Role of αVβ3 integrin in embryo implantation in the mouse

Integrin, a heterodimeric adhesive molecule composed of α and β subunits, can regulate cell adhesion and trafficking. Recent data have documented that, at the “implantation window” stage, α Vβ 3 integrin participates in the maternal-fetal interaction and becomes a potential marker of uterine receptivity. Furthermore, it can affect invasiveness of embryo. This work made a further study about its action mechanism. Results of indirect immunofluorescence and laser scanning confocal microscopy showed that α Vβ 3 integrin was clearly expressed in the mouse blastocyst. Injection of α Vβ 3 integrin antiserum into a uterine horn of a pregnant mouse on day 3 markedly decreased the number of embryos implanted (P < 0.001). In a co-culture model, α Vβ 3 integrin antisera at 1︰100 and 1︰200 dilutions significantly depressed the attachment and outgrowth reactions of blastocysts on monolayer of uterine epithelial cells. Analysis of correlation manifested that the inhibitory effect of α Vβ 3 integrin antiserum was dosage/dilution-dependent. Thus, α Vβ 3 integrin is an essential factor in the uterine endometrium for embryo implantation in the mouse. This integrin distinctly expressed in the mouse blastocyst at “implantation” stage affected the process of embryo implantation by route of mediating both the attachment and the outgrowth processes of blastocyst on uterine epithelial cells.