The vascular architecture of the chick chorioallantoic membrane: sequential quantitative evaluation using corrosion casting.

Microvascular corrosion casting was used for evaluating qualitatively and quantitatively angiogenesis in the chick chorioallantoic membrane (CAM). Series of CAMs from day 8 to 18 were examined. The density of plexus capillaries increases rapidly until day 10 and then remains constant. The vessels connected to the plexus (first order vessels) increase in number and length between days 10 and 12. The vessels initiating from first-order vessels (second order) also increase in number but remain nearly the same in lengths and diameters. Compared to previous studies using stereomicroscopy, significant differences in vessel numbers and lengths exist, which can be explained by the low resolution and magnification resulting in too low vascular densities of the pre- and post-capillaries. The third-order vessels increase in number until day 12 when they reach a plateau, whereas higher-order vessels increase in number. These results give an insight into the vascular development of this organ, and provide the basis for assessing the targets and effects of angiogenic or antiagiogenic agents.