A novel in vitro assay for rapid screening of embryotoxicity in multiple species

Comprehensive analysis of environmental and health hazards posed by pharmaceutical products and pollutants is essential for human safety, and the assessment protocols include animal testing. However, there is an emphasis on adopting the principle of 3Rs, which encourages the utilization of non-animal as well as alternate animal models. Due to more than one cell type, embryos are considered as an alternative to animal models. The current assays are phenotypic and there is thus a need for an analytical method for rapid assessment of embryotoxicity. Alamar blue (AB) is a colorimetric dye used for measuring viability in cell culture, and we have tested if this dye can be repurposed to assess embryotoxicity. Using snail embryos, we show that AB can be used to assess the biological activity of whole embryos and also for the embryotoxicity assessment in a medium-throughput manner. Furthermore, we also show that the clusters of snail eggs can be directly used to test embryotoxicity both for qualitative and quantitative protocols. Importantly, we have extended the application of this novel assay to fruit fly and zebrafish, also suggesting that this method can either substitute or complement the existing embryotoxicity assays.