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Fanali LZ, Franco-Belussi L, Bonini-Domingos CR, de Oliveira C. Effects of benzo[a]pyrene on the blood and liver of Physalaemus cuvieri and Leptodactylus fuscus (Anura: Leptodactylidae). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 237:93-102. [PMID: 29477119 DOI: 10.1016/j.envpol.2018.02.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 01/13/2018] [Accepted: 02/09/2018] [Indexed: 05/14/2023]
Abstract
Benzo[a]pyrene (BaP) is a bio-accumulative toxic compound found in the atmosphere, water, and soil that may affect the life cycle of amphibians. In this study, a few contamination biomarkers, such as hepatic melanomacrophages (MMs), mast cells, erythrocyte micronuclei (MN) and white blood cells were used to determine how BaP acts in these cells in the anurans Physalaemus cuvieri and Leptodactylus fuscus. Animals of both species were divided into three treatment groups: 1 day, 7 days and 13 days, subcutaneously injected 2 mg/kg BaP diluted in mineral oil and control group with only mineral oil. After 7 days, BaP caused the frequency of MN to increase in both species while reducing melanin area. The micronucleus frequency increased due to the genotoxicity of BaP, while the decreasing melanin area may be related to the inhibition of tyrosinase activity, an enzyme responsible for regulating melanogenesis, decreasing the synthesis of melanin. The mast cell density increased in all groups and in both species as a response to the inflammatory action of BaP. These cells respond to nonspecific inflammatory effects leading, therefore, to this response in all treatments. The percentage of leukocytes remained unchanged probably due to great intraspecific variability. Additionally, the leukocyte profiles of both species were characterized and the differences were attributed to extrinsic factors. In short, BaP can affect the integrity of several organs and tissues, and cell functions leading to the conclusion that this compound is hepatotoxic, genotoxic and immunotoxic for anurans.
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Affiliation(s)
- Lara Zácari Fanali
- Graduate Program in Animal Biology, Universidade Estadual Paulista (UNESP), São José do Rio Preto, São Paulo, 15054-000, Brazil.
| | - Lilian Franco-Belussi
- Department of Biology, Universidade Estadual Paulista (UNESP), São José do Rio Preto, São Paulo, 15054-000, Brazil; Graduate Program in Biotechnology and Environmental monitoring, CCTS, Federal University of São Carlos, 18052-780, Sorocaba, São Paulo, Brazil
| | | | - Classius de Oliveira
- Department of Biology, Universidade Estadual Paulista (UNESP), São José do Rio Preto, São Paulo, 15054-000, Brazil
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Hou R, Huang C, Rao K, Xu Y, Wang Z. Characterized in Vitro Metabolism Kinetics of Alkyl Organophosphate Esters in Fish Liver and Intestinal Microsomes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:3202-3210. [PMID: 29439571 DOI: 10.1021/acs.est.7b05825] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Tris(2-butoxyethyl) phosphate (TBOEP) and tris( n-butyl) phosphate (TNBP) are the most commonly used alkyl organophosphate esters (alkyl-OPEs), and they increasingly accumulate in organisms and create potential health hazards. This study examined the metabolism of TNBP and TBOEP in Carassius carassius liver and intestinal microsomes and the production of their corresponding monohydroxylated and dealkylated metabolites. After 140 min of incubation with fish liver microsomes, the rapid depletion of TNBP and TBOEP were both best fitted to the Michaelis-Menten model (at administrated concentrations ranging from 0.5 to 200 μM), with a CLint (intrinsic clearance) of 3.1 and 3.9 μL·min-1·mg-1 protein, respectively. But no significant ( P > 0.05) biotransformation was observed for these compounds in intestinal microsomes at any administrated concentrations. In fish liver microsomes assay, bis(2-butoxyethyl) hydroxyethyl phosphate (BBOEHEP) and bis(2-butoxyethyl) 3-hydroxyl-2-butoxyethyl phosphate (3-OH-TBOEP) were the most abundant metabolites of TBOEP, and dibutyl-3-hydroxybutyl phosphate (3-OH-TNBP) was the predominant metabolite of TNBP. Similarly, the apparent Vmax values (maximum metabolic rate) of BBOEHEP and 3-OH-TNBP were also respectively highest among those of other metabolites. Further inhibition studies were conducted to identify the specific cytochrome P450 (CYP450) isozymes involved in the metabolism of TNBP and TBOEP in liver microsomes. It was confirmed that CYP3A4 and CYP1A were the significant CYP450 isoforms catalyzing the metabolism of TNBP and TBOEP in fish liver microsomes. Overall, this study emphasized the importance of hydroxylated metabolites as biomarkers for alkyl-OPEs exposure, and further research is needed to validate the in vivo formation and toxicological implications of these metabolites.
