Investigations on the endometrial response to intrauterine administration of N-acetylcysteine in oestrous mares.

The research investigates how the treatment of N-acetylcysteine (NAC) affects the endometrial response in oestrous mares. It found that NAC does not harm endometrial function and may have anti-inflammatory benefits.

Study Design and Procedure

• The researchers worked with twelve mares in oestrous, a stage in their reproductive cycle. These mares were randomly assigned to either a control group or a treatment group.
• The treatment group was given an intrauterine infusion of 5% N-acetylcysteine (NAC), while the control group received a saline solution. Both infusions were given at a total volume of 140 ml.
• Endometrial biopsies were taken from five of the mares after 24 hours, and the remaining seven after 72 hours.
• The biopsies were then evaluated based on several factors including the integrity of the luminal epithelium, the number of polymorphonuclear neutrophils (a type of white blood cell), and staining indicators for various biological markers.

Results of the Study

• The researchers found no statistical difference in endometrial epithelial cell integrity between the control and treatment groups at either the 24 or 72-hour marks.
• There was also no significant difference in the number of polymorphonuclear neutrophils detected in the endometrial biopsies from both groups 24 hours after treatment.
• However, 72 hours after treatment, the control group showed a significantly higher number of PMNs compared to the treatment group, suggesting that NAC may influence the presence of these immune system components.
• The intensity of staining for cyclooxygenase 2, a marker of inflammation, was significantly higher in the control group after 72 hours compared to the NAC treatment group indicating that NAC may have an anti-inflammatory effect.
• Researches saw no difference in staining for Ki-67, a marker for cell proliferation, indicating that NAC does not affect this aspect of cell function.
• There was slightly more staining with the lectin wheat germ agglutinin in NAC treated mares than in controls 72 hours after treatment, though the significance of this observation is not discussed.
• The PAS staining of mucus in deep uterine glands, a measure of mucus production and secretion, differed significantly between the control and NAC treatment groups 24 hours after treatment.

Conclusion

• The results of the study suggest that the administration of N-acetylcysteine does not have a negative impact on endometrial function in horses.
• Furthermore, evidence of a potential anti-inflammatory effect was observed, as shown by lower PMN counts and less intense COX2 staining in the NAC treatment group.