Mouse embryo toxicity of IL-6 in peritoneal fluids from women with or without endometriosis

BACKGROUND: To determine whether there is a factor (or factors) in the peritoneal fluid of endometriosis patients that impairs embryo growth and embryo implantation. METHODS: Growth and development of two-cell mouse embryos which were cultured in media with peritoneal fluid from women with or without endometriosis and interleukin-1-beta (IL-1beta), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) levels in conditioned media were measured. RESULTS: The blastocyst rate in the non-endometriosis group was 46.4 +/- 31.1%, and that of the endometriosis group was 54.6 +/- 28.7%. Logistic regression analysis using the criteria of blastocyst development in 454 embryos, showed that the peritoneal fluid from endometriosis could promote (p=0.015) but IL-6 could arrest embryo growth to blastocyst (p=0.025). IL-1beta and TNF-alpha levels had no significant effect on blastocyst formation. CONCLUSION: Peritoneal fluid from women with endometriosis was not toxic to mouse embryo development. However, IL-6 in the peritoneal fluid deteriorated the growth and development of mouse embryos.