title: Allergen-induced oxygen radical release from bronchoalveolar lavage cells and airway hyperresponsiveness in dogs.
abstract: Allergen inhalation causes airway hyperresponsiveness and airway inflammation in dogs. The purpose of this study was to determine whether allergen-induced airway hyperresponsiveness is associated with increases in oxygen radical production from bronchoalveolar lavage (BAL) cells. A group of 10 random-source dogs were studied twice, 4 wk apart. On each occasion, acetylcholine (ACh) airway responsiveness was measured before and 24 h after inhalation of Ascaris suum or its diluent, followed by BAL. The response to ACh was expressed as the concentration causing an increase in lung resistance of 5 cm H2/O/L/s above baseline. Spontaneous and phorbol myristate acetate (PMA)-stimulated (2.4 mumol/L) oxygen radical release were measured, for 10 min each, from washed BAL cells (4 x 10(6) cells/ml) by luminol-enhanced chemiluminescence in a luminometer at 37 degrees C. Superoxide anion production was measured using a cytochrome c assay. Allergen inhalation caused bronchoconstriction, airway inflammation, and airway hyperresponsiveness. The acetylcholine provocative concentration fell from 7.47 mg/ml (% SEM 1.61) before to 1.23 mg/ml (% SEM 1.62) after allergen (p < 0.0001). Allergen inhalation significantly increased absolute neutrophil (p = 0.03) and eosinophil (p = 0.02) counts in BAL. Spontaneous (p < 0.0003) and PMA-stimulated (p < 0.0005) chemiluminescence and superoxide anion production (p = 0.039) were increased after allergen inhalation. The allergen-induced increases in chemiluminescence were significantly correlated with the increases in ACh airway hyperresponsiveness (r = 0.75, p < 0.012). These results indicate that inhaled allergen increases oxygen radical release from bronchoalveolar lavage cells and supports the hypothesis that oxygen radicals are important in causing allergen-induced airway hyperresponsiveness.
authors.affiliation: Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
authors.forename: W H
authors.initials: WH
authors.lastname: Stevens
authors.forename: M D
authors.initials: MD
authors.lastname: Inman
authors.forename: J
authors.initials: J
authors.lastname: Wattie
authors.forename: P M
authors.initials: PM
authors.lastname: O'Byrne
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000403:Airway Resistance; D000485:Allergens; D000818:Animals; D017165:Ascaris suum; D016535:Bronchial Hyperreactivity / Q000378:metabolism*; D001985:Bronchial Provocation Tests; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology*; D004285:Dogs; D004804:Eosinophils; D007958:Leukocyte Count; D008163:Luminescent Measurements; D009504:Neutrophils; D013481:Superoxides / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D000485:Allergens; D013481:Superoxides; D000109:Acetylcholine; D013755:Tetradecanoylphorbol Acetate