表皮干细胞体外分离与培养

SEPARATION AND CULTURE OF EPIDERMAL STEM CELL in vitro

探索和建立表皮干细胞体外分离与培养的技术方法。通过酶消化法获得幼鼠表皮 ,并制成单表皮细胞悬液 ,以表皮干细胞培养基 ,即无钙EMEM培养基 (添加 9%FBS ,0 0 5mmol/LCaCl2 ,4ng/mlEGF ,0 5ng/ml硫酸庆大霉素及 5 0 %成纤维细胞条件培养基 )置细胞培养箱内培养。成纤维细胞条件培养基为无钙EMEM培养基(添加 9%FBS、0 0 5mmol/LCaCl2 、0 5 μg/ml硫酸庆大霉素 )培养幼鼠皮肤块 4 8h后所得培养液。将 1×10 6/ml上述培养的角质形成细胞经TGG细胞消化液 37℃下振荡消化后 ,接种至鼠Ⅳ型胶原包被的培养瓶内 ,37℃下静置 10～ 15min,留用快速贴壁细胞继续培养 ,所得细胞分别以能否呈克隆状生长和透射电镜观察其超微结构及β1整合素、K19免疫细胞化学染色进行鉴定。结果显示 ,鼠Ⅳ型胶原包被的培养瓶内快速贴壁细胞经继续培养 ,可见细胞呈克隆状生长。电镜观察其超微结构示非成熟细胞特征 ,β1整合素、K19免疫细胞化学染色阳性。研究表明 ,表皮干细胞可在体外分离与培养 ,本实验方法为较好方法之一。

To investigate the culture method for epidermal stem cell in vitro. Rat skin was peeled from the subcutaneous tissue gently, and cut into small pieces, then incubated for 24h in 0 25%trypsin in a 4℃ shaker. The epidermis was separated from the dermis, and shaken for 10min in 0 25% trypsin at 37℃ to dissociate into single cells. Digestion was terminated by the addition of culture medium +10% serum, and the cells were gently centrifuged and resuspended in the culture medium, which constituted EMEM without calcium, supplemented with 0 05mmol/L CaCl 2 , 9% chelexed FBS, 4ng/ml EGF, 0 5μg/ml gentamicin, and 50% fibroblast conditioned medium (CM ). The CM ( EMEM without calcium, 0 05mmol/L CaCl 2 , 9% chelexed FBS, 0 5μg/ml gentamicin ) was collected from freshly isolated primary neonate fibroblast cultures after 48h, which were passed through a filter with 0 45μm pores, and stored at -20℃ for use. 1×10 6 /ml epidermal cells were incubated for 10～15min at 37℃ on dishes coated with collagen Ⅳ, then the nonadherent cells were rinsed off. The adherent cells were grown to confluency. Cultures were subcultured in a solution of TGG for 5～10min. Once free of the dish, cells were centrifuged, resuspended in fresh medium, and then cultured at 1×10 5 /ml. Cultures were observed for colony formation under a phase contrast microscope, and the structure of the rapidly adherent cells was observed under electron microscopy; the expression of β 1 integrin and K19 was detected in the rapidly adherent cells and colony cells with SP immunohistochemical methods. The results showed that the cells selected by rapid adherence to collagen type Ⅳ formed large colonies at 7 days, and showed a im mature feature under electron microscopy, manifesting β 1 integrin and K19 expression. It is suggested that epidermal stem cells could be cultured in vitro .