Mouse embryos were exposed to exogenously added AT-RA (all trans-retinoic acid) for 12h in vitro at the stage of EB (early allantoic bud) and LB(late allantoic bud), and whole mount in situ hybridization was carried out with digoxigenin-labelled otx2 antisense RNA probe. When the embryos were treated with 4×10-6M AT-RA at the both stage, the tormation of foregut was inhibited or reduced, and the head fold of some treated embryos were projected less than that of the controls, and the neural groove appears undulate. Otx2 expression of the EB stage embryos treated with 4×10-6M AT-RA was receded anteriorly or very faint. No change in the pattern of 0tx2 expression was seen in the LB stage embryos treated with 4-6×10-6M RA, but in a few of these embryos its expression became faint.%以全反式视黄酸(all trans-retinoic acid, AT-RA)体外处理EB(early allantoic bud)期和LB(late allantoic acid)期的小鼠胚胎,然后用洋地黄毒苷(digoxigenin)标记的0tx2反意义RNA探针对整体胚胎进行原位杂交.以 4×10-6mol/l的AT-RA处理,抑制或减少了胚胎的前肠形成,经处理的胚胎的头褶没有对照的那样明显向腹部突出,其神经沟也不整齐;经处理的EB期胚胎,其0tx2表达范围剧烈地向前退缩或只有很微弱的表达;但以同样浓度处理LB期胚胎时,与对照相比,0tx2的表达除了在极少数胚胎中变得弱一些以外,在绝大多数胚胎中其表达模式没有变化.
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