A GFP endometriosis model reveals important\n\t\t\t\t morphological characteristics of the angiogenic\n\t\t\t\t process that govern benign and malignant diseases

Endometriosis involves the growth of\n\t\t\t\t endometriotic tissue outside the uterine cavity, and is\n\t\t\t\t frequently associated with different malignancies. A\n\t\t\t\t well-reported alteration in the disease microenvironment\n\t\t\t\t is the proliferation of new blood vessels around the\n\t\t\t\t lesions, as part of a necessary repertory to contribute to\n\t\t\t\t the invasiveness and development of infiltrating\n\t\t\t\t endometriosis. Therefore, the establishment of a reliable\n\t\t\t\t experimental model is essential to elucidate the\n\t\t\t\t contribution of angiogenesis and to develop new\n\t\t\t\t therapeutic approaches to endometriosis treatment. For\n\t\t\t\t this purpose we transplanted endometrial fragments from\n\t\t\t\t green fluorescent protein (GFP)-mice (n=20) into the\n\t\t\t\t peritoneal cavity of wild-type mice (n=20), and then\n\t\t\t\t analyzed the morphological changes and the process of\n\t\t\t\t angiogenesis. The lesions were cystic and vascularized,\n\t\t\t\t and showed morphological hallmarks such as\n\t\t\t\t endometrial glands and stroma. An increase in\n\t\t\t\t endometriotic lesion vascular density was revealed by\n\t\t\t\t immunostaining and RNAm expression for Vegf and its\n\t\t\t\t receptor Flk-1, and the lesions were confirmed as a\n\t\t\t\t tissue-donor source by GFP fluorescent cells. The same\n\t\t\t\t pattern was observed through staining of activated\n\t\t\t\t macrophages and an increase of about 25% in the\n\t\t\t\t number of macrophage-positive cells was also\n\t\t\t\t demonstrated in endometriotic lesions by flow\n\t\t\t\t cytometry, which concords with previous data that\n\t\t\t\t correlate endometriosis, angiogenesis and inflammation.\n\t\t\t\t According to our understanding, this is the first\n\t\t\t\t demonstration that the pattern of the angiogenic process\n\t\t\t\t in the GFP endometriosis model is very similar to that of\n\t\t\t\t cancer. These observations will be useful for\n\t\t\t\t investigation of the process of angiogenesis involved in\n\t\t\t\t the attachment and invasion of endometrial cells, as well\n\t\t\t\t as an in vivo platform model to study the effects of\n\t\t\t\t antiangiogenic drugs.