Alveolar cells in cyclophosphamide-induced lung injury. II. Pathogenesis of experimental endogenous lipid pneumonia

An ultrastructural and histological study was made to analyse the structura l and cellular features of the pulmonary lesions produced in Wistar rats by intraperitoneal (i.p.) administration of cyclophosphamide (two i.p. doses of 150 mg CF/1 kg bw/1 mi PBS). Rats exposed to cyclophosphamide (CF) devel oped a condition whose morphological picture corresponded to endogenous lip id pneumonia and/or pulmonary alveolar proteinosis-like changes. Damage to the endothelium and neutrophil accumulation in lung vascular bed were found to be potential initiators of endogenous lipid pneumonia-type changes. The possibility of the evolution of the acute lung injury into endogenous lipi d pneumonia-type changes and into alveolar proteinosis-like changes was dem onstrated. The results of the study supplement the existing theories of pul monary alveolar proteinosis pathogenesis.