Follicular fluid of women with endometriosis stimulates the proliferation of endometrial stromal cells

The peritoneal environment in endometriosis is known to have growth-promoting effects on endometrial cells. To investigate whether follicularfluid, a contributor to the peritoneal fluid, stimulates endometrial cellproliferation, we incubated endometrial stromal cells in culture withvarious dilutions of follicular fluid obtained from women with or withoutendometriosis undergoing oocyte retrieval for in- vitro fertilization. Cellproliferation assays were performed using follicular fluid from 28 women(without endometriosis, n = 13; with endometriosis, n = 15) in eightdifferent endometrial stromal cell culture set-ups. Cell proliferation wasassessed by a colorimetric method. Maximum cell proliferation was detectedwhen endometrial cells were incubated with 50% dilution of follicular fluidfor 48 h. Follicular fluid from women with endometriosis inducedsignificantly higher cell proliferation than follicular fluid from womenwithout endometriosis (P < 0.05). Our findings indicate that follicularfluid contents may contribute to the growth-promoting factors in theperitoneal fluid of women with endometriosis.