少儿瘢痕组织和正常皮肤表皮干细胞增殖分化特征的比较研究

A COMPARATIVE STUDY ON THE PROLIFERATION AND DIFFERENTIATION CHARACTERISTICS OF EPIDERMAL STEM CELLS IN NORMAL SKIN AND SCAR OF CHILDREN

研究少儿增生性瘢痕组织和正常皮肤表皮干细胞增殖分化特征与规律的差异 ,探讨这些差异与烧伤后创面瘢痕愈合的关系。采用免疫组织化学Elivision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。结果显示 ,少儿增生性瘢痕组织表皮基底层表达β1整合素与K19的阳性细胞数较健康皮肤明显减少 ,阳性强度降低。其瘢痕组织表皮中表达K14的阳性细胞仅位于表皮底部 2～ 3层 ,明显少于健康皮肤 ,而K10表达阳性细胞则较健康皮肤分布广泛。提示少儿增生性瘢痕组织表皮基底层干细胞和短暂扩充细胞明显少于健康皮肤 ,且其瘢痕组织表皮干细胞的分化过程与健康皮肤不同 ,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。少儿瘢痕组织表皮的修复能力下降 ,细胞的分化行为紊乱 ,这可能是少儿瘢痕组织表皮结构与功能改变。

To study the location and expression characteristics of epidermal stem cells in normal skin and scar epidermis of children, and to explore the relationship between the differences of these two epidermal stem cells and wound healing after burn. β1 integrin and keratin 19 (K19) were used as the biochemical markers to identify stem cells and transit amplifying cell, keratin 14 (K14) and keratin 10 (K10) were used as the markers for post-mitotic cells and terminally-differentiated cells, respectively. Normal skin and scar tissue were obtained from children of 4 to 12 years of age. Elivision two-step immunohistochemistry was used. The results showed that in the immunostained tissue sections, the positive β1 integrin and K19 expression cells were observed in 2～3 layers above the basal layer, whereas K10 expression cells were observed in all epidermal cells except basal cell layer in the scar tissue. Observations revealed that the number of stem cells and transit amplifying cells were less in the scar tissue than that in the normal skin, the differentiation process of scar epidermal stem cells was different from that of normal skin, and the proportion between post-mitotic cells and terminally-differentiated cells was abnormal. The results indicated that the self-renewal ability of the scar epidermis was lowered, and the differentiation process of it was deranged, and this might be considered to be a reason of abnormality of structure and function of the epidermis of scar tissue, and its poorer ability in wound healing.