Ultrastructural changes of alveolar cells due to intratracheally administered detergent solutions

Ultrastructural changes following the intratracheal injection of detergent solutions are described at the lobular level in rabbits, in which the main affected components were the large granulous alveolocytes, the local source of synthesis of phospholipids participating in the formation of lung surfactant. Irrespective of their location on the internal face of interlobular septa or at the intersection of alveolar walls, these cells suffered the direct influence of the detergent solution and presented the reduction of the intracellular formation of osmiophilic lamellated bodies to its nuclear and ribosomal phases, and a rapid release of previously formed osmiophilic bodies from ergastoplasmic cisternae by means of an active membrane-vesicular flow up to exocytosis. This process achieved a more or less complete emptying of membrane-bounded vesicles which persisted after the phospholipid release. The released lamellated bodies were engulfed by macrophages. The flat membranous alveolocytes presented here and there only an increased amount of pinocytotic and transcytotic vesicles. The alveolar walls and mainly the interlobular septa were thickened, especially due to an increased amount of ground matrix, collagen proteins and sometimes collagen fibrils.