体外培养对小鼠植入前胚胎DNA甲基转移酶表达模式影响的研究

Expression patterns of Dnmtl and Dnmt3b in preimplantational mouse embryos and effects of in-vitro cultures on their expression

目的研究小鼠植入前胚胎DNA甲基转移酶（Dnmt）1和3b的表达模式及体外培养对其表达的影响。方法应用荧光免疫细胞化学法检测在体内和体外培养的小鼠植入前胚胎Dnmtl、Dnmt3b的表达。结果Dnmtl、Dnmt3b在体内组2、4、8细胞胚胎和桑椹胚的胞浆内均呈高表达，在囊胚期则为胞浆内低表达，而核内均无明显表达；Dnmtl、Dnmt3b在体外组囊胚期前胚胎的表达模式均与体内组相似，为胞浆内高表达，而囊胚期则为胞核内低表达。结论体外培养改变了小鼠囊胚期Dnmtl、Dnmt3b的表达模式，影响基因的表达水平和表达模式。

Objective To investigate the expression patterns of DNA methytransferasel and 3b （Dnmtl and Dnmt3b） in preimplantation mouse embryos and the effects of in-vitro cultures on their expressions. Methods Immuno- cytochemistry was used to detect the expressions of Dnmtl and Dnmt3b in mouse embryos at the stage of two-cell, four-cell, eight-cell, morula, and blastocyst in both in-vivo and in-vitro groups. Results In the in-vivo group, the obvious expres- sions of Dnmtl and Dnmt3b were observed in the cytoplasm of two-cell, four-cell, eight-cell, and morula embryos. But in blastocysts, their expressions were significantly reduced. In the in-vitro group, the expression patterns of Dnmtl and Dn- mt3b in pre-blastocyst embryos were similar to those of the in-vivo group. In blastocysts, the Dnmtl and Dnmt3b fluores- cence were weakly expressed in the nuclei but not in the cytoplasm. Conclusion In-vitro culture environment could change the expression patterns of Dnmtl and Dnmt3b, which might affect the correct embryonic gene expression.