The effect of aldosterone on Na+/K+/ATPase expression and development of embryos derived from vitrified-warmed sheep oocytes

Media supplementation with various compounds in order to increase the oocyte developmental competence is of particular importance. This experiment was conducted to evaluate the effect(s) of media supplementation with aldosterone on embryo development and Na+/K+/ATPase expression following sheep oocyte vitrification. The abattoir-derived sheep COCs (cumulus oocyte complexes) were randomly allocated into six experimental groups: IVM of fresh and vitrified COCs in the presence of aldosterone followed by IVF/IVC (F-IVM and Vit-IVM groups, respectively); IVM/IVF of fresh and vitrified COCs followed by IVC wherein the embryos were exposed to aldosterone on Day 4 of IVC (F-D4 and Vit-D4 groups, respectively); and IVM/IVF and IVC of fresh and vitrified COCs in the absence of aldosterone (F-Cont and Vit-Cont groups, respectively). The expression of Na+/K+/ATPase α1 and β1 subunits in embryos were assessed at morula and blastocyst stages with related primary antibodies. The hatching rate was greater in aldosterone supplemented groups in both fresh and vitrified COCs compared to their controls. The expression of Na+/K+/ATPase β1 subunit was significantly greater in F-D4 and Vit-D4 groups compared to other groups. The ICM/Total ratio in F-IVM was greater compared to the other groups. In conclusion, addition of aldosterone to the IVM and IVC media could improve the hatching rate of blastocysts derived from both fresh and vitrified COCs. These improvements, in D4 supplemented groups, might be related to the greater expression of Na+/K+/ATPase β1 subunit induced by aldosterone supplementation.