EFFECTS OF DIESEL EXHAUST ON ALLERGIC AIRWAY INFLAMMATION IN MICE

Background: Eosinophilic infiltration and goblet cell hyperplasia were induced by the intratracheal instillation of diesel exhaust particles and ovalbumin in mice. However, it is unknown whether its results dif fer from the effects of the inhalation of diesel exhaust and allergen. Objectives: The purpose of this study was to compare the effects of d iesel exhaust inhalation and intratracheal instillation of diesel exha ust particles in a murine asthma model. Methods: ICR mice were exposed to 3 mg soot per cubic meter of diesel exhaust for 6 weeks. After the first week, animals were sensitized by intraperitoneal injection of o valbumin and aluminum hydroxide gel, After 5 weeks of diesel exhaust e xposure the mice were challenged with ovalbumin, The animals were kill ed 1, 2, 3, and 7 days after the challenge and investigated for airway inflammation, hyperplasia of goblet cells, airway hyperresponsiveness , local cytokine expression, and antigen-specific IgE and IgG1 product ion. Results: Exposure to diesel exhaust enhanced infiltration of eosi nophils and neutrophils in murine airways even 1 day after the challen ge, An increment of goblet cells under the bronchial epithelium was fo llowed by the recruitment of inflammatory cells. Furthermore, exposure to diesel exhaust combined with ovalbumin sensitization enhanced resp iratory resistance and expression of IL-5 in lung tissue and IgG1 prod uction but not IgE, However, diesel exhaust alone did not induce patho logic changes in mice, Conclusions: Diesel exhaust enhanced allergic a irway inflammation, hyperplasia of goblet cells, and airway hyperrespo nsiveness caused bg ovalbumin sensitization.