Experimental Respiratory Distress Syndrome in Dogs Observation on pulmonary infrastructures / 第三军医大学学报

ABSTRACT

The changes of the pulmonary ultrastructures of 15 dogs of respiratory distress syndrome (RDS)induced with intravenous injections of different doses of oleic acid under different methods of management (nontreated and treated with scopolamine) were observed after the animals were killed 6 hours and 24 hours after injection. The changes were similar on all the specimens except that those of the dogs killed at the earlier interval were less severe. The nontreated dogs and the dogs treated with scopolamine slso showed similar changes, which indicates that scopolamine is useless in treating the RDS produced by oleic acid.Correlating to the accumulation of neutrophils in the capillaries, the authors suggested that the injury induced by oleic acid to the capillary endothelium, besides the chemical toxic action of the drug, was also due to the complement and the toxic oxygen radicals produced by neutrophils.It was found that the hyaline membrane consisted of plasma protein granules in some cases and fibrin in others but no necrosis of the epithelial cells underneath the hyaline membrane was seen. Some authers suggested that the different constituents of the hyaline membrane were resulted from the precipitation of the edema-tous fluid protein on the surface of alveoli, but this suggestion could not be confirmed either by the electron microscopic study of othrs or by ours.There was a large amount of surfactant found in the intraalveolar space and vacuolation was seen, which indicates that no reduction of surfactant occurred in RDS but there was some alteration of its nature resulting in the loss of its activity.