Analysis of trophectoderm markers in domestic cat blastocysts cultured without zona pellucida.

Domestic cat embryos generated by fertilization (IVF) and cultured without the zona pellucida have a reduced implantation capacity after embryo transfer at the blastocyst stage. The objective of this study was to evaluate the expression of trophectoderm markers in domestic cat blastocysts cultured without the zona pellucida. Two experimental groups were selected: (1) domestic cat embryos generated by IVF and cultured normally (zona intact group, ZI); and (2) domestic cat embryos generated by IVF and cultured without a zona pellucida (zona-free group, ZF). In the ZF group, the zona pellucida of the presumptive zygote was removed and these were cultured using the well of the well (WOW) system. culture was carried out for 7 days. The cleavage, morula and blastocyst rates were estimated. Finally, the relative expression levels of the trophectoderm markers , , and , the cell adhesion marker and the apoptosis marker were evaluated by RT-qPCR in the blastocysts. The Wilcoxon test was used to evaluate differences ( < 0.05). No differences were observed in the cleavage, morula and blastocyst rates between the ZF and ZI groups. No differences were found in the expression of , , and between groups. The expression of and was higher in ZF blastocysts than in ZI blastocysts. In conclusion, the culture without the zona pellucida generates an overexpression of and in the domestic cat blastocysts. More studies are needed to confirm if this overexpression might affect development.