Fig. 4From: Mitochondrial dysfunction in airways and quadriceps muscle of patients with chronic obstructive pulmonary diseaseCorrelation between mitochondrial membrane potential and ETC protein expression levels in quadriceps muscle. (a) Correlations between bronchial mitochondrial membrane potential (ΔΨm) and protein expression levels of lung electron transport chain (ETC) complex proteins I and (b) lung ETC complex protein II. (c) Correlation between quadriceps mitochondrial membrane potential (ΔΨm) and muscle ETC complex protein I and (d) muscle ETC complex protein II ● never-smokers (n = 5), ■ ex-smokers (n = 5) and ▲COPD GOLD Grade 2 (n = 5)Back to article page