Morphology of oleic acid-induced lung injury. Observations from computed tomography, specimen radiography, and...

Previously, we reported that oleic acid infusion in dogs produced a patchy and predominantly peripheral increase in lung density. The present study examines in more detail the morphology of the early stages of development of the oleic acid lesion using computed tomography (CT), specimen radiography, and conventional histology. Dogs were sacrificed 10, 30, 60, and 240 minutes after infusion of oleic acid (.05 ml/kg). After freezing in dry-ice, the thorax was scanned and cut into 1-cm thick sections. Frozen sections were then contact radiographed and sampled for histology. Within 10 minutes of infusion, subtle increases in peripheral lung density were visible on the contact radiographs. Patchy areas of peripheral density, resembling secondary lobules, were especially prominent 60 and 240 minutes after infusion. These lesions were often clearly associated with the distal bronchovascular structures. Histologic signs of edema were present in all animals sacrificed 30 or more minutes after receiving oleic acid. These correlative studies provide additional insight into the early subgross development of oleic acid-induced injury by showing the relationship between the developing edema and the bronchovascular structure of the lung.