Oral contraceptives suppress cell proliferation and enhance apoptosis of eutopic endometrial tissue from patients with endometriosis

OBJECTIVE: To evaluate the effects of administering combination oral contraceptives (COCs) to patients with endometriosis on the regulation of cell growth in the eutopic endometrium. DESIGN: Prospective study. SETTING: Research institute and clinical fertility center. PATIENT(S): Thirteen women with untreated endometriosis and 13 controls. INTERVENTION(S): Biopsy specimens of the eutopic endometrium were obtained from all subjects. Apoptosis, cell proliferation, and Bcl-2 and Bax expression were examined at the epithelial and stromal levels in the eutopic endometrium from patients with endometriosis before and after 30 days of daily exposure to COCs and from controls. MAIN OUTCOME MEASURE(S): Apoptotic cells were detected by using the dUTP nick-end labeling assay; Ki-67, Bcl-2, and Bax expressions were assessed by using immunohistochemical techniques. RESULT(S): After exposure to COCs, apoptosis was significantly increased in the eutopic endometrium compared with before COC administration, both at epithelial and stromal levels. Cell proliferation was significantly lowered by COCs. CONCLUSION(S): COCs showed a positive effect on patients with endometriosis by down-regulating cell proliferation and enhancing apoptosis in the eutopic endometrium.