RESEARCH ARTICLE Interplay between Endometriosis and Pregnancy in a Mouse Model

Objectives To evaluate the effect of endometriosis on fertility and the levels of the IL-2 and IFN-γ in the peritoneal fluid in a mouse model; to evaluate the effect of pregnancy on endometriotic le-sion growth, apoptosis and cell proliferation. Study Design Two month old C57BL/6 female mice underwent either a surgical procedure to induce endo-metriosis or a sham surgery. Four weeks after surgery mice were mated and sacrificed at day 18 of pregnancy. Number of implantation sites, fetuses and fetal weight were recorded. Endometriotic lesions were counted, measured, excised and fixed. Apoptosis and cell prolif-eration were evaluated in lesions by TUNEL and immunohistochemistry for PCNA respec-tively. Levels of IL-2 and IFN-γ were assessed by ELISA in the peritoneal fluid. Results Pregnancy rate (i.e. pregnant mice/N) decreased in mice with endometriosis. However there were no significant differences in resorption rate, litter size and pup weight between