Scintigraphic measurement of uterine clearance in normal mares and mares with recurrent endometritis.

This research investigates the impact of certain factors on the clearance of a certain radiocolloid (Technetium 99m-albumin colloid) from the uterus of mares, specifically looking at differences between normal mares and mares susceptible to a common uterine infection called endometritis. The study found that normal mares clear more than 50% of the colloid within a certain timeframe, while those susceptible to endometritis or with poor cervical dilation may show delayed uterine clearance.

Objective and Methodology

• The research aimed to study the clearance rate of Technetium 99m-albumin colloid (99mTc-microAA), a radiocolloid, from the uterine lumen of mares. The measure was taken within four hours of intrauterine infusion.
• Fifteen mares were studied over two consecutive cycles on Day 3 of oestrus and 48 hours after ovulation.
• The mares were categorized into three groups: Group 1 composed of four nulliparous (never given birth) mares, Group 2 consisting of four multiparous (have given birth) mares, both resistant to endometritis, and Group 3 made up of seven multiparous mares susceptible to endometritis.

Results

• It was found that mares in Group 1 and Group 2 cleared more 99mTc-microAA from their uteri than did mares in Group 3 during oestrus, and 48 h after ovulation.
• It was observed that in Group 1 and Group 2, more than 50% of the colloid was cleared in seven mares while none in the remaining mare, apparently due to lack of cervical relaxation.
• For Group 3 mares, the mean percentage of cleared 99mTc-microAA was negligible, but some amount of 99mTc-microAA was cleared by three of the seven mares during four of the six studies carried out.
• When the radiocolloid was infused into the uterus of three reproductively normal mares during dioestrus, the clearance was insignificant.

Conclusion

• The study concluded that infusion of the radiocolloid into the uterus did not negatively affect the endometrial integrity, as determined through endometrial biopsy.
• It was observed that the mares tolerated the procedure well.
• Indicating scintigraphy’s utility, the researchers concluded that it could be used to detect impaired mechanical clearance of the uterus and hinted at the physiological or pathological implications.
• It was found that reproductively normal mares cleared more than 50% 99mTc-microAA within two hours of infusion. In contrast, mares susceptible to endometritis or with poor cervical dilation showed delayed uterine clearance.