[Electron microscopic studies of the lungs of rats in pneumothorax]

Ultrastructural investigations were carried out of the lungs of rats following experimentally induced atelectasis, employing continuous pneumothorax (from 2 to 48 hours). It was established that pneumothorax caused atelectatic alterations mainly in the peripheral portions of the lungs (swelling of the endothelium of the alveolar capillaries, edema of the alveolar septae, increase in the amount of the connective tissue fibres, disintegration and separation of the structural parts covering the capillaries, and accumulation of exudate in the alveolar lumen). These changes grew with the advancement of the postoperation time, i.e., atelectasis was shown to grow in dynamics, particularly well manifested on the 24th hour.