RESUMEN
OBJECTIVE: To study the developmental toxicity of Caowu and its mechanism on rat embryos. METHODS: Whole embryo culture was applied to test the effects of Caowu on rat embryos during the critical period of organogenesis. All embryos isolated on gestational day 9.5 were exposed to different concentrations of Caowu. The growth and differentiation of the embryos at the end of the 48 h culture period were observed. RESULTS: The embryonic growth and development were adversely affected by Caowu at the concentration of 2.5 mg/mL, which were represented as reduced yolk sac diameters, decreased number of somites, and lower morphological scores. With the increase of the concentrations of Caowu, more severe teratogenic effects appeared, including cardiac defect (undivided cardiac tube and inflated pericardial cavity), irregular somites, and brain malformation such as narrow brain vesicles. CONCLUSION: Caowu has direct embryotoxic effects on rats during the organogenesis period. We suggest that pregnant women in the first trimester use Caowu with cautions before a conclusion has been made.