202305Nakao

研究発表を行った学会；36th International Mammalian Genome Conference
2023年3月29-31日　（つくば国際会議場/オンライン ハイブリッド開催）
タイトル； Efficient production of in vivo fertilized oocytes from female mice by treating inhibin antiserum and gonadotropins.
発表者；中尾　聡宏氏
（熊本大学　生命資源研究・支援センター　資源開発分野）
要旨；
Laboratory mouse ovulates 8 to 10 oocytes and almost all oocytes are fertilized by natural mating. Previously, we developed a high-yield technique for superovulation using inhibin antiserum and equine chorionic gonadotropin (IASe) that produces 100 oocytes from a single female mouse at 4 weeks old. However, after mating with the superovulated female mouse using IASe, only about 20 oocytes were fertilized. To overcome the limitation of in vivo fertilization, we examined the optimal condition to mating with the superovulated female mouse using IASe. In this study, we examined the effects of ovulation and mate timing on fertilization rate. First, we checked the ovulation timing and classified the three periods, pre-, during-, and post-ovulation. Mated female mice at during- and post-ovulation showed higher fertilization rates than female mice at pre-ovulation. The number of embryos obtained at post-ovulation was three times higher than at pre-ovulation. After embryo transfer, the fertilized oocytes were normally developed into live pups. These results suggested that synchronizing the timing of ovulation and mating increased the efficacy of fertilization in superovulated female mice. This technique will be applicable to efficiently produce in vivo fertilized oocytes used for making genetically modified mice and achieve the reduction of animal numbers following the 3Rs principle.