Abstract
The eutopic endometrium provides novel insights into endometriotic pathophysiology and treatment. However, no in vivo models currently available are suitable for eutopic endometrium in endometriosis. In this study, we present new endometriotic in vivo models associated with eutopic endometrium using menstrual blood-derived stromal cells (MenSCs). First, we isolated endometriotic MenSCs (E-MenSCs) and healthy MenSCs (H-MenSCs) from the menstrual blood of patients with endometriosis (n = 6) and healthy volunteers (n = 6). Then, we identified MenSCs' endometrial stromal cell properties using adipogenic and osteogenic differentiation. A cell counting kit-8 and wound healing assay were used to compare the proliferation and migration capability between E-MenSCs and H-MenSCs. Seventy female nude mice were used to prepare endometriotic models related to eutopic endometrium by implanting E-MenSCs relying on three approaches, including surgical implantation using scaffolds seeded with MenSCs, and subcutaneous injection of MenSCs in the abdomen and the back (n = 10). H-MenSCs or scaffolds only were implanted in control groups (n = 10). One month after the surgical implantation and 1 week after the subcutaneous injection, we evaluated modeling by hematoxylin-eosin (H&E) and immunofluorescent staining of human leukocyte antigen α (HLAA). Fibroblast morphology, lipid droplets, and calcium nodules in E-MenSCs and H-MenSCs identified their endometrial stromal cell properties. We noticed that the proliferation and migration of E-MenSCs were considerably enhanced compared to H-MenSCs (P < 0.05). E-MenSCs implanted in nude mice formed ectopic lesions using three approaches (n = 10; lesions formation rate: 90%, 115%, and 80%; average volumes: 123.60, 27.37, and 29.56 mm3), while H-MenSCs in the nude mice shaped nothing at the implantation sites. Endometrial glands, stroma, and HLAA expression in these lesions further verified the success and applicability of the proposed endometriotic modeling. Findings provide in vitro and in vivo models and paired controls associated with eutopic endometrium in women with endometriosis using E-MenSCs and H-MenSCs. The approach of subcutaneous injection of MenSCs in the abdomen is highlighted due to non-invasive, simple, and safe steps, a short modeling period (1 week), and an excellent modeling success rate (115%), which could improve the repeats and success of endometriotic nude mice model and shorten the modeling period. These novel models could nearly intimate human eutopic endometrial mesenchymal stromal cells in the progress of endometriosis, opening a new path for disease pathology and treatment.