Effect of Ozone Exposure on Experimentally Induced Allergic Rhinitis in Rats

Jeon, Woo Jin; Byun, Sang Nae; Kim, Young Min; Kim, Byung Kook; Rha, Ki Sang; Park, Chan Il

Abstract

BACKGROUND AND OBJECTIVES: Epidemiologic and clinical trials have suggested that ozone exposure increase airway hyperresponsiveness and inflammatory response to allergen challenge in allergic asthmatics. But the effect of ozone exposure on the allergic rhinitis is still unclear. The purpose of this study was to determine whether ozone increases the nasal inflammatory response to allergen challenge in experimentally induced allergic rhinitis.
MATERIALS AND METHODS
Forty Sprague- Dawley rats were divided into four groups : (A) NSS (normal saline) group, (B) group challenged by allergen (ovalbumin), (C) group exposed to ozone, and (D) group exposed to ozone followed by allergen (ovalbumin) challenge. To induce the allergic rhinitis in group B and D, rats was immunized intraperitoneally with ovalbumin, followed by intranasal nebulization of ovalbumin. In group C and D, rats were exposed to 0.3 ppm ozone for 3 days (6 hr/day). We recorded the symptoms (snort and scratching) for 5 min after the last nebulization. We also examined the infiltration of inflammatory cells, morphological changes of nasal mucosa, and Evans blue extravasation in septal rnucosa.
RESULTS
Infiltration of neutrophils in nasal mucosa was significantly increased in group D compared with group B (p <0.05). Morphological changes such as loss of cilia and epithelial hyperplasia were more pronounced in group D than in group B (p <0.05). Evans blue extravasation was significantly higher in group D than in group B (p<0.05). CONCLUSION: These results may suggest that ozone enhances the inflammatory responses to allergens in allergic rhinitis patients.