QUANTIFICATION OF TUMOR-INDUCED ANGIOGENESIS ON CHICKEN EMBRYO CHORIOALLANTOIC MEMBRANE

Angiogenesis is a process of sprouting of new microvessels from existing blood vessels. The tumoral development and the metastasis process are angiogenesis dependent, because the growing tumor needs a capillaries network that provides nutrients and oxygen. The chicken chorioallantoic membrane (CAM) is an experimental in vivo model which offer many advantages, such as the high natural vascularization and high reproducibility, besides the simplicity and low cost. The CAM contains extracellular matrix proteins, which mimics the physiological cancer cell environment. The counting of the total number of vessels allows a determination of pro-and anti-angiogenic effects of different stimulus, therefore patterning an effective method is necessary. The general goal of the present study was to evaluate the angiogenic potential of a human colon adenocarcinoma cell line (HT29) and propose a method to quantify angiogenesis induced by cancer cells on the CAM. Embryos were cultivated in an ex ovo system. At the eighth day, collagen implants containing cancer cells in different concentrations were added on the top of CAM. At the eleventh day, the photographic records were made by using stereoscope microscope and were determined four scores for vessels quantification and characterization. Vessels counting were done in a specific area around the implant, and edition of the captured images were done using Image Pro Plus software. Our results showed a significant increase in vessels that do not section the implant. It was demonstrated that HT29 cells induce a change in the pattern of growth of new blood vessels when placed on CAM into collagen implants and can be used as an experimental model for investigating the effect of different compounds on tumor-induced angiogenesis.