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Affiliation(s)
- Rui Hou
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Chao Huang
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , China
- University of Chinese Academy of Sciences , Beijing 100049 , China
| | - Kaifeng Rao
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , China
| | - Yiping Xu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , China
| | - Zijian Wang
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences , Chinese Academy of Sciences , Beijing 100085 , China
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ARMITAGE JAMESM, ERICKSON RUSSELLJ, LUCKENBACH TILL, NG CARLAA, PROSSER RYANS, ARNOT JONA, SCHIRMER KRISTIN, NICHOLS JOHNW. Assessing the bioaccumulation potential of ionizable organic compounds: Current knowledge and research priorities. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2017; 36:882-897. [PMID: 27992066 PMCID: PMC6172661 DOI: 10.1002/etc.3680] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 07/20/2016] [Accepted: 11/04/2016] [Indexed: 05/19/2023]
Abstract
The objective of the present study was to review the current knowledge regarding the bioaccumulation potential of ionizable organic compounds (IOCs), with a focus on the availability of empirical data for fish. Aspects of the bioaccumulation potential of IOCs in fish that can be characterized relatively well include the pH dependence of gill uptake and elimination, uptake in the gut, and sorption to phospholipids (membrane-water partitioning). Key challenges include the lack of empirical data for biotransformation and binding in plasma. Fish possess a diverse array of proteins that may transport IOCs across cell membranes. Except in a few cases, however, the significance of this transport for uptake and accumulation of environmental contaminants is unknown. Two case studies are presented. The first describes modeled effects of pH and biotransformation on the bioconcentration of organic acids and bases, while the second employs an updated model to investigate factors responsible for accumulation of perfluorinated alkyl acids. The perfluorinated alkyl acid case study is notable insofar as it illustrates the likely importance of membrane transporters in the kidney and highlights the potential value of read-across approaches. Recognizing the current need to perform bioaccumulation hazard assessments and ecological and exposure risk assessment for IOCs, the authors provide a tiered strategy that progresses (as needed) from conservative assumptions (models and associated data) to more sophisticated models requiring chemical-specific information. Environ Toxicol Chem 2017;36:882-897. © 2016 SETAC.
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Affiliation(s)
- JAMES M. ARMITAGE
- University of Toronto Scarborough, Toronto, Ontario, Canada
- Address correspondence to
| | - RUSSELL J. ERICKSON
- Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, US Environmental Protection Agency, Duluth, Minnesota, USA
| | - TILL LUCKENBACH
- Department Bioanalytical Ecotoxicology, UFZ — Helmholtz Centre for Environmental Research, Leipzig, Germany
| | - CARLA A. NG
- Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - RYAN S. PROSSER
- School of Environmental Sciences, University of Guelph, Guelph, Ontario, Canada
| | - JON A. ARNOT
- University of Toronto Scarborough, Toronto, Ontario, Canada
- ARC Arnot Research and Consulting, Toronto, Ontario, Canada
| | - KRISTIN SCHIRMER
- Eawag, Department of Environmental Toxicology, Swiss Federal Institute of Aquatic Science and Technology, Duebendorf, Switzerland
- EPFL, School of Architecture, Civil and Environmental Engineering, Lausanne, Switzerland
- Institute of Biogeochemistry and Pollutant Dynamics, ETHZ, Zurich, Switzerland
| | - JOHN W. NICHOLS
- Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, US Environmental Protection Agency, Duluth, Minnesota, USA
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Fanali LZ, Valverde BSDL, Franco-Belussi L, Provete D, de Oliveira C. Response of digestive organs of Hypsiboas albopunctatus (Anura: Hylidae) to benzo[α]pyrene. AMPHIBIA-REPTILIA 2017. [DOI: 10.1163/15685381-00003101] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Anurans are exposed to several pollutants. One of these is benzo[α]pyrene (BaP). This compound is produced by incomplete combustion and is toxic to the liver and intestine, where it is metabolized. Here, we tested how different concentrations of BaP affect the thickness of small intestine and liver melanomacrophages (MMCs) ofHypsiboas albopunctatusduring short- and long-term exposures. We conducted an experiment with a 3 × 2 factorial design to answer these two questions. Male specimens were separated into groups injected with either 3 or 7 mg/kg of BaP and euthanized after either 72 or 168 h. Then, we measured the thickness of the intestinal epithelium and the area occupied by MMCs. The thickness of intestinal epithelium decreased in both high and low concentration for short-term exposure compared to control, and increased in the long-term group in both low and high concentrations. The short-term decrease in thickness is due to the damage caused by BaP on the absorptive capacity of the epithelium, whereas the epithelium increased its thickness and recovered normal activity in the long-term. High BaP concentration decreased the area of MMCs in the short-term group. The increase in MMCs is associated with the detoxifying role of these cells, while the decrease was triggered by cellular stress due to high BaP concentration. The concentrations of BaP we used are close to those found in polluted environments. Therefore, water contaminated with BaP can potentially affect the morphology of internal organs of anurans.
