Scanning electron microscopy: arterial endothelial integrity after fixation at physiological pressure

The luminal surface of normal rabbit aorta was examined by scanning electron microscopy (SEM) after outlining endothelial cells by staining intercellular junctions with silver. When aortas were fixed in situ at physiological pressure before processing for SEM, a reliable assessment of the morphological integrity of the endothelium was possible. In contrast, when aortas were excised and placed in fixative, contraction of the sub-endothelial structures made interpretation of endothelial integrity difficult.