Time Course of Changes in Surface Tension and Morphology of Alveolar Epithelial Cells in Co2-induced Hyaline Membrane Disease.

Carbon dioxide (CO2) exposure was found to result in production of pulmonary hyaline membranes in rodents by a number of investigators (1-3). In previous studies with Niemoeller (4), we were able to show that incidence of hyaline membrane formation progressively decreases in guinea pigs during prolonged exposure to CO2 after compensation of the respiratory acidosis, suggesting a nonspecific acidosis effect. A lack of surface-active material (surfactant) has been observed in lungs of newborn infants with atelectasis and hyaline membranes (5). The question arose whether the transient C02-induced hyaline membrane formation is associated with a loss in lung surfactant and changes in alveolar lining cells, since previous studies show a relationship between lung surfactant and transformation of lamellar bodies of alveolar lining cells. Buckingham and Avery (6) were able to detect a surfactant in the lung of the fetal mouse on the same day of gestation on which Woodside and Dalton (7) noted the first appearance of lamellar bodies in the alveolar lining cells. Klaus and co-workers (8) demonstrated that 1) after vagotomy of guinea pigs, the lung surfactant and the number of alveolar bodies are reduced, 2) the surfactant is found in the mitochondrial fraction of ultracentrifuged lungs and not in the mitochondrial fractions of liver and spleen, and 3) toads and pigeons lack both surfactant and lamellar bodies. This report extends the observations of Klaus and co-workers and brings further evidence for