Induction of peritoneal endometriosis in nude mice with use of human immortalized endometriosis epithelial and stromal cells: a potential experimental tool to study molecular pathogenesis of endometriosis in humans

Objective: To determine whether a mixed population of immortalized human endometriosis epithelial and stromal cells is able to induce peritoneal endometriosis in nude mice. Design: Prospective experimental study. Human immortalized endometriosis epithelial and stromal cells were xenografted into ovariectomized nude mice. Macroscopically, the number of induced endometriosis-like lesions and their color were determined. Microscopically, histomorphology of endometriosis glands and their structure were analyzed, and comparisons were made with tissue from spontaneous endometriosis in women. Setting: College of Veterinary Medicine and Biomedical Sciences, Texas A&M University. Animals: Seven ovariectomized nude mice. Intervention(s): Minimal invasive procedures were performed to administer estrogen pellets and transplant immortalized human endometriosis epithelial and stromal cells into nude mice. Main Outcome Measure(s): Peritoneal endometriosis-like lesions induced in nude mice were characterized and compared with spontaneous peritoneal endometriosis in women. Result(s): Xenografts of human immortalized endometriosis epithelial and stromal cells into the peritoneal cavity of the recipient nude mice are able to proliferate, attach, invade, reorganize, and establish peritoneal endometriosis. Endometriosis glands at different stages of growth were present in induced endometriosis-like lesions. Proliferating cell nuclear antigen, metalloproteinase 2, estrogen receptor-alpha, cyclooxygenase-2, and prostaglandin E-2 receptors EP2 and EP4 proteins were expressed in both endometriosis glandular epithelia] and stromal cells of the induced endometriosis-like lesions. Conclusion(s): This xenograft model could be used as a potential experimental tool to understand the molecular and cellular aspects of the pathogenesis of endometriosis in humans. (Fertil Steril (R) 2009;91:2199-209. (C) 2009 by American Society for Reproductive Medicine.)