Effects of cycle stage and sampling procedure on interpretation of endometrial cytology in mares.

The research explores the impact of the reproductive cycle stage and sampling methods on endometrial cytology results in mares. It concludes that the endometritis diagnosis majorly relies on cell-based evaluation tactics.

Study Objective and Methodology

• The study was designed to determine the influence of mare reproductive cycle stages on cytological results, the efficacy of cytology derived from endometrial biopsy versus cytobrush, and the consistency between different cytological sample evaluation techniques.
• Mares at different stages of their reproductive cycle, including estrus, diestrus, and anestrus, participated in the study. Samples were obtained from 46 mares in estrus, 48 in diestrus and 33 in anestrus.
• The samples were assessed under two standardized criteria involving polymorphonuclear cells counting. Criterion I required counting a total of 300 cells and recording the polymorphonuclear cell percentage. Criterion II involved determining the polymorphonuclear cells per high power field.
• Moreover, histological examinations of endometrial biopsy samples were conducted. The consistency of cytological and histological results was compared.

Key Findings

• Regardless of the sample collection process, endometritis diagnosis was significantly higher using Criterion I. Meaning, a higher count of polymorphonuclear cells could be an indication of endometritis.
• When evaluating the agreement of polymorphonuclear cells infiltration into the endometrial luminal epithelium and stratum compactum with cytology results (as per Criterion I), the agreement levels varied depending on the mare’s cycle state – fair for anestrous mares, poor for diestrous mares, and moderate for mares in estrus.
• When cytological smears were assessed according to criterion II, the consistency between the histological and cytological results was consistently poor. This highlights the challenges in interpreting cytology results based on the count of polymorphonuclear cells per high-field power.

Conclusion

• The research concludes by stating the cytological evaluation of the mare endometrium should be based on the number of polymorphonuclear cells in relation to epithelial cells and not on the number of polymorphonuclear cells related to the high power field. The former approach delivers a more precise diagnosis or detection of endometritis.