Effect of intrauterine infusion of Escherichia coli endotoxin in postpartum pony mares.

This research studied the impact of inserting Escherichia coli endotoxin in mares after giving birth. The study found that total white blood cell and neutrophil counts changed across time in treatment groups after the infusions, but without much effect on the mares’ rectal temperature.

Experiment Details

• The research involved fifteen pony mares which were assigned into one of three treatment groups after giving birth.
  • Group 1 – Six mares were infused with 35ml of sterile saline solution into the uterine lumen within 24 hours after birth.
  • Group 2 – Six mares were infused with 300mg of Escherichia coli endotoxin into the uterine lumen within 24 hours after parturition.
  • Group 3 – Three mares were infused with 300mg of E. coli endotoxin into the uterine lumen between 72 and 96 hours after parturition.

Experiment Process

• Rectal temperatures were taken at various points before and after the treatment. Venous blood samples were gathered at these times as well for routine White Blood Cells (WBC) counts.
• The data gathered were then analyzed using a repeated measurement design.
• Linear and quadratic orthogonal contrasts were performed in instances where significant time and interaction with time occurred.
• The pretreatment averages of WBC and neutrophil counts were compared with each of their nadir posttreatment averages by a t-test when treatment-by-time interaction was significant for the parameter.

Research Findings

• The mares’ rectal temperature, 37.9 +/- 0.1 C, remained stable and did not noticeably differ across the treatment groups after the infusions.
• In contrast, the total WBC and neutrophil counts had varied among the treatment groups over time.
• For treatment groups 1 and 3, both the total WBC and neutrophil counts after the infusions were similar to the count before the treatment.
• However, in treatment group 2 which was introduced to E. coli endotoxin within 24 hours after parturition, the WBC count decreased from a pretreatment average of 11.5 +/- 0.4 X 10(3) cells/mm3 to a nadir concentration of 10.0 +/- 0.6 X 10(3) cells/mm3 by one hour after the endotoxin was infused into the uterus. This significant change in WBC count indicates a response to the introduction of the endotoxin.