Vascular corrosion casting: Review of advantages and limitations in the application of some simple quantitative methods

Vascular corrosion casting has been used for about 40 years to produce repl icas of normal and abnormal vasculature and microvasculature of various tis sues and organs that could be viewed at the ultra-structural level. In comb ination with scanning electron microscopy (SEM), the primary application of corrosion casting has been to describe the morphology and anatomical distr ibution of blood vessels in these tissues. However, such replicas should al so contain quantitative information about that vasculature. This report sum marizes some simple quantitative applications of vascular corrosion casting . Casts were prepared by infusing Mercer resin or diluted Mercer resin into the vasculature. Surrounding tissues were removed with KOH, hot water, and formic acid, and the resulting dried casts were observed with routine SEM, The orientation, size, and frequency of vascular endothelial cells were de termined from endothelial nuclear imprints on various cast surfaces. Vascul ar volumes of heart, lung, and avian salt gland were calculated using tissu e and resin densities, and weights. Changes in vascular volume and function al capillary density in an experimentally induced emphysema model were esti mated from confocal images of casts. Clearly, corrosion casts lend themselv es to quantitative analysis. However, because blood vessels differ in their compliances, in their responses to the toxicity of casting resins, and in their response to varying conditions of corrosion casting procedures, it is prudent to use care in interpreting this quantitative data. Some of the ap plications and limitations of quantitative methodology with corrosion casts are reviewed here.