Acute lung injury induced by cadmium aerosol. II. Free airway cell response during injury and repair

Abstract

This paper presents a study of the effects of cadmium chloride aerosol on free airway cell populations. Rats were given a single exposure to aerosolized 0.005 M CdCl2 dissolved in physiologic saline. CdCl2 exposure induced a fivefold increase to 43.2 X 10(6) total cells at 4 days as compared with 11.1 X 10(6) in saline-exposed controls and 8.4 X 10(6) in unexposed rats (P less than 0.001). Differential counts showed a peak of polymorphonuclear leukocytes (PMN) at 3 days after CdCl2 exposure, whereas values for saline-exposed animals showed no change from values for unexposed animals (P less than 0.001). Four days after CdCl2 exposure thepredominant cell was the alveolar macrophage (AM), which showed a highly significant increase in number and size over saline-exposed and unexposed animals. A significant increase in lymphocytes also occurred, with a peak at 4 days. At 10 days after exposure, AM were still more numerous after CdCl2 exposure (P less than 0.001), but all other cell types had returned to control levels. Correlation with previous ultrastructural studies on CdCl2 exposure suggested the peak of PMN coincided with Type I cell necrosis. In contrast, AM predominated durion and phagocytosis occur.