title: Involvement of superoxide anions in ozone-induced airway hyperresponsiveness in unanesthetized guinea pigs.
abstract: To evaluate the involvement of superoxide in ozone (O(3))-induced airway hyperresponsiveness, we studied the effects of superoxide dismutase (SOD), a scavenger of superoxide anion, and apocynin, an inhibitor of superoxide anion-generating NADPH oxidase in phagocytes, on the airway responses induced by O(3) in unanesthetized guinea pigs. Airway responsiveness was measured by PC(200)Mch, the concentration required to produce a doubling in the baseline specific airway resistance to an inhaled methacholine aerosol, in spontaneously breathing animals. Before exposure to 3 ppm O(3) for 30 min, animals inhaled either SOD (5000 U/ml) or vehicle for 5 min. Although SOD did not affect PC(200)Mch in the air control group, this agent reduced the O(3)-induced airway hyperresponsiveness. Repeated administration of apocynin (12 mg/kg for 4 days) also attenuated the O(3)-induced airway hyperresponsiveness. These data suggest that superoxide may be involved in the pathogenesis of O(3)-induced airway hyperresponsiveness, possibly through the stimulation of superoxide anions release from bronchoalveolar phagocytes. The data also suggest a potential therapeutic role for antioxidants in oxidant injury by air pollutants.
authors.affiliation: The First Department of Internal Medicine, Yokohama City University, School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kudo
authors.forename: M
authors.initials: M
authors.lastname: Nishikawa
authors.forename: H
authors.initials: H
authors.lastname: Ikeda
authors.forename: T
authors.initials: T
authors.lastname: Okubo