Ovarian steroids affect prostaglandin production in equine endometrial cells in vitro

<jats:p>This study aimed to evaluate the influence of ovarian steroids on equine endometrial epithelial and stromal cells, specifically i) prostaglandin (PG) production in a time-dependent manner, ii) specific PG synthases mRNA transcription and protein expression, and iii) cell proliferation. After passage I, cells were exposed to vehicle, oxytocin (OT, positive control, 10<jats:sup>−7</jats:sup>M), progesterone (P<jats:sub>4</jats:sub>, 10<jats:sup>−7</jats:sup>M), 17β estradiol (E<jats:sub>2</jats:sub>, 10<jats:sup>−9</jats:sup>M), or P<jats:sub>4</jats:sub>+E<jats:sub>2</jats:sub>for 12, 24, 48, or 72 h. Following treatment, PG concentration was determined using the direct enzyme immunoassay (EIA) method. Alterations in<jats:italic>PG</jats:italic>synthases mRNA transcriptions,<jats:italic>PG</jats:italic>synthases protein expression, and cell proliferation in response to the treatments were determined after 24 h using real-time PCR, western blot, or 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide respectively. After 24 h, E<jats:sub>2</jats:sub>and P<jats:sub>4</jats:sub>+E<jats:sub>2</jats:sub>increased PGE<jats:sub>2</jats:sub>and PGF<jats:sub>2</jats:sub><jats:sub>α</jats:sub>secretion as well as specific prostaglandin-endoperoxide synthase-2 (PTGS2), PGE<jats:sub>2</jats:sub>synthases (PGES), and PGF<jats:sub>2</jats:sub><jats:sub>α</jats:sub>synthases (PGFS) expression in the epithelial cells (<jats:italic>P</jats:italic><0.05). Additionally, E<jats:sub>2</jats:sub>and P<jats:sub>4</jats:sub>+E<jats:sub>2</jats:sub>increased PTGS2 expression in stromal cells after 24 h (<jats:italic>P</jats:italic><0.05). In stromal cells, P<jats:sub>4</jats:sub>+E<jats:sub>2</jats:sub>increased PGE<jats:sub>2</jats:sub>production as well as PGES expression after 24 h (<jats:italic>P</jats:italic><0.05). Both E<jats:sub>2</jats:sub>and P<jats:sub>4</jats:sub>+E<jats:sub>2</jats:sub>increased PGF<jats:sub>2</jats:sub><jats:sub>α</jats:sub>production by stromal cells after 24 h (<jats:italic>P</jats:italic><0.05). Ovarian steroids affected proliferation of stromal and epithelial cells during the 24-h incubation period (<jats:italic>P</jats:italic><0.05). We provide evidence that ovarian steroids affect PG production in equine endometrial cells, upregulating PTGS2, PGES, and PGFS expression. Ovarian steroid-stimulated PG production could be an important mechanism occurring in the equine endometrium that is involved in the regulation of the estrous cycle and early pregnancy.</jats:p>