title: Green tea diet decreases PCB 126-induced oxidative stress in mice by up-regulating antioxidant enzymes.
abstract: Superfund chemicals such as polychlorinated biphenyls pose a serious human health risk due to their environmental persistence and link to multiple diseases. Selective bioactive food components such as flavonoids have been shown to ameliorate PCB toxicity, but primarily in an in vitro setting. Here, we show that mice fed a green tea-enriched diet and subsequently exposed to environmentally relevant doses of coplanar PCB exhibit decreased overall oxidative stress primarily due to the up-regulation of a battery of antioxidant enzymes. C57BL/6 mice were fed a low-fat diet supplemented with green tea extract (GTE) for 12 weeks and exposed to 5 μmol PCB 126/kg mouse weight (1.63 mg/kg-day) on weeks 10, 11 and 12 (total body burden: 4.9 mg/kg). F2-isoprostane and its metabolites, established markers of in vivo oxidative stress, measured in plasma via HPLC-MS/MS exhibited fivefold decreased levels in mice supplemented with GTE and subsequently exposed to PCB compared to animals on a control diet exposed to PCB. Livers were collected and harvested for both messenger RNA and protein analyses, and it was determined that many genes transcriptionally controlled by aryl hydrocarbon receptor and nuclear factor (erythroid-derived 2)-like 2 proteins were up-regulated in PCB-exposed mice fed the green tea-supplemented diet. An increased induction of genes such as SOD1, GSR, NQO1 and GST, key antioxidant enzymes, in these mice (green tea plus PCB) may explain the observed decrease in overall oxidative stress. A diet supplemented with green tea allows for an efficient antioxidant response in the presence of PCB 126, which supports the emerging paradigm that healthful nutrition may be able to bolster and buffer a physiological system against the toxicities of environmental pollutants.
authors.affiliation: Superfund Research Center, University of Kentucky, Lexington, KY 40536, USA; Department of Chemistry, College of Arts and Sciences, University of Kentucky, Lexington, KY 40506, USA.
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: Newsome
authors.affiliation: Superfund Research Center, University of Kentucky, Lexington, KY 40536, USA; Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, KY 40536, USA.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Petriello
authors.affiliation: Superfund Research Center, University of Kentucky, Lexington, KY 40536, USA; Department of Food Science and Biotechnology of Animal Resources, College of Animal Bioscience and Technology, Konkuk University, Seoul 143-701, Republic of Korea.
authors.forename: Sung Gu
authors.initials: SG
authors.lastname: Han
authors.affiliation: Superfund Research Center, University of Kentucky, Lexington, KY 40536, USA; Graduate Center for Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, KY 40536, USA.
authors.forename: Margaret O
authors.initials: MO
authors.lastname: Murphy
authors.affiliation: Superfund Research Center, University of Kentucky, Lexington, KY 40536, USA; Graduate Center for Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, KY 40536, USA.
authors.forename: Katryn E
authors.initials: KE
authors.lastname: Eske
authors.affiliation: Superfund Research Center, University of Kentucky, Lexington, KY 40536, USA; Division of Cardiovascular Medicine, College of Medicine, University of Kentucky, Lexington, KY 40536, USA.
authors.forename: Manjula
authors.initials: M
authors.lastname: Sunkara
authors.affiliation: Superfund Research Center, University of Kentucky, Lexington, KY 40536, USA; Division of Cardiovascular Medicine, College of Medicine, University of Kentucky, Lexington, KY 40536, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Morris
authors.affiliation: Superfund Research Center, University of Kentucky, Lexington, KY 40536, USA; Department of Animal and Food Sciences, College of Agriculture, Food and Environment, University of Kentucky, Lexington, KY 40536, USA.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Hennig
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001483:Base Sequence; D002851:Chromatography, High Pressure Liquid; D017931:DNA Primers; D004032:Diet; D004798:Enzymes / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018384:Oxidative Stress / Q000187:drug effects*; D011078:Polychlorinated Biphenyls / Q000633:toxicity*; D016133:Polymerase Chain Reaction; D053719:Tandem Mass Spectrometry; D013662:Tea; D015854:Up-Regulation / Q000187:drug effects*
chemical_list: D000975:Antioxidants; D017931:DNA Primers; D004798:Enzymes; D013662:Tea; D011078:Polychlorinated Biphenyls; C023035:3,4,5,3',4'-pentachlorobiphenyl
keywords: AhR; Antioxidant response; Green tea; Nrf2; Oxidative stress; PCB toxicity