Abstract: Objective: To investigate the effect of TLR3 ligation on expression of angiogenic factors in primary trophoblast cells and evaluate the possible role of TLR3 signal pathway in the pathogenesis of hypertensive diorders in pregnancy. Methods The first trimester human trophoblast cells and immortalized human trophoblast cell line Swan71 were stimulated with Poly(I:C) (TLR3 specific ligand). sFlt-1 and PlGF protein and mRNA expression were evaluated by ELISA and Real-time PCR respectively at different time points. TLR3 mRNA expression was also determined by Real-time PCR. Results 24，48 and 120 h after Poly(I:C) stimulation, concentration of sFlt-1 in the conditioned media of Swan71 was significantly increased compared with non-treatment control (P < 0.05). Poly(I:C) (10 μg/mL) significantly induced sFlt-1 mRNA (P < 0.05), while suppressed PlGF mRNA (P < 0.05) in primary trophoblast cells. Induced expression of sFlt-1 mRNA showed a time and dose-dependent manner, which reached the highest effect 2 h after Poly (I:C) stimulation (P < 0.05). At the same time, PlGF mRNA expression was decreased significantly (P < 0.05). Expression of TLR3 mRNA was significantly increased 8 h up to 12 h after Poly(I:C) stimulation (P < 0.05). Conclusion TLR3 activation induced synthesis and secretion of sFlt-1, while inhibit PlGF in trophoblast cells, which lead to disturbance of angiogenesis and be involved in the pathophysiology of hypertensive disorders in pregnancy.

Key words: Key words: hypertensive disorders in pregnancy, TLR3, sFlt-1, PlGF