The Oxidative Stress And DNA Damage Of Benzo(a)Pyrene Mediated By5-lipoxygenase In Human Bronchial Epithelia Cell

[Objective] The oxidative stress and oxidative damage of B(a)P mediated by5-LOX in HBE cells were studied to provide novel clues for exploring the mechanisms of5-LOX mediated chemicals DNA damage and carcinogenesis, at the same time to further prove that RNA inter-ference is an effective technology to inhibit the metabolic activation of5-LOX;[Method] All the normal HBE cells, cells treated with5-LOXshRNA and NC cells were exposed to three different conce-ntrations (16μmol、32μmol/L、64μmol/L) of benzo(a)pyrene for24h.Cellular ROS,8-hyd-roxydeoxyguanosine (8-OHdG) levels and malondialdehyde (MDA) con-tent were measured by the multifunctional fluorescence microplate reader and microplate reader; the activities of catalase (CAT) and superoxide dismutase (SOD) were determined by spectrophotometer. In addition, the effect of specific5-lipoxygenase inhibitor (AA861) or chemical inhibitors of other metabolic enzymes on all the biomarkers of oxidative stress and oxidative damage mentioned above were compared, so did the5-LOXshRNA cells and normal HBE cells treated with AA861;[Results] Benzo(a)pyrene can induce oxidative stress in HBE cells by increasing ROS lever signi-ficantly in the32、64μmol/L B(a)P treatment group (p<0.05), the activity of antioxidant enzyme SOD was increased fist and then decreased gradually(p<0.01), the activity of CAT was markedly increased in the64μmol/L treatment group (p<0.01). While the non-enzymatic antioxidant GSH was reduced significantly(p<0.01). B(a)P can also increase MDA and8-OHdG content in cells (p<0.05), which indicate that cells were suffering from severe lipid peroxidation and DNA oxidative damage. However, the oxidative stress and oxidative damage in HBE cells induced by benzo(a)pyrene can be significantly inhibited by5-LOXsiRNA and specific inhibitor of5-LOX (AA-861). In a word,5-LOXshRNA plays an more effective role in preventing B(a)P-induced oxidative damage;[Conclusions] The oxidative stress and oxidative damage caused by B(a)P can be protected by5-LOXshRNA and specific inhibitor of5-LOX (AA-861).It might be related to the inhibition of the metabolic activation of B(a)P mediated by5-LOX. It is supposed that B(a)P was mainly activated by5-LOX to produce ROS, oxidative stress and oxidative DNA damage in HBE cells, the latter is involved in the carcinogenic mecha nism of B(a)P. Meanwhile, it is the RNAi that can significantly attenuate oxidative DNA damage induced by B(a)P.