成人正常皮肤和瘢痕组织表皮干细胞定位与表达特征的研究

目的：观察成人正常皮肤和瘢痕组织中表皮干细胞定位与β1整合素和角蛋白19、14、10（K19、K14、K10）的表达，探讨两种组织表皮干细胞表达特征的差异。方法：取6例大面积深度烧伤患伤后1年的增生性瘢痕组织，另取6例健康志愿对应部位的全层皮肤。采用免疫组织化学Eivision两步法，检测表皮干细胞、短暂扩充细胞特异表达的β1整合素和K19以及分化表皮细胞表达的K14和K10。结果：瘢痕组织表皮基底层表达β1整合素与K19的阳性细胞数较正常皮肤明显减少，阳性强度降低，其表皮中表达K14的阳性细胞仅位于表皮底部2－3层，而K10表达阳性细胞则较正常皮肤分布广泛；瘢痕组织皮肤的分化过程亦不相同，处于有丝分裂后分化阶段的细胞比例降低，而终末分化细胞的比例明显增高。结论：瘢痕组织表皮的修复能力下降。细胞的分化行为紊乱，可能是导致瘢痕组织表皮结构与功能改变、愈合能力下降的原因之一。

Study on the location and the expression characteristics of epidermal stem cells in normal adult skin and scar tissue

OBJECTIVE: To investigate the different location and the expression characteristics of epidermal stem cells in normal adult skin and scar tissue. METHODS: Skin tissue specimens were harvested from the corresponding sites from 6 healthy volunteers and from scar tissue of 6 patients 1 year after major deep burn. beta1 integrin and keratin 19 (K19) were employed as the biochemical markers for stem cells and transit amplifying cells identification and keratin 14 (K14) and keratin 10 (K10) as markers for post-mitotic cells and terminally differentiated cells respectively. Integrin and keratin were determined by Elivision two-step immunohistochemistry. RESULTS: The expression of beta1 integrin and the K19 positive cell count in the epithelial basal layers of scar tissue were evidently decreased and weakened than those in normal adult healthy skin. Furthermore, the positive cells expressing K14 in epidermis of scar tissue were only located in 2 - 3 layers of basal epidermis, and their number was much less than that in normal adult skin. Whereas the cells positively expressing K10 were distributed wider in area than that in normal healthy skin. The epidermal stem cells and transit amplifying cells in scar epidermis were much less in number than that in normal skin. The differentiation process of scar epidermal stem cells was different from that of normal skin. And the proportions of post-mitotic cells and terminally differentiated cells were abnormal. CONCLUSION: The results indicated that the self-renewal ability of the scar epidermis was decreased, and the differentiation process of it was in disorder, which may be a reason for the abnormality of structure and function of the epidermis in scar, and a reason for the decreased ability of wound healing of scar tissue.