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Affiliation(s)
- Lara Zácari Fanali
- Graduate Program in Animal Biology, Universidade Estadual Paulista (UNESP), 15054-000 São José do Rio Preto, São Paulo, Brazil
| | - Bruno Serra de Lacerda Valverde
- Graduate Program in Animal Biology, Universidade Estadual Paulista (UNESP), 15054-000 São José do Rio Preto, São Paulo, Brazil
| | - Lilian Franco-Belussi
- Department of Biology, Universidade Estadual Paulista (UNESP), 15054-000 São José do Rio Preto, São Paulo, Brazil
- Current address: Graduate program in Biotechnology and Environmental monitoring, CCTS, Federal University of São Carlos (UFSCar), 18052-780 Sorocaba, São Paulo, Brazil
| | - Diogo B. Provete
- FAPESP post-doctoral fellow, Department of Environmental Sciences, Federal University of São Carlos (UFSCar), 18052-780 Sorocaba, São Paulo, Brazil
- Gothenburg Global Biodiversity Centre, Box 461, SE-405 30 Göteborg, Sweden
| | - Classius de Oliveira
- Department of Biology, Universidade Estadual Paulista (UNESP), 15054-000 São José do Rio Preto, São Paulo, Brazil
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Lo JC, Letinski DJ, Parkerton TF, Campbell DA, Gobas FAPC. In Vivo Biotransformation Rates of Organic Chemicals in Fish: Relationship with Bioconcentration and Biomagnification Factors. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:13299-13308. [PMID: 27993034 DOI: 10.1021/acs.est.6b03602] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In vivo dietary bioaccumulation experiments for 85 hydrophobic organic substances were conducted to derive the in vivo gastrointestinal biotransformation rates, somatic biotransformation rates, bioconcentration factors (BCF), and biomagnification factors (BMF) for improving methods for bioaccumulation assessment and to develop an in vivo biotransformation rate database for QSAR development and in vitro to in vivo biotransformation rate extrapolation. The capacity of chemicals to be biotransformed in fish was found to be highly dependent on the route of exposure. Somatic biotransformation was the dominant pathway for most chemicals absorbed via the respiratory route. Intestinal biotransformation was the dominant metabolic pathway for most chemicals absorbed via the diet. For substances not biotransformed or transformed exclusively in the body of the fish, the BCF and BMF appeared to be closely correlated. For substances subject to intestinal biotransformation, the same correlation did not apply. We conclude that intestinal biotransformation and bioavailability in water can modulate the relationship between the BCF and BMF. This study also supports a fairly simple rule of thumb that may be useful in the interpretation of dietary bioaccumulation tests; i.e., chemicals with a BMFL of <1 tend to exhibit BCFs based on either the freely dissolved (BCFWW,fd) or the total concentration (BCFWW,t) of the chemical in the water that is less than 5000.
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Affiliation(s)
- Justin C Lo
- Department of Biological Sciences, Simon Fraser University , Burnaby, British Columbia V5A 1S6, Canada
| | - Daniel J Letinski
- ExxonMobil Biomedical Sciences, Inc. , Annandale, New Jersey 08801, United States
| | - Thomas F Parkerton
- ExxonMobil Biomedical Sciences, Inc. , Spring, Texas 77339, United States
| | - Dave A Campbell
- Department of Statistics and Actuarial Science, Simon Fraser University , Surrey, British Columbia V5A 1S6, Canada
| | - Frank A P C Gobas
- Department of Biological Sciences, Simon Fraser University , Burnaby, British Columbia V5A 1S6, Canada
- School of Resource and Environmental Management, Faculty of the Environment, Simon Fraser University , Burnaby, British Columbia V5A 1S6, Canada
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Xiao R, Arnot JA, MacLeod M. Towards an improved understanding of processes controlling absorption efficiency and biomagnification of organic chemicals by fish. CHEMOSPHERE 2015; 138:89-95. [PMID: 26047570 DOI: 10.1016/j.chemosphere.2015.05.053] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 05/13/2015] [Accepted: 05/17/2015] [Indexed: 06/04/2023]
Abstract
Dietary exposure is considered the dominant pathway for fish exposed to persistent, hydrophobic chemicals in the environment. Here we present a dynamic, fugacity-based three-compartment bioaccumulation model that describes the fish body as one compartment and the gastrointestinal tract (GIT) as two compartments. The model simulates uptake from the GIT by passive diffusion and micelle-mediated diffusion, and chemical degradation in the fish and the GIT compartments. We applied the model to a consistent measured dietary uptake and depuration dataset for rainbow trout (n=215) that is comprised of chlorinated benzenes, biphenyls, dioxins, diphenyl ethers, and polycyclic aromatic hydrocarbons (PAHs). Model performance relative to the measured data is statistically similar regardless of whether micelle-mediated diffusion is included; however, there are considerable uncertainties in modeling this process. When degradation in the GIT is assumed to be negligible, modeled chemical elimination rates are similar to measured rates; however, predicted concentrations of the PAHs are consistently higher than measurements by up to a factor of 20. Introducing a kinetic limit on chemical transport from the fish compartment to the GIT and increasing the rate constant for degradation of PAHs in tissues of the liver and/or GIT are required to achieve good agreement between the modelled and measured concentrations for PAHs. Our results indicate that the apparent low absorption efficiency of PAHs relative to the chemicals with similar hydrophobicity is attributable to biotransformation in the liver and/or the GIT. Our results provide process-level insights about controls on the extent of bioaccumulation of chemicals.
