Embryotoxic effects of EGTA-induced hypocalcemic condition on cultured rat embryos

EGTA-treated rat serum was added to the culture medium and tested the toxic effect of EGTA on development of embryo using 11.5-day-old embryo in vitro. Exposure of the embryo to the medium treated with 25 micrograms/ml of EGTA for 2 or 24 hours caused a variety of teratogenic effects such as tail and hind limb bud deformities and facial anomalies (cleft lip). At a higher concentration of EGTA (50 micrograms/ml), damage of yolk sac (shrinkage type), developmental anomalies and dead fetuses were frequently observed. Embryonic growth and differentiation were only moderately affected under any experimental conditions. Calcium levels in EGTA-treated culture medium at doses of 25 and 50 micrograms/ml were significantly reduced as compared to the non-treated medium. These results suggested that the teratogenic action of EGTA is closely related to the decrease of calcium level in the medium.