Expression and function of in mouse endometrium during early pregnancy.

Embryo implantation is a complex process involving synchronised crosstalk between a receptive endometrium and functional blastocysts. Apoptosis plays an important role in this process as well as in the maintenance of pregnancy. In this study, we analysed the expression pattern of programmed cell death 4 (), a gene associated with apoptosis in the mouse endometrium, during early pregnancy and pseudopregnancy by real-time quantitative polymerase chain reaction, hybridisation, Western blotting and immunohistochemistry. The results showed that was increased along with days of pregnancy and significantly reduced at implantation sites (IS) from day 5 of pregnancy (D5). The level of at IS was substantially lower than that at interimplantation sites (IIS) on D6 and D7. In addition, expression in the endometrium was reduced in response to artificially induced decidualisation and Downregulation of gene expression in cultured primary stromal cells promoted decidualisation, while upregulation inhibited the decidualisation process by increasing apoptosis. These results demonstrate that is involved in stromal cell decidualisation by mediating apoptosis and therefore plays a role in embryo implantation in mice.