Sophoricoside fails the embryo implantation by compromising the uterine endometrial receptivity at implantation "window" of pregnant mice.

Sophoricoside (SOPH) is an isoflavone glycoside isolated from the fruits of Sophora japonica. Since its first isolation in 1961, there are rare findings about the effects of SOPH on reproductive system. In the present study, the pregnant mice administrated by different doses of SOPH were used to explore the effect of SOPH on embryo implantation, especially on the endometrial receptivity. The statistical results showed that the number of implanted embryos was gradually declining along the increasing dose of SOPH. When the administrated dose of SOPH was 600 mg/kg per day, great changes were observed in the exposed uterine morphology and up-regulated progesterone receptor (PR) and down-regulated estrogen receptor α (ERα), E-cadherin, matrix metalloproteinase-2 (MMP-2) and integrin β3 were also found in SOPH-exposed uterine. These findings demonstrated that SOPH exposure reduced the number of implanted embryos in a dose-dependent manner and failed the embryo implantation through altering the morphology of uterine and compromising the endometrial receptivity.