Abstract
There is an increasing awareness of the importance of the nasal epithelium as a target site for chemically induced toxicity and carcinogenicity. Extrapolating inhalation toxicology results from animal studies to humans remains a difficult task, however, due to varied and marked interspecies differences. Studies of the distribution of nasal lesions may provide insight into the mechanisms involved in toxicant-induced nasal pathology and improve the human risk assessment process. It becomes important to continually expand the database on nasal toxicologic pathology by providing a careful description and mapping of lesions from inhalation toxicology studies. In this brief review, the commonly encountered distribution of nasal lesions in the rodent and the factors that influence this 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.