Aryl hydrocarbon receptor knockout rats are insensitive to the pathological effects of repeated oral exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin
Autor: | J. Craig Rowlands, Abraham Nyska, Robert A. Budinsky, Greg D. Martin, Marie Lawson, Russell S. Thomas, Renee R. Hukkanen, Debra K. Layko, Rosa Anna Manno, Andrea Grassetti, Joshua A. Harrill |
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Rok vydání: | 2015 |
Předmět: |
0301 basic medicine
medicine.medical_specialty Knockout rat Hematology Lung biology business.industry Adipose tissue respiratory system Toxicology Aryl hydrocarbon receptor medicine.disease_cause Muscle hypertrophy 03 medical and health sciences 030104 developmental biology Endocrinology medicine.anatomical_structure Internal medicine medicine biology.protein Histopathology Carcinogenesis business |
Zdroj: | Journal of Applied Toxicology. 36:802-814 |
ISSN: | 0260-437X |
Popis: | Sustained activation of the aryl hydrocarbon receptor (AHR) is believed to be the initial key event in AHR receptor-mediated tumorigenesis in the rat liver. The role of AHR in mediating pathological changes in the liver prior to tumor formation was investigated in a 4-week, repeated-dose study using adult female wild-type (WT) and AHR knockout (AHR-KO) rats treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Beginning at 8 weeks of age, AHR-KO and WT rats were dosed by oral gavage with varying concentrations of TCDD (0, 3, 22, 100, 300 and 1000 ng kg(-1) day(-1) ). Lung, liver and thymus histopathology, hematology, serum chemistry and the distribution of TCDD in liver and adipose tissue were examined. Treatment-related increases in the severity of liver and thymus pathology were observed in WT, but not AHR-KO rats. In the liver, these included hepatocellular hypertrophy, bile duct hyperplasia, multinucleated hepatocytes and inflammatory cell foci. A loss of cellularity in the thymic cortex and thymic atrophy was observed. Treatment-related changes in serum chemistry parameters were also observed in WT, but not AHR-KO rats. Finally, dose-dependent accumulation of TCDD was observed primarily in the liver of WT rats and primarily in the adipose tissue of AHR-KO rats. The results suggest that AHR activation is the initial key event underlying the progression of histological effects leading to liver tumorigenesis following TCDD treatment. Copyright © 2015 John Wiley & Sons, Ltd. |
Databáze: | OpenAIRE |
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