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Histomorphometric and Histochemical Changes in the Mare Tuba Uterina During the Oestrous Cycle and Follicular Cyst Condition.
Abstract: This study evaluated histomorphometric and histochemical changes in the mare tuba uterina during different reproductive stages and under follicular cyst conditions. Forty nonpregnant mares were classified into follicular, luteal, post-ovulation and follicular cyst groups (n = 10/group). Histological evaluation of the isthmus, ampulla and infundibulum was performed using haematoxylin and eosin staining, while periodic acid-Schiff (PAS) staining was used to assess epithelial secretory activity. Morphometric parameters included number of primary mucosal folds, fold length, epithelial height and fold thickness. Descriptive observations indicated that the infundibulum possessed the most elaborate mucosal architecture, whereas the isthmus exhibited the simplest organization. Comparisons among reproductive stages were performed separately within each oviductal region. Across all oviductal regions, the follicular phase demonstrated the highest morphometric values, characterized by increased fold number, epithelial height and fold dimensions (p < 0.05). In contrast, most morphometric parameters decreased during the luteal and post-ovulation stages. For most variables, post-ovulation values remained higher than those observed during the luteal phase. The ampulla exhibited the strongest PAS reactivity during the luteal phase, with abundant apical PAS-positive granules indicating enhanced epithelial secretory activity, whereas moderate staining was observed during the follicular phase. Mares with follicular cysts showed the lowest morphometric values in all oviductal regions and weak, irregular PAS reactivity. These findings demonstrate that the mare tuba uterina undergoes pronounced cyclical remodelling influenced by ovarian status. Follicular cysts were associated with altered histological and secretory characteristics of the oviduct, which may compromise the physiological environment required for normal reproductive function.
© 2026 Wiley‐VCH GmbH. Published by John Wiley & Sons Ltd.
Publication Date: 2026-08-15 PubMed ID: 42603111PubMed Central: PMC13476905DOI: 10.1111/ahe.70166Google Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
Summary
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Overview
- This study analyzed structural and chemical changes in the mare’s fallopian tube (tuba uterina) during the reproductive cycle and in the presence of follicular cysts.
- It aimed to understand how tissue architecture and secretory activity vary with reproductive stages and ovarian cyst conditions, potentially affecting fertility.
Background and Objectives
- The mare tuba uterina, analogous to the fallopian tube in humans, plays a critical role in gamete transport, fertilization, and maintaining an optimal environment for early embryo development.
- Previous knowledge about how the mare’s oviduct changes during different reproductive phases or in pathological conditions like follicular cysts was limited.
- This study’s goal was to evaluate both morphological (histomorphometric) changes and secretory activity (histochemical changes) of the mare tuba uterina during:
- The follicular phase (before ovulation)
- The luteal phase (after ovulation)
- Post-ovulation phase
- Follicular cyst condition
Materials and Methods
- Forty nonpregnant mares were divided equally into four groups representing reproductive stages and the follicular cyst condition (10 mares per group).
- Three regions of the mare’s oviduct were studied:
- Isthmus (near uterus)
- Ampulla (middle segment)
- Infundibulum (near ovary)
- Histological staining techniques used:
- Haematoxylin and eosin staining — to analyze tissue architecture and conduct histomorphometric measurements.
- Periodic acid-Schiff (PAS) staining — to detect epithelial secretory activity by visualizing carbohydrate-rich secretory granules.
- Morphometric parameters quantified included:
- Number of primary mucosal folds (which increase surface area)
- Fold length
- Epithelial height
- Fold thickness
Key Findings
- Mucosal Architecture:
- Infundibulum showed the most complex and elaborate mucosal folds, indicating a highly folded surface.
- Isthmus had the simplest mucosal organization, likely reflecting functional differences along the tube.
- Reproductive Stage Changes:
- Across all parts of the oviduct during the follicular phase:
- Highest morphometric values were recorded, with increased fold number, epithelial height, and fold dimensions.
- This suggests the oviduct is maximally prepared structurally to support gamete and embryo transport.
- During luteal and post-ovulation phases:
- Most morphometric parameters decreased, indicating tissue remodeling after ovulation.
- Values post-ovulation remained somewhat higher than during the luteal phase, perhaps reflecting gradual recovery towards the next cycle.
- Across all parts of the oviduct during the follicular phase:
- Secretory Activity (PAS Staining):
- Ampulla exhibited the strongest secretory activity during the luteal phase, with abundant apical PAS-positive granules in epithelial cells.
- Moderate secretory staining was observed during the follicular phase.
- This suggests that secretions are hormonally regulated and vary with ovarian cycle stages, likely influencing the microenvironment for fertilization and embryo support.
- Follicular Cyst Condition Effects:
- Mares with follicular cysts showed the lowest morphometric values across all regions.
- Weak and irregular PAS reactivity indicated impaired or altered epithelial secretory function.
- These changes may create a suboptimal environment for fertilization or early embryo development, potentially contributing to reproductive failure or subfertility associated with cystic conditions.
Conclusions and Implications
- The mare tuba uterina undergoes marked cyclical remodeling in structure and secretory activity, driven by ovarian hormonal status throughout the estrous cycle.
- This remodeling ensures optimal oviductal conditions tailored for different reproductive stages, supporting gamete transport, fertilization, and embryo viability.
- The presence of follicular cysts disrupts normal histological architecture and secretory patterns, potentially compromising fertility by altering the physiological environment.
- Understanding these changes can help in veterinary reproductive management and in developing treatments for reproductive disorders tied to follicular cysts.
Cite This Article
APA
Van Dung B, Anh NTL, Nam NH.
(2026).
Histomorphometric and Histochemical Changes in the Mare Tuba Uterina During the Oestrous Cycle and Follicular Cyst Condition.
Anat Histol Embryol, 55(5), e70166.
https://doi.org/10.1111/ahe.70166 Publication
Researcher Affiliations
- Department of Animal Surgery and Theriogenology, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam.
- Department of Animal Surgery and Theriogenology, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam.
- Department of Animal Surgery and Theriogenology, Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hanoi, Vietnam.
MeSH Terms
- Animals
- Female
- Horses / physiology
- Horses / anatomy & histology
- Estrous Cycle / physiology
- Follicular Cyst / veterinary
- Follicular Cyst / pathology
- Fallopian Tubes / anatomy & histology
- Fallopian Tubes / physiology
- Uterus / anatomy & histology
- Periodic Acid-Schiff Reaction / veterinary
Conflict of Interest Statement
The authors declare no conflicts of interest.
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