Background It has been identified that in patients with pre-eclampsia, several factors were released into the serum, which can regulate the proliferation of vascular smooth muscle cells and stimulate the synthesis of extracellular matrix (ECM). However, the signal transduction pathway of the growth factors and cytokines synthesized by endothelial cells leading to the proliferation and ECM synthesis of human umbilical arterial smooth muscle cell (HUASMC) is unknown. The aim of this study was to research the effects of protein kinase C (PKC) inhibitor, polymyxin B (PMB), on the proliferation, nuclear factor-kappa B (NF-κB) activation, and expression of procollagen I and III mRNA in HUASMC cultured with pre-eclamptic umbilical sera. Methods Normal HUASMCs were treated with pre-eclamptic umbilical serum (pre-eclamptic group), pre- eclamptic umbilical serum plus PMB (PMB group), or normal umbilical serum (normal group). The expression of I-κB, NF-κB was detected by Western blotting after the HUASMC was incubated for 2 hours. The proliferation of HUASMC was evaluated by MTT, the cell cycle was analyzed by flow cytomerty, and the expression of procollagen I, III mRNA was measured by RT-PCR assay after HUASMC was incubated for 48 hours. ANOVA was used for statistical analysis. Results Umbilical sera in pre-eclampsia could stimulate the proliferation, the DNA synthesis, the transition of G0+G1 phase or G2/M phase to S and phase, the activation of NF-κB, and the expression of procollagen I mRNA of HUASMC as compared with normal umbilical sera (P<0.01). PMB could inhibit the proliferation, the DNA synthesis, the transition of G0+G1 or G2/M phase phase to S phase, the activation of NF-κB, and the expressions of procollagen I mRNA of HUASMC stimulated by umbilical sera in pre-eclampsia (P<0.01). Conclusion PKC-NF-?B signal transduction pathway may play a key role in SMC phenotype modulation, which is more important in the pathogenesis of placental blood vessel in pre-eclampsia. Background It has been identified that in patients with pre-eclampsia, several factors were released into the serum, which can regulate the proliferation of vascular smooth muscle cells and stimulate the synthesis of extracellular matrix (ECM). However, the signal transduction pathway of the growth factors and cytokines synthesized by endothelial cells leading to the proliferation and ECM synthesis of human umbilical arterial smooth muscle cells (HUASMC) is unknown. The aim of this study was to research the effects of protein kinase C (PKC) inhibitor, polymyxin B PMB) on the proliferation, nuclear factor-kappa B (NF-κB) activation, and expression of procollagen I and III mRNA in HUASMC cultured with pre-eclamptic umbilical sera. Methods Normal HUASMCs were treated with pre-eclamptic umbilical serum -eclamptic group, pre-eclamptic umbilical serum plus PMB (PMB group), or normal umbilical serum (normal group). The expression of I-κB, NF-κB was detected by Western blotting after the HUASMC was incubated by 2 hours. The proliferation of HUASMC was evaluated by MTT, the cell cycle was analyzed by flow cytomerty, and the expression of procollagen I, III mRNA was measured by RT-PCR assay after HUASMC was incubated for 48 hours. ANOVA was used for statistical analysis. Results Umbilical sera in pre-eclampsia could stimulate the proliferation, the DNA synthesis, the transition of G0 + G1 phase or G2 / M phase to S and phase, the activation of NF-κB, and the expression of procollagen I mRNA of HUASMC compared to normal umbilical sera (P <0.01). PMB could inhibit the proliferation of the DNA synthesis, the transition of G0 + Gl or G2 / M phase phase to S phase, the activation of NF- , and the expressions of procollagen I mRNA of HUASMC stimulated by umbilical sera in pre-eclampsia (P <0.01). Conclusion PKC-NF-? B signal transduction pathway may play a key role in SMC phenotype modulation, which is more important in the pathogenesis of placental blood vessel in pre-eclamp sia.