Effect of bovine oviductal fluid on DNA methylation of bovine blastocysts produced in vitro

BARRERA, ANTONIO D.; GARCIA, ELINA V.; HAMDI, MERIEM; SÁNCHEZ CALABUIG, MARÍA JESÚS; RIZOS, DIMITRIOS; GUTIÉRREZ ADÁN, ALFONSO

Austin, Texas

Congreso; 43rd Annual Conference of International Embryo Technology Society; 2017

International Embryo Technology Society

The supplementation of the in vitro culture medium with factors present in the natural milieu in which embryo develops could mimic the in vivo developmental environment in in vitro conditions. The aims of this study were to: (1) evaluate the developmental progression of bovine embryos cultured in vitro in the presence or absence of bovine oviductal fluid (OF), and (2) determine changes of epigenetic marks in blastocysts derived from embryos cultured with OF to examine the response of the embryo to maternal factors in vitro. Presumptive zygotes were cultured in control medium and medium supplemented with 1.25% OF during three temporal intervals: from zygote until 16-cell stage, from zygote until 8-cell stage and from 8-cell to 16-cell stage. Methylation levels of different genomic regions were analyzed by bisulfite sequencing in blastocysts developed from the experimental groups. No differences were registered for cleavage rate (52 hpi), proportion of embryos at 52 and 98 hpi neither in blastocyst yield (D7-8) among analyzed groups. The genomic regions showed low methylation levels in blastocysts derived from embryos cultured from zygote to 16-cell stage compared to control group and others OF treated groups. In conclusion, OF do not modifies developmental kinetics in vitro. However, OF induces changes in the epigenetic marks of specific regions of embryonic genome. This fact suggests a response of the embryo to oviductal factors during early development. Thus, the use of OF as a supplement during in vitro embryo culture represent a strategy for the study of the interaction between oviduct and early embryo.