Occurrence of Foreign Body Rhinitis in F344 Rats During Toxicologic Studies

The incidences and lesions of foreign body rhinitis due to hairs and/or diet powders were investigated in Fischer 344 DuCrj rats subjected to 13 week-toxicity and 2 year-carcinogenicity studies. During the 2 year-carcinogenicity studies, rhinitis was disclosed in 207 of 600 (34.5%) male and 71 of 600 (11.8%) female rats of the untreated control groups. In all cases the foreign bodies concerned were animal hairs. The lesions were detected only in aged rats but not in those younger than 4 months of age. The incidence was higher in males than females, and most lesions were located at the level of the incisive papilla.