An early endometrial vascular indicator of completed orientation of the embryo and the role of dorsal endometrial encroachment in mares.
Abstract: The spherical equine embryonic vesicle is mobile throughout the uterine lumen for several days before becoming fixed in the caudal segment of a uterine horn on Day 16 (ovulation = Day 0). Orientation refers to the position of the embryo proper at the periphery of the vesicle relative to the position of the mesometrial attachment. In mares, the embryonic pole of the vesicle is antimesometrial after completion of orientation. Day of vesicle fixation, differential thickening of the endometrium near the mesometrial attachment, and orientation of the embryonic vesicle were studied in 30 ponies, using B-mode and color-Doppler transrectal ultrasonography. The thickness of the endometrium at the mesometrial aspect of the vesicle divided by the thickness at the antimesometrial aspect was termed the encroachment ratio. At the future site of fixation, the first increase (P < 0.05) in the encroachment ratio occurred between 4 and 1 days before fixation. An early vascular indicator of the future position of the embryo proper was discovered by color-Doppler imaging and consisted of a colored spot in the image of the endometrium close to the wall of the embryonic pole. The early indicator was detected in each mare 0.5 +/- 0.1 days after fixation and 2.5 +/- 0.2 days before first detection of the embryo proper. The position of the early indicator when first detected at the periphery of the embryonic vesicle was not significantly different from the position of the embryo proper when first detected. Results supported the hypothesis that differential thickening of the endometrium precedes orientation and indicated that orientation occurs immediately after fixation.
Publication Date: 2005-10-19 PubMed ID: 16237147DOI: 10.1095/biolreprod.105.047621Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
The research explores the precise moment of embryo fixation in equine reproduction and further proposes that differential-thickening of the endometrium happens prior to orientation and after fixation.
Study of Vesicle Fixation
- The research is centered around the process of equine embryonic vesicle fixation and orientation within the female reproductive system.
- The term ‘vesicle fixation’ is used to define the time when the embryo comes to rest at a specific location within the uterus.
- In this study, vesicle fixation was observed in 30 ponies, with special emphasis on noting the exact timing and place of this event.
Understanding Orientation
- Orientation, as used in the study, describes the position of the embryonic vesicle in relation to the mesometrial attachment.
- In mares, the embryonic pole is positioned opposite the mesometrial side after orientation is complete.
- The study explores the changes that occur leading to this moment of orientation.
The Encroachment Ratio
- An important concept introduced in this study is the encroachment ratio – the thickness of the endometrium at the mesometrial side of the vesicle divided by the thickness at the opposing side.
- Noticeable increase in the encroachment ratio occurred between 4 and 1 days before fixation at the future site of fixation.
Early Vascular Indicator
- The study successfully revealed an early vascular indicator – or signal – of the future position of the embryonic vesicle.
- This colored spot can be detected by using color-Doppler imaging and was seen in each of the mares 0.5 +/- 0.1 days following fixation and 2.5 +/- 0.2 days before the embryo was first detected.
- The position of the early indicator did not significantly differ from the position of the embryo when it was first detected, explaining its utility in tracking orientation.
Study’s Key Findings
- The study established that a differential thickening of the endometrium occurs prior to the orientation of the embryonic vesicle.
- Additionally, it appears that orientation occurs immediately subsequent to fixation, giving new insights into the timeline of embryonic development.
Cite This Article
APA
Silva LA, Ginther OJ.
(2005).
An early endometrial vascular indicator of completed orientation of the embryo and the role of dorsal endometrial encroachment in mares.
Biol Reprod, 74(2), 337-343.
https://doi.org/10.1095/biolreprod.105.047621 Publication
Researcher Affiliations
- Eutheria Foundation, Cross Plains, Wisconsin 53528, USA.
MeSH Terms
- Animals
- Biomarkers
- Embryo Implantation
- Endometrium / blood supply
- Endometrium / diagnostic imaging
- Female
- Horses
- Pregnancy
- Pregnancy, Animal
- Ultrasonography, Doppler, Color
Citations
This article has been cited 2 times.- Madhavan MK, DeMayo FJ, Lydon JP, Joshi NR, Fazleabas AT, Arora R. Aberrant uterine folding in mice disrupts implantation chamber formation and alignment of embryo-uterine axes.. Development 2022 Jun 1;149(11).
- Diel de Amorim M, Klein C, Foster R, Dong L, Lopez-Rodriguez MF, Card C. Expression of Oxytocin/Neurophysin I and Oxytocinase in the Equine Conceptus from Day 8 to Day 21 Post-Ovulation.. Animals (Basel) 2022 Mar 22;12(7).
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
