Quantitation of bronchiolar epithelial proliferation in A23187-exposed guinea pigs.

Aerosol exposure to the ionophore A23187 results in PMN accumulation, airway epithelial injury and prolonged airway constriction. Bronchiolar epithelial damage in ionophore-exposed guinea pigs was quantitated by measuring epithelial proliferation using bromodeoxyuridine (BRDU). Animals were killed at 24, 48 or 72 hours post-ionophore exposure and lungs were collected for H & E and immunostaining. Numerical scores were assigned for morphologic changes and the number of labeled cells per mm of airway was determined. Significant increases in labeled epithelial cells were evident at 48 hours. Inflammation and epithelial damage scores also were elevated. These results indicate that ionophore exposure results in pulmonary inflammation and bronchiolar epithelial proliferation as assessed by BRDU labeling.