Comparative pathology of the nasal mucosa in laboratory animals exposed to inhaled irritants.

The nasal cavity is susceptible to chemically induced injury as a result of exposure to inhaled irritants. Some responses of the nasal mucosa to inhaled toxicants are species specific. These species-related differences in response may be due to variations in structural, physiologic, and biochemical factors, such as gross nasal cavity structure, distribution of luminal epithelial cell populations along the nasal airway, intranasal airflow patterns, nasal mucociliary apparatus, and nasal xenobiotic metabolism among animal species. This paper reviews the comparative anatomy and irritant-induced pathology of the nasal cavity in laboratory animals. The toxicologist, pathologist, and environmental risk assessor must have a good working knowledge of the similarities and differences in normal nasal structure and response to injury among species before they can select animal models for nasal toxicity studies, recognize toxicant-induced lesions in the nasal airway, and extrapolate experimental results to estimate the possible effects of an inhaled toxicant on the human nasal airway.