title: [Cytochrome C oxidase expression and endothelial cell apoptosis in lungs of patients with chronic obstructive pulmonary disease].
abstract: OBJECTIVE
  To observe the expression and activity of cytochrome C oxidase and pulmonary endothelial apoptosis in lungs of COPD patients, and therefore to investigate the pathogenesis of COPD.
  
  
  METHODS
  According to COPD diagnostic criteria and patients' smoking status, 20 patients who had undergone lung resections were divided into 3 groups: group A, non-smokers without COPD (7 patients); group B, smokers without COPD (7 patients); and group C, smokers with COPD (6 patients). Their normal lung tissues were used in the study. TUNEL assay was used to assess pulmonary vascular endothelial apoptosis. Cytochrome C oxidase (COX) activity was measured by spectrophotometry. Semi-quantitative polymerase chain reaction and Western blot were used to measure COX subunit II (COXII) mRNA and protein expression respectively. Moreover, immunohistochemistry was used to detect COXII protein expression in pulmonary endothelial cells. One-way ANOVA and LSD-t test were used for statistics.
  
  
  RESULTS
  The apoptotic index of pulmonary vascular endothelial cells in group C [(13.8 ± 1.9)%] was significantly higher than that in group B [(9.6 ± 0.8)%] and group A [(5.9 ± 1.0)%]. While COX activity and COXII mRNA expression of lung tissues and COXII protein expression of pulmonary endothelial cells in group C [(4.4 ± 0.7) × 10⁵ U/kg, (0.76 ± 0.17) and (14.5 ± 1.6), respectively] were significantly lower than those in group A [(7.6 ± 0.4) × 10⁵ U/kg, 0.86 ± 0.20 and 23.8 ± 3.4, respectively] and group B [(6.0 ± 0.6) × 10⁵ U/kg, 0.81 ± 0.15 and 18.6 ± 2.1, respectively] (t = -13.66 - 13.27, all P < 0.05). The correlation analyses showed that COX activity was correlated positively with FEV₁ % pred and FEV₁/FVC (r = 0.84, 0.91, all P < 0.01), but negatively with smoking index (r = -0.78, P < 0.01). The apoptotic index of pulmonary vascular endothelial cells was negatively correlated with COXII expression (r = -0.75, P < 0.01).
  
  
  CONCLUSIONS
  Increased pulmonary vascular endothelial apoptosis and decreased COX expression and activity, which were often associated with cigarette smoking, were present in COPD patients. COX might mediate the pulmonary vascular endothelial apoptosis in COPD.
authors.affiliation: Department of Respiratory Medicine, the Second Xiangya Hospital of Central South University, Changsha 410011, China.
authors.forename: Min
authors.initials: M
authors.lastname: Yang
authors.forename: Ping
authors.initials: P
authors.lastname: Chen
authors.forename: Hong
authors.initials: H
authors.lastname: Peng
authors.forename: Qin
authors.initials: Q
authors.lastname: Shen
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D017209:Apoptosis; D003576:Electron Transport Complex IV / Q000378:metabolism*; D042783:Endothelial Cells / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D008168:Lung / Q000166:cytology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism* / Q000473:pathology*; D012907:Smoking
chemical_list: C117108:cytochrome C oxidase subunit II; D003576:Electron Transport Complex IV