Abstract: Objective To explore the spatial and temporal expression of Fzr1 protein during the development of placenta, and observe the effect of Fzr1 on the invasion and proliferation of trophoblast cells. Methods To observe the expression level and localization of Fzr1 protein using Western blot and immunohistochemical methods, and detect the effect of Fzr1 on trophoblast cell invasion and proliferation by RNA interference technology, Transwell and MTS methods. Results (1) Immunostaining revealed that Fzr1 protein was strongly expressed in the cytotrophoblast and syncytiotrophoblast cells of villi during early pregnancy. Positive signals were mainly located in the cytoplasm. In the third trimester of pregnancy, Fzr1 protein was expressed in the syncytiotrophoblast, and expression levels significantly decreased. Positive signal was located in the nucleus. Western blot studies showed that Fzr1 protein levels in the third trimester decreased by 4.88 times compared with early pregnancy (P<0.01). (2) Transwell studies revealed that Fzr1 siRNA significantly enhanced the invasion of JAR cells compared with blank control (P<0.01), but scrambled siRNA had no significantly change. (3) MTS results showed that Fzr1 siRNA significantly enhanced the proliferation of JAR cells compared with blank control (P<0.01), but scrambled siRNA had no significantly change. Conclusions Fzr1 protein was temporally and spatially expressed at the placenta of normal pregnancy, and Fzr1 gene silencing could promote the invasion and proliferation of trophoblast cell.

Key words: Key words: Fzr1, siRNA, trophoblast cells, invasion, proliferation