Endometrial biopsy findings in mares with contagious equine metritis.

The study explored the changes that occur in horse womb tissues, as a result of a sexually transmitted disease called Contagious Equine Metritis. The research also evaluated the usefulness of utilizing biopsy in diagnosing this condition.

Research Methodology

• The study was carried out on 10 naturally infected mares and one Pony mare who was intentionally infected with Contagious Equine Metritis.
• Endometrial biopsy samples were collected from the mares both before and after treatment in 1977.
• The researchers conducted histopathological studies on these samples to observe the effects of the infection on the womb tissues.

Key Findings

• The infected mares exhibited clear histopathological changes. Initial signs included a brief but high presence of certain types of white blood cells (polymorphonuclear cells) in the lining of the womb and the connective tissues (stroma).
• This was followed by an immediate and pronounced infiltration of mononuclear cells (another type of white blood cells), including numerous plasma cells, into the stroma.
• The cellular lining of the womb responded to the infection by undergoing rapid cell reproduction which may be an indication of regeneration in response to the disease.
• Even after apparent recovery from the initial sharp response, strange looking vacuoles (spaces within cells) containing a mix of shapeless and granular substance as well as decaying white blood cells, continued to be present along with the basement membrane for weeks following infection.
• Of the nine mares whose specimens were collected after treatment, a mixed reaction was noted.

The Usefulness of Endometrial Biopsy

• Endometrial biopsy proved handy in highlighting the unique response of the womb tissues to infection in individual mares even before the bacteria causing the infection was identified.
• However, biopsy had limited use as a screening test since some mares were able to carry the bacteria in their lower genital tract without showing significant signs of acute endometritis (inflammation of the womb).