IGF-II and IGFBP-1 reversely regulate blastocyst implantation in mouse

Abstract

Insulin-like growth factor (IGF)-II and IGF binding protein (IGFBP)-1, members of IGF family, are important in the cyclic development of endometrium and the blastocyst implantation. In the present study, the indirect immunofluorescence showed that IGF-II and IGFBP-1 were specifically expressed at the maternal-fetal interface. In a co-culture system, IGF-II significantly enhanced the attachment and outgrowth of the blastocyst on monolayer of uterine epithelial cells, while IGFBP-1 did not affect the blastocyst attachment, but markedly inhibited the blastocyst outgrowth. The results of zymography showed that IGF-II enhanced the activities of MMP-2 and MMP-9, while IGFBP-1 did not affect the activities of MMP-2 and MMP-9. In conclusion, the equilibrium between the invasion of trophoblast and the inhibition of deciduas may be regulated by the interaction between the IGF-II-expressing invading cytotrophoblast and maternal deciduas-derived IGFBP-1.