Cyclical cervical function in the mare involves remodelling of collagen content, which is correlated with modification of oestrogen receptor 1 abundance.

The study investigates how collagen content and hormone receptor abundance in mares’ cervices vary through different stages of the oestrous cycle, as these may play a significant role in the mechanism of cervical dilation.

Objective of the Research

• The study aimed to shed light on the mechanisms of cervical dilation in mares. Two primary hypotheses were tested: one related to the variance in collagen content in histological samples of the mares’ cervices, and the other regarding the change in hormone receptor abundance in the equine cervix with the stage of the oestrous cycle and site within the cervix.

Methodology

• Researchers collected tissue samples and jugular vein blood samples from 15 different mares.
• The Masson’s Trichome staining method was used to assess the collagen content.
• The abundance of hormone receptors was evaluated using techniques such as RT-PCR, qRT-PCR, and immunohistochemistry.

Findings

• It was discovered that in the sub-epithelial stroma, less collagen was observed during the follicular phase than the luteal phase, irrespective of the part of the cervix (caudal, mid, or cranial).
• Similarly, in the deep stroma, there was lesser collagen staining during the follicular stage in the mid and cranial cervical regions.
• Molecular analyses revealed the presence of PTGER2, PTGER3, PGR, and ESR1 mRNA transcripts in the cervix.
• A higher proportion of cells were found to be positive for the ESR1 protein during the follicular phase in both the sub-epithelial and the deep stroma.
• A negative correlation was observed between ESR1 abundance in the epithelium and collagen staining in the sub-epithelial and deep stroma.

Significance of the Research

• The findings present new information about mare cervical biology, enhancing understanding of collagen content’s changes and its relationship with ESR1 protein abundance during the oestrous cycle.
• The study suggests the ESR1 receptor as a potential player in controlling cervical dilation. More in-depth research in this direction could lead to new interventions and treatments related to equine reproductive health.