Pre-chemotactic and chemotactic properties of uterine fluid from mares with experimentally induced endometritis.

The research investigates the impact of uterine fluid collected from mares, which have had endometritis experimentally induced, on the shape and movement of horse neutrophils (a type of white blood cells), at varying intervals after infection.

Experimental Procedure

• The researchers induced endometritis, which is an inflammatory condition of the inner lining of the uterus, in pony mares using Streptococci. This was done while the mares were in estrus, a phase in their reproductive cycle when they are sexually active and ready for fertilization.
• Uterine fluid was collected from the mares 30, 60, 120 or 240 minutes post-infection, and this fluid was tested for its in vitro (outside the body) physiological effects on equine neutrophils – which are immune cells in the body that help fight off infection and disease.

Results and Conclusion

• It was observed that the maximum response occurred between 30 and 60 minutes post-infection and continued to linger until 240 minutes.
• The “chemo-attractant” is a substance contained in the uterine fluid that attracts neutrophils, thereby enhancing the body’s immune response. This chemo-attractant was found to have both heat-labile (susceptible to change or destruction on heating) and heat-stable (not changing or deteriorating with heat) components.
• The heat-stable components of the chemo-attractant were found to be active even at low concentrations, indicating they could still attract neutrophils and promote an immune response without requiring a large amount of substance.
• This study implies that the body’s immune response, at least in the case of uterine inflammation in mares, is swift (occurring between 30 to 60 minutes) with a sustained action up to 240 minutes and is essentially driven by both heat stable and labile components in the uterine fluid. These findings could have relevance in understanding and treating infections and inflammatory conditions in the reproductive tract of mares.