Expression Of Translationally Controlled Tumor Protein (TCTP) In Mice Uterus Of Early Pregnancy And Its Possible Significance During Embryo Implantation

BackgroundThe translationally controlled tumor protein (TCTP) was initially found in tumor tissue, and then was separated from other organism in succession. The translationally controlled tumour protein (TCTP) is a highly conserved protein that is widely expressed in animals, plants and yeast. Initially TCTP was thought to be a growth-related protein, previous studies have shown that TCTP involves in many biological processes, it is a histamine-releasing factor and is important for cell growth, division and proliferation, in addition, TCTP has recently identified to be a novel small weight heat shock protein, and can protect cellular proteins from heat shock damage by acting as a molecular chaperone. TCTP also was reported to be a direct role of in human placenta calcium transport and regulated calcium handling in the trophoblast cells. Moreover, Our previous study of serial analysis of gene expression (SAGE) analysis showed that the TCTP expression in mice uterus was up-regulated during the window of implantation. According to these findings and our previous study, it suggests TCTP may involve in embryo implantation and early embryo development. But whether it is a key factor during embryo implantation remains unclear, so in this study we examined the expression of TCTP in mice uterus of early pregnancy by qRT-PCR, Western blot and immunohistochemistry, and preliminarily studies the function of TCTP by injecting TCTP antisense oligodeoxynucleotides. Our studies are helpful to examine its possible significance during embryo implantation, and provide us experimental evidence for exploring the molecular mechanism of embryo implantation.MethodThe levels of TCTP mRNA in early pregnancy mice uterus during D1-D7 was examined by qRT-PCR, and the expression of TCTP protein in early pregnancy mice uterus was examined by Western blot and immunohistochemistry. Then TCTP mRNA and protein on D4 ad D6 of pregnancy and pseudopregnant uterus was examined by qRT-PCR,Western blot and immunohistochemistry. Injection of antisense oligodeoxynucleotides to TCTP into D3.5 of pregnant mice uteri was carried out to investigate the effect of TCTP on embryo implantation, 24h later, the mice uterus were collected, and TCTP mRNA and protein was examined by qRT-PCR, Western blot and immunohistochemistry, and the number of implanted embryos was amounted on D8 of pregnancy. ResultThe result of qRT-PCR shows TCTP mRNA level were upgraded from D2 to D5 of pregnancy, and reached a maximal level on D5, then dramatically decreased on D6 and D7. The result of Western blot and immunohistochemistry was consistent with that obtained qRT-PCR in the early pregnancy. Expression of TCTP was mainly in the luminal epithelium and gland on D1 and D2 of pregnany, and reached a maximal level on D5 in the gland, luminal epithelium and stroma cells. The level of TCTP in the uterus of pseudopregnant mice was lower than the level of preg- nant uterus on D4 and D6(*P<0.05). Furthermore, injection of antisense oligodeoxynucleotides to TCTP into the mice uterine horn on D3.5 of pregnancy obviously suppressed the expression of TCTP as expected and reduced the number of the implanted embryos compared with the control(* P<0.05).ConclusionThe expression pattern of TCTP is temporal and spatial in pregnant mice, and reach maximum in the period of implantation window, and injection of antisense oligodeoxynucleotides to TCTP into the mice uterine horn obviously suppressed the expression of TCTP, and reduced the number of the implanted embryos, these findings suggest it is closely related to embryo implantation, and may play a significant role in regulating mice embryo implantation.