外源视黄酸对小鼠早期胚胎形态及Otx2基因表达的影响

Exogenously Added Retinoic Acid Effects on Expression of Otx2and on Morphology in Early Mouse Embryos

以全反式视黄酸（ａｌｌｔｒａｎｓ－ｒｅｔｉｎｏｉｃａｃｉｄ，ＲＡ）体外处理ＥＢ（ｅａｒｌｙａｌｌａｎｔｏｉｃｂｕｄ）期和ＬＢ（Ｌａｔｅａｌｌａｎｔｏｉｃａｃｉｄ）期的小鼠胚胎，然后用洋地黄毒苷（ｄｉｇｏｘｉｇｅｎｉｎ）标记的Ｏｔｘ２反意义ＲＮＡ探针对整体胚胎进行原位杂交．０．５×１０－６ｍｏｌ～２×１０－６ｍｏｌ的ＲＡ处理ＥＢ和ＬＢ期胚胎１２ｈ后对其形态学和Ｏｔｘ２表达都没有影响；以４×１０－６ｍｏｌ的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面突出，其神经沟也不整齐；以４×１０－６ｍｏｌ的ＲＡ处理ＥＢ期的胚胎，其ＯｔＸ２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，与对照胚胎相比，ＯｔＸ２的表达除了在极少数胚胎中变得弱一些外，在绝大多数胚胎中其表达模式没有变化．

Mouse embryos were exposed to exogenously added RA(retinoic acid)for 12h in vitro at the stage of EB(early allantoic bud)and LB(late allantoic bud),and wholemount in situ hybridization was carried out with digoxigenin-labelled Otx2 antisense RNAprobe.The treatment of RA at a concentration of 0.5 × 10-6mol-2 × 10-6mol has no effecton the morphology of both EB and LB stage embryos,and on the expression pattern of Otx2as well.When the embryos were treated with 4 × 10-6mol RA at the both stage,the formation of foregut was inhibited or reduced,and the head fold of some treated embryos wereprojected less than that of the controls,and the neural groove appears curved.Otx2 expression of the EB stage embryos treated with 4 × 10-6mol RA was receded anteriorly of veryfaint.No change in the pattern of Otx2 expression was seen in the LB stage embryos treatedwith 4-6× 10-6mol RA, but in a few of these embryos its expression became faint.