Fig. 1

Morphological changes of normal and abnormal embryos on gestational day 11.5 (a–d). Observation of embryonic development under a dissecting microscope (Scale bars: 1 mm). a Normal embryos (from control group); b–d abnormal embryos from the lometrexol 40 mg/kg body weight group, the NTD embryos showed failure closure of hindbrain of the neural tube (b, arrow), craniofacial malformation (c) and growth retardation (d) separately. e–h Photomicrographs of coronal sections at the same plate of hindbrain (black lines in a and b) using hematoxylin and eosin staining (Scale bars: e, f 100 μm; g, h 50 μm). (e, g) Normal embryos; (f, h) NTD embryos. g was magnifying (e). h was magnifying (f). exencephalycraniofacial malformation