Lipoxygenase Protein Expression In Four Cell Lines And Its Effect On The Oxidative Caused By Benzidine In SV-HUC Cell

[Objective] The protein expression of lipoxygenases is studied in four human cell lines (SV-HUC、HBE、HTR-8、HaCat), and5-LOX protein compared with CYP1B1/2E1; at the same time the relationship between oxidative stress effect of benzidine and5-LOX was researched in SV-HUC cells; to provide more clues for biotransformation and damage of xenobiotics mediated by lipoxygenase.[Method]①The protein expressions of5-LOX、12-LOX、15-LOX-2、CYP1B1、CYP2E1in human cell lines are tested by western blot;②SV-HUC cells were exposed to three different concentration (50、100、200μmol) of benzidine for24h. intracellular ROS levels measured by fluorescence spectrophotometer, the activities of intracellular superoxide dismutase (SOD)、hydrogen peroxide (CAT) and the content of antioxidants (GSH) detected by spectrophotometer, cellular malondialdehyde (MDA) by multifunctional fluorescence microplate reader. In addition, the effect of specific inhibitor of5-LOX (AA861) was also determined on all the biomarkers of oxidative stress mentioned above.[Results]①Western blot results show that both the5-LOX and15-LOX-2protein were expressed in the four cell lines, benzo(a)pyrene and benzidine can induce5-LOX protein expression; in SV-HUC cells, the expression of5-LOX protein are more than CYP1B1, but have no difference from CYP2E1.②Benzidine can induce oxidative stress in SV-HUC cells by increasing ROS level and the activity of CAT significantly in the100、200μmol/L benzidine treated group (p<0.05), the cellular content of MDA was markedly increased in200μmol/L treated group, the activity of SOD was increased first and then decreased graduadlly (p<0.05), while the antioxidant GHS was significantly decreased (p<0.05). However, the oxidative stress and oxidative damage in SCV-HUC cells which caused by benzidine can be effectively inhibited by AA861(the specific inhibitor of5-LOX), especially in10μmol/L.[Conclusion]5-LOX is probably the major LOX isozyme to co-oxidative exogenous chemical in the four cell lines; AA861have protective effecs on the oxidative stress and oxidative damage induced by benzidine in SV-HUC cells. It is inferd that benzidine can be actived through5-LOX to produce ROS and oxidative stress, and AA861can inhibit the co-oxidative process.