Konishi I, Fujii S, Okamura H, Mori T
J Anat. 1984 Sep;139 ( Pt 2)(Pt 2):239-52.
Prenatal development of uterine smooth muscle was studied by light and electron microscopy in specimens obtained from ten human fetuses between 12 and 40 weeks gestation. Light microscopical observation of transverse sections of the body of the uterus revealed that the outer, subserosal layer of elongated cells was distinguishable from 14 weeks. This layer was more cellular than the inner layer and increased its thickness with advancing age. Ultrastructurally, the mesenchymal cells of the uterus did not contain myofilaments until 16 weeks. At 18 weeks, however, spindle shaped cells in the outer layer had a few filaments with dense bodies and well developed organelles and were identified as immature smooth muscle cells. By 31 weeks, the cells in this layer developed into almost mature smooth muscle cells, which contained abundant cytoplasmic filaments, dense plaques and surface vesicles along the cell membrane, and an external lamina. Therefore, in the human fetal uterus, smooth muscle differentiation begins at about 18 weeks and myometrium is formed in the outer layer of the wall by 31 weeks gestation. In the inner layer of the uterus that corresponds to the endometrial stroma, in addition to fibroblast-like cells, there were cells with plump cytoplasm which contained well developed granular endoplasmic reticulum and Golgi apparatus and which were identified around blood vessels by 26 weeks. These features resembled those of predecidual cells, and suggested the influence of sex steroids on the human fetal uterus.
利用光镜和电镜对10例妊娠12至40周的人类胎儿标本进行子宫平滑肌的产前发育研究。子宫体横切面的光镜观察显示，14周起可区分出外层的浆膜下细长细胞层。该层细胞比内层更多，且随年龄增长厚度增加。超微结构上，子宫间充质细胞直到16周才含有肌丝。然而，18周时，外层的梭形细胞有一些含致密体的细丝和发育良好的细胞器，被鉴定为未成熟平滑肌细胞。到31周时，该层细胞发育成几乎成熟的平滑肌细胞，含有丰富的胞质细丝、致密斑和沿细胞膜的表面小泡以及一层外板。因此，在人类胎儿子宫中，平滑肌分化约在18周开始，到妊娠31周时肌层在子宫壁外层形成。在与子宫内膜基质相对应的子宫内层，除了成纤维样细胞外，还有细胞质丰满的细胞，其含有发育良好的粗面内质网和高尔基体，到26周时在血管周围被鉴定出来。这些特征类似于蜕膜前细胞，提示性类固醇对人类胎儿子宫有影响。
