表皮细胞生长因子治疗创面出现的干细胞岛现象

Epidermal growth factor induce the epithelial stem cell island formation in the regenerated epidermis

目的 从细胞分化角度研究皮肤干细胞分布与增殖分化特征 ,以及这些特征在加速受创皮肤再生中的作用。方法 取 8例经重组人表皮细胞生长因子 (rhEGF)治疗而愈的溃疡创面皮肤 ,7例经磺胺嘧啶银治疗而愈的创面皮肤以及 3例流产胎儿、3例儿童和 2例正常成人皮肤 ,用过氧化酶标记的链霉卵白素 (SP)免疫组化法研究 β1整合素、角蛋白 19(K19)、角蛋白 14(K14)以及角蛋白 10(K10 )的表达特征。结果 免疫组织化学染色显示 ,经rhEGF治疗的创面表皮干细胞和短暂扩充细胞不仅数量多 ,而且体积增大 ,在再生表皮基底层与角质层之间出现若干干细胞岛。这些干细胞岛的特征是 β1整合素和K19染色阳性 ,在组织学上与基底层干细胞没有直接联系 ,为一类独立的岛状结构。经K14与K10等系列染色鉴别研究表明 ,在正常成人、青少年、胎儿以及未用rhEGF治疗的对照创面皮肤均未发现类似的干细胞岛现象。结论 在经rhEGF治疗的创面表皮中出现的干细胞岛是一种特殊和独立的细胞学结构 ,可能由已经分化成熟的细胞逆分化而来。其机制涉及生长因子对细胞分化调控等诸方面。

Objective To explore the cell reversion and epithelial stem cell distribution in skins from different developed stages and regenerated epidermis treated with rhEGF. Methods Tissue biospies from 8 regenerated ulcer skins treated with recombinant human epidermal growth factor (rhEGF) were used to evaluate the cell reversion and stem cell distribution in epidermis . The expression of β1 integrin, keratin 19 (K19), keratin 14 (K14) and keratin 10 (K10) in skin was detected with Streptavidin/Peroxidase (SP) immunohistochemical methods. Another 15 biopsies including 7 cases from the regenerated epidermis treated with SD Ag, 3 cases from fetus (24 weeks), 3 cases from children and 2 cases from adults were used as the controls. Results Immunohistochemical stain from β1 integrin and keratin 19 showed that there were some stem cell islands in epidermis treated with rhEGF. These cells were small and exhibiting positive expression with β1 integrin and K19 stain. They were isolated, bearing no anatomic relation with the epithelial stem cells in the basal layer. The serial identification experiments indicated that there were no similar stem cell islands in skins from normal adult skin, fetus or child′s skin and the regenerated epidermis treated with SD Ag. All of these results supported that these β1 integrin and K19 positive stain cells were the stem cells. Conclusions The results indicated that these stem cell islands were the specific and individual cell structures in rhEGF treated wounds. There is a possibility that these cells come from the cell reversion from differentiated cells to undifferentiated stem cells.