Reduced uterine receptivity for mouse embryos developed from in-vitro matured oocytes

Purpose: The outcomes of in-vitro maturation (IVM) are inferior compared to those of IVF. The purpose of the study was to compare the implantation rates of IVM- and in-vivo maturation (IVO)- derived embryos, and to evaluate their effects on uterine receptivity. Methods: The IVM- and IVO- oocytes were obtained from female mice, fertilized and transferred to separate oviducts of the same pseudo-pregnant mice. After 5 days, the implanted blastocysts were dissected out of the uterine horns, and the uterine horns were analyzed for the expression of mRNAs encoding leukemia inhibitory factor, heparin-binding epidermal growth factor, insulin-like growth factor binding protein-4, progesterone receptor, and Hoxa-10. Results: The maturation rate of the IVM- oocytes was 81.2 %. The fertilization rate of the IVM oocytes was lower than that of the IVO oocytes (50.5 % vs. 78.0 %, p = 0.038), as was their implantation rate (14.5 % vs. 74.7 %, p <0.001). All 5 mRNAs examined were expressed at significantly lower levels in the uterine horns that received the IVM-derived embryos than in those that received the IVO-derived embryos. Conclusions: The IVM-derived embryos are less competent in inducing expression of implantation-related mRNAs in the uterine horn.