Correlations between histologic endometrial lesions in mares and clinical response to intrauterine exposure with Streptococcus zooepidemicus.

The research investigates the connection between microscopic changes, known as histologic lesions, in the endometrium of mares (female horses) and their susceptibility to chronic uterine infection. The study determined that mares with no pathological changes were less likely to develop such infections and the severity of changes increased the susceptibility to infection.

Study Design

• Four groups of mares were formed based on the degree of lesions present in their endometrial biopsy samples. Group 1 had no changes, group 2 had mild changes, group 3 had moderate changes, and group 4 had severe changes, including inflammation and fibrosis.
• Each mare was exposed to 5 x 10(6) of Streptococcus zooepidemicus (a common bacteria) directly into the uterus to see the inflammatory response and assess susceptibility to chronic uterine infection (CUI).
• A mare was considered susceptible to CUI if it had more than one neutrophil (a type of white blood cell) per five high-magnification (400x) microscope fields and more than twenty colonies of S. zooepidemicus 96 hours after being exposed to the bacteria.

Findings

• A significant correlation was found between the grade of the biopsy and susceptibility to CUI among the groups.
• Mares with no histologic changes were less likely to develop infections, suggesting they have a resistance to CUI.
• Mares with severe changes were more likely to develop infections, suggesting an increased susceptibility to CUI.
• Mares with mild to moderate changes had inconsistent correlation with infection susceptibility or resistance.

Implications

• The findings of this study provide valuable insight into understanding the susceptibility of mares to CUI, which could aid in determining appropriate treatment or prevention strategies for this condition.
• By associating endometrial changes with CUI susceptibility, the study emphasizes the importance of regular endometrial health checking in mares.
• Further research is needed to determine the biological mechanisms behind this correlation and to investigate if similar patterns can be found in other species as well.