Svalander P C, Odin P, Nilsson B O, Obrink B
Department of Human Anatomy, University of Uppsala, Sweden.
Development. 1987 Aug;100(4):653-60. doi: 10.1242/dev.100.4.653.
A variety of cellular interactions is involved in the process of implantation of the mammalian embryo into the uterine tissue. Recent discoveries have demonstrated that intercellular recognition and adhesive events are governed by a class of cell surface molecules known as cell adhesion molecules (CAMs). In the present report, we have investigated the occurrence of the well-characterized cell adhesion molecule cell-CAM 105 on the surface of rat pre- and peri-implantation embryos of various stages. This was carried out by indirect immunofluorescence microscopy employing affinity-purified rabbit antibodies against cell-CAM 105. The embryonal stages investigated comprised morulae, normal day-4 blastocysts, and delayed and adhesive blastocysts obtained by using the method of experimentally delayed implantation. Cell-CAM 105 was absent in the early-morula stage, but in normal day-4 blastocysts and delayed blastocysts a specific staining for cell-CAM 105 was seen on the entire surface. However, adhesive-stage blastocysts exhibited a marked polarity with staining of the polar trophoblast cells. Scanning electron microscopy of adhesive-stage blastocysts revealed that the stronger staining of the polar region was not due to a greater number of microvilli on the polar trophoblast cells. Thus, it seems as if cell-CAM 105 is lost or masked from the surface of the mural trophoblast cells of adhesive-stage rat blastocysts. Since the mural trophoblast cells are the first to adhere to the uterine luminal epithelium during the onset of implantation and subsequently invade the uterine stroma, we suggest that the apparent downregulation of cell-CAM 105 in the mural trophoblast cells might be linked to the acquisition of trophoblast invasiveness.
多种细胞间相互作用参与了哺乳动物胚胎植入子宫组织的过程。最近的研究发现表明，细胞间识别和黏附事件受一类称为细胞黏附分子（CAMs）的细胞表面分子调控。在本报告中，我们研究了特征明确的细胞黏附分子细胞-CAM 105在大鼠不同阶段着床前和着床期胚胎表面的出现情况。这是通过间接免疫荧光显微镜法进行的，该方法使用了针对细胞-CAM 105的亲和纯化兔抗体。所研究的胚胎阶段包括桑椹胚、正常的第4天囊胚，以及通过实验性延迟着床方法获得的延迟囊胚和黏附囊胚。细胞-CAM 105在早期桑椹胚阶段不存在，但在正常的第4天囊胚和延迟囊胚的整个表面都可见到细胞-CAM 105的特异性染色。然而，黏附期囊胚表现出明显的极性，极性滋养层细胞有染色。黏附期囊胚的扫描电子显微镜检查显示，极性区域较强的染色并不是由于极性滋养层细胞上有更多的微绒毛。因此，似乎黏附期大鼠囊胚的壁滋养层细胞表面的细胞-CAM 105丢失或被掩盖了。由于壁滋养层细胞在着床开始时是最先黏附于子宫腔上皮并随后侵入子宫基质的，我们认为壁滋养层细胞中细胞-CAM 105的明显下调可能与滋养层侵袭性的获得有关。
