Expression of translationally controlled tumor protein (TCTP) in the uterus of mice of early pregnancy and its possible significance during embryo implantation

BACKGROUND: Translationally controlled tumor protein (TCTP) is a highly conserved, growth-related protein. Previous studies showed that TCTP is involved in many biological processes and it is essential for early embryo development and proliferation of embryonic stem cells. However, whether TCTP plays a role during embryo implantation remains unclear. This paper examines the expression and the role of TCTP in the uterus of mice during early pregnancy. METHODS: The expression of TCTP in the uterus of mice during early pregnancy was examined by quantitative real-time PCR, immunohistochemistry and western blot. A functional study of TCTP in embryo implantation of mice was also performed by intrauterine injection with antisense oligodeoxynucleotides (A-ODNs) of TCTP on day 3 (D3) of pregnancy. RESULTS: The TCTP mRNA levels were significantly upgraded from D3 to D5 of pregnancy and reached maximum levels on D5, then dramatically decreased on D6 and D7. The levels of the TCTP protein detected by western blot were consistent with those of the mRNA. Immunohistochemistry analysis showed that the TCTP protein was mainly located in the luminal and the glandular epithelium on D1 and D2 of pregnancy and reached maximum levels on D5 in the luminal and glandular epithelium and in the stromal cells. The levels of TCTP in the pseudo-pregnant uterus of mice were lower than those of pregnant mice on D4 and D6. Furthermore, inhibiting the TCTP expression by intrauterine injection with A-ODNs of TCTP on D3 of pregnancy significantly reduced the number of the implanted embryos compared with the control. CONCLUSIONS: This study demonstrated that TCTP may play a significant role in embryo implantation in mice.