中文摘要：

目的：研究基质金属蛋白酶-9（MMP-9）、基质金属蛋白酶-2（MMP-2）及其组织抑制因子（TIMP-2）在不同胎龄的胎儿皮肤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胎儿皮肤的结构特征后，提取18例不同胎龄（13～33周）的胎儿皮肤总RNA后，分离mRNA，用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：MMP-9、MMP-2和TIMP-2基因在不同发育时期的胎儿皮肤组织中的表达变化规律相似。在早期妊娠胎儿皮肤中，这3种基因表达较弱，随着胎儿生长发育，MMP-9，MMP-2和TIMP-2基因表达逐渐增强，妊娠晚期的皮肤组织内，这3种基因表达产物的灰密度比值分别是妊娠早期的8．8、2．4和3．1倍，基因表达水平显著升高（P〈0．05）。结论：MMP-9，2和TIMP-2对皮肤的生长发育、结构功能的维持以及创面修复具有重要的调节作用。妊娠早期，TIMP-2基因低表达可能与胎儿皮肤创面无瘢痕愈合相关，而妊娠晚期皮肤中TIMP-2基因表达增强可能是创面愈合后形成瘢痕的机制之一。

英文摘要：

Objective： To explore the change in gene expression in matrix metalloproteinases （MMP-2, MMP-9） and tissue inhibitor of metalloproteinase-2 （TIMP-2） in fetal skin at different developmental stages, and their potential biological significances. Methods： Human fetal skin biopsies were obtained from spontaneous abortion at different gestational ages from 13--33 weeks. After morphological characteristics of skin at different developmental stages were detected with routine pathological methods, gene expression of MMP-9, MMP-2 and TIMP-2 was respectively determined with reverse transcription-polymerase chain reaction（RT-PCR）. Results： The changeable tendencies of gene expression of MMP-9, MMP-2 and TIMP-2 were similar in different skin specimens at various developmental stages. In early gestational fetal skin, genes of MMP-9, MMP-2 and TIMP-2 were weakly expressed. Along with fetal skin development, the expression levels of these 3 genes were progressively increased. In late gestational skin, the expression levels of MMP-9, MMP-2 and TIMP-2 were significantly increased （P〈0.05）, while the gray ratios of transcripts of these 3 genes were 8.8, 2.4 and 3.1 times of those in early gestational skin respectively. Conclusion： The endogenous MMP-9, 2 and TIMP-2 might be involved in fetal skin development and in maintenance of cutaneous structure and function, and also in wound healing. Lower gene expression of TIMP-2 in early gestational skin may be the underlying mechanism of the scar-free healing, while higher gene expression of TIMP-2 might be associated with scar-forming healing in late gestational skin.