毛囊干细胞定位和体外向表皮分化

目的研究毛囊干细胞在毛发不同生长周期中定位和体外向表皮分化能力。方法采用免疫荧光染色检测皮肤组织中K19表达;分离毛囊干细胞并体外培养,以成纤维细胞为底物,采用气-液界面立体培养,形态学观察毛囊干细胞体外向表皮分化能力。结果K19阳性细胞主要定位于毛囊外根鞘。生长期毛发中,K19阳性细胞主要位于毛囊外根鞘膨突处和下部毛球部;退行期和静止期毛发中K19阳性细胞则沿毛囊外根鞘处连续分布,并在新的生长周期开始再次分开为两处。体外采用真皮类似物立体培养外根鞘细胞,获得具有多层表皮结构的皮肤类似物。结论毛囊干细胞主要定位于毛囊外根鞘,并随毛囊周期性生长有所迁移,体外具有形成表皮结构的能力。

Localization and differentiation of hair follicle stem cells

Objective To identify the localization of hair follicles stem cell (HFSC) in different stages of hair and explore the differentiating capacity of HFSC into epidermis in vitro. Methods HFSC were detected by K19 immunostaining in normal human skin. Then, the isolated HFSC through enzyme digestion were seeded on dermal equivalent (DE) and cultured between the air-liquid interfaces for 14 days. Skin-equivalents was harvested and used for evaluation. Results HFSC mainly located in outer root sheet in hair follicle and human anagen hair follicles containing two distinct reservoirs for K19-positive cells located in the bulge and bulb of the follicle. These two reservoirs fused in line of outer root sheets during the catagen-telogen transition phase and individualized again in the newly forming anagen hair follicle. Based on DE, growing HFSC built a multi-layered and confined epidermis. Conclusion HFSC located in outer root sheets can promote hair cycle and differentiate into epidermis in vitro.