title: Antioxidant and inflammatory responses of healthy horses and horses affected by recurrent airway obstruction to inhaled ozone.
abstract: BACKGROUND
  Inhaled ozone can induce oxidative injury and airway inflammation. Horses affected by recurrent airway obstruction (RAO) have a decreased pulmonary antioxidant capacity, which may render them more susceptible to oxidative challenge. It is currently unknown whether RAO-affected horses are more susceptible to oxidative stress than those unaffected by RAO.
  
  
  OBJECTIVE
  To determine whether ozone exposure induces greater oxidative stress and airway inflammation in RAO-affected horses in remission than in healthy horses.
  
  
  METHODS
  Seven healthy control horses and 7 RAO-affected horses were exposed to 0.8 ppm ozone for 2 h at rest.
  
  
  RESULTS
  At baseline, bronchoalveolar lavage fluid (BALF) ascorbic acid concentrations were lower in RAO-affected horses than healthy controls. Ozone appeared to preferentially oxidise glutathione rather than ascorbic acid 6 h after exposure. Individual healthy and RAO-affected horses demonstrated oxidation of BALF glutathione after ozone exposure. Overall, RAO-affected horses did not demonstrate increased oxidative stress following ozone exposure, compared with healthy horses. Ozone did not induce significant airway inflammation in either group.
  
  
  CONCLUSIONS
  RAO-affected horses in remission are not more sensitive to ozone despite a decreased pulmonary antioxidant capacity. Sensitivity to ozone appears to be independent of initial pulmonary antioxidant status.
  
  
  CONCLUSIONS
  Horses with high susceptibility to oxidative stress may benefit from antioxidant supplementation.
authors.affiliation: Centre for Equine Studies, Animal Health Trust, Lanwades Park, Kentford, Newmarket, Suffolk, UK.
authors.forename: C M
authors.initials: CM
authors.lastname: Deaton
authors.forename: D J
authors.initials: DJ
authors.lastname: Marlin
authors.forename: N C
authors.initials: NC
authors.lastname: Smith
authors.forename: C A
authors.initials: CA
authors.lastname: Roberts
authors.forename: P A
authors.initials: PA
authors.lastname: Harris
authors.forename: R C
authors.initials: RC
authors.lastname: Schroter
authors.forename: F J
authors.initials: FJ
authors.lastname: Kelly
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000032:analysis*; D001205:Ascorbic Acid / Q000032:analysis; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology; D016022:Case-Control Studies; D005260:Female; D005978:Glutathione / Q000378:metabolism; D006734:Horse Diseases / Q000139:chemically induced / Q000378:metabolism*; D006736:Horses / Q000378:metabolism*; D008173:Lung Diseases, Obstructive / Q000378:metabolism / Q000503:physiopathology / Q000662:veterinary*; D008297:Male; D010083:Oxidants, Photochemical / Q000009:adverse effects*; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects; D010126:Ozone / Q000009:adverse effects*; D012008:Recurrence
chemical_list: D000975:Antioxidants; D010083:Oxidants, Photochemical; D010126:Ozone; D005978:Glutathione; D001205:Ascorbic Acid