【摘要】 利用电镜观察人胎盘绒毛的合胞体时，发现妊娠早期已有代表退化现象的合胞体结形成，此时合胞体结的核染色质分布均匀，近核区的粗面内质网渠扩大。从妊娠中期开始合胞体结的核染色质出现凝缩及边集，近核区粗面内质网渠扩大明显，并可见合胞体结游离面断裂及绒毛间隙有浓缩细胞核和部分胞质。发现提示合胞体细胞的凋亡是从形成合胞体结开始，再经过核染色质凝缩与边集及近核区粗面内质网渠的扩张，最后造成合胞体结游离面断裂及浓缩的核与部分胞质脱离合胞体更多还原

【Abstract】 Using electron microscope to study the fine structure of human placental syncytium, it was found that syncytial knots (SKs), which had heen considered as a degenerative phenomenon, were already formed during the early pregnancy. In SKs the nuclear chromatin was distributed diffusedly, and the cisternae of juxtanuclear rough endoplasmic reticulum (rER) were dilated. From the mid-pregnancy on, the nuclear chromatin of SKs was aggregated and condensed marginally. The cisternae of juxtanuclear rER were dilated distinctly. Breaks on the free surface of SKs were found occasionally. Condensed nuclei with a part of cytoplasm were visible in the intervillous space. These finding suggested that apoptosis of placental syncytium begins with the for-mation of SKs. After the aggregation and marginal condensation of the nuclear chromatin, and dilatation of the cisternae of juxtanuclear rER, free surface of SKs breaks up and the condensed nuclei with a part of cytoplasm escape out of the syncytium.更多还原