Endometrial and luteal gene expression of putative gene regulators of the equine maternal recognition of pregnancy.

The research paper focuses on enhancing our understanding of changes in gene expression relating to oxytocin and prostaglandin activity during early stages of equine pregnancy. The study mainly investigated the role of oxytocinase in luteal and endometrial tissues at different post-ovulation days in pregnant and diestrus mares.

Methods and Findings

• Biopsies were acquired from endometrial and luteal tissues in horses on days 8, 10, 12 and 15 after ovulation, both in pregnant and diestrus (non-pregnant) states. These samples were examined through real-time qPCR, a technique for determining gene expressions.
• The research discovered time-dependent variations in endometrial gene expression for SLC2A4, SLC2A1, PTGES, OXTR, and LNPEP. The gene expression varied over time meaning it was not constant at different stages of the pregnancy.
• Between day 10 and day 15 of pregnancy, a lower relative abundance was found in PTGFR and PLA2G2C genes in the endometrial tissue.
• On the other hand, the OXT and OXTR genes were found to display higher expressions on days 10 and 15 of pregnancy, implying their critical roles at these stages.
• In the luteal tissue, an increased relative abundance of ESR1, PTGS2, PTGFR, PTGES gene transcripts was discovered on day 12, both in pregnant and diestrus states.
• Also, a sharp increase was noticed in the expression of OXTR and OXT genes, while LNPEP had higher relative abundance on days 10 and 12.

Implication of Findings

• In the context of the study, relative abundance refers to the relative amount of a specific gene present at a given time. It gives an indication of the degree of gene expression.
• The variations in gene expressions could influence prostaglandin secretion. Prostaglandin E2 (PGE2) has a vital role in pregnancy due to its protective influence on the luteal tissue.
• Enhancement of SLC2A1 gene expression during pregnancy likely supports the high metabolic activity of luteal tissue by increasing glucose uptake.
• One significant finding was the presence of oxytocinase (LNPEP) in both endometrial and luteal tissues. The role of this enzyme in oxytocin-induced prostaglandin secretion, however, remains unclear and might need further investigation.