Films from lung washings as a mechanism model for lung injury by ozone

¹ Toxicology Section, Division of Occupational Health, Public Health Service, Cincinnati, Ohio

Saline washings of the mouse lung were layered on various hypophases. With serum dialysate present in the hypophase, film pressure in the presence of ozone increased over that in its absence. Addition of Tapazole (2-methyl-1-mercaptoimidazole) or AET (aminoethylisothiouronium bromide-HBr) protected the films from the action of ozone if serum dialysate was present in the hypophase, but film pressures were rapidly reduced in its absence. Both Tapazole and AET protect mice from otherwise lethal doses of ozone. The results indicate the presence of a surface-active film in the alveolus which, together with the hypophase upon which it resides, forms a primary barrier against production of pulmonary edema by ozone. However, this barrier, because of increase in its surface pressure, may be a primary cause of emphysema produced in animals by long-term exposure to ozone. Destruction of the surface-active material of the barrier should produce atelectasis and/or pulmonary edema as a result of increased surface tension.