title: Sodium arsenite induced reactive oxygen species generation, nuclear factor (erythroid-2 related) factor 2 activation, heme oxygenase-1 expression, and glutathione elevation in Chang human hepatocytes.
abstract: Liver is one of the major target organs of arsenic toxicity and carcinogenesis. Nuclear factor (erythroid-2 related) factor 2 (Nrf2) is a redox-sensitive transcription factor, regulating critically cellular defense responses against the toxic metallic arsenic in many cell types and tissues. This study was conducted to evaluate the hepato-cellular Nrf2 and Nrf2-regulated antioxidant reactions of sodium arsenite exposure in Chang human hepatocytes. Nrf2 and heme oxygenase-1 (HO-1) protein levels were detected by Western blot, and Nrf2-regulated HO-1 mRNA expressions were determined using semiquantitative RT-PCR by 0∼50 μmol/L of sodium arsenite exposure for 2, 6, 12, and 24 h. We also observed the changes of intracellular reactive oxygen species (ROS) and total cellular glutathione (GSH) by flow cytometry and spectrophotometry, respectively. Our results showed that intracellular ROS were both dose- and time-dependent induced by inorganic arsenic; Cellular Nrf2 protein levels increased rapidly after 2 h of exposure, elevated significantly at 6 h, and reached the maximum at 12 h. The endogenous Nrf2-regulated downstream HO-1 mRNA and protein were also induced dramatically and lasted for as long as 24 h. In addition, intracellular GSH levels elevated in consistent with Nrf2 activation. Our findings here suggest that inorganic arsenic alters cellular redox balance in hepatocytes to trigger Nrf2-regulated antioxidant responses promptly, which may represent an adaptive cell defense mechanism against inorganic arsenic induced liver injuries and hepatoxicity.
authors.affiliation: Department of Occupational and Environmental Health, Liaoning Provincial Key Laboratory of Arsenic Biological Effect and Poisoning, School of Public Health, China Medical University, Shenyang 110001, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Li
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.forename: Bo
authors.initials: B
authors.lastname: Zhu
authors.forename: Xinyu
authors.initials: X
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Xu
authors.forename: Huihui
authors.initials: H
authors.lastname: Wang
authors.forename: Yongyong
authors.initials: Y
authors.lastname: Hou
authors.forename: Quanmei
authors.initials: Q
authors.lastname: Zheng
authors.forename: Guifan
authors.initials: G
authors.lastname: Sun
mesh_terms: D018053:Arsenites / Q000633:toxicity*; D002460:Cell Line; D004785:Environmental Pollutants / Q000633:toxicity*; D005978:Glutathione / Q000235:genetics / Q000378:metabolism*; D051547:Heme Oxygenase-1 / Q000235:genetics / Q000378:metabolism*; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017670:Sodium Compounds / Q000633:toxicity*
chemical_list: D018053:Arsenites; D004785:Environmental Pollutants; D051267:NF-E2-Related Factor 2; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D017670:Sodium Compounds; C017947:sodium arsenite; D051547:Heme Oxygenase-1; D005978:Glutathione