PRELIMINARY EVALUATION OF IN-VITRO PRESCREEN ASSAYS FOR DEVELOPMENTALTOXICANTS BASED ON CULTURED MURINE PREIMPLANTATION EMBRYOS AND A CELL-LINE DEVELOPED FROM A BOVINE PREIMPLANTATION EMBRYO

The purpose of this research was to evaluate in vitro assays and compa re their efficiency in accurate prediction of the potential of chemica ls to cause abnormal embryonic/foetal development. In vitro assays wer e based on cultured murine preimplantation embryos and a continuous ce ll line derived from a bovine preimplantation embryo. Preimplantation embryos collected from superovulated mice were cultured for 72 hr in t he presence of I0-fold dilutions of coded compounds. In vitro embryoni c development was considered normal if the embryos hatched from the zo na pellucida (with normal-appearing inner cell mass and trophoblast ce lls) and attached to the culture plate at the end of the culture perio d. The embryonic cells were seeded in 96-well plates, cultured for 24 hr in control media, exposed to 10- and twofold dilutions of test comp ounds for 72 hr, and finally were stained and counted. The inhibitory concentration (IC50) and lethal concentration (LC(50)) were the concen trations (mM) that decreased embryonic development or cell viability b y 50%, and were calculated for three model compounds and 10-12 coded c ompounds (known developmental toxicants and non-toxicants). The concor dance between in vivo animal developmental toxicity data and the murin e and bovine assays was 83 and 87%, respectively. These accuracies are similar to those of other available assays, and the bovine assay has the added advantage of being simple to perform and economical (about U S$100 per assay). Copyright (C) 1996 Published by Elsevier Science Ltd