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Affiliation(s)
- Ruiyang Xiao
- Department of Environmental Science and Analytical Chemistry, Stockholm University, Svante Arrhenius väg 8, SE-11418 Stockholm, Sweden; Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha 410083, China.
| | - Jon A Arnot
- ARC Arnot Research & Consulting, 36 Sproat Avenue, Toronto, Ontario M4M 1W4, Canada; Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
| | - Matthew MacLeod
- Department of Environmental Science and Analytical Chemistry, Stockholm University, Svante Arrhenius väg 8, SE-11418 Stockholm, Sweden
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Zhang H, Pan L, Tao Y. Antioxidant responses in clam Venerupis philippinarum exposed to environmental pollutant hexabromocyclododecane. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2014; 21:8206-8215. [PMID: 24920430 DOI: 10.1007/s11356-014-2801-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 03/12/2014] [Indexed: 06/03/2023]
Abstract
The objective of this study was to assess the potential toxic effects of hexabromocyclododecane (HBCD) on tissues of clam Venerupis philippinarum using parameters of antioxidant defenses and oxidative stress. Antioxidant biomarkers including ethoxyresorufin-O-deethylase (EROD), glutathione S-transferase (GST), superoxide dismutase (SOD), and glutathione (GSH), as well as DNA damage and lipid peroxidation (LPO) in gills and digestive glands of V. philippinarum, were analyzed after a 1-, 3-, 6-, 10-, and 15-day exposure to seawater containing HBCD at environmentally related concentrations, respectively. The results showed that the activity of most antioxidant enzymes increased, and different trends were detected with exposure time extending. The oxidative stress could be obviously caused in the gills and digestive glands under the experimental conditions. This could provide useful information for toxic risk assessment of environmental pollutant HBCD.
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Affiliation(s)
- Hui Zhang
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, People's Republic of China
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8
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Nichols JW, Hoffman AD, ter Laak TL, Fitzsimmons PN. Hepatic Clearance of 6 Polycyclic Aromatic Hydrocarbons by Isolated Perfused Trout Livers: Prediction From In Vitro Clearance by Liver S9 Fractions. Toxicol Sci 2013; 136:359-72. [DOI: 10.1093/toxsci/kft219] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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9
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Karami A, Christianus A, Ishak Z, Syed MA, Courtenay SC. The effects of intramuscular and intraperitoneal injections of benzo[a]pyrene on selected biomarkers in Clarias gariepinus. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2011; 74:1558-1566. [PMID: 21636131 DOI: 10.1016/j.ecoenv.2011.05.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Revised: 04/28/2011] [Accepted: 05/16/2011] [Indexed: 05/30/2023]
Abstract
This study investigated the dose-dependent and time-course effects of intramuscular (i.m.) and intraperitoneal (i.p.) injection of benzo[a]pyrene (BaP) on the biomarkers EROD activity, GST activity, concentrations of BaP metabolites in bile, and visceral fat deposits (Lipid Somatic Index, LSI) in African catfish (Clarias gariepinus). Intraperitoneal injection resulted in 4.5 times higher accumulation of total selected biliary FACs than i.m. injection. Hepatic GST activities were inhibited by BaP via both injection methods. Dose-response relationships between BaP injection and both biliary FAC concentrations and hepatic GST activities were linear in the i.p. injected group but nonlinear in the i.m. injected fish. Hepatic EROD activity and LSI were not significantly affected by BaP exposure by either injection route. We conclude that i.p. is a more effective route of exposure than i.m. for future ecotoxicological studies of PAH exposure in C. gariepinus.
