Ultrastructural changes of the rabbit lung after a 5 ppm nitric oxide exposure.

Four male rabbits were continuously exposed to 5 ppm nitric oxide for 14 days. Four rabbits served as controls. Specimens from pulmonary arterioles and alveolar tissue were examined by light and transmission electron microscopy. The most conspicuous findings were fluid-containing vacuoles inside the arteriolar endothelial cells and/or in the intercellular junctions. Thickening of the alveolo-capillary membrane due to accumulation of edema fluid in the interstitial space was also observed.