ULTRASTRUCTURAL STUDY ON THE ALVEOLAR-CAPILLARY INJURY WITH PULMONARY EDEMA INDUCED BY OLEIC ACID IN DOGS

Oleic acid induced pulmonary edema was subjected as an experimental model of ARDS. Three adult mongrel dogs were injected with 0.09 ml/kg of oleic acid into the pulmonary artery and sacrificed 2 hours later. Light and electron microscopic studies were carried out on the pulmonary specimen. The light microscopic findings showed bronchovascular cuffs and alveolar flooding. The electron microscopic findings of the mildly to moderately damaged lesions showed that the interstitial tissues were thickened with edema fluid and alveolar spaces were filled with plasma exudate containing erythrocytes, strands of fibrin, macrophages, and electron dense material that surfactant and lamellar bodies resembled, while the capillary endothelium and alveolar epithelium appeared normal. The electron microscopic findings of severely damaged lesions showed that both endothelium and epithelium were degenerative.

It was concluded that ultrastructural changes were more characteristic of permeability than of hemodynamic edema.