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 differ from the effects of the inhalation of diesel exhaust and allergen.


OBJECTIVE
The purpose of this study was to compare the effects of diesel exhaust inhalation and intratracheal instillation of diesel exhaust 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 ovalbumin and aluminum hydroxide gel. After 5 weeks of diesel exhaust exposure, the mice were challenged with ovalbumin. The animals were killed 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 production.


RESULTS
Exposure to diesel exhaust enhanced infiltration of eosinophils and neutrophils in murine airways even 1 day after the challenge. An increment of goblet cells under the bronchial epithelium was followed by the recruitment of inflammatory cells. Furthermore, exposure to diesel exhaust combined with ovalbumin sensitization enhanced respiratory resistance and expression of IL-5 in lung tissue and IgG1 production but not IgE. However, diesel exhaust alone did not induce pathologic changes in mice.


CONCLUSIONS
Diesel exhaust enhanced allergic airway inflammation, hyperplasia of goblet cells, and airway hyperresponsiveness caused by ovalbumin sensitization.
Miyabara
Y
Y
Research Team for Health Effects of Air Pollutants, National Institute for Environmental Studies, Ibaraki, Japan.
Ichinose
T
T
Takano
H
H
Lim
H B
HB
Sagai
M
M
D000818:Animals; D000918:Antibody Specificity; D001249:Asthma / Q000209:etiology* / Q000276:immunology / Q000503:physiopathology*; D016535:Bronchial Hyperreactivity / Q000209:etiology; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D007073:Immunoglobulin E / Q000096:biosynthesis / Q000276:immunology; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D010047:Ovalbumin / Q000494:pharmacology; D001335:Vehicle Emissions / Q000009:adverse effects*
D001335:Vehicle Emissions; D007073:Immunoglobulin E; D010047:Ovalbumin