Apoptosis and expression of Bcl-2 and Bax in eutopic endometrium from women with endometriosis

Objective: To evaluate and compare spontaneous apoptosis and Bcl-2 and Bax expression in eutopic endometrium from women with and without endometriosis. Design: Apoptosis and Bcl-2 and Bax expression were examined in eutopic endometrium from women with and without endometriosis. Setting: Instituto de Biologı́a y Medicina Experimental-CONICET, Department of Gynecology and Department of Gynecological Pathology, Clı́nicas University Hospital, Buenos Aires, Argentina. Patient(s): Women with untreated endometriosis (n = 14) and controls (n = 16). Intervention(s): Collection of endometrial samples during diagnostic or therapeutic laparoscopy. Main Outcome Measure(s): Apoptotic cells were detected with use of the dUTP nick-end labeling (TUNEL) assay; Bcl-2 and Bax expressions were assessed with use of immunohistochemical techniques. Result(s): Spontaneous apoptosis was significantly lower in eutopic endometrium from patients with endometriosis, compared with healthy controls (2.26 ± 0.53 and 9.37 ± 1.69 apoptotic cells/field, respectively) and was independent of cycle phase. An increased expression of Bcl-2 protein was found in proliferative eutopic endometrium from patients with endometriosis. Bax expression was absent in proliferative endometrium, whereas there was an increase in its expression in secretory endometrium from both patients and controls. Conclusion(s): Women with endometriosis show decreased number of apoptotic cells in eutopic endometrium. The abnormal survival of endometrial cells may result in their continuing growth into ectopic locations.