MHC Class II positive cells and T cells in the equine endometrium throughout the oestrous cycle.

This research investigates how the number and distribution of MHC Class II positive cells and T cells in the equine endometrium change throughout the horse’s oestrous cycle. More of these cells are present during the follicular phase, and hormone treatments can also influence their numbers.

Research Objective

• The aim of this study was to investigate the quantity and distribution of Major Histocompatibility Complex (MHC) Class II positive cells and T cells within the equine endometrium throughout the horse’s oestrous cycle. The researchers were particularly interested in whether the different phases of the cycle (follicular and luteal) would affect these cell populations.

Key Findings

• The study found that there were significantly more MHC Class II positive cells in certain layers of the endometrium (the stratum compactum and stratum spongiosum) during the follicular phase of the oestrous cycle compared to the luteal phase.
• Similarly, more T cells were observed in the stratum compactum during the follicular phase, though this pattern was not seen in the stratum spongiosum.
• When mares that had their ovaries removed were treated with the hormone oestradiol, there was a noticeable increase in the number of both MHC Class II positive cells and T cells in the endometrium. This result was compared with mares treated with progesterone, which did not show the same increase.
• Finally, the researchers documented an escalation in the expression of the MHC Class II antigen by endometrial epithelial cells in mares treated with oestradiol as well as in some naturally cycling mares during the follicular phase of the cycle.

Implication of Findings

• The findings suggest that there is indeed variation in the number and distribution of MHC Class II positive cells and T cells in the equine endometrium depending on the phase of the oestrous cycle.
• This fluctuation might be influenced by hormonal changes that occur naturally throughout the cycle or induced by hormonal treatment.
• Further exploration is required to understand the full implications of these findings, both for the basic biology of the equine reproductive system and potentially for veterinary medicine and breeding practices.