Progressive Pulmonary Pathology of Two Organofluorine Compounds in Rats

Abstract Rat lungs were studied by light and electron microscopy to morphologically characterize the development of lung injury associated with the inhalation of two organo-fluorine compounds, perfluoroisobutylene (PFIB) and bis(trifluoromethyl) disulfide (TFD). Rats were exposed to test compounds in an inhalation chamber and euthanatized at 5 min, 30 min, 90 min, 4 h, 12 h, 24 h, and 72 h postexposure. Inhalation of the compounds resulted in a progressive pulmonary pathology dominated by pulmonary edema and fibrin deposition, which peaked at 12 to 24 h but which resolved to a large extent by 72 h postexposure. The edema was microscopically evident as early as 5-30 min after exposure. Endothelial change was the earliest recognized lesion by electron microscopy and was produced by both compounds. This was characterized by increased pinocytotic-vesicular activity and increased electron density of endothelial cells. Injury to type I and II pneumocytes was also evident, but appeared more severe in the lungs of TFD-exposed rats. The morphologic pathogenesis of the edema appears related to the primary endothelial changes and Concomitant pneumocyte damage.