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Title: Evaluation of Aroclor 1260 exposure in a mouse model of diet-induced obesity and non-alcoholic fatty liver disease

Polychlorinated biphenyls (PCBs) are persistent organic pollutants associated with non-alcoholic fatty liver disease (NAFLD) in epidemiologic studies. The purpose of this study was to evaluate the hepatic effects of a PCB mixture, Aroclor 1260, whose composition mimics human bioaccumulation patterns, in a mouse model of diet-induced obesity (DIO). Male C57Bl/6J mice were fed control diet or 42% high fat diet (HFD) and exposed to Aroclor 1260 (20 mg/kg or 200 mg/kg in corn oil) for 12 weeks. A glucose tolerance test was performed; plasma/tissues were obtained at necropsy for measurements of adipocytokine levels, histology, and gene expression. Aroclor 1260 exposure was associated with decreased body fat in HFD-fed mice but had no effect on blood glucose/lipid levels. Paradoxically, Aroclor 1260 + HFD co-exposed mice demonstrated increased hepatic inflammatory foci at both doses while the degree of steatosis did not change. Serum cytokines, ALT levels and hepatic expression of IL-6 and TNFα were increased only at 20 mg/kg, suggesting an inhibition of pro-inflammatory cytokine production at the 200 mg/kg exposure. Aroclor 1260 induced hepatic expression of cytochrome P450s including Cyp3a11 (Pregnane-Xenobiotic Receptor target) and Cyp2b10 (constitutive androstane receptor target) but Cyp2b10 inducibility was diminished with HFD-feeding. Cyp1a2 (aryl hydrocarbon Receptor target)more » was induced only at 200 mg/kg. In summary, Aroclor 1260 worsened hepatic and systemic inflammation in DIO. The results indicated a bimodal response of PCB-diet interactions in the context of inflammation which could potentially be explained by xenobiotic receptor activation. Thus, PCB exposure may be a relevant “second hit” in the transformation of steatosis to steatohepatitis. - Highlights: • Aroclor 1260 exposure decreased adiposity in mice fed with high fat diet • Aroclor 1260 exposure induced steatohepatitis in diet-induced obese mice • Aroclor 1260 (20 and 200 mg/kg) induced Cyp2b10 and Cyp3a11 (CAR/PXR target genes) • Aroclor 1260 at 200 mg/kg induced Cyp1a2 (AhR target gene)« less
Authors:
 [1] ;  [2] ;  [1] ;  [2] ;  [1] ; ;  [3] ; ;  [4] ;  [1] ;  [1] ;  [5] ;  [5]
  1. Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY 40202 (United States)
  2. Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition, University of Louisville School of Medicine, Louisville, KY 40202 (United States)
  3. Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, Louisville, KY 40202 (United States)
  4. Cellular and Molecular Pathology Branch, National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 (United States)
  5. (United States)
Publication Date:
OSTI Identifier:
22439836
Resource Type:
Journal Article
Resource Relation:
Journal Name: Toxicology and Applied Pharmacology; Journal Volume: 279; Journal Issue: 3; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; AMINOTRANSFERASES; BLOOD; CORN OIL; DIET; FATS; GENES; GLUCOSE; HEMATOXYLIN; INFLAMMATION; LIVER; LYMPHOKINES; METABOLIC DISEASES; MICE; POLYCHLORINATED BIPHENYLS; RADIOPROTECTIVE SUBSTANCES; RECEPTORS; SCANNING ELECTRON MICROSCOPY