The Study of Identification of Ectopic Endometrial Stem Cells and Its Markers in Mouse Model of Endometriosis

Objective To identify and locate adult stem cells in ectopic endometrium and to find their markers in endometriosis. Methods The female nude mice were pulse labeled using 5-bromo-2-deoxyuridine (BrdU) for 5 consecutive days, 24 h prior to the endometriosis rat model was established. The label-retaining cells (LRCs) were identified by detecting BrdU labeling rate using immunohistochemistry on 4 h , 1-week, 3-week, 5-week, 6-week,7-week , 8-week and 9-week after injection. The expression levels of CD34 and CD146 on LRCs were detected by double staining of immunohistochemistry. Results The maximum BrdU labeling rates were (69.89±0.78)% and (73.27±1.06)% for epithelial and stromal cells respectively. After a 6-week and 8-week chase, (2.07±0.19)% epithelial cells and (4.63±0.72)% stromal cells retained BrdU labeling respectively, which were considered to be epithelial and stromal LRCs. Both the epithelial LRCs and the stromal LRCs were mainly located in the boundary of the lesions. LRCs did not co-express CD34. CD146 co-expressed on a few stromal LRCs. Conclusion Two kinds of stem cells were identified successfully in ectopic endometrium by label-retaining cell approach, which were epithelial and stromal LRCs, both located in the boundary of the lesions. It seems that CD34 is not the marker for ectopic endometrial stem cells. CD146 maybe the candidate marker for ectopic endometrium but without specificity.