Denker H W, Tyndale-Biscoe C H
Cell Tissue Res. 1986;246(2):279-91. doi: 10.1007/BF00215890.
Embryo implantation remains superficial (epithelio-chorial type) in most marsupials including the Macropodidae, but does involve formation of specialized contact zones of the trophoblast with the uterine epithelium. Since in eutherian mammals proteinases appear to play a central role in implantation-initiation mechanisms, a systematic histochemical investigation of proteinase patterns as related to implantation was performed in the tammar wallaby, Macropus eugenii (Macropodidae). Tammar uteri with embryos were collected at diapause and at days 7, 17, 18, 19, 20, 21 and 26 of the 27-day gestational period. Proteinase patterns were studied using a sensitive histochemical gelatin-substrate-film test previously optimized for the detection of trophoblast-dependent proteinase (blastolemmase) in the rabbit. Proteinase patterns were correlated with light-microscopical morphology of the processes of shedding of the extracellular embryo coverings (shell membrane) and attachment of the trophoblast to the uterine epithelium. At acid pH values an intracellular proteinase is detected in yolk sac endoderm and trophoblast as well as in endometrial glands and certain stromal cells. This enzyme is proposed to be a cathepsin indicating high catabolic activity connected particularly with protein transport from the endometrium into the yolk sac. Peak activity is found in the avascular (bilaminar) yolk sac at the phase when contact with the endometrium is being established. A particularly interesting proteinase active at alkaline pH values is detected in the trophoblast-endoderm complex. This enzyme appears to be extruded into the interface between trophoblast and uterine epithelium where it shows maximal activity for only approximately one day, around day (18-)19, exclusively in the bilaminar (avascular) yolk sac. The activity is correlated with the process of shedding of the extracellular embryo coverings (shell membrane) and of subsequent attachment of the trophoblast to the uterine epithelium, in the bilaminar but not the trilaminar (vascular) yolk-sac region. This is the first report on an extracellular (alkaline) proteinase activity possibly serving a specific function in embryo implantation in a marsupial.
在包括大袋鼠科在内的大多数有袋类动物中，胚胎着床仍停留在表面（上皮绒毛膜型），但确实涉及滋养层与子宫上皮形成特殊的接触区。由于在真兽类哺乳动物中，蛋白酶似乎在着床起始机制中起核心作用，因此在袋狸（Macropus eugenii，大袋鼠科）中进行了一项与着床相关的蛋白酶模式的系统组织化学研究。在滞育期以及27天妊娠期的第7、17、18、19、20、21和26天收集带有胚胎的袋狸子宫。使用先前针对检测兔中滋养层依赖性蛋白酶（胚泡膜酶）进行优化的灵敏组织化学明胶底物膜试验研究蛋白酶模式。蛋白酶模式与细胞外胚胎覆盖物（壳膜）脱落以及滋养层附着于子宫上皮的过程的光学显微镜形态相关。在酸性pH值下，在卵黄囊内胚层、滋养层以及子宫内膜腺体和某些基质细胞中检测到一种细胞内蛋白酶。该酶被认为是一种组织蛋白酶，表明具有高分解代谢活性，特别是与蛋白质从子宫内膜转运到卵黄囊中有关。在与子宫内膜建立接触的阶段，在无血管（双胚层）卵黄囊中发现了峰值活性。在滋养层 - 内胚层复合体中检测到一种在碱性pH值下具有活性的特别有趣的蛋白酶。这种酶似乎被挤出到滋养层与子宫上皮之间的界面，在那里它仅在大约第（18 - ）19天左右在双胚层（无血管）卵黄囊中显示出约一天的最大活性。该活性与细胞外胚胎覆盖物（壳膜）的脱落以及随后滋养层在双胚层而非三胚层（血管）卵黄囊区域附着于子宫上皮的过程相关。这是关于一种细胞外（碱性）蛋白酶活性可能在有袋类动物胚胎着床中发挥特定功能的首次报道。
