一氧化氮与胚胎异常发育的相关性研究

为了解开一氧化氮（ＮＯ）是否与畸胎发生有关这一谜团和进一步阐明砷致畸作用机理，本实验应用诱生型ＮＯ合成酶（ｉＮＯＳ）组织化学、扫描电镜（ＳＥＭ）及体内致畸试验等方法研究了砷对小鼠卵黄囊胎盘（ＹＳＰ）和胚胎发育的影响。结果表明ＹＳＰ细胞ｉＮＯＳ表达与砷浓度之间存在明显的剂量—反应关系（Ｐ＜０．０５）；ＳＥＭ观察可见ＹＳＰ内皮层和间皮层细胞受损；光镜下可见ＹＳＰ变小、萎缩和微血管分化不良；随着染毒剂量的升高，畸胎率和死胎率亦逐步增加，最高分别达到５６．８％和２４．７％；畸胎的主要表现是神经管未闭，心包积液和体位异常等。研究结果率先提示过量ＮＯ与畸胎发生及致畸机理关系密切；推荐在致畸研究中ｉＮＯＳ可作为一种有效的生物标志物。

A Study on the Relation between Nitric Oxide and Abnormal Development of Embryos

The authors investigated the effects of arsenic on mouse embryo and yolk sac placenta (YSP) during a critical period of early morphogenesis by means of histochemical staining technique,scanning electron microscope (SEM) and so on. There were no obvious poinsoning signs of pregnant female mice. Experimental results showed there was a dose response relationship between arsenic level and iNOS expression ( P <0 05). Histopathological changes under SEM and light microscope were noticed, including retardation of yolk sac growth and vessels differentiation, atrophic microvilli and disintegrative or cavernous damages of both endodermal epithelium and mesodermal mesothelium in particular. With the increase of arsenic concentration, teratogenic rate and mortality increased. The maximum incidences were 56.8% and 24.7% respectively.Dysmorphogenetic embryos were characterized by open neural tube, hydropericardium and abnormal flexions. We firstly discovered excessive NO was involved in embryonic development and teratogenesis .iNOS can serve as an effective biomarker in teratological research.