Gulamhusein A P, Beck F
J Anat. 1975 Nov;120(Pt 2):349-65.
Light and electron microscopic observations on the development and structure of the extra-embryonic membranes of the ferret are described. By day 16 of pregnancy trophoblastic villi consisting of a cytotrophoblastic core with a peripherally located phagocytic syncytiotrophoblast have penetrated deeply into the endometrium. During its invasion the syncytiotrophoblast removes endometrial glandular cells and some of the adjacent stromal tissue. The maternal blood vessels remain intact and eventually become surrounded by the syncytiotrophoblast. A marked hypertrophy of the maternal capillary endothelium then begine. By day 28 the maternal capillary endothelial cells attain their maximum height. The cytoplasm of these cells contains numerous cisternae of rough endoplasmic reticulum and a well-developed Golgi apparatus, features which are typical of protein-secreting cells. The maternal blood vessels are separated from the syncytiotrophoblast by a thick layer of amorphous material which stains positively with PAS. Alcian blue staining in the presence of critical concentrations of magnesium chloride indicates the presence of both sulphated and carboxylated acid mucopolysaccharides. It may be that the amorphous material contributes significantly to the nutritional requirements of the developing fetus. Invaginations of the syncytiotrophoblast plasma membrane facing this amorphous layer are often seen. Coated vesicles and substances in contact with the outer surface of the membrane are therefore likely to be endocytozed. The acid phosphatase in the syncytiotrophoblast is consistent with the presence of lysosomes and catabolic function. Regions of paraplacental cellular trophoblast which lie in close association with the endometrium, but do not penetrate it, appear to specialize in endocytosis. The haemophagus organ, which is located at the antimesometrial pole, is the site of rupture of maternal blood vessels, and the extravasated blood lies in close association with the chorio-allantoic membrane. The maternal blood cells ingested by the trophoblast in this area are presumably an important source of iron for the embryo. The cellular trophoblast in the paraplacental regions is well equipped with hydrolytic enzymes, as shown by histochemical tests for acid phosphatase. It seems likely that these regions are concerned with embryotrophic endocytotic nutrition supplementing endothelio-chorial nutrition.
本文描述了雪貂胚外膜发育和结构的光镜及电镜观察结果。妊娠第16天时，由细胞滋养层核心和外周吞噬性合体滋养层组成的滋养层绒毛已深深侵入子宫内膜。在侵入过程中，合体滋养层清除子宫内膜腺细胞和一些相邻的基质组织。母体血管保持完整，最终被合体滋养层包围。随后母体毛细血管内皮开始明显肥大。到第28天时，母体毛细血管内皮细胞达到最大高度。这些细胞的细胞质含有大量粗面内质网池和发达的高尔基体，这些特征是蛋白质分泌细胞的典型特征。母体血管与合体滋养层之间被一层厚厚的无定形物质分隔开，该物质经PAS染色呈阳性。在临界浓度的氯化镁存在下进行阿尔辛蓝染色表明存在硫酸化和羧化酸性粘多糖。无定形物质可能对发育中胎儿的营养需求有重要贡献。经常可见合体滋养层质膜面向该无定形层的内陷。因此，与膜外表面接触的有被小泡和物质可能被内吞。合体滋养层中的酸性磷酸酶与溶酶体的存在和分解代谢功能一致。与子宫内膜紧密相连但不侵入其中的胎盘旁细胞滋养层区域似乎专门进行内吞作用。位于反系膜极的噬血器官是母体血管破裂的部位，外渗的血液与绒膜尿囊膜紧密相连。该区域被滋养层摄取的母体血细胞大概是胚胎铁的重要来源。胎盘旁区域的细胞滋养层富含水解酶，酸性磷酸酶的组织化学检测显示了这一点。这些区域似乎与补充内皮绒毛膜营养的胚胎营养内吞性营养有关。
