Effect of age and endometrial degenerative changes on uterine blood flow during early gestation in mares.

The research article investigates the impact of age and endometrial degeneration on uterine blood flow in horses, revealing that both aging and endometrial degeneration decreased uterine blood flow during certain stages of early pregnancy.

Study Design

• The research experiment was split into three distinct studies, with the aim of analyzing how age and the state of the horse’s endometrium (the inner lining of the uterus) affected uterine blood flow.
• Throughout each study, measurements for uterine vascular perfusion and the pulsatility index (a measure of blood flow variation) were taken daily from the day of ovulation to either day 12 or day 20, depending on if the mares were pregnant or not.
• Each study group consisted of seven mares.

Study 1: Examination of Semen Infusion Impact

• In the first study, horses were divided into three groups: those that had not been inseminated, those inseminated but not pregnant, and those inseminated and pregnant.
• This study observed an increase in uterine vascular perfusion and a decrease in the pulsatility index in the non-inseminated and inseminated pregnant mares between days 3 and 5. These measurements did not change in the inseminated, non-pregnant mares.

Study 2: Investigation of Age Effects

• In the second study, the mares were divided according to their age into young, adult, and old groups.
• It was found that in both young and adult mares, uterine vascular perfusion in the uterine horn (one side of the horse’s Y-shaped uterus) carrying the embryo was significantly higher than that in the opposite horn from days 12 to 20. In contrast, old mares showed similar vascular perfusion in both horns, except for day 15.

Study 3: Analysis of Endometrial Degenerative Changes

• The third study analyzed pregnant mares with varying degrees of endometrial degeneration, from minimal to severe.
• The results indicated that the uterine vascular perfusion was significantly lower in mares with severe degeneration compared to those with minimal or moderate degenerative changes. Especially following day 15, the blood flow in the uterine horn carrying the embryo was consistently greater than in the opposing horn in mares with minimal endometrial changes.

Conclusion

• The research article concludes by signaling a key discovery showing that the blood flow to the uterus during early gestation is less in older mares and those with significant endometrial degeneration, potentially impacting the pregnancy outcome.