Reproduction Abstracts

Introduction: Prostaglandin F2α (PGF2α) is mainly known to be involved in luteolysis. However, our recent studies indicate that PGF2α synthesis and its receptor (PTGFR) expression are up-regulated in the porcine endometrium during embryo implantation. Aims of present study were: i) to immunolocalize PTGFR protein in uterus; ii) to elucidate the involvement of PGF2α-PTGFR signaling in angiogenesis in the porcine endometrium.

Methods: Sections of uterus collected on day 12 of the estrous cycle and pregnancy were processed for immunolocalization of PTGFR protein by IHC. Effect of PGF2α on vascular endothelial growth factor (VEGFA) synthesis and secretion by endometrium was studied by incubation of endometrial explants collected from gilts (n=6) on day 12 of the estrous cycle with PGF2α (100 nM, 1 μM) and fluprostenol (1 μM) for 24 h. After incubation, VEGFA mRNA expression was assessed by qPCR. Concentration of VEGFA in culture media was measured by RIA. Subsequently, primary endothelial cells from porcine endometrium (EnPrim) were treated by PGF2α (100 nM) alone or incubated in the presence/absence of VEGFR inhibitor (AAL-993) with conditioned media from endometrial explants treated with vehicle or 1 μM PGF2α together/without PTGFR antagonist (AL8810). Cell proliferation was assessed by colorimetric method.

Resulst and discussion: PTGFR protein was localized mainly in luminal and glandular epithelium as well as in blood vessels. PGF2α (1 μM) and fluprostenol (1 μM) elevated VEGFA gene expression and secretion by endometrial explants (P<0.05). Conditioned media from PGF2α-treated endometrial explants increased (P<0.001) proliferation of EnPrim. This effect was abolished by blocking of PTGFR in endometrial explants as well as by blocking VEGFR in endothelial cells. No direct effect of PGF2α was observed on endothelial cells proliferation. Our results indicate indirect PGF2α-PTGFR involvement in angiogenic changes in porcine uterus by elevation of endometrial VEGFA content, followed by stimulation of endothelial cells proliferation.

Supported by NSC (2012/05/E/NZ9/03493). Piotr Kaczynski is supported by European Union programme (CIiTT/RIM WiM/2014/26).