title: Interaction of ozone and allergen challenges on bronchial responsiveness and inflammation in sensitised guinea pigs.
abstract: BACKGROUND
  Environmental pollutants such as ozone may interact with airway responses to allergen in sensitised individuals.
  
  
  METHODS
  We examined the effects of a single exposure to ozone (1 ppm for 1 h) on bronchial responsiveness to acetylcholine (ACh) aerosol 3 and 24 h after single ovalbumin (OA) challenge in OA-sensitised anaesthetised guinea pigs. Broncho-alveolar lavage (BAL) was performed and protein content and differential cell counts were determined.
  
  
  RESULTS
  Ozone increased bronchial responsiveness at 3 h but not at 24 h, while OA alone had no effect. At 3 h after ozone, OA induced further, but non-significant increases in bronchial responsiveness to ACh, but at 24 h after ozone, there was enhanced responsiveness. Neutrophil counts in BAL fluid increased at 3 and 24 h after exposure to ozone alone, but there were no further increases with ozone followed by OA exposure. Protein concentration was significantly increased in the ozone and OA groups at 3 and 24 h (163.4 +/- 25.6 and 128.7 +/- 7.4 mg/ml, respectively) compared to 54.0 +/- 18.1 mg/ml in the control group (p < 0.02 and p < 0.01, respectively).
  
  
  CONCLUSIONS
  Our data demonstrate an interaction of OA with ozone exposure on bronchial responsiveness; one underlying mechanism could be through damage at the endothelial-epithelial barrier.
authors.affiliation: Department of Thoracic Medicine, National Heart and Lung Institute, Imperial College of Science, Technology & Medicine, London, UK.
authors.forename: J
authors.initials: J
authors.lastname: Sun
authors.forename: H
authors.initials: H
authors.lastname: Koto
authors.forename: K F
authors.initials: KF
authors.lastname: Chung
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000485:Allergens / Q000008:administration & dosage*; D000818:Animals; D001980:Bronchi / Q000187:drug effects / Q000276:immunology / Q000293:injuries; D016535:Bronchial Hyperreactivity / Q000209:etiology* / Q000276:immunology*; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology; D006168:Guinea Pigs; D007114:Immunization; D007249:Inflammation / Q000209:etiology / Q000276:immunology; D008297:Male; D010047:Ovalbumin / Q000008:administration & dosage / Q000276:immunology; D010083:Oxidants, Photochemical / Q000633:toxicity*; D010126:Ozone / Q000633:toxicity*; D011506:Proteins / Q000378:metabolism
chemical_list: D000485:Allergens; D010083:Oxidants, Photochemical; D011506:Proteins; D010126:Ozone; D010047:Ovalbumin; D000109:Acetylcholine