Effect of peritoneal fluid from women with endometriosis on implantation in the mouse model.

Objective: To investigate the potential role of peritoneal fluid (PF) from women with or without endometriosis in implantation in mice with use of the delayed implantation model.

Design: A murine experimental model with markers of uterine receptivity and prospective comparison of the effects of human PF on implantation.

Setting: Academic university and hospital program.

Intervention(s): PF collected from women with and without endometriosis was injected intraperitoneally into recently mated mice.

Main Outcome Measure(s): Implantation sites were counted in treated and untreated animals, and the alphavbeta3 integrin was measured in the pregnant mouse uterus by immunohistochemistry with in situ hybridization. Leukemia inhibitory factor and the beta3 subunit of alphavbeta3 were measured by Northern blot during early pregnancy and after injections of PF.

Result(s): Animals receiving PF from infertile women with endometriosis had a reduction in the number of implantation sites compared with animals that received PF from fertile women or from patients with recently treated endometriosis. In the mouse, expression of alphavbeta3 and leukemia inhibitory factor peaked at the time of implantation and was reduced by injections of human PF from infertile patients with endometriosis.

Conclusion(s): Leukemia inhibitory factor and alphavbeta3 are coexpressed at the time of implantation in the mouse. PF from women with endometriosis has a detrimental effect on embryo implantation, perhaps by adversely affecting uterine receptivity.