Urocortin在人足月胎盘合体滋养细胞表达的亚细胞定位

目的: 利用冰冻超薄切片免疫电镜技术, 观察研究urocortin在人足月胎盘合体滋养细胞上的表达与亚细胞定位。方法: 取材5例足月胎盘组织块固定在4%多聚甲醛液中, 每例标本分成两部分, 一部分做常规石蜡包埋切片, 免疫组化染色, 光镜下观察; 另一部分做冰冻超薄切片, A蛋白-金免疫标记, 透射电镜下观察。 结果: (1) 光镜下观察可见: urocortin主要分布在足月胎盘合体滋养细胞的胞质内。(2) 免疫电镜下观察可见: 抗urocortin金颗粒主要见于合体滋养细胞的粗面内质网上, 也见于细胞核膜上和细胞核内。结论: 足月胎盘的合体滋养细胞能合成和分泌urocortin, urocortin在胞质内合成后可内化（internalization）入胞核内, 提示人胎盘上作为肽类激素的urocortin可能存在“胞内分泌（intracrine）”现象。

Expression and subcellular localization of urocortin in syncytiotrophoblast of human term placenta

AIM: To obverse the expression and localization of urocortin on ultrathin cryosections of syncytiotrophoblast of human term placenta with immunocytochemistry technique under transmission electron microscope. METHODS: The human term placenta tissue from Cesarean delivery and normal labor were fixed in 4% paraformaldehyde, and then divided into two parts. One part was for regular immunocytochemistry under microscope, and the other part was used to prepare ultrathin cryosections for immunocytochemistry under transmission electron microscope. RESULTS: 1.Uroncortin mainly distributed in cytoplasm of syncytiotrophoblast of human term placenta under microscope. Urocortin also appeared in cytoplasm in some stromal cells. 2. Under transmission electron microscope, the anti-urocortin gold particles were observed in cytoplasm of syncytioptrophoblast ultrathin cryosections and sited on rough-surfaced endoplasmic reticulum. The anti-urocortin gold particles also appeared on nucleus and nuclear membrane of syncytiotrophoblast. CONCLUSION: Syncytiotrophoblast of human term placenta synthesized and secreted urocortin. The internalization of urocortin within syncytiotrophoblast nuclear indicates that urocortin may act as intracrine.