Exposure to ozone aggravates nasal allergy-like symptoms in guinea pigs.

The ability of O3 exposure to aggravate ovalbumin (OVA)-induced nasal allergy-like symptoms was studied in guinea pigs. Guinea pigs were exposed to filtered air or to 0.4 ppm O3 for 5 weeks. During the exposure, 1% OVA or saline was administered into the nasal cavities once a week. Sneezes and nasal secretions were measured for a 20-min period following OVA administration. The number of eosinophils infiltrating both nasal epithelium and subepithelium and titers of specific anti-OVA-IgG were measured 24 h after the last administration. Ozone increased OVA-induced sneezing and nasal secretion, as well as induced nasal hyper-responsiveness to physical stimuli. The number of eosinophils infiltrating the nasal subepithelium was increased by O3, and the titer of anti-OVA-IgG tended to increase in the O3-exposed animals. Thus, exposure to O3 aggravated nasal allergy-like symptoms by inducing nasal hyper-responsiveness, the infiltration of eosinophils, and by tending to increase the production of anti-OVA-IgG.