Problem: Our previous study showed that in vitro culture of human endometrial tissue in a three-dimensional (3D) fibrin matrix could mimic the early stages of endometriosis with invasion, gland and stroma formation and sprouting of new vessels. The objective of the present study was to evaluate the expression of glycodelin (Gd) and cyclooxygenase-2 (COX-2), two angiogenic factors, to further validate the 3D culture model of endometriosis.
Method of study: Human endometrial fragments were obtained from endometrial biopsies and placed in a 3D fibrin matrix culture. Immunohistochemistry with specific antibodies to Gd and COX-2 was used to examine endometrial epithelium and blood vessels, and 4, 6-diamidino-2-phenylindole staining was used for nuclear identification.
Results: Three-dimensional culture of human endometrial tissue in the fibrin matrix resulted in the proliferation of endometrial stromal cells, glandular epithelium and angiogenesis. Gd positive glandular epithelium was seen in 85% of wells with developing endometrial glands and COX-2 positive new vessels were seen in 80% of wells with angiogenesis-like structures after 4 weeks of culture.
Conclusion: Our findings confirm that angiogenesis occurs following the culture of endometrial tissue in the 3D fibrin matrix, and suggests that Gd and COX-2 might play important roles in promoting neovascularization and cell proliferation in the establishment of endometriosis.