The Role Of T-Lymphoma Invasion And Metastasis Inducing Protein 1 In Early Pregnancy In Mice

Background:Blast cyst implantation is one of the earliest events in reproduction of humans and mammals that determines whether pregnancy will develop successfully. Successful implantation depends on invasive blastocyst, acceptive endometrium and their synchronization. There is a short period defined'window'of uterine receptivity for implantation, the so-called"implantation window". Implantation in all mammals involves shedding of the zona pellucida, followed by orientation, apposition, attachment and adhesion of the blastocyst to the endometrium. The regulation of early embryo development and the detailed molecular mechanism of implantation by which embryos invade into the uterus remains poorly understood, due to the large number of genes and the complexity of the systems involved. The large number of researches showed that there were striking similarities between normal embryonic development and neoplasm metastasis, proto-oncogene and tumor suppressor gene are becoming hot spot in blastocyst implantation.T-lymphoma invasion and metastasis inducing protein 1 (Tiam1) is involved in tumorigenesis processes, including cell migration, adhesion and invasion, proteolysis, cytoskeleton reorganization, cell morphological transformation and intracellular signaling. These processes are also critical for embryo implantation, although the role of Tiam1 during embryo implantation remains poorly understood. The aim of this study was to investigate the spatio-temporal expression of Tiam1 in endometria of mice comparing early pregnancy and non-pregnancy. Fluorescent quantitative-PCR, immunohistochemical and Western blotting analysis showed that the expression of Tiam1 mRNA and protein in endometria of pregnant mice was higher than that of non-pregnant mice, and gradually increased from day 1 of pregnancy, reached a maximum level on day 5 and then declined on day 6 and day 7. Immunohistochemistry showed that Tiam1 protein was present in luminal epithelium from days 3–5 of pregnancy and in gland epithelium from day 4 to day 6 and enhanced significantly in stromal cells on day 5, regarded as the'implantation window'period. The number of implantation sites was greatly decreased by the intrauterine injection with anti-Tiam1 polyclonal antibody in the early morning of the day 4 of pregnancy. These findings suggest that Tiam1 might play an important role in embryo implantation in mice. Objective: To investigate the role of Tiam1in the mice endometrium during blastocyst implantation. Methods:1. Endometria of un-pregnant and pregnant mice day2, day3, day4, day5, day6, day7 entered into the study. There are 7 study groups, each group have 20 mice. 1.1 Real-time fluorescence quantitative PCR (FQ-PCR) was used to analyze Tiam1 mRNA expression in the endometria of mice1.2 Immuno- histochemical technique was used to locate Tiam1 protein expression in the endometria of mice.1.3 Western Blot was adopted to detect the expression amount of Tiam1 in the endometria of mice.2. To analyze the influence of Tiam1 in embryonic implantation, the number of blastocyst implantation was registered on pregnant day 9 after mice being injected anti-Tiam1 antibody in horn of uterus at 8:00AM-9:00AM on the pregnant day 4.Results:1. Fluorescent quantitative-PCR result showed that the expression of Tiam1 mRNA in endometria of pregnant mice was higher than that of non-pregnant mice, and gradually increased from day 2 of pregnancy, reached a maximum level on day 5 and then declined on days 6 and day 7.2. Immunohistochemistry analyses showed that Tiam1 protein was present in luminal epithelium from day 3–5 of pregnancy and in gland epithelium from days 4 to 6 and enhanced significantly in stromal cells on day 5, regarded as the'implantation window'period.3. Western Blot result showed the expression of Tiam1protein in endometria of pregnant mice was higher than that of non-pregnant mice, and gradually increased from day 2 of pregnancy, reached a maximum level on day 5 and then declined on days 6 and day 7.4. The number of implantation sites was greatly decreased by the intrauterine injection with anti-Tiam1 polyclonal antibody in the early morning of the day 4 of pregnancy.Conclusion: These findings suggest that Tiam1 might play an important role in embryo implantation in mice.