Abstract: Abstract   Objective  To identify and locate adult stem cells in ectopic endometrium and to find its markers using the 5-bromo-2-deoxyuridine (BrdU) labeling method in mouse model of endometriosis. Method  The female nude mice were pulse labeled by BrdU for 5 consecutive days, 24h prior to the endometriosis model was established. The label-retaining cells(LRCs) were identified by getting BrdU labeling rate by immunohistochemistry on 4h，1w, 3w, 5w, 6w,7w，8w,9w when the last injection was finished. The expression level of CD34 and CD146 on LRCs were detected by double staining of immunohistochemistry. Result  The maxium BrdU labeling rate was 69.89±0.78% and 73.27±1.06% for epithelial and stromal respectively. After a 6-week and an 8-week chase, 2.07±0.19% epithelial cells and 4.63±0.72% stromal cells retaind 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 and the mice tissues where the lesion was implanted. The positive expression rate of CD34 and CD146 were 19.32±0.03% and 14.76±0.03% respectively. CD34 did not co-expressd on LRCs, 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 located in the boundary of the lesions and the mice tissues where the lesion was implanted. It seems that CD34 was not the marker for ectopic endometrial stem cells, whether CD146 can be the candidate marker for ectopic endometrial stem cells or not by combining with other markers deserving further research.

Key words: Endometriosis, stem cell, staining and labeling, bromodeoxyuridine, immunohistochemistry, antigens, CD34, 抗原