Pulmonary thrombosis in the course of shock remains life-threatening, despite advances in diagnosis, prophylaxis and therapy of the disease. Tumour necrosis factor-alpha (TNF-alpha) is an important mediator of shock. The aim of this study was to analyze the morphological changes in the pulmonary capillary bed in rats after intraperitoneal administration of multiple doses of TNF-alpha (10 microg TNF-alpha/24 h for 5 days; biological activity of 2-4x10(7)U/mg of protein). Morphological investigations were undertaken by light and transmission electron microscopy with emphasis on pulmonary thrombopoiesis. The study confirmed that the lungs may be an important site of extramedullary thrombopoiesis in the course of shock. The observations also suggested that megakaryocytes shed large fragments of cytoplasm within the pulmonary capillary bed and that megakaryocytes with copious cytoplasm occlude pulmonary vessels.
Copyright 1999 W.B. Saunders Company Ltd.