Differential expression of Angiopoietin-3 in mouse uterus during early pregnancy

Embryo implantation is a sophisticated process by which the blastocyst makes the first physical and physiological contact with the uterine luminal epithelium. A successful implantation requires a receptive endometrium, a normal and functional embryo at the blastocyst developmental stage and a synchronized crosstalk between maternal and embryonic tissues. Angiogenesis is crucial to successful implantation and decidualization, however, as an important angiogenic growth factor, the effect of Angiopoietin-3 (Ang-3) in the process of implantation and decidualization is still unknown. The aim of this study was to investigate the expression of Ang-3 in the mouse uterus during early pregnancy, pseudopregnancy, delayed implantation and artificial decidualization using reverse transcription polymerase chain reaction (RT-PCR). The results showed that Ang-3 mRNA was slightly expressed in mouse uterus on days 1-4 of pregnancy, and the expression was gradually increased from days 5 to 8 of pregnancy, and reached the highest level on day 8 of pregnancy. Moreover, the expression of Ang-3 mRNA on the implantation site on day 5 of pregnancy was significantly higher than that of the non-implantation site. Ang-3 mRNA expression was detected through days 1-5 of pseudopregnancy and highly expressed on day 3. In the delayed implantation uterus and activated implantation sites, Ang-3 mRNA was highly expressed in activated implantation sites compared with the delayed implantation uterus. Similarity, Ang 3 mRNA was strongly detected in the decidualized uterus under artificial decidualization. These results suggest that the Ang-3 may play an important role in the process of mouse embryo implantation and decidualization.