NASAL LESION DISTRIBUTION AND TOXICITY IN THE SQUAMOUS EPITHELIAL REGION

There is an increasing awareness of the importance of the nasal epithe lium as a Larger site for chemically induced toxicity and carcinogenic ity. Extrapolating inhalation toxicology results from animal studies t o humans remains a difficult task, however, due to varied and marked i nterspecies differences. Studies of the distribution of nasal lesions may provide insight into the mechanisms involved in toxicant-induced n asal pathology and improve the human risk assessment process. It becom es important to continually expand the database on nasal toxicologic p athology by providing a careful description and mapping of lesions fro m inhalation toxicology studies. In this brief review, the commonly en countered distribution of nasal lesions in the rodent and the factors that influence distribution are presented. In addition, histology and toxicant-induced lesions of the nasal squamous epithelium, which lines the entrance to the upper respiratory tract, are addressed.