A corrosion casting/scanning electron microscope method that simultaneously demonstrates clear outlines of endothelial cells and three-dimensional vascular organization

This paper describes a method that can definitively demonstrate endothelial cell boundaries on corrosion casts of arteries, veins, and capillaries. Af ter perfusion with silver nitrate, a casting medium was injected into the e ntire vascular bed. The injected tissues were either exposed to light or im mersed in the photographic developer to develop the silver halide, and corr oded in a 5% NaOH solution at 60% overnight. Observations of the casts cont aining water in a low vacuum scanning electron microscope equipped with a c ooling stage clearly showed endothelial cell boundaries on casts of every t ype of vessel as well as their three-dimensional architecture. The low vacu um scanning electron microscope images of wet casts were almost identical i n quality to the back-scattered electron images of dried casts without any coating. Secondary electron images of the dried casts with metal coating cl early showed endothelial cell outlines and nuclear imprints. The secondary electron images at high magnification indicated that silver granules were p recipitated in the grooves along endothelial cell boundaries on the casts. Since this method can demonstrate endothelial cell boundaries of every type of vessel in addition to their three-dimensional architecture, it will be a powerful tool for examining endothelial cell morphology and microvascular organization in pathological as well as normal tissues.