Ensaio da membrana corioalantoide (cam): modelo experimental como alternativa à utilização de animais em pesquisa e suas aplicações

Abstract

In view of the new incentives to follow the principle of 3Rs established by science in the 21st century, there has been a global trend for the adoption of alternative methods to animal experimentation in research. One of the most promising alternatives is the chick embryo chorioallantoic membrane assay (CAM), a technique that has been used for many years as a robust experimental model for the elucidation of several biological questions. Thus, the purpose of this study was to present a narrative literature review which demonstrates the potential use of the CAM assay as an alternative model to animal experimentation, emphasizing its relevance in the scientific field. A detailed description of different cultivation protocols and advantages and limitations of the assay was presented, comparing it with other commonly used in vivo models. A few of the most relevant applications of this method were also described, identifying publications related to its use and concluding with a summarized update of the scientific contributions and perspectives of using this model in the international scenario. This review indicated that the CAM assay has numerous advantages compared to other experimental models, such as: low cost, simplicity, reproducibility and accessibility. With this model, researchers are able to study several processes associated with angiogenesis and the effect of substances on tissue vascularization. Being naturally immunodeficient and highly vascularized, the CAM may receive transplantations from different tissues and species. This model also allows a rapid screening process of several samples during pre-clinical trials. Moreover, it does not require major ethical concerns, as no pain is perceived by the chick embryos. The CAM has been applied in several studies related to tissue engineering, tumor growth and metastasis, drug development, toxicological profile and angiogenic and antiangiogenic activity of molecules. It is expected that the use of this method will expand in the coming years, mainly due to its popularization and the incentive to validate new alternative methodologies. Until now, Brazilian legislation does not have any mentions concerning the ethical aspects of the use of this model, but the country's participation in this regard is increasingly prominent. In conclusion, the CAM assay represents a very effective and versatile in vivo model for several preclinical studies, as it is able to complement in vitro assays before proceeding to experiments with mammalian models, which shows its potential as an alternative method to the use of animals for scientific purposes.