Abstract: Objective To investigate the biological characteristics of epithelial cells from different segments of hair follicle and localization of follicular stem cells. Methods The epithelial cells of hair follicles were cut into three parts:upper segment, lower segment and bulb, they were dispersed to single cells by 0.125% trypsin and 0.02% EDTA, then cultured respectively on a feeder cell layer of human dermal fibroblasts, and passaged or organotypically cultured on collagen gel of fibroblasts. Results The keratinocytes from upper segment grew best, with the most numerous colonies and passage-times. The bulb cells grew worst. A few of keratinocytes from lower-segment showed continuing growth colonies. When cocultured on collagen gel of fibroblasts, the keratinocytes from upper-segment formed a piece of well differentiated epidermis. Conclusion The keratinocytes from the upper-segment of hair follicle have the strongest proliferative potntial and best differentiation ability which support the hypothesis that the steem cells of follicle are localized in the bulge area.

Key words: Hair follicle, Stem cell