RESUMEN
More than 40% of infertilities are due to endometriosis. Ultrustructural and histochemical study of endometrium will help to clarify the etiology of endometriosis. The aim of the present study was to investigate the ultrastructure and occurrence of apoptosis in endometrial cells of women with or without endometriosis. In the present case-control study, endometrial specimens from 12 women without endometriosis [as control] and 12 women with endometriosis [as case] were examined. Specimens for control group were obtained from the patients that were referred to gynecology hospital for hysterectomy due to various reasons. In case group the endometriosis was diagnosed according to laparoscopy and endometrial samples were taken using pippel biopsy. The specimens from both case and control groups were processed for Transmission Electron Microscopy [TEM], TUNEL reaction technique and morphometric studies. The results show that endometrial epithelium lost its continuity in women with endometriosis and endometrial cells have euchromatic nucleus in comparison to those from non-endometriosis. There were several apoptotic cells in the luminal and glandular endometrial epithelium and stroma from endometrium of control group. However, apoptotic cells were rarely seen in the endometrium from women with endometriosis. The difference in number of apoptotic cells between two groups statically was significant [p<0.001]. Regarding the ultrastructural characteristics of endometrial epithelial cells and comparison of apoptotic occurrence in control and case groups it is concluded that endometrial cells in endometriosis group have higher potential to survive and possibly implant.