Degenerative endometrial changes do not change the functional capacity of immigrating uterine neutrophils in mares.

This study explores the impact of degenerative changes in the uterine lining (endometrosis) on the functionality of white blood cells (neutrophils) in horses. The researchers found that these changes do not impact the abilities of these immune cells to function and defend against infection.

Research Methodology

• A model of endometritis (inflammation of the uterus lining) was used in this study. The researchers used recombinant human interleukin-8 (rhIL-8), an immune cell attractant, to draw white blood cells, specifically polymorphonuclear neutrophilic granulocytes (PMN), to the uterus.
• After six hours following the application of rhIL-8, the researchers flushed out the uterus linings of 15 mares with a saline solution.
• They then conducted flow cytometric tests, a method used to measure physical and chemical characteristics of cells, to determine the number, health, type, ability to generate reactive oxygen species (ROS), and capacity to engulf bacteria (phagocytic activity) of the PMN.

Research Findings

• The researchers found that rhIL-8 attracted equally high numbers of healthy PMN into the uteri in horses with and without endometrosis.
• The expression of the molecule CD11a/CD18 (LFA-1) was significantly upregulated in uterine neutrophils. This protein complex plays a key role in the immune response, including the recruitment of leukocytes, and plays a role in inflammatory response.
• Conversely, major histocompatibility complex class I molecules were expressed at lower densities. These are proteins that display antigen fragments on the cell surface, aiding in the immune response.
• Moreover, uterine PMNs have the same ability to phagocytose opsonized streptococci (engulf and destroy bacteria) as blood PMN, but demonstrated a higher capacity to generate reactive oxygen species (ROS), which are involved in cell signaling and homeostasis.
• Generally, on average, uterine PMN of mares with degenerative endometrial changes manifested identical functional and phenotypical traits to those of mares with healthy endometrium.

Conclusions

• Overall, the study concludes that degenerative endometrium changes do not affect the uterine neutrophil’s functionality in horses, suggesting that their immune response capabilities are not compromised despite such changes.