| ObjectiveIt is generally accepted that successful implantation is the result of reciprocal interactions between the implantation-competent blastocyst and receptive uterus. The endometrium is known to become receptive only for short periods in rodents; the timely arrival of the embryo at a receptive endometrium is crucial.More importantly, the maintenance and progression of decidualization in uterus is essential for implication.The implantation process is controlled by a number of complex molecules, such as hormones, cytokines, growth factors and so on. There were many literatures showed microRNAs regulated and affected a variety of biological processes, including development,tissue morphogenesis, maintenance of tissue identity, cell growth, differentiation, apoptosis, and metabolism. DICER and DROSHA are microRNA processing enzymes that are required for the maturation of miRNAs. So, the expression of them may affect the mature and expression of microRNA Because miRNAs play an important role in embryo implantation. So,we speculated Drosha and Dicer may also play a role in embryo implantation.On the female reproduction, death of early embryos and abnormal structure and function of the female reproductive system are observed after Dicer is knocked out in the mice.However, the expression of Drosha in mouse uteri and its role in the process of embryo implantation are still unclear.Our DGE analysis of mRNA expression revealed that Drosha mRNA in the mouse uterus at implantation sites was significantly higher compared to inter-implantation sites. We hypothesized that Drosha plays an important role in embryo implantation in mice. Here, we explored the expression condition of DROSHA in mouse uterus during early pregnancy, pseudopregnancy and in artificially induced decidualization stromal cells. In addition, we investigated whether P4 and E2 regulated the expression of DROSHA, and further investigated its function in the course of embryo implantation.Methods(1) Explore the expression of Drosha in mouse uteri during early pregnancy and pseudopregnancy using real-time quantitative PCR, immunohistochemistry and western blot. To explore the correlation of Drosha in the uterus of mice with the steroid hormones E2 and P4 by immunohistochemistry and western blot.(2) Investigate the expression of Drosha in mouse uterus after injection of the uterine horn with corn oil which was to induce decidualization.(3) At the same time, we established a mouse primary stromal cell culture system to further explore the role of Drosha in the decidualization of mouse uterine stromal cells.Results(1) The protein and mRNA of Drosha levels trended to be up-regulated around the implantation window and reached a peak on d6 of pregnancy.(2) Compared to inter-implantation sites (IIS) on d5 of pregnancy, the expression of Drosha was striking higher at implantation sites (IS).(3) Expression of Drosha in pseudocyesis mice was significantly lower than the normal pregnancy mice.(4) Expression of Drosha is regulated by P4 in the mouse uterus after the steroid hormone treatment.(5) DROSHA was expressed higher inartificially induced deciduas-lization compared with control.(6) The expression of Drosha and decidualization marker genes exhibited a similar upregulation in cultured decidualizing stromal cells.ConclusionThe results indicated that the expression of Drosha in mouse uterus has a spatio-temporal features during early pregnancy and pseudopregnancy. The high content of Drosha in mouse uteri during the implantation window and artificial induction of decidual model, in addition, Drosha was regulated by P4 which suggest that Drosha may be involved in the process of embryo implantation. Thus, we speculated that when the process of implantation occurs, the organism requires a large number of microRNAs to ensure a perfect pregnancy. DROSHA might play an important role in early pregnancy as a critical enzyme essential for post-transcriptional miRNA processing. |
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