Polychlorinated Biphenyl Quinone Metabolites Induce Oxidative Stress In HepG2 Cells And Protective Role Of Dihydrolipoic Acid

Polychlorinated biphenyls (PCBs) is synthetic organic compounds, and a wide range of pollution has been left in the air, water, soil environment, which began producing and using science the late 1920s. PCBs, as the typical persistent organic environment pollutant, has the characters of recalcitrance, high toxicity, bioaccumulation, long-distance migration and stable physical and chemical properties, belongs to semi-volatile or volatile substance, and has strong corrosive. Although PCBs is stable, it can be metabolized to the hydroxylation of PCBs with catalysis of cytochrome P450, and further oxidation of the high activity of PCBs quinone. Numerous studies indicate that PCBs can cause cellular oxidative stress, but the oxidative stress study of the metabolites of PCBs—PCBs quinone is still in the blank. So, direct study the oxidative stress of PCBs quinone is really necessary.The in endogenous antioxidant system plays an important role in free radical scavenging and inhibition of oxidative stress. Antioxidants, as free radical scavengers can effectively complement the deficiencies of the vivo antioxidant, plays a significant role in protecting the balance of redox level. Studies have shown that the cellular oxidative stress and apoptosis caused by xenobiotics can get a certain ease in the present of antioxidants. Lipoic acid as a fat and water soluble antioxidants, has a significant protective effect to organism.The main work of this paper is as follows:using HepG2 cells as a carrier, researching the cytotoxicity of the 4 kind of PCBs which has different position and number chlorine through a rang of experiment, such as cell viability, reactive oxygen species levels, lipid peroxidation, superoxide dismutase,catalase glutathione and glutathione transfer enzymes. At the same time, we also studied the ability of Dihydrolipoic acid antagonist free radicals.All the works above confined that PCBQ can induce oxidative stress. PCBQ decreased cell viability, emphasized SOD, lipid oxidized, increased SOD reactivity, but the CAT activity, GSH level and GST activity were weakened. In the present of LA, oxidative stress was mitigated. From the experiment results, we found that the four PCBQ are related between them, and the 3C1-PCBQ is most toxicity than others.