# Morphology, Glycan Pattern, Heat Shock Proteins, and Sex Steroid Receptors Expression in the Tubal Fimbria Epithelium of the Baboon Papio hamadryas during the Menstrual Cycle

## TL;DR

This study examines how the baboon's oviduct fimbria changes during the menstrual cycle, focusing on cell structure, sugar patterns, and protein expression, which could help understand primate reproduction.

## Contribution

The study provides new insights into the preovulatory phase-specific morphology and molecular markers in baboon oviduct fimbria epithelium.

## Key findings

- Ciliated and nonciliated cells are present only during the preovulatory phase.
- Nonciliated cells express HSP60 and HSP90 in apical blebs and nuclear ERα and PR.
- Ciliated cells show HSP70, HSP90, and PR in cilia during the preovulatory phase.

## Abstract

The early crosstalk between the ovulated oocytes and the oviduct occurs in the fimbria, which is sensitive to the sex hormone fluctuation. Morphological and molecular changes were investigated in the oviductal fimbria epithelium of the baboon (Papio hamadryas) during the menstrual cycle. A well-differentiated epithelium consisting of ciliated and nonciliated cells was present only during the preovulatory phase when the epithelial surface displayed acidic glycans, complex fucosylated N-glycans, and oligolactosamine residues. Nonciliated cells contained small apical protrusions and thin microvilli, suggesting secretory and absorptive activities. In addition, nonciliated cells expressed HSP60 and HSP90 in the apical blebs as well as nuclear estrogen and progesterone receptors. Interestingly, ciliated cells displayed HSP70, HSP90, and progesterone receptors in the cilia. The findings, in addition to adding to knowledge of the baboon oviduct, may represent a benchmark for translational studies of the primate oviduct, including humans.

The oviductal fimbria is the first extraovarian anatomical structure that the cumulus–oocyte complex (COC) encounters, and is sensitive to sex hormone changes. The morphology, glycan pattern, expression of heat shock proteins (HSPs), estradiol receptor (ER), and progesterone receptor (PR) were investigated in the oviductal fimbria epithelium of the baboon (Papio hamadryas) during the menstrual cycle. The morphology was investigated by light and scanning electron microscopy; the glycopattern was characterized using conventional and lectin histochemistry; HSPs (60, −70, −90), ER, and PR were localized immunohistochemically. Well-differentiated ciliated and nonciliated cells were present only during the preovulatory phase. The nonciliated cells contained small apical protrusions and thin microvilli. During the preovulatory phase (1) the luminal surface of the fimbria displayed acidic glycans, complex N-glycans containing fucose, and oligolactosamine residues; (2) nonciliated cells expressed HSP60 and HSP90 in the apical blebs, HSP70 in the nucleus and cytoplasm, as well as nuclear ERα and PR; (3) ciliated cells showed HSP70 in the nucleus, cytoplasm, and cilia that also expressed HSP90 and PR. These results are related to the function of the fimbria where the early COC–oviduct crosstalk occurs and may represent a benchmark for translational studies of other primates.