Effect of irradiation on vascularization of corneas grafted onto chorioallantoic membranes.

Several studies have shown that total body irradiation decreases the angiogenic response to corneal cauterization. This inhibition could be due to alterations in angiogenic stimuli within injured corneas and/or to a decreased ability of irradiated animals to respond to such stimuli. To determine whether total body irradiation specifically affects angiogenic stimuli within injured corneal tissue, cauterized corneas from mice exposed to 900 rads of total body irradiation and from non-irradiated controls were grafted onto the chorioallantoic membranes (CAM) of chick embryos and their abilities to stimulate the ingrowth of healthy embryonic blood vessels were compared.

An evaluation of methods to quantitate the chick chorioallantoic membrane assay in angiogenesis.

The vascular responses by chick chorioallantoic membranes (CAM) to more than 150 normal and chemically injured rat corneas grafted to shell-less chicken CAMs were evaluated independently by three observers in a masked fashion by in vivo stereomicroscopy, projections of colored transparencies, and by light microscopy of tissue sections of the grafts. The experience gained from this study is reviewed as a point of focus for the strengths and weaknesses of the CAM technique in the assay of potential angiogenic substances. Despite certain shortcomings, the CAM technique can provide useful information relevant to studies on angiogenesis, particularly when the subjective CAM method is supplemented by histological evaluation of grafted tissues.

Angiogenic activity in injured rat corneas as assayed on the chick chorioallantoic membrane.

The temporal appearance of an angiogenic effect in chemically cauterized rat corneas was determined by studying the responses that they induced in the vessels of the chick chorioallantoic membrane (CAM). Injured rat corneas were grafted to the CAM from 90 minutes to 7 days after cautery. As controls, uninjured rat corneas and corneas of healthy rats cauterized immediately after death were also grafted.