Objective: To establish a novel endometriosis model that allows for repetitive in vivo analyses of angiogenesis in ectopic endometrial tissue.
Design: Intravital fluorescence microscopic study.
Setting: Institute for Clinical and Experimental Surgery, University of Saarland.
Animal(s): Female Syrian golden hamsters equipped with skinfold chambers.
Intervention(s): Large (0.5 mm2) and small (0.1 mm2) endometrial fragments were mechanically isolated and transplanted autologously into skinfold chambers of untreated hormonally synchronized or bilaterally ovariectomized hamsters.
Main outcome measure(s): Angiogenesis, vascularization, and microhemodynamics were analyzed over a 14-day period.
Result(s): In untreated controls, endometrial fragments developed complete microvascular networks during the experimental observation period. Interestingly, microvascular blood flow was higher in large than in small fragments. Histologic examinations revealed proliferating endometriosis-like lesions with dilated endometrial glands surrounded by a richly vascularized stroma. Vascularization of endometrial fragments in synchronized animals did not differ from that of untreated controls. In contrast, endometrial fragments in ovariectomized animals showed a delay in angiogenesis and a significantly decreased blood perfusion, indicating the essential role of ovarian estrogens for ectopic vascularization and perfusion of endometrial tissue.
Conclusion(s): This novel model of endometrial tissue transplantation is a useful experimental approach, not only to focus on the in vivo pathogenesis of endometriosis but also to develop antiangiogenic strategies for the treatment of this disease.