title: Oxygen therapy at low flow causes oxidative stress in chronic obstructive pulmonary disease: Prevention by N-acetyl cysteine.
abstract: Exposure to high oxygen concentration produces toxicity by free radical release. We aimed to study: whether stable chronic obstructive pulmonary disease (COPD) patients present an unbalance in the blood redox status; the effect of oxygen administration on blood redox balance; the efficacy of N-acetyl-cysteine (NAC) treatment against the oxidative stress-induced by oxygen administration and whether it is dose-related. To this, 45 stable state III COPD patients were recruited and reduced glutathione (GSH) and oxidised glutathione (GSSG) in erythrocytes and thiol proteins (P-SH) and carbonyl proteins (PC) in both erythrocytes and plasma were evaluated. All COPD patients underwent 2 l/m oxygen for 18 h and NAC at 1200 or 1800 mg/day or placebo for 48 h starting with oxygen administration. Blood samples were collected at basal conditions, after 8 and 18 h of oxygen administration and 24 h after oxygen withdrawal.
  
  
  RESULTS
  COPD patients present an unstable redox equilibrium mainly due to plasma sulphydryl protein depletion. Oxygen administration oxidize erythrocyte GSH, decrease P-SH and increase PC levels in both plasma and erythrocytes. NAC administration counteract the oxidative stress and at the highest dose completely prevent protein oxidation. In conclusion, stable state III COPD patients present an unstable redox balance; long term low flow oxygen administration induces systemic oxidative stress, which is prevented by NAC treatment.
authors.affiliation: University of Foggia, Department of Medical and Occupational Sciences, Foggia, Italy.
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Foschino Barbaro
authors.forename: Gaetano
authors.initials: G
authors.lastname: Serviddio
authors.forename: Onofrio
authors.initials: O
authors.lastname: Resta
authors.forename: Tiziana
authors.initials: T
authors.lastname: Rollo
authors.forename: Rosanna
authors.initials: R
authors.lastname: Tamborra
authors.forename: Giovanna
authors.initials: G
authors.lastname: Elisiana Carpagnano
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Vendemiale
authors.forename: Emanuele
authors.initials: E
authors.lastname: Altomare
mesh_terms: D000111:Acetylcysteine / Q000008:administration & dosage / Q000494:pharmacology*; D001798:Blood Proteins / Q000378:metabolism; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects*; D010100:Oxygen / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology / Q000627:therapeutic use; D010102:Oxygen Inhalation Therapy / Q000009:adverse effects*; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000378:metabolism* / Q000628:therapy*
chemical_list: D001798:Blood Proteins; D010100:Oxygen; D000111:Acetylcysteine