Induction of Endometriotic Nodules In an Experimental Baboon Model mimicking Human Deep nodular Lesions

Objective: To establish an experimental model for the study of deep nodular endometriosis.

Design: Induction of nodular endometriosis in baboons by grafting different uterine specimens to the peritoneal cavity.

Setting: Research and university facilities.

Animal(s): Ten baboons, to develop a model of induced deep nodular endometriosis.

Intervention(s): Biopsies of endometrium, and endometrium plus the junctional zone (JZ), full uterine thickness, and myometrium grafted to the peritoneum.

Main Outcome Measure(s): Macroscopic descriptions recorded for observed induced lesions; staining with hematoxylin and eosin for histological evaluation and specific antibodies (CK22, CD10) for immunohistochemical studies; and analysis of surface area and volume of lesions, glandular density, and invasion of surrounding organs.

Result(s): The incidence of induced nodular endometriosis was 100%, but the extent depended on the tissue grafted. Lesions induced after grafting specimens containing the JZ were statistically significantly larger than those not containing the JZ. Surrounding organ invasion was reported in more than 40% of lesions after grafting specimens containing the JZ.

Conclusion(s): The first experimental model of nodular endometriosis allows investigation of deeper nodular lesions as well as invasion phenomena associated with nodular lesions.