Abstract:

Objective    To screen reliable molecular markers for epidermal stem cells(ESCs) in mice by using the double immunofluorescence labeling technique and labelretaining cells(LRCs). Methods     The epidermis was labeled for 7 days with 5-bromodeoxyuridine(BrdU) in postnatal day 5(P5) mice, followed by a trace period of up to 12 weeks. The tissue of the mice was frozen and sliced in a frozen microtome after 90 days. Slices were stained with polyclonal antibodies of anti-β1 integrin, P63 and CD34 and monoclonal antibodies of anti-Brdu, and then observed under a fluoroscope. Results    After 90 days, few LRCs were found in a region of the outer root sheath adjacent to the insertion of the arrector pili muscle, known as the bulge region. The percentage of double immunofluorescence cytochemically stained β1 integrin-and BrdU-positive cells was 81% in all β1-positive cells, and 94% in all BdrU-positive cells. The percentage of P63-and BrdU-positive cells was 65% in all P63-positive cells, and 86% in all BdrU-positive cells. The percentage of CD34- and BrdU-positive cells was 30% in all CD34-positive cells, and 62% in all BdrU-positive cells. Conclusion    Among these molecular markers, β1 integrin, with highest accordance with BrdU, is the best molecular marker for ESCs, and P63 is the next best.

Key words: Label-retaining cells; Molecular markers for epidermal stem cells; Double immunofluorescence labeling technique