EN
The aim of this work was to examine specimens from 56 mares subjected to endometrial biopsy. Special attention was paid to inflammatory cells and mast cells. It was found that endometritis eosinophilica evolved into endometritis lymphocytaria. The development of endometrosis was accompanied by a slight increase in the relative number of mast cells in the interstitial tissue. At the same time, diffused eosinophils and variable numbers of lymphocytes and macrophages were present. These results may suggest that the primary inflammatory process in endometrium contributes to the secondary progressive interstitial fibrosis. The process of the activation of eosinophils, lymphocytes, mast cells and macrophages may result from hormonal disturbances and may reflect a pathological stimulation of these cells by estrogens through specific nuclear receptors.