The Effects Of Macrophages In The Mouse Uterus During Peri-implantation Period

BACKThere is a special immune micro-environment in the endometrium under the complex role of neural-endocrine-immune system during early pregnancy.lt can prevent from infecting pathogens,at the same time make endometrial receptivity and embryo development in the synchronization to help embryo implantation. The mechanism of maternal-fetal immune tolerance still is unclear,but it is certainly that immune cells play an important role in the embryo implantation.Macrophages as a permanent immune cells of uterus,have a significant roles in the maintenance of normal pregnancy.De et al reported that the number of macrophages in the uterus has changed in the estrous cycle and different pregnancy stages.Previous studies showed that the majority of macrophages in the endometrium mainly around the spiral arteries and glands which were the starting point of embryo implantation and deciduacation.But in the non-implantation regional,the proportion of macrophages accounted for lymphocytes significantly reduced.So it is speculated that macrophages in the uterus during peri-implantation endometrium,which distribute in the different space with the time of pregnancy and were enriched in the implantation sites,may be closely related to the decidualization of endometrium. F4/80 is a specific antigen of mature macrophages in the mice,usualliy localized in the cell of membrane and cytoplasm.And the NO in the endometrium has played an important role in follicular development,ovarian of hormone secretion,embryo implantation and maintenance of pregnancy.Because NOS is the only rate-limiting enzyme of NO, there is more research has focused on NOS.Inducible NOS,also as macrophage type,only expressed under the stimulate of cytokines and lipopolysaccharide,and comes from macrophages,glial cells and so on.The main role of NO is involved in inflammation and defensed against pathogens. So we select pregnancy mouse as the study object,to explore the changes of the number and distribution of F4/80-macrophage and iNOS around the period of implantation.There are a critical means in the study of mechanisms of maternal-fetal immune tolerance,moreover to provide a new way for transplantation immunology research in some extent.OBJECTIVEThe aim is to establish the pseudopregnancy mouse model during early pregnancy, and to study the changes of amount of macrophages in the uterus and peripheral blood and the expression of iNOS during peri-implantation period. By analyzing the difference between implantation sites and non-implantation tissue exploring the role of macrophages in the course of maternal-fetal tolerance.METHODSMatedals divided into two groups:control group (the male mice was ligated the vas deferens) and operated group.Using HE staining and electron microscopy to observe the uterine morphology and structure.Detection the macrophages by the methods of flow cytometry and immunohistochemistry in the blood and uterus to study the change and distribution of macrophages during early pregnancy.RESULTS 1. The results of morphology and HE staining in mouse uterus showed that the pseudopregnancy model was successful.2. The date of FCM found that the number of macrophages in operated group was significantly higher than in control group.3. The result of immunohischemistry showed that the positive macrophage not only change the amount but also the distribution.In control group,most macrophages were lie in endometrium.And before D4.5,the macrophage which mainly lied in endometrium and myometrium was in peak in group of D2.5 (P<0.05),and at the beginging of D4.5,the number of macrophage was significantly reduced (P<0.05) and gradually transferred to perimetrium.4. In control group,a lot of the iNOS-positive cells were lie in endometrium and myometrium.With the time of pregnancy goes by,the iNOS-positive cells which mainly lied in endometrium were in peak in group of D2.5 (P<0.05),and were lest of D6.5,and at the beginging of D4.5,the number of iNOS-positive cells were significantly reduced in perimetrium (P<0.05),but they were more than in control group.5. The difference of macrophage between implantation sites and non-implantation tissue was statistically significant (P=0.013),it was mostly lie in endometrium.But there were no difference of the amount of iNOS.CONCLUSIONSThe amount of macrophages in peripheral blood is increased significantly during peri-implantation. However, it is a little relationship between in peripheral blood and in the uterine.The result is suggest that the changes of macrophages in mouse uterus are different with in peripheral blood,macrophages in peripheral blood can not reflect the functional of uterine tissue.The positive cells of F4/80 and iNOS distribute the whole uterus,with the time gradually migrating to the myometrium and perimetrium from the endometrium.The high number of F4/80 and iNOS are decrease after embryo implantation. The result is suggest that the mouse of macrophages in early pregnancy may be involved in endometrial receptivity and immune tolerance in the formation of maternal interface when the embryo implantate.The number of F4/80 and LIF in mouse uterine implantation sites are significantly higher than that of the non-implantation sites, the result may suggest that macrophages play an important role in the couse of choose embryo site.