Ovarian histopathological changes in mares with uterine endometrosis

The aim of the study was to find out the relationship between the progression of endometrosis and the appearance of the structural microscopic changes in mares' ovaries. The investigation was performed on slaughtered mares of various age and breed. Four groups each received a portion of the specimens, and designation to group was according to the stage of endometrosis determined on the basis of Kenney's classification. Uterine and ovarian sections were stained with haematoxylin and eosin. The results of the microscopic evaluation were compared between mares classified into specific Kenney's categories. It was shown that an increase in ovarian follicular cysts was related to mares' ages and correlated with significant progression of the endometrosis. These observations suggest that the same aetiological factors may take part both in triggering disorders of ovarian oo/folliculogenesis and in spurring uterine endometrosis. Further more detailed methods of investigation are needed to elucidate the mechanisms of both disease processes.