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Affiliation(s)
- Ali Karami
- Department of Aquaculture, Faculty of Agriculture, University Putra Malaysia, 43400 Selangor, Malaysia.
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10
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Richardson BJ, Mak E, De Luca-Abbott SB, Martin M, McClellan K, Lam PKS. Antioxidant responses to polycyclic aromatic hydrocarbons and organochlorine pesticides in green-lipped mussels (Perna viridis): do mussels "integrate" biomarker responses? MARINE POLLUTION BULLETIN 2008; 57:503-514. [PMID: 18499194 DOI: 10.1016/j.marpolbul.2008.02.032] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Revised: 01/06/2008] [Accepted: 02/21/2008] [Indexed: 05/26/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCs) are generally present in the marine environment in complex mixtures. The ecotoxicological nature of contaminant interactions, however, is poorly understood, with most scientific observations derived from single contaminant exposure experiments. The objective of this experiment was to examine dose-response relationships between antioxidant parameters and body contaminant levels in mussels exposed to different exposure regimes under laboratory conditions. Accordingly, the green-lipped mussel, Perna viridis, was challenged with a mixture of PAHs (anthracene, fluoranthene, pyrene, benzo[a]pyrene) and OC pesticides (alpha-HCH, aldrin, dieldrin, p,p'-DDT) over a 4 week period. Contaminants were delivered under four different dosing regimes, with all treatments receiving the same total contaminant load by the end of the exposure period. Antioxidant biomarkers were measured after 1, 2, 3 and 4 weeks, including glutathione (GSH), gluathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and lipid peroxidase (LPO). GST and CAT were induced in hepatic tissues in most of the exposure regimes, with the majority of significant induction occurring in a constant exposure regime and a two-step alternate exposure regime. Significant differences among exposure regimes were detected in the body burden of contaminants after 28 days. Hepatic CAT and GSH are proposed as potentially useful biomarkers as they showed good correlation with target contaminants and were not readily affected by different dosing patterns.
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Affiliation(s)
- Bruce J Richardson
- Department of Biology and Chemistry, Research Centre for Coastal Pollution and Conservation, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong.
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Hornung MW, Cook PM, Fitzsimmons PN, Kuehl DW, Nichols JW. Tissue distribution and metabolism of benzo[a]pyrene in embryonic and larval medaka (Oryzias latipes). Toxicol Sci 2007; 100:393-405. [PMID: 17804863 DOI: 10.1093/toxsci/kfm231] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The need to understand chemical uptake, distribution, and metabolism in embryonic and larval fish derives from the fact that these early life stages often exhibit greater sensitivity to xenobiotic compounds than do adult animals. In this study, a 6-h acute waterborne exposure immediately after fertilization was used to quickly load the egg with benzo[a]pyrene (BaP). This exposure was used to mimic the initial egg concentration of a persistent bioaccumulative toxicant that could result from maternal transfer. We used multiphoton laser scanning microscopy (MPLSM) in combination with conventional analytical chemistry methods to characterize the tissue distribution of BaP and its principal metabolites in medaka embryos and post-hatch larvae. Embryonic metabolism of BaP was evident by MPLSM prior to liver formation or heart development. A major product of this metabolism was identified by liquid chromatography/mass spectrometry as BaP-3-glucuronide. MPLSM showed that metabolites were sequestered within the yolk, biliary system, and gastrointestinal tract. When the gastrointestinal tract became patent a few days after hatch, the metabolites were rapidly eliminated. These findings indicate that some of the earliest embryonic tissues are metabolically competent and that redistribution of BaP and its metabolic products occurs throughout development. Rapid metabolism of BaP substantially reduces the body burden of parent chemical in the developing embryo, potentially reducing toxicity. It remains unclear whether metabolism of BaP in medaka embryos leads to the formation of DNA adducts associated with genotoxic effects or yields metabolites that later lead to other toxicity in juveniles or adults.
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Affiliation(s)
- Michael W Hornung
- US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, Duluth, MN 55804, USA.
