Vinyl acetate casts of emphysematous rat lungs.

Emphysema was induced in rats by chronic exposure to a papain aerosol according to established methods. The emphysematous changes were evaluated by previously described histological and biochemical parameters and by a new method employing infiltration of the lungs with vinyl acetate to make casts of the air spaces of the pulmonary tree. The weights and gross and microscopic appearance of the casts demonstrated the emphysematous changes in lungs of the papain-treated rats. Vinyl acetate casting may offer a new and useful tool in evaluating experimental induction of emphysema in rats.