Endometrial Histomorphometry of Anestrous Mares Under the Influence of Different Embryo Transfer Hormonal Protocols.

The research examines how different hormonal protocols affect the endometrium properties of mares who are not in their reproductive cycle. It found that estradiol priming before progesterone treatment improves glandular activity and density, bringing it close to what is observed in reproductively active mares.

Introduction and Methodology

• The research aimed to study the influence of different hormone protocols on the endometrium morphometry (size and shape) of anestrous (non-reproductive) mares.
• To achieve this, 26 mares were allocated to four distinct treatment groups. Each group received different doses of two hormones – Estradiol Benzoate (EB) and Long-Acting Progesterone (LA P4).
• The groups were EB2.5LAP4, EB5LAP4, EB10LAP4, and LAP4. The numbers represent the respective dosage of EB in each group, followed by a single dose of LA P4. The LAP4 group only received LA P4.
• Additionally, there was a control group composed of cyclic mares (those in their reproduction cycle).
• Endometrial biopsies were collected before and after the hormonal treatments for their histological and histomorphometric analysis.
• The factors assessed were Luminal Epithelium Height (LEH), Glandular Epithelium Height (GEH), Endometrial Thickness (ET), and Glandular Density (GD).

Results and Conclusion

• Post the hormonal interventions, morphometric changes were noted in groups EB5LAP4 and EB10LAP4, that received higher doses of both EB and P4.
• Five days after LA P4 administration (D5), all assessed factors were similar across all groups that had received EB treatment.
• Furthermore, on D5, the morphometric details for the EB-treated groups were akin to the cyclic mare control group.
• Most variables in the LAP4 group, which made do without EB, were also similar to other groups, although its Glandular Density (GD) and Glandular Epithelium Height (GEH) were less compared to the control group.
• This finding underscores the importance of estradiol priming before administration of progesterone in terms of improving glandular density and activity.