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12
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Nichols JW, Fitzsimmons PN, Burkhard LP. In vitro-in vivo extrapolation of quantitative hepatic biotransformation data for fish. II. Modeled effects on chemical bioaccumulation. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2007; 26:1304-19. [PMID: 17571698 DOI: 10.1897/06-259r.1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Hypothetical in vitro biotransformation rate and affinity values for fish were extrapolated to a set of in vivo whole-body metabolism rate constants. A one-compartment model was then used to investigate potential effects of metabolism on chemical bioaccumulation as a function of octanol/water partitioning (Kow). In a second model-based effort, in vitro data were incorporated into a physiologically based toxicokinetic (PBTK) model for fish. The two models predict similar effects on bioaccumulation when calculated in vivo intrinsic clearance values (CL(IN VIVO,INT) are less than 50% of estimated liver blood flow (Q(LIVER). When CL(IN VIVO,INT) approaches Q(LIVER), the PBTK model predicts a greater effect on bioaccumulation than the one-compartment model. This result is attributed to the structure of the PBTK model, which provides for first-pass clearance of chemicals taken up from food. Uncertainties inherent to in vitro-in vivo extrapolations of hepatic metabolism data include the effects of protein binding, inaccurate estimation of in vivo metabolism by in vitro assays, and failure to account for metabolism in other tissues. Model-based predictions of bioaccumulation within a natural setting also must account for possible metabolism at multiple trophic levels. The models described in this study can be used to perform in vitro-in vivo metabolism comparisons with fish, estimate in vitro biotransformation parameters on the basis of measured chemical residues in field-collected animals, and calculate the level of in vitro metabolic activity required to limit bioaccumulation of all compounds to a specified value.
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Affiliation(s)
- John W Nichols
- U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, 6201 Congdon Boulevard, Duluth, Minnesota 55804, USA.
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Fitzsimmons PN, Lien GJ, Nichols JW. A compilation of in vitro rate and affinity values for xenobiotic biotransformation in fish, measured under physiological conditions. Comp Biochem Physiol C Toxicol Pharmacol 2007; 145:485-506. [PMID: 17360241 DOI: 10.1016/j.cbpc.2006.12.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2006] [Revised: 12/28/2006] [Accepted: 12/30/2006] [Indexed: 12/08/2022]
Abstract
Scientific literature from the past 25 years was searched to obtain in vitro biotransformation rate and affinity data for fish. To maximize the environmental relevance of this dataset, we focused on studies conducted at multiple substrate concentrations, and established acceptance criteria with respect to assay temperature and pH. Altogether, enzyme rate and affinity parameters are provided for 43 species and 77 compounds. In all but three instances, the reported reactions exhibited saturation at high substrate concentrations and could be used to calculate Michaelis-Menten rate (Vmax) and affinity (Km) constants. Most of this information was obtained using in vitro systems derived from liver tissue. Information from non-hepatic tissues was included, however, to provide a basis for comparisons among tissues. Where possible, in vitro enzyme parameters were examined to compare: (1) hepatic metabolism of a common substrate within a species, (2) hepatic metabolism of common substrates by different species, and (3) metabolism of a common substrate by different tissues of one species. Comparisons within species highlight a number of factors that may substantially influence xenobiotic metabolism in fish including gender, life stage, and acclimation temperature. Limited data suggest that Vmax and Km for the same reaction may vary by up to three orders of magnitude among species.
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Affiliation(s)
- Patrick N Fitzsimmons
- U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, 6201 Congdon Boulevard, Duluth, Minnesota 55804, USA.
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Nichols JW, Schultz IR, Fitzsimmons PN. In vitro-in vivo extrapolation of quantitative hepatic biotransformation data for fish. I. A review of methods, and strategies for incorporating intrinsic clearance estimates into chemical kinetic models. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2006; 78:74-90. [PMID: 16513189 DOI: 10.1016/j.aquatox.2006.01.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2005] [Revised: 12/20/2005] [Accepted: 01/08/2006] [Indexed: 05/06/2023]
Abstract
Scientists studying mammals have developed a stepwise approach to predict in vivo hepatic clearance from measurements of in vitro hepatic biotransformation. The resulting clearance estimates have been used to screen drug candidates, investigate idiosyncratic drug responses, and support chemical risk assessments. In this report, we review these methods, discuss their potential application to studies with fish, and describe how extrapolated values could be incorporated into well-known compartmental kinetic models. Empirical equations that relate extrapolation factors to chemical log K(ow) are given to facilitate the incorporation of metabolism data into bioconcentration and bioaccumulation models. Because they explicitly incorporate the concept of clearance, compartmental clearance-volume models are particularly well suited for incorporating hepatic clearance estimates. The manner in which these clearance values are incorporated into a given model depends, however, on the measurement frame of reference. Procedures for the incorporation of in vitro biotransformation data into physiologically based toxicokinetic (PBTK) models are also described. Unlike most compartmental models, PBTK models are developed to describe the effects of metabolism in the tissue where it occurs. In addition, PBTK models are well suited to modeling metabolism in more than one tissue.
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Affiliation(s)
- John W Nichols
- U.S. Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, Duluth, MN 55804, USA.
