Parkening T A
J Anat. 1976 Nov;122(Pt 2):211-30.
Sixty six implantation sites from 18 golden hamsters were examined with light and electron microscopy between 4 and 5 1/2 days of pregnancy (post-ovulation). At 4 days some blastocysts began to invade the uterine epithelium, with trophoblastic processes penetrating and engulfing portions of the uterine epithelium. The majority of epithelial cells appeared normal before invasion, although at two implantation sites three or four adjoining epithelial cells were necrotic before penetration by the trophoblast. In general the epithelial cells were degenerating at the time the trophoblast invaded the epithelium. Inclusions, representing portions of the engulfed epithelium, and varying in size and electron density, were present throughout the invading trophoblast cells at 4 1/2 and 5 days of pregnancy. At 5 1/2 days the uterine epithelium had disappeared and the embryo was now almost completely surrounded by blood lacunae.
在妊娠4至5.5天（排卵后），对18只金黄仓鼠的66个植入部位进行了光镜和电镜检查。在4天时，一些囊胚开始侵入子宫上皮，滋养层细胞突起穿透并吞噬部分子宫上皮。在滋养层侵入之前，大多数上皮细胞看起来正常，不过在两个植入部位，有三四个相邻的上皮细胞在被滋养层穿透之前已经坏死。一般来说，当滋养层侵入上皮时，上皮细胞正在退化。在妊娠4.5天和5天时，代表被吞噬上皮部分的内含物大小和电子密度各异，存在于整个侵入的滋养层细胞中。在5.5天时，子宫上皮已消失，胚胎几乎完全被血窦包围。
