TGF-β异构体及其受体在胎儿和成人皮肤中的表达

Expression of TGF-β isoforms and their type Ⅰ receptor in fetal and adult skins

目的 观察转化生长因子 β 3种异构体 (TGF β1,TGF β2和TGF β3)与其Ⅰ型受体TGF βR(Ⅰ )在胎儿和成人皮肤中的表达及其可能的生物学意义。方法 用免疫组化S P法检测这 4种蛋白在 14例胎儿和 6例成人皮肤中的定位和表达量。结果 在妊娠早期的胎儿皮肤中 ,TGF β1、TGF β2、TGF β3和TGF βR(Ⅰ )呈弱阳性表达 ,随着胎儿生长发育 ,这 4种蛋白的阳性细胞率逐渐增大 ,在后期妊娠胎儿和成人皮肤中这 4种蛋白表达明显升高。其中TGF β因子主要分布于表皮细胞、内皮细胞和部分成纤维细胞中 ,TGF βR(Ⅰ )则定位于表皮基底层细胞和部分成纤维细胞的细胞膜上。 结论 TGF β及其Ⅰ型受体可能对皮肤的发生、结构功能的维持以及伤后修复十分重要。在妊娠早期的胎儿皮肤中 ,TGF β1、TGF β2和TGF βR(Ⅰ )低表达可能与胎儿皮肤创面无瘢痕愈合相关。

Purpose To investigate the localization and expression three isoforms of transforming growth factor β (TGF β1, β2, β3) and their Ⅰ type receptor, TGF βR(Ⅰ), in fetal and adult skins. Methods Skins of 14 specimens of fetuses and 6 specimens of adults were taken, embedded with paraffin, and sectioned. Immunohistochemistry method was used to detect the expression intensity and distribution of these proteins. Results Positive immunohistochemical signals of TGF β1, β2, β3 and TGF βR(Ⅰ) could be found in fetal and adult skins. In skins derived from young fetus, the positive signals of these proteins were very weak. Along with the increment in gestational age, the positive cellular rates of TGF β1, β2, β3 and TGF βR(Ⅰ) in skins were elevated progressively. In elder fetal and adult skins, the positive cellular rates of these proteins were significantly raised compared with younger fetus. TGF β1, β2 and β3 were mostly distributed in epidermal cells, endothelial cells and some fibroblasts, while TGF βR(Ⅰ) was mainly located in the cellular membrane of keratinocytes and some fibroblasts. Conclusions The endogenous TGF β and TGF β R(Ⅰ) might be involved in the cutaneous development, the cutaneous structure maintenance and wound healing. The relative lack in protein contents of TGF β1,TGF β2 and TGF βR(Ⅰ) in skins of younger fetuses might be one of the reason why wounds in fetal skin are healed by regenerating rather than by scarring.