Goto Y, Noda Y, Shiotani M, Kishi J, Nonogaki T, Mori T
Department of Gynecology and Obstetrics, Kyoto University Faculty of Medicine, Japan.
J Assist Reprod Genet. 1993 Apr;10(3):197-201. doi: 10.1007/BF01239221.
The purpose of this study is to elucidate the fate of embryos transferred into the uterus.
Implantation rates were compared between synchronous and asynchronous intrauterine embryo transfers in mice. Then transferred embryos were recovered from the uterus and examined morphologically 24 hr after transfer. Moreover, the same transfer-recovery experiments were performed after ligation of the uterus two-thirds from the uterotubal junction immediately before transfer.
The implantation rate was high (58.4% per embryo, 87.5% per recipient) when blastocysts were transferred into the uteri of recipients of pseudopregnant Day 4, but it was very low (0-2.4% per embryo, 0-8.3% per recipient) when blastocysts were transferred to recipients of pseudopregnant Day 2, or two-cell embryos into recipients of pseudopregnant Days 2 and 4. When transferred embryos were recovered from the uterus 24 hr after transfer, few embryos (1.4%) were recovered in asynchronous transfers, while 66.3% of the embryos were recovered in synchronous transfers. However, from recipients in which the lower portions of uteri were ligated, embryos at more advanced stages were recovered even in asynchronous transfers.
These results suggest that discharge from the uterus is one of the major causes of the low implantation rate for asynchronous transfer.
本研究旨在阐明移植到子宫内的胚胎的去向。
比较小鼠同步和异步子宫内胚胎移植的着床率。然后在移植后24小时从子宫中回收移植的胚胎并进行形态学检查。此外，在移植前立即从子宫输卵管连接处结扎子宫三分之二后进行相同的移植-回收实验。
将囊胚移植到假孕第4天的受体子宫中时，着床率很高（每个胚胎58.4%，每个受体87.5%），但将囊胚移植到假孕第2天的受体中，或将二细胞胚胎移植到假孕第2天和第4天的受体中时，着床率非常低（每个胚胎0-2.4%，每个受体0-8.3%）。移植后24小时从子宫中回收移植的胚胎时，异步移植中回收的胚胎很少（1.4%），而同步移植中66.3%的胚胎被回收。然而，在子宫下部被结扎的受体中，即使在异步移植中也能回收更晚期的胚胎。
这些结果表明，子宫排出是异步移植着床率低的主要原因之一。
