Abstract:  Objective：To investigate whether  NQO1 [NAD(P)H: quinine oxidoreductase 1] gene played a role in schisandrin B (Sch B) attenuating cells damages in the human trophoblast HTR-8/SVneo cells (HTR-8/SVneo) induced by Benzo(a) pyrene (BaP). Methods：On the basis of previous experiments, siRNA technology, MTS cell proliferation assay and real-time PCR were used to analyze the changes of protective rate in HTR-8/SVneo cells induced by Sch B after NQO1 siRNA, and the changes of NQO1 mRNA expression in different groups before and after NQO1 siRNA. Results：At the level of cell proliferation, after NQO1 siRNA, inhibition rate in HTR-8/SVneo cells induced by 20 μmol/L BaP-incresed to 30.48%, while the protection rates in HTR-8/SVneo cells induced by 0.50, 1.00 and 2.00 μmol/L Sch B decresed to 4.68%, 9.56%, 14.85% respectively. Besides, at the level of gene expression, the ability of 0.10, 0.25, 0.50, 1.00, 2.00, 5.00 μmol/L Sch B to activate NQO1 significantly decreased after NQO1 siRNA, and the expression of NQO1 mRNA was respectively reduced to 1.22, 1.24, 1.30, 1.53, 1.71, 2.01, 1.29 times as much as 1.36, 1.40, 1.46, 1.79, 2.30, 2.91, 1.42 times that of the control group before NQO1 siRNA. Conclusions：NQO1 was associated with Sch B attenuating BaP-induced HTR-8/SVneo cells damages.

Key words: Benzo(a)pyrene, Schisandrin B, Trophoblast cell, NQO1, Oxidoreductases