Oxytocin enhances clearance of radiocolloid from the uterine lumen of reproductively normal mares and mares susceptible to endometritis.

The given research studies the effect of oxytocin on the clearance of a radiocolloid named technetium 99m albumin colloid from the uterine lumen in mares. The study indicates that oxytocin appears to enhance clearance, potentially offering a novel way to treat mares exhibiting impaired uterine clearance.

Objective and Methodology

• The primary aim of this study was to assess the impact of oxytocin on expelling technetium 99m albumin colloid (99mTc-microAA) from the uterine lumen in horses. This research could offer insights into new strategies for treating mares that show signs of impaired uterine clearance.
• 13 horses were utilized in the study, seven of which (Group 1) were assessed as ‘susceptible’ to endometritis, and the other six (Group 2) were classified as ‘resistant.’ This classification was based on their reproductive history, with Group 1 consisting of multiparous horses and Group 2 containing a mix of nulliparous and multiparous horses.
• The measurement technique applied was scintigraphy, which was carried out throughout four consecutive oestrous cycles. The measurement moments were on the 3rd day of oestrus during the first and third cycles, and 48 hours after ovulation in the second and fourth cycles.
• In cycles three and four, 20 international units (IU) of oxytocin were given intravenously after the initial scintigraphy.

Results and Conclusion

• Results indicated that all mares cleared more than 90% of the 99mTc-microAA within 30 minutes of receiving oxytocin. This stands in stark contrast to the mares that did not receive any oxytocin, where Group 1 horses cleared negligible amounts of the radiocolloid (less than 5%) and Group 2 horses removed 50-80% of it.
• The administration of oxytocin caused no signs of colic in horses.
• Based on these findings, the researchers concluded that oxytocin could potentially be an effective treatment to enhance uterine clearance of radiocolloid in horses, particularly in those mares exhibiting impaired uterine clearance.