A Comparative Study on the Expression of Telomerase Reverse Transcriptase in Different Development Stages of Human Epidermal Stem Cells in vitro

Aim: The main reasons for limiting the replication and expansion ability of the adult stem cells in vitro are the loss of telomerase activity and the changes of related proliferation gene expression, in which telomerase reverse transcriptase(TERT) plays a key role. In this chapter, we focus on the isolation, culture and identification of the epidermal stem cells derived from human fetus, child and adult skins, and compare the TERT expression of the different developmental periods of the epidermal stem cells. Methods: The skin samples of child, adult and fetus were disposed with Trypsin-EDTA respectively. The epidermal stem cells were isolated and purified by means of the type IV collagen rapid adhering method and cultured in vitro using keratinocyte serum free medium contained epidermal growth factor and fetal bovine serum. The keratinocytes were used as the control groups. The colony forming efficiency were calculated. The β1 integrin, keratin19 and p63 transcription factor were detected by the immunocytochemical stain and the image quantitative analysis. Results: The cultured cells revealed colony growth, the colony forming efficiency of the epidermal stem cell is higher than the keratinocyte. The β1 integrin,k19 and p63 had positive expression in the epidermal stem cells but not the keratinocyte cells. The TERT expression level of the fetus epidermal stem cells was higher than that of the adult and the child. The detection of the average value of absorbance and positive area of each group exhibited that the value decreased with the age. Conclusion: The expression of TERT in the cultured human epidermal stem cells derived from human fetus, child and adult skins were all positive. And the expression intensity level was followed as the period of the fetus, the child and the adult. It showed that the induction and the reinforcement of the telomerase reverse transcriptase activity may have important influence in the maintenance of the self-renewal and proliferation ability of the epidermal stem cell.