DIESEL EXHAUST INHALATION ENHANCES AIRWAY HYPERRESPONSIVENESS IN MICE

Background: Repeated intratracheal instillation of diesel exhaust part icles and ovalbumin-induced airway hyperresponsiveness and airway infl ammation in mice. However, the effects of daily inhalation of diesel e xhaust may differ from the effects of direct instillation. Methods: Th erefore, mice were exposed to diesel exhaust by inhalation 12 h per da y for 3 months. Before the diesel exhaust exposure, ovalbumin was inje cted intraperitoneally as a sensitization. After 3 weeks of diesel exh aust exposure, these mice were challenged with ovalbumin every 3 week thereafter. Results: Diesel exhaust exposure with antigen challenge in duced airway hyperresponsiveness and airway inflammation which was cha racterized by increased numbers of eosinophils and mast cells in lung tissue. The recruitment of inflammatory cells was accompanied by an in crement in goblet cells on bronchial epithelium. Diesel exhaust exposu re alone also enhanced airway hyperresponsiveness, but did not induce eosinophilic infiltration and/or an increment in goblet cells. Conclus ion: Diesel exhaust inhalation enhanced airway hyperresponsiveness and airway inflammation caused by ovalbumin sensitization in mice.