Nitrogen Dioxide-induced Eosinophilia and Mucosal Injury in the Nose of the Guinea Pig

Abstract

Nitrogen dioxide exposure-induced mucosal pathology of the guinea pig nose was studied. Guinea pigs were exposed to 3 ppm or 9 ppm of nitrogen dioxide for 6 h a day. 6 times weekly for 2 weeks. and sacrificcd 24 h after the final exposure. Exposure to 3 ppm of nitrogen dioxide resulted in decreased ciliary activity and slight eosinophil accumulation on the epithelium and submucosal layer. More serious pathologies were observed in the nose of guinea pigs exposed to 9 ppm of nitrogen dioxide, including a more prominent eosinophil influx to the epithelium and epithelial injury due to activation of eosinophils. Epithelial damage induced by nitrogen dioxide could lead to hyperresponsiveness and may result in a prolonged allergic inflammation. Our study suggests that environmental nitrogen dioxide may contribute to hyperresponsiveness and thus be involved in the increased morbidity of allergic rhinitis.

Key Words:

• nitrogen dioxide
• ciliary activity
• nose
• eosinophilia
• mucosal injury.