Effect Of Embryo Deferred Implantation On Pregnancy Outcome In Mice

According to the world health organization(WHO)predicts what infertility will become the third largest disease only to tumors and cardio-cerebrovascular diseases.At present,although assisted reproductive technology has become an important means of treatment of infertility,however,its success rate is still remains at 40% ~ 50% level,final birth rate is 1 ~5% in the animal’s somatic cell nuclear transfer technology.The blastocyst implantation failure is a key link in limits application process of these technologies.The blastocyst implantation is an extremely complicated and delicate maternal-fetal interaction process,it involving multiple the continuous dynamic physiological events and these physiological events must be synchronous coordination.The blastocyst implantation requires both an activated blastocyst,also need the receptive uterus,and both must be synchronized in order to complete physiological processes of blastocyst apposition,attachment,invasion,development and differentiation.Successful implantation is a key link in embryo development and pregnancy outcome.In mammals including humans,implantation failure is a major factor that low pregnancy rate.Clinical studies have shown that the average pregnancy success rate is about 30%,normal reproductive women within one menstrual cycle.Only 50 ~ 60% early pregnancy embryos can develop to 20 weeks in successful ovulation and pregnancy,implantation failure has been considered as the major cause,reaching approximate 70%.Therefore,this study focused on the effects of embryo delayed implantation on pregnancy,explore its pathogenesis and study and reveal molecular basis of embryo implantation time and establish and maintain of early pregnancy a physiological regulation mechanism in for further.To solve the high abortion rate and low birth rate after embryo transfer for provide the theoretical basis,to improve animal reproductive efficiency for increase the economic benefit,and to provide technical support for the protection of the endangered animals.The blastocysts of the fourth day(d 4)pregnancy were transplanted into the receptor d 4,d 5,and d 6 in the uterus by embryo transfer technology,observe the condition of pregnancy and statistics gestational lengths and litter size.24 h,48 h,72 h and 8 d after the transplantation respectively check the Numbers of the implantation site and placental absorb and placenta development.In addition,to check decidualization status by the artificial induced decidualization.To screen and verify d 4 and d 5 uterine genes by the Microarray and the real-timer RT-PCR method.According to the results of mouse embryo in delay 1 day(day 5)also can be induced implantation and decidual occurrence,and delayed 2 days will not be implanted.Compared with normal group(day 4),embryo absorb rate was obviously increased in delayed implantationgroup,and litter size significantly reduced and Prolonged pregnancy.The screened 284 differential expression uterine genetic by Microarray.Taken together,our findings suggest that the mouse embryos beyond uterine implantation window could also initiate implantation,but it lead to abnormal implantation spacing and abnormal placenta and then affects the pregnancy outcome.The uterine regulation may be the main factors of unequal implantation spacing and abnormal placenta.We have successfully established a reliable uterine genetic database at receptive and non-receptive in mice.