Effects of trypan blue on rat and rabbit embryos cultured in vitro

Mouse and rat whole embryo cultures are widely used in teratogenicity studies. We attempted to improve the technique of culturing rabbit embryo. Rabbit embryos of the Japanese White strain were explanted on day 9, 10 or 11 of gestation and cultured for 24 or 48 hr. Rabbit embryos on day 9 of gestation were cultured in 100% rabbit serum with a gas mixture containing 20% O(2) for the first 24 hr and 95% O(2) for the following 24 hr. Rabbit embryos on day 10 or 11 of gestation were cultured in 100, 80 or 60% rabbit serum with a gas mixture of 95% O(2) for 48 or 24 hr. The development of embryos cultured for 48 hr from day 9 or day 10 or for 24 hr from day 11 was nearly the same as that of embryos that had developed in vivo. These results indicate that rabbit embryo culture is a useful and promising technique in teratogenicity studies. We then examined the effects of trypan blue on cultured rat and rabbit embryos. Slc:SD rat embryos on day 9.5 of gestation were explanted and cultured in rat serum exposed to trypan blue (300-2700 mug/ml) for 48 hr. Rabbit embryos on day 9 or 10 of gestation were explanted and cultured in rabbit serum containing trypan blue (300-2700 mug/ml) for 48 or 24 hr. Cultured rat embryos exposed to trypan blue showed neural tube abnormalities, and all growth parameters were suppressed with increasing concentrations of trypan blue. However, trypan blue had no effect on cultured rabbit embryos. These results indicate that trypan blue has species-specific effects on embryos.