[Ultrastructural transformation of blood capillaries following implantation of a DMBA pellet].

CNS blood capillary wall in the area of DMBA pill implantation was studied by electron microscopy 1--270 days following the implantation. Blood capillaries were shown to take an active part in precancerous processes. It was noted, in particular, that DMBA induced very suggestive alterations in the endothelial cells in the form of lipid-like structures, previously reported by the authors in the so-called hairy cells, appearing in the cytoplasm 24 hr after the experiment initiation. The appearance of such structures is considered as possible secondary product of the inter-action of DMBA and lipoprotein complexes of the membrane with subsequent dissolution of the carcinogen in lipids. The basal layer of blood capillaries was found to undergo considerable alterations in the form of its progressive rarification, widening the homogenization. A possible role of the altered basal layer in the accumulation of DMBA metabolites is discussed.