Takeuchi I K
J Toxicol Sci. 1979 Nov;4(4):405-16. doi: 10.2131/jts.4.405.
To clarify the light and electron microscopic changes accompanying embryonic death from a lethal dose of arsenic acid, MP 1 pregnant rats were injected i.p. with 30 mg/kg arsenic acid at 1:30 p.m. on day 9 of gestation (the neurulation stage). At 4 hours after treatment, some cell necrosis occurred in the neuroectoderm and the mesoderm of the embryo. At six hours later, cell necrosis increased in the neuroectoderm and the mesoderm, whereas those in the surface ectoderm and the endoderm were very few. In the embryo 12 hours after treatment, abnormal mitotic cells exhibiting vesiculation of the endoplasmic reticula, and abnormal interphase cells characterized by the ring-shaped nucleoli in the nucleus and the enlargement of cisternae of the endoplasmic reticula and the nuclear envelope, were observed in the neuroectoderm and the mesoderm. Debris from cell necrosis and the said abnormal mitotic and interphase cells were ejected from the neuroectoderm into the amniotic coele. In the embryo 24 hours later, neurulation was stopped and the V-shaped neural fold remained. The somite formation was retarded. The surviving cells in the embryo sometimes contained phagocytic vesicles in the cytoplasm, but no other anomalies were encountered. It was considered that a variety of metabolic reactions may be disturbed by arsenic acid, resulting in numerous cell necrosis and abnormal mitotic and interphase cells in the neuroectoderm and the mesoderm of the rat embryo.
为阐明致死剂量砷酸导致胚胎死亡时的光镜和电镜变化，在妊娠第9天（神经胚形成期）下午1:30给11只怀孕大鼠腹腔注射30mg/kg砷酸。处理后4小时，胚胎的神经外胚层和中胚层出现一些细胞坏死。6小时后，神经外胚层和中胚层的细胞坏死增加，而表面外胚层和内胚层的细胞坏死很少。处理后12小时的胚胎中，在神经外胚层和中胚层观察到有内质网囊泡化的异常有丝分裂细胞，以及细胞核内有环形核仁、内质网池和核膜扩大为特征的异常间期细胞。细胞坏死的碎片以及上述异常有丝分裂和间期细胞从神经外胚层排入羊膜腔。24小时后的胚胎，神经胚形成停止，V形神经褶依然存在。体节形成延迟。胚胎中存活的细胞有时细胞质内含有吞噬泡，但未发现其他异常。认为砷酸可能干扰多种代谢反应，导致大鼠胚胎神经外胚层和中胚层出现大量细胞坏死以及异常有丝分裂和间期细胞。
