title: Pregnancy achieved by transferring blastocysts into endometrial stroma in mice.
abstract: To prevent the extra-uterine discharge of transferred embryos, we directly inserted mouse embryos into the endometrial stroma (intra-endometrial embryo transfer). A 27G injection needle was inserted near the utero-tubal junction into the endometrial stroma. After removal of the needle, a glass micropipette was inserted and one embryo was transferred with a very small amount of culture medium. To determine the feasibility of this method, the uterine lumen was flushed with phosphate-buffered saline from the tubal ends immediately after transferring blastocysts into pseudopregnant mice on day 2 and day 4. The rates of recovery of embryos from the uterine lumen were 5.0% (1/20; day 4) and 15.0% (3/20; day 2). These results suggest that a high rate of intra-endometrial embryo transfer is possible. The embryonic viability rates (number of viable grown fetuses/number of blastocysts transferred) of this method were 50.0% (28/56; day 4) and 25.0% (5/20; day 2). Living offspring were delivered from both recipients which had received embryos on day 2 and day 4 of pseudopregnancy. In human in-vitro fertilization and embryo transfer, attempts have also been made to immobilize the embryos, and this method might be clinically applicable. Moreover, this method will be a good in-vivo model for studies on the mechanism of implantation.
authors.affiliation: Department of Gynaecology and Obstetrics, Faculty of Medicine, Kyoto University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Goto
authors.forename: Y
authors.initials: Y
authors.lastname: Noda
authors.forename: K
authors.initials: K
authors.lastname: Narimoto
authors.forename: Y
authors.initials: Y
authors.lastname: Umaoka
authors.forename: T
authors.initials: T
authors.lastname: Tokura
authors.forename: T
authors.initials: T
authors.lastname: Mori
mesh_terms: D000034:Abortion, Veterinary / Q000517:prevention & control*; D000818:Animals; D001755:Blastocyst; D046508:Culture Techniques; D004624:Embryo Transfer / Q000379:methods*; D004717:Endometrium; D005260:Female; D051379:Mice; D008813:Mice, Inbred ICR; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*