative to Coomassie blue-stained bands after H₂O₂ treatment. (D) Representative Western blots showing levels of lipid peroxidation with or without H₂O₂ treatment in COPD cultured myotubes derived from 12 COPD patients (1–12). Tubulin detection is used as a loading control. (E) Variation of lipid peroxidation relative to tubulin expression levels following H₂O₂ treatment. (n.s.) indicates statistically non-significant. (*) and (**) indicate statistical significance at P≤0.05 and P<0.01, respectively. The medians are indicated.</p

Expression levels of protein synthesis markers after H₂O₂ treatment.

<p>(A) Variation of IGF-1 mRNA expression in COPD myotubes after H₂O₂ treatment. (B) Representative Western blots showing expression levels of phosphorylated-AKT (P-AKT) and AKT in cultured COPD myotubes derived from 12 COPD patients (1–12), with or without H₂O₂ treatment. Tubulin expression is used as a loading control. (C) Variation of the P-AKT/AKT ratio relative to tubulin expression levels following H₂O₂ treatment. (n.s.) indicates statistically non-significant. The medians are indicated.</p

Expression levels of protein synthesis markers after ascorbic acid treatment.

<p>(A) Variation of IGF-1 mRNA expression in COPD myotubes after ascorbic acid treatment. (B) Representative Western blots showing expression levels of phosphorylated-AKT (P-AKT) and AKT in cultured COPD myotubes derived from 12 COPD patients (1–12), with or without ascorbic acid treatment. Tubulin expression is used as a loading control. (C) Variation of the P-AKT/AKT ratio relative to tubulin expression levels following ascorbic acid treatment. (n.s.) indicates statistically non-significant. The medians are indicated.</p

Characteristics of the study groups.

<p>Characteristics of the study groups.</p

Primers used.

<p>Primers used.</p

Expression levels of protein breakdown markers after ascorbic acid treatment.

<p>Variation of MuRF1 (A), atrogin-1 (C), FoxO1 (E), FoxO3 (G) and myostatin (H) RNA expression levels in COPD myotubes after ascorbic acid treatment. Variations of MuRF1 (B), atrogin-1 (D) and FoxO1 (F) protein expression relative to tubulin expression in COPD myotubes after ascorbic acid treatment, and the representative Western blots showing their expression levels as well as tubulin expression in cultured COPD myotubes derived from 12 COPD patients (1–12). (n.s.) indicates statistically non-significant. (*), (**) and (***) indicate statistical significance at P≤0.05, P<0.01 and P<0.001, respectively. The medians are indicated. Statistical analysis showing correlations between the variations in the RNA expression of MuRF1 and: (I) the variations in myotube diameter, and (J) the variations in the RNA expression of FoxO1, after ascorbic acid treatment.</p

Oxidative stress status after ascorbic acid treatment.

<p>(A) The variation of ROS production in COPD myotubes is shown after ascorbic acid treatment. (B) Representative Western blots showing levels of protein carbonylation with or without ascorbic acid treatment for the myotubes cultures derived from 12 COPD patients (1–12). Coomassie blue-stained gels are used for loading control. (C) Variation of protein carbonylation relative to Coomassie blue-stained bands after ascorbic acid treatment. (D) Representative Western blots showing levels of lipid peroxidation with or without ascorbic acid treatment in COPD cultured myotubes derived from 12 COPD patients (1–12). Tubulin detection is used as a loading control. (E) Variation of lipid peroxidation relative to tubulin expression levels following ascorbic acid treatment. (n.s.) indicates statistically non-significant. (*) and (***) indicate statistical significance at P≤0.05 and P<0.001, respectively. The medians are indicated.</p

Diameter of COPD and healthy subject myotubes after ascorbic acid treatment.

<p>Representative images of COPD myotubes (A) or healthy subject myotubes (C) with or without ascorbic acid treatment, showing fluorescence double-labeling using an anti-troponin T antibody (green) and Hoechst (blue). Bar = 200 μm. Analysis of the variation of the COPD myotube diameter (B) or the healthy subject myotube diameter (D) after ascorbic acid treatment. (E) Diameter of myotubes from healthy subjects and COPD patients, cultured with or without ascorbic acid. (*) and (***) indicate statistical significance at P≤0.05 and P<0.001, respectively. (n.s.) indicates statistically non-significant. The medians are indicated.</p