The Expression of Markers Related to Ovarian Germline Stem Cells in the Mouse Ovarian Surface Epithelium and the Correlation with Notch Signaling Pathway.

BACKGROUND/AIMS Ovarian germline stem cells (OGSCs) have been shown to mainly exist in the ovarian surface epithelium (OSE), but the activity changes of germline stem cells during different reproductive stages and the potential regulatory signaling pathway are still unknown. The Notch signaling pathway plays a key role in cell development, primordial follicles and stem cell proliferation. However, whether it plays a role in the proliferation of OGSCs is unknown. Here, we analyzed the activity changes of germline stem cells and the correlation between germline stem cells and the Notch signaling pathway. METHODS The expression of germline stem cell markers Mvh, Ooc4 and the Notch molecules Notch1, Hes1, and Hes5 were detected during 3 days (3d), and 2, 12, 20 months (2m, 12m, 20m) mouse ovarian surface epithelium samples. DAPT, a specific inhibitor of the Notch pathway, was used to observe the influence of Notch signaling in the germline stem cells. RESULTS The results showed that the levels of MVH and OCT4 decreased substantially with reproductive age in ovarian surface epithelium, and the same tendency was detected in the Notch signaling molecules Notch1, Hes1 and Hes5. Dual-IF results showed that the germline stem cell markers were co-expressed with Notch molecules in the ovarian surface epithelium. While, the expression of MVH and OCT4 were reduced when the ovaries were treated with DAPT and the levels were attenuated with increasing dose of DAPT. CONCLUSION Taken together, our results indicate that the viability of OGSCs decreased with the age of the mouse ovaries, and the activity of OGSCs in the ovarian surface epithelium may be related to the Notch signaling pathway.