Toluene Diisocyanate-Induced Allergic Rhinitis in Guinea Pigs: Investigating the Relation between Eosinophil Infiltration and Epithelial Injury

ABSTRACT

It is well known that many eosinophils are infiltrated in the bronchial and nasal mucosa of allergic patients, and that eosinophil granule proteins can injure the bronchial epithelium. But it is uncertain whether epithelial injury occurs in the nasal mucosa of patients with allergic rhinitis and, if so, whether the injury is related with the eosinophil infiltration. The present study was made with the aim of determining the correlation between eosinophil infiltration and epithelial injury in the nasal mucosa of guinea pigs with experimentally induced nasal allergy. 2,4-Toluene diisocyanate (TDI) is considered to be a causative agent of allergic pulmonary disorder and allergic rhinitis. Guinea pigs were sensitized by applying TDI onto their bilateral nasal vestibules once a day for five consecutive days. Symptom scores, peripheral blood and histopathology of the nasal mucosa in the inferior turbinate were examined in both allergy and control group. The symptom scores were significantly higher in allergy group than in control group and the eosinophils of peripheral blood were found significantly higher in the allergy groups, especially in groups sacrificed 24 and 48 hour after provocation. As well, there was a positive correlation between how heavily infiltrated the eosinophils were and the level of epithelial loss in the nasal mucosa. The correlation was prominent in groups sacrificed 24 and 48 hour after provocation. The findings indicate that the epithelial injury occurs in the nasal mucosa of guinea pigs with nasal allergy and that injury is related to the eosinophil infiltration.