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15
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Doi AM, Lou Z, Holmes E, Venugopal CS, Nyagode B, James MO, Kleinow KM. Intestinal bioavailability and biotransformation of 3,3',4,4'-tetrachlorobiphenyl (CB 77) in in situ preparations of channel catfish following dietary induction of CYP1A. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2006; 77:33-42. [PMID: 16364462 DOI: 10.1016/j.aquatox.2005.10.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2005] [Revised: 05/03/2005] [Accepted: 10/14/2005] [Indexed: 05/05/2023]
Abstract
Previous studies with the catfish in situ perfused intestinal preparation have demonstrated a significant decline in the intestinal bioavailability of a coplanar polychlorinated biphenyl (PCB), 3,3',4,4'-tetrachlorobiphenyl (CB 77)(14C-TCB) dose in animals pre-exposed in vivo to TCB. This response was accompanied by CYP1A induction in the intestine, but little effect upon the oxidative metabolism of the subsequent in situ dose of [14C]-TCB. To ascertain the basis of these responses and the intestine specific contributions, the intestinal bioavailability and metabolism of [14C]-TCB were examined in the in situ intestinal preparation following in vivo exposure to beta-naphthoflavone (BNF; 0, 10 or 50 mg BNF/kg diet for 10 days), BNF was selected as a known inducer of CYP1A and as a compound with a structure unlikely to influence or directly partake in diffusion based TCB concentration gradients. Appreciable amounts of [14C]-TCB molar equivalents (Meq) reached the perfused circulation of the intestinal preparation for all treatments. While BNF pre-exposure elicited induction of CYP1A activities aryl hydrocarbon hydroxylase (AHH) (9.2-12.5-fold) and elicited modest morphological changes (muciparous) in the intestine these changes were not associated with alterations in [14C]-TCB Meq bioavailability. [14C]-TCB metabolism in the intestinal mucosa ranged between 0.54 and 1.27%, for all treatments. As with bioavailability, intestinal metabolism of [14C]-TCB was not significantly influenced in either extent or profile by induction of CYP1A activity as associated with BNF treatment. Four metabolites were found in mucosal sample extracts of which three were tentatively identified as 2-OH-TCB, 4-OH-3,3',4',5-TCB, and 4,4'-diOH-3,3',5,5' tetrachlorobiphenyl. A fourth unknown metabolite presented chromatographic characteristics suggestive of another dihydroxylated metabolite. These data when examined alone and compared to the literature suggest that the intestine may metabolize [14C]-TCB slowly and independent of CYP1A, resulting in somewhat different profiles than published for other organs. In addition, it is likely that previous [14C]-TCB bioavailability findings in the perfused intestine may be based on TCB concentration gradients rather than biotransformation.
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Affiliation(s)
- Adriana M Doi
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Skip Bertman Dr., Baton Rouge, LA 70803, USA
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Cavret S, Feidt C. Intestinal metabolism of PAH: in vitro demonstration and study of its impact on PAH transfer through the intestinal epithelium. ENVIRONMENTAL RESEARCH 2005; 98:22-32. [PMID: 15721880 DOI: 10.1016/j.envres.2004.10.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2003] [Revised: 05/11/2004] [Accepted: 10/29/2004] [Indexed: 05/24/2023]
Abstract
Food would seem to be one of the main ways of animal and human contamination with polycyclic aromatic hydrocarbons (PAHs). In vivo studies suggest a transfer in intestinal epithelium by diffusion, which appears extensively governed by the physicochemical properties of PAHs, particularly lipophilicity. However, other mechanisms, such as metabolism, are considered to intervene. Our work aimed at testing in vitro intestinal metabolism and defining its impact on transepithelial transport of PAHs. Caco-2 cells were cultivated on permeable filters and incubated with 14C-labeled benzo[a]pyrene (BaP), pyrene (Pyr), and phenanthrene (Phe), which differ in their physicochemical properties. The results showed that the cells were able to metabolize the compounds. In basal media, Phe appeared to be the least hydroxylated molecule (45% after a 6-h exposure), followed by Pyr (65%) and finally BaP (96%). Inhibition of PAH metabolism showed a determinant effect on kinetics profiles. Transfer in the basal compartment of BaP, Pyr, and Phe radioactivities was, respectively, 26, 4, and 2 times lower with inhibitors, corroborating that intestinal metabolism of PAHs would have a positive impact on their transfer, an impact that increased with their lipophilicity. Furthermore, after a 6-h incubation, metabolites were also detected in apical medium. These findings suggested that intestinal metabolism might play a key role in intestinal barrier permeability and thus in the bioavailability of tested micropollutants.
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Affiliation(s)
- Séverine Cavret
- ISARAlyon, 31 place Bellecour, F-69288 Lyon Cedex 02, France.
