The Role And Mechanism Of FOXO3a In Endometrial Decidualizaion During Early Pregnancy

Objective: Embryo implantation depends on the interaction between an active embryo and a receptive uterus,which is accompanied by decidualization.Decidualization of mice is endometrial stromal cells proliferate and differentiate into a special type of decidua cells,which provides support and nutrition for the development of embryo implantation.FOXO3a(Forkhead box O3a)is a highly conserved transcription factor involved in a variety of physiological processes,including cell growth,proliferation,and differentiation.It was confirmed that FOXO3 a played an important role in the activities of various organs and cell proliferation and differentiation,but its role in the process of endometrial decidualization remains unclear.Therefore,our study aims to investigate the role of FOXO3 a in the process of mouse endometrial decidualization and its possible mechanism.Methods:1.Western blot and immunohistochemistry were used to detect the expression pattern of FOXO3 a in mice normal pregnancy model and pseudopregnancy model.2.The induced decidualization model of mice in vivo and induced decidualization model of primary endometrial stromal cells in vitro were established.Western blot,immunohistochemistry,immunofluorescence and RT-PCR were used to detect FOXO3 a expression after induced decidualization in vivo and in vitro.In the above model,FOXO3a-siRNA was used to detect the expression of decidualization markers,and to explore whether knocking down the expression of FOXO3 a could affect endometrial decidualization.3.The artificial induced decidualization model in vivo and the induced model of primary endometrial stromal cells in vitro using FOXO3a-siRNA was established.Western blot,immunohistochemistry,RT-PCR and flow cytometry were used to detect cell proliferation and apoptosis.4.FOXO3a-siRNA was used in the normal pregnancy mice model to observe the number of embryos on day 7 of pregnancy in mice,and detected the decidualization related markers and cell proliferation or apoptosis by molecular biology methods.Using normal pregnancy model to detect FOXO3 a adjusting the endometrial decidualization again.Results:1.Western blot and immunohistochemistry showed that FOXO3 a expression was significantly higher on days 4 to 7 of pregnancy in mice than on day 1 of pregnancy,and the expression of FOXO3 a was significantly higher at the implantation site than the inter implantation site at the same day of pregnancy.The expression of FOXO3 a at the implantation site was mainly expressed in uterine stromal cells and glandular epithelial cells.The results of the pseudopregnancy model showed that FOXO3 a expression was also significantly increased on day of 6 of pseudopregnancy compared with the first day of the pseudopregnancy.2.FOXO3 a expressed significantly up-regulated after induced decidualization in vivo and vitro.The side of induced decidual uterus injected FOXO3a-siRNA was lack of swelling in mice.The expression of ALPL,a marker of decidualization,was significantly impaired.Consistent with the results in vivo,knocking down the expression of FOXO3 a in primary mouse endometrial stromal cells through FOXO3a-siRNA in vitro,the decidualization related marker MMP9,BMP2 and MMP2 were significantly down-regulated,proliferation-related protein Ki67 and PCNA were significantly up-regulated,and apoptosis-related proteins PARP,Bax,caspase-3,Cleaved caspase-3,bcl-2 and Fas were significantly down-regulated.3.Knocking down the expression of FOXO3 a by injecting FOXO3a-siRNA in vivo,the number of embryos on day 7 of pregnancy was significantly reduced,and resulted in abnormal pregnancy.Further detection revealed that the expression of decidualization related marker BMP2 was significantly down-regulated,the expression of proliferation-related proteins Ki67 and PCNA were up-regulated,the expression of apoptosis-related proteins Bcl-2 and Fas were decreased,the cell apoptosis was significantly down-regulated.Conclusion: FOXO3 a could maintain the process of decidualization in mice,and it's related to the cell apoptosis.