|dc.description.abstract||Objective - To investigate the presence and localization of the hyaluronan receptor CD44
in the reproductive tract of the mare.
Animals Six adult mares
Procedures - Tissue sections of ovaries, oviducts and uterus were obtained from healthy
mares. Positive control samples were obtained from the same mares and were processed
together with the reproductive tissues. These control tissues included synovium and
lymph node. The samples were fixed in 10% buffered neutral formalin or
glutaraldehyde/formalin. Formalin samples were stained with hematoxylin-eosin to rule
out pathologic changes or processed for immunohistochemical analysis. The later
samples were stained with a primary monoclonal antibody against CD44 (Rat anti-CD44s
monoclonal) and a secondary rabbit, anti-rat antibody (Biotinylated Rabbit anti-Rat). The
slides were evaluated under light microscopy for binding of specific antibody. Results
were described according to stain identification, location, percentage of stained cells
(CD44-reactive cells per 100 cells of one histological stratus). Samples fixed with
glutaraldehyde/formalin were stained with the primary antibody Rat anti-CD44s
monoclonal and gold conjugated protein A. These samples were evaluated using a
transmission electron microscope for localization of gold particles.
Results Positive immunolabelling for CD44 was found in all the tissues evaluated.
CD44 was localized in the uterine endometrium but not in the uterine glands. Positive
immunolabelling was found all throughout the epithelial cells in all tubal segments
evaluated. This stain was confined to the ad-luminal surface and supra-nuclear regions.
The areas of higher uptake were found on the basal surface of the tubular epithelial cells.
Both inner and outer portions of the ovaries had cell that were populations positive for
CD44. Serosal epithelia were intermittently positive.
Conclusions and Clinical Relevance This is the first time CD44 has been identified in
the reproductive tract of the mare. The localization of CD44 in the ovaries, oviducts and
endometrium, suggest a role of CD44-HA in fertilization and embryonic implantation in