Effects of intrauterine infusion of Escherichia coli endotoxin in anestrous and steroid treated pony mares.

The research examines the absorption of Escherichia coli endotoxin in horse uteri and the influence of hormones progesterone and estrogen on this process, concluding that such endotoxins are not absorbed in significant quantities, and their absorption is not affected by these hormones.

Study Design

• The research team performed three consecutive crossover experiments using six mature pony mares in anestrous (non-mating) condition, with a two-week recovery period in between.
• The mares were divided into two groups and subjected to intrauterine infusion, either with saline or E. coli endotoxin. The procedure was swapped and repeated after 14 days, completing a crossover design (Period 1).

Effect of Hormones

• In Periods 2 and 3, the mares were treated with estradiol-17beta (a type of estrogen) and progesterone respectively for 5 days before undergoing intrauterine infusions.
• The goal was to observe any effect of these hormones on the absorption of E. coli endotoxin within the equine uterus.

Data Collection and Analysis

• Various parameters were monitored on the day of intrauterine infusions, like rectal temperatures and periodic blood samples through the jugular vein. These samples were analyzed for total white blood cell counts and using Limulus Amebocyte Lysate Assays – a test for the detection of bacterial endotoxins.

Results and Conclusion

• No significant alterations were observed in the parameters across the treatment groups, indicating that E. coli endotoxin did not get absorbed from the uterus of anestrous pony mares in significant quantities to produce any morbid condition.
• The study also revealed that prior exposure to exogenous progesterone or estradiol-17beta did not influence the absorption of E. coli endotoxin from the equine uterus.