Abstract: Objective: To study the oxidative damage of benzo[a]pyrene（BaP） in HTR8-SVneo cells, and to explore the protective effect of Schizandrin B（Sch B）. Methods：The HTR8-SVneo cells were in vitro cultured, and the oxidative stress damage model was induced by BaP of different doses （0.1，0.5，2.0 μmol/L）. The experiment were designed as the control group, the BaP group, and the Sch B（0.1，0.5，2.0 μmol/L） groups. The oxydic parameters and antioxidative indexes were detected. Results：Compared with control group，the BaP group had significantly lower levels of GSH-Px and SOD and higher levels of LDH，MDA，NO and iNOS（P＜0.05）. The Sch B groups（0.1,0.5,2.0 μmol/L） had significantly higher levels of SOD and GSH-Px and lower levels of LDH，MDA，NO and iNOS than the BaP group（P＜0.05）. Conclusions：Sch B can rebalance between oxidation and anti-oxidation in the HTR8-SVneo cells treated by BaP， suggesting the protective effects of Sch B on oxidative damage.

Key words: Benzo（a）pyrene, Schizandrin, Trophoblasts, Superoxide dismutase, Glutathione peroxidase, L-lactate dehydrogenase, Malondialdehyde, Nitric oxide, Nitric oxide synthase