Effects of intrauterine devices on proteins in the uterine lavage fluid of mares.

The research illustrates an examination of the potential mechanisms whereby intrauterine devices (IUDs) inhibit luteolysis in mares. It investigates changes in the protein profile of endometrial secretome, collected from various groups of mares, to help elucidate the underlying processes.

Research Methodology

• The study involved 27 mares which were grouped based upon whether they were inseminated (AI) or had an IUD inserted on Day 3 post ovulation.
• These groups included pregnant inseminated mares (AI-P; n = 8), non-pregnant inseminated mares (AI-N; n = 4), and mares with IUD (n = 15).
• IUD mares were further sub-categorized into prolonged (IUD-P; n = 7) and normal luteal phase (IUD-N; n = 8) based on ultrasound examinations, serum levels of progesterone and PGFM (prostaglandin F metabolite) on Days 14 and 15, and COX-2 (cyclooxygenase-2) results on Day 15.
• The analysis was conducted using two-dimensional difference gel electrophoresis (2D-DIGE) on the uterine lavage fluids collected on Day 15.

Research Findings

• The 2D-DIGE analyses identified ten proteins with statistically different abundance across the groups.
• Of these proteins, malate dehydrogenase 1, increased sodium tolerance 1, aldehyde dehydrogenase 1A1, prostaglandin reductase 1, albumin, and hemoglobin were highest in pregnant mares.
• T-complex protein 1 was found in the greatest abundance in non-pregnant mares.
• Annexin A1 and 6-phosphogluconolactonase were predominant in mares with IUDs.

Conclusion and Implications

• The results indicate that the functioning of IUDs may be linked to inflammatory responses, suggested by the elevated presence of annexin A1 and 6-phosphogluconolactonase in the IUD mares.
• This could be a vital discovery in understanding the effects of IUDs on the equine reproductive system and may potentially hold implications for the humans use of IUDs as well.