Effects of recombinant OVGP1 protein on in vitro bovine embryo development

Previously, our group demonstrated that recombinant porcine oviductin (pOVGP1) binds to the zona pellucida (ZP) of in vitro-matured (IVM) porcine oocytes with a positive effect on in vitro fertilization (IVF). The fact that pOVGP1 was detected inside IVM oocytes suggested that this protein had a biological role during embryo development. The aim of this study was to evaluate the effects of pOVGP1 on bovine in vitro embryo development. We applied 10 or 50 µg/ml of pOVGP1 during IVF, embryonic in vitro culture (IVC), or both, to evaluate cleavage and embryo development. Blastocyst quality was assessed by analyzing the expression of important developmental genes and the survival rates after vitrification/warming. pOVGP1 was detected in the ZP, perivitelline space, and plasma membrane of blastocysts. No significant differences (P > 0.05) were found in cleavage or blastocyst yield when 10 or 50 µg/ml of pOVGP1 was used during IVF or IVC. However, when 50 µg/ml pOVGP1 was used during IVF + IVC, the number of blastocysts obtained was half that obtained with the control and 10 µg/ml pOVGP1 groups. The survival rates after vitrification/warming of expanded blastocysts cultured with pOVGP1 showed no significant differences between groups (P > 0.05). The use of pOVGP1 during IVF, IVC, or both, increased the relative abundance of mRNA of DSC2, ATF4, AQP3, and DNMT3A, the marker-genes of embryo quality. In conclusion, the use of pOVGP1 during bovine embryo in vitro culture does not affect embryo developmental rates but produces embryos of better quality in terms of the relative abundance of specific genes.