The chorioallantoic membrane: A novel approach to extrapolate data from a well-established method

The chorioallantoic membrane (CAM) of the chicken embryo is a highly vascularized extra-embryonic structure that has been widely used as an in vivo model for the evaluation of angiogenesis. This study was designed to optimize data extrapolation from the most exploited experimental protocol to improve its efficiency and the reliability of the obtainable results. In our study, we followed the most common procedure for CAM assay, employing retinoic acid and vascular endothelial growth factor as standards. CAMs were photographed at t0, t24, and t48; then, the main parameters of the predefined vascular network/area were evaluated. Subsequently, their variations in each CAM were calculated comparing them within the same CAM over the course of the whole treatment (t24 and t48), also comparing the treated CAMs respect to the untreated ones. Thus, we provide a novel approach aimed at extrapolating data from CAM assay that allows to (i) have a greater reliability and richness of data; (ii) better estimate the potential pro- and anti-angiogenic activity of new candidate drugs; (iii) save both eggs and time for the experiments.