Effect of exposure to 500 ppm sulfur dioxide on the lungs of the ferret.

Male ferrets (Mustela putorius furo) were exposed 3 h/day, 3 days/week for 12 weeks to 500 ppm SO2. Determinations were made of airway responsiveness by producing histamine dose-effect curves. Lung tissues were fixed and studied by light and electron microscopy. Epithelial cells of the trachea and bronchus were most affected. Lesions observed included changes in ciliated cells, edema and cell infiltration. The most responsive animals to histamine were 2 from the exposed group. Nasal discharge and dried mucus were observed after 3 days of exposure. Coughing was first noted after 2 weeks. Results favor further pursuit of the use of the ferret as a model for human airways disease.