Prostacyclin receptor signaling and early embryo development in the mouse.

Background: Prostacyclin (PGI(2)) plays an important role in mouse embryo development and implantation. However, it is unclear whether its action is mediated via the I prostaglandin receptor (IP).

Methods: We compared the preimplantation development of IP deleted (IP-/-) embryos and wild-type (WT) embryos. We also evaluated the effect of iloprost, a stable PGI(2) analog, and L-165041, a peroxisome proliferator activated receptor delta (PPARdelta) ligand, on IP-/- versus WT embryos. Finally, we compared the development of heterozygous IP deficient embryos carrying a normal maternal IP allele versus paternal IP allele.

Results: Development of IP-/- embryos lagged behind WT embryos and was not enhanced by either the PGI(2) analog or the PPARdelta ligand. WT embryos had slightly higher, although statistically not significant, implantation rates than IP-/- embryos. Heterozygous IP deficient embryos carrying a normal maternal IP allele showed better development and responded to the PGI(2) analog, unlike those carrying the normal paternal IP allele.

Conclusions: IP receptors play an important role in preimplantation embryo development and mediate the embryo's response to exogenous PGI(2). Early embryo development depends on the oocyte IP receptor.