The Impact Of Ovarian Stimulation On Embryos Developmental Ability In Mice

Objective To observe the impact of ovarian stimulation on embryo development and implantation in mice. And to analysis the relationship between levels of the LIF protein and LIF mRNA and the implantation of embryos from stimulated and non-stimulated cycles.Methods To establish pregnancy models of mice which the transferred embryos are from stimulated and non-stimulated cycles. Compare the difference of fertility rate, cleavaged oocyte rate, good quality embryos rate, blastocysts rate, pregnancy rate, and implantation rate between the groups of stimulated and non-stimulated cycles, and the level of LIF protein and LIF mRNA on the day that the embryos were transferred were checked by immunohistochemistry and in situ hybridization respectively.Results The study showed that the ovarian stimulated mice have more oocytes /embryos developed, and have the same fertility rate, same cleavaged oocyte rate, but lower good quality embryos rate, lower blastocysts rate, lower pregnancy rate, and lower implantation rate when compared with the non-stimulated mice. The level of LIF protein and LIF mRNA on the day that the embryos were transferred were same when compared between the groups of psudopregnant recipient mice which the embyos transffered were from stimulated and non-stimulated cycles, the groups with one baby pregnancy and more than one baby pregnancy, but it had a higher level of LIF protein and LIF mRNA in the pregnancy group when compared with the group that had no pregnant.Conclutions Ovarian stimulation may impaire the developmental competence and the quality of oocytes / embryos, thus may reduce the pregnancy rate and implantation rate even if the psudopregnant recipient mice has the same levels of LIF protein and LIF mRNA on day 4 of psudopregnancy.