Makabe S, Naguro T, Heyn R, Motta P M
Department of Gynaecology and Obstetrics, Toho University School of Medicine, Tokio, Japan.
Ital J Anat Embryol. 1995;100 Suppl 1:525-33.
The ultrastructure of human Leydig cells at different stages of the testicular prenatal development is described by means of transmission and scanning electron microscopy. Between 5 and 7 weeks of gestation (w.g.) the interstitial tissue of the gonad is filled with small undifferentiated mesenchymal cells, migrating primordial germ cells and blood vessels. When the embryo is 7 to 8 weeks-old Leydig cells (LC) appear in basically two morphological patterns, light and dark cells. Their most significative feature is the development of the smooth endoplasmic reticulum (SER) as a dense tubulo-vesicular network and the presence of numerous pleomorphic mitochondria with mainly lamellar cristae. At 14 and 16 w.g. the testicular interstitium reaches the maximum development; the cytoplasm of the LC shows a widespread network of anastomosing tubules of the SER and mitochondria with tubular cristae. Fetal LC show a partial cell coat, lack the crystals of Reinke, have few lipid droplets and show no signs of massive cell degeneration, at least until 16 w.g. These ultrastructural modifications in fetal LC are in accordance with the changes in both steroidogenic activity and hCG levels reported by the literature to occur at this stage of development. Junctional complexes were often observed among LC from 7 to 8 w.g. onwards.
通过透射电子显微镜和扫描电子显微镜描述了人类睾丸产前发育不同阶段的睾丸间质细胞的超微结构。在妊娠5至7周（w.g.）时，性腺的间质组织充满了小的未分化间充质细胞、迁移的原始生殖细胞和血管。当胚胎为7至8周大时，睾丸间质细胞（LC）基本上以两种形态模式出现，即亮细胞和暗细胞。它们最显著的特征是滑面内质网（SER）发育为密集的管状-泡状网络，以及存在大量主要具有板层嵴的多形线粒体。在14和16 w.g.时，睾丸间质达到最大发育；LC的细胞质显示出广泛的SER吻合小管网络和具有管状嵴的线粒体。胎儿LC显示出部分细胞被膜，缺乏雷氏晶体，脂质滴很少，并且至少在16 w.g.之前没有大量细胞变性的迹象。胎儿LC的这些超微结构改变与文献报道的在此发育阶段发生的类固醇生成活性和hCG水平的变化一致。从7至8 w.g.起，经常在LC之间观察到连接复合体。
