胎儿和出生后机体皮肤内转化生长因子-β_1基因表达的变化

Expression characteristics of transforming growth factor-β_1 in human skin at different development stages of gestation

目的 探讨转化生长因子 β1 (TGFβ1 )及其转录因子 sm ad2和 smad3基因在不同胎龄的胎儿和出生后机体皮肤组织中表达的变化特征及其可能的生物学意义。方法 用病理学技术检测不同发育时期皮肤的结构特征后 ,提取 18例不同胎龄 (13～ 32周 )的胎儿皮肤和 6例出生后机体皮肤组织的总 RNA后 ,分离 m RNA,用逆转录聚合酶链反应 (RT PCR)方法检测这 3种基因在不同组织中的表达变化规律。结果 TGFβ1 、smad2和 smad3基因在不同发育阶段的皮肤组织中都有表达。在早期妊娠胎儿的皮肤组织中 ,TGFβ1 和 smad2基因表达较弱 ,随着胎龄的增加 ,皮肤组织内这两种基因表达逐渐增强 ,在出生后机体的皮肤组织中 ,这两种基因的表达量分别为妊娠早期皮肤的 1.3倍和 5 .9倍 ,基因表达显著升高 (P<0 .0 5 )。smad3基因的表达呈不同的变化规律 ,在妊娠早期的皮肤组织中 ,该基因的表达较强 ,随着胎儿的生长发育 ,该基因表达逐渐降低 ,而在出生后机体的皮肤组织内 ,smad3基因表达产物的灰度值又升至 0 .2 72±0 .0 2 2 ,与早期妊娠胎儿皮肤相比差异不明显 (P>0 .0 5 )。结论 TGFβ1 、sm ad2和 smad3基因在不同发育阶段人皮肤组织内都有表达 ,显示 TGFβ1 介导的信号通路可能对皮肤的发生、结构功能的维持以及伤后修复?

ObjectiveTo investigate gene expression of transforming growth factorβ_1 (TGFβ_1) and its two upstream signalling factors (smad2 and smad3) in fetal skin at different gestational ages and postnatal skin and its potential biological significance. MethodsFetal skin samples of human embryo were obtained from spontaneous abortions at different gestational ages ranging from 13 to 32 weeks ,and also skin collected from patients undergoing plastic surgery. After morphological characteristics of skin at different developmental stages were examined histologically,gene expressions of TGFβ_1,smad2 and smad3 in skin specimens at different developmental stages were examined with reverse transcriptionpolymerase chain reaction analysis (RTPCR). ResultsGene expression of TGFβ_1,smad2 and smad3 could all be detected in fetal skin and skin after birth. In skin from early gestational fetus,gene expressions of TGFβ_1 and smad2 were weak. Along with advance in gestational age,gene expression of these two genes in skin became progressively stronger. In skin from late gestational fetus and skin after birth,the transcription contents of these two genes were significantly increased compared with early gestation fetus (P<0.05). On the contrary ,gene expression of smad3 was apparently higher in younger fetal skin versus elder compared with that of late fetal skin (P<0.05). In skins after birth,the levels of smad3 gene expression was elevated to the level similar to that in early gestational fetal skin. ConclusionThe signal pathway mediated by TGFβ_1 might be involved in regulating development of the skin at embryonic stage and in designating cutaneous structure and function,and also in wound healing after birth. The relative lack in expression of TGFβ_1 and smad2 genes in skins from younger fetuses might contribute to fetal scarless healing,in which the role of smad3 needs to be further investigated.