Fatty acids and the initial events of endothelial damage seen by scanning and transmission electron microscopy

A method was developed for observing changes in the endothelial cells in rabbit ear veins in vivo by scanning electron microscopy. Injection of fatty acids into the ear vein caused damage to the endothelium. The first signs of damage seen were marked bulges in the nuclei and loss of the rhomboidal shape of the endothelial cells. More severe damage included loss of nuclei, leaving holes in the cytoplasm. Some parts of the damaged endothelium showed complete separation of cells from each other and exposure of sub-endothelial tissue to which platelets with pseudopodia were adhering. Damage to the endothelium was produced by arachidonic, linoleic, gamma-linolenic, 8,11,14-eicosatrienoic, 5,8,11,14,-eicosatetraenoic or 15-hydroperoxy-5,8,11,13-eicosatetraenoic acids. The effect of arachidonic acid was not prevented by pre-treating the animals with aspirin. It appears that damage produced by the fatty acids is non-specific.