Wooding F B
J Reprod Fertil Suppl. 1982 Nov;31:31-9.
Binucleate cells are found in the fetal trophectodermal epithelium of all ruminant placentas so far examined. They are present in fairly constant proportions from implantation to parturition. Light microscope investigations initially indicated that binucleate cells migrated across the feto-maternal junction, but subsequent electron microscope studies could find no evidence for this. The demonstration that placental lactogen in the sheep placenta is restricted to the binucleate cells prompted a re-examination of their function. The development of a selective stain for binucleate cells on electron microscope sections facilitated the demonstration that migration does occur in cows, deer, goats and sheep at all stages of pregnancy. Counts of the frequency of binucleate cells and their migration indicated that most, if not all, binucleate cells migrated, and supporting evidence was obtained using autoradiographic and immunocytochemical techniques. The result of the migration is fusion of a binucleate cell with a uterine epithelial cell or a syncytial layer. This fusion delivers the characteristic binucleate cell granules close to the maternal circulation while maintaining the trophectodermal barrier to other feto-maternal exchange. The ruminant binucleate cell therefore seems to play a central role in forming the structures and secretions at the feto-maternal interface which may be crucial in establishing and maintaining pregnancy.
在迄今所检查的所有反刍动物胎盘的胎儿滋养外胚层上皮中均发现了双核细胞。从着床到分娩，它们以相当恒定的比例存在。光学显微镜研究最初表明双核细胞会穿过胎儿 - 母体交界处迁移，但随后的电子显微镜研究并未找到相关证据。绵羊胎盘催乳素仅限于双核细胞这一发现促使人们重新审视它们的功能。在电子显微镜切片上对双核细胞进行选择性染色的技术发展，有助于证明在奶牛、鹿、山羊和绵羊的整个孕期各阶段均会发生迁移。对双核细胞频率及其迁移情况的计数表明，即便不是全部，大多数双核细胞都会迁移，并且利用放射自显影和免疫细胞化学技术获得了支持证据。迁移的结果是双核细胞与子宫上皮细胞或合体层融合。这种融合将特征性的双核细胞颗粒传递至靠近母体循环的位置，同时维持滋养外胚层对其他胎儿 - 母体物质交换的屏障作用。因此，反刍动物的双核细胞似乎在形成胎儿 - 母体界面的结构和分泌物方面发挥着核心作用，这对于建立和维持妊娠可能至关重要。
