Immunohistochemical and histochemical identification of proteins and carbohydrates in the equine endometrium Expression patterns for mares suffering from endometrosis.

The research paper studies the deviations in the secretion patterns of the uterine gland in mares affected by endometrosis using endometrial biopsies, histochemical and newly established immunohistochemical methods. It reveals that fibrotic foci in uterine glandular epithelia have a distinct protein and carbohydrate pattern of expression which is not influenced by hormonal changes during the estrous cycle.

Research Objectives and Methods

• The aim of the study was to determine variations in the secretion patterns of the uterine gland at the cellular level in mares suffering from endometrosis. Different types and degrees (mild to severe, active and inactive, destructive and non-destructive) of endometrosis were studied.
• The researchers obtained forty-eight endometrial biopsies from affected mares. The expression of certain proteins (uteroglobin, uteroferrin, calbindinD9k, and uterocalin) that can be identified by immunohistochemistry using polyclonal antibodies were examined.
• A histochemical method, the PAS-reaction, was used to identify glycogen and mucopolysaccharides were stained with alcian blue.

Key Findings

• The uterine glandular epithelia within fibrotic foci exhibited a pattern of protein and carbohydrate expression largely independent of hormonal changes during the estrous cycle.
• Compared to non-affected glands, the study found that most epithelial cells in areas affected by periglandular fibrosis exhibited a decreased intensity of immunostaining for proteins, especially in the case of destructive endometrosis.
• However, cervical mucus staining intensity was strong within the areas of severe destructive endometrosis.
• Only a few basal glandular epithelial cells, specifically within cystic glands, stained for mucopolysaccharides. This behavior is typically seen within the luminal epithelia.
• The study also found that slight alterations in glandular proteins and carbohydrate reaction patterns caused by only a single fibrotic focus were generally identified in uterine flushings. These were more detectable in cases of severe endometrosis.
• The high sensitivity of the methods used in this study facilitates further studies on uterine secretion patterns in the context of routine evaluations of endometrial biopsies.