Fig 2: The effect on PLAC1 expression by hypoxia andsiRNA in trophoblast cell. Trophoblast cells were incubated in either normoxia (21% O2) or hypoxia (0.4% O2) for 48 h and then we detected the PLAC1 protein of trophoblast by Western blotting (A). Expression of PLAC1 significantly reduced in hypoxia concentration compared with normal oxygen (B). Values represent mean ± SD, n = 3, *P < .05. Cells were cultured and transfected with scrambled siRNA, PLAC1 siRNA or blank, PLAC1siRNA significantly reduced PLAC1 expression in trophoblast cell, and there is no significantly difference between blank and scrambled groups (A, B). Values represent mean ± SD, n = 3, *P < .05,**P < .01.

Fig 3: The effect of PLAC1 on trophoblast apoptosis. Flow cytometric analysis of Annexin V-FITC and PI after both staining of Swan-71 and Jar cells, transfected for 48 hours. Alive cell (Annexin V-/PI-) populations were located in the lower left quadrant (LL), early apoptotic cell (Annexin V+/PI-) populations in lower right quadrant (LR), late apoptotic (Annexin V+/PI+) populations in upper right quadrant (UR), and necrotic cells (Annexin V-/PI+) were present in the upper left quadrant (UL). We determined the apoptosis with the data by the sum of early and late apoptotic cells finally. Values represent mean ± SD, n = 6 per group, **P < .01.

Fig 4: Immunohistochemistry staining for PLAC1 and expression of PLAC1 protein in placenta between normal pregnancy (N) and severe preeclampsia (PE). The positive brown staining in the placental tissues show that PLAC1 expressed in the trophoblast both normal pregnancy (A) and severe preeclampsia (B). PLAC1 protein (30 ug per lane) extracts from placental tissues of normal pregnancy and severe preeclampsia was determined by Western blotting, and there were significant decrease of PLAC1 expression in severe preeclampsia (PE) than control (C, D). Values represent mean ± SD, n = 19 per group, ***P < .001.