Effect of 5-azadeoxycytidine and retinoic acid on expression of genomic imprinting in parthenogenetic mouse embryos

The action of two types of substances has been studied: 5-azadeoxycytidine and retinoic acid, which have a demethylation effect on DNA in the development process of diploid parthenogenetic mouse embryos. The effect of 5-azadeoxycytidine on hybrid mice (CBA × C57BL/6)F1 in vitro for 6 h, in the presence of single cell parthenogenetic embryos during the S-phase of the cell cycle has been studied. After developing to the blastocyst stage in vitro, parthenogenetic embryos were transplanted into the uterus of false pregnant females. It has been determined that a concentration of 0.1 μM 5-azadeoxycytidine activates embryonic development in the preimplantation period until the blastocyst stage (69% in experiment; 61% in the control) and during postimplantation, it increases the number of available space in the uterus for implantation (76% in experiment; 63% in the control). The effect of retinoic acid on parthenogenetic embryos from inbred C57BL/6 or CBA mice lines was studied by adding it to single cell embryos in a medium in vitro for 96 h. Treating parthenogenetic embryos C57BL/6 with retinoic acid concentrations 0.1 μM or 0.5 μM significantly increased the number of spaces for embryo implantation, 76% and 78% respectively, as against 57% for untreated embryos. Addition of similar doses of retinoic acid to the nutrient medium containing CBA parthenogenetic mouse embryos does not improve implantation (as with embryos C57BL/6), and a concentration of 2.0 μM is toxic to the embryos. During the period of postimplantation, parthenogenetic embryos of mouse lines C57BL/6 treated with retinoic acid just as the controls, did not develop to the somite stage. Mouse lines CBA had 45% of their embryos which were used as controls, developing to the advanced somite stages. However, the number of embryos treated with retinoic acid does not increase. Thus the treatment of two parthenogenetic embryos from inbred mice lines and their hybrids with compounds which demethylate DNA (5-azadeoxycytidine and retinoic acid) creates an opportunity for partial modulation of genomic imprinting and an increase in the survival rate of such embryos.