11-deoxy prostaglandin F(2α), a thromboxane A2 receptor agonist, partially alleviates embryo crowding in Lpar3((-/-)) females.

OBJECTIVE To determine cyclooxygenase-derived prostanoid signaling in alleviating embryo crowding in the Lpar3((-/-)) females. DESIGN Experimental mouse model. SETTING Research laboratories. ANIMAL(S) Wild-type, Lpar3((+/-)), and Lpar3((-/-)) mice. INTERVENTION(S) Intraperitoneal (IP) administration of prostaglandin E(2) (PGE(2)), cPGI (a stable analogue of PGI(2)), and 11-deoxy prostaglandin F(2α) (11-deoxy PGF(2α), a thromboxane A(2) receptor agonist) to preimplantation gestation day 3.5 Lpar3((-/-)) females. MAIN OUTCOME MEASURE(S) Implantation sites were detected by blue dye reaction and embryo spacing was determined by the distribution of the implantation sites along the uterine horns on gestation day 4.5; pregnancy outcome was measured by litter size at birth. RESULT(S) Administration of PGE(2) + cPGI on gestation day 3.5 Lpar3((-/-)) females restored on-time implantation but did not affect embryo spacing or the number of implantation sites detected on gestation day 4.5; PGE(2) + cPGI treatment increased litter size at birth. Administration of PGE(2) + cPGI + 11-deoxy PGF(2α) on gestation day 3.5 Lpar3((-/-)) females rescued on-time implantation, partially dispersed the clustered implantation sites normally observed in the Lpar3((-/-)) females, increased the number of implantation sites detected on gestation day 4.5, and increased litter size at birth. CONCLUSION(S) The thromboxane A(2) receptor agonist 11-deoxy PGF(2α) can partially alleviate embryo crowding in the Lpar3((-/-)) females and embryo crowding likely contributes to reduced litter size in the Lpar3((-/-)) females.