Dynamics of early postradiation changes in capillary endothelium (quantitative electron microscopic analysis

: Oedema, breakage and fragmentation of plasmolemma and mitochondrial damages developed in rats 1-48 h following total-body X-irradiation (4.5 Gy). These changes were most pronounced 2-6 h after exposure, when they spread over 20-30% of the population, and accompanied by the appearance of wide gaps in the endothelial layer and maximal accretion of free lipids in the endotheliocyte cytoplasm. Changes in the sizes and number of mitochondria were responsible for the tendency toward the increase in their relative total volume which was most pronounced after 12 h.