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Cavret S, Rychen G, Feidt C. IN VITRO INTESTINAL TRANSFER AND METABOLISM OF POLYCYCLIC AROMATIC HYDROCARBONS. Polycycl Aromat Compd 2004. [DOI: 10.1080/10406630490471573] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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18
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Yeung HY, Wong CC, Wong MH, Wong CKC. Differential expression of CYP1A1 mRNA in gill, intestine and liver of tilapia fed with PCB Aroclor-1254 and Aroclor-1260 spiked food. CHEMOSPHERE 2003; 52:1659-1665. [PMID: 12867200 DOI: 10.1016/s0045-6535(03)00543-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The differential expression of cytochrome P4501A1 gene expression (CYP1A1) in liver, intestine and gill of juvenile tilapia following oral exposure to polychlorinated biphenyl (PCB) Aroclor-1254 or Aroclor-1260 spiked food were investigated. The fish was fed with 0.1 g/g of body weight each day of the spiked food with a concentration of approximately 8 ppm. Fish fed with betaNF- or acetone-spiked food were used as positive and negative controls, respectively. On day 1, 3 and 7 of post-treatment, the fish were sampled and analyzed for the total accumulated levels of PCBs, as well as the induced levels of CYP1A1 mRNA. Our results indicated that the fish fed with PCBs-spiked food showed a time-dependent bioaccumulation of PCBs. The time course studies also revealed that in the first 3 days of feeding, significant increases in CYP1A1 were found in intestine (betaNF: 320% and Aroclor-1260: 290%), followed by liver (betaNF: 144%, Aroclor-1260: 123% and Aroclor-1254: 110%). The transcript levels, then declined slowly. There was no induction of gill CYP1A1 mRNA expression in all treatment groups. Among all the tested tissues, the highest intestinal CYP1A1 transcripts induction has highlighted its prompt response to dietary PCBs exposure. Our study supported the important role of intestine in response to dietary PCBs exposure. In addition, in the present study the relative potency of Aroclor-1260 over Aroclor-1254 in stimulating CYP1A1 expression was discussed, indicating that the highly chlorinated PCBs had a higher potency of bioaccumulation and CYP1A1 mRNA induction.
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Affiliation(s)
- H Y Yeung
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Kowloon, Hong Kong
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19
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Doi AM, Holmes E, Kleinow KM. P-glycoprotein in the catfish intestine: inducibility by xenobiotics and functional properties. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2001; 55:157-170. [PMID: 11595306 DOI: 10.1016/s0166-445x(01)00180-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The p-glycoprotein (pgp)-mediated multixenobiotic resistance (MXR) mechanism of aquatic animals has been associated with protection against pollution. Recent studies in mammals suggest that intestinal pgp may modulate intestinal bioavailability of dietary xenobiotics. In order to further delineate this mechanism in the catfish, these studies: (1) examined the pgp-related distribution in the intestine and liver of catfish, (2) evaluated the MXR response following exposure to various dietary xenobiotics and a prototypic pgp inducer and (3) evaluated pgp functional activity in membrane vesicles, using prototypic substrates and inhibitors. For this purpose, catfish were exposed in vivo to the pgp inducer vincristine (VIN), and the xenobiotics beta-naphthoflavone (BNF), benzo[a]pyrene (BaP), and 3,4,3',4'-tetrachlorobiphenyl (TCB). Membrane vesicles, prepared from liver and intestine (proximal and distal sections) of control and exposed catfish, were subjected to SDS PAGE, Western Blot, and detection with the pgp C219 monoclonal antibody. Transport activity was evaluated in vitro using the pgp substrate [3H]vinblastine (VBL), and the pgp inhibitor verapamil (VP). Immunoblot studies demonstrated a pgp-related protein of approximately 170 kDa in the intestine and liver of catfish. This protein appears to be very susceptible to degradation, and was present in higher levels in the liver, in comparison to the intestine, where regional differences were not observed. Dietary exposure to the pgp substrate VIN, or the xenobiotics BNF, BaP, and TCB, did not appear to affect pgp-related reactivity. Transport studies with VBL indicate that the pgp-related protein of the catfish intestine displays classic pgp-mediated multidrug resistance (MDR) characteristics, such as energy-dependency, and sensitivity to VP. These studies suggest that the pgp-related protein in the catfish intestine and liver is not only immunochemically, but also functionally related to the mammalian MDR. Moreover, the results presented indicate that pgp-related reactivity and transport in intestinal vesicles of catfish may be influenced by factors including method sensitivity, sample collection, sample preparation, and immunoblot conditions.
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Affiliation(s)
- A M Doi
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, South Stadium Drive, Baton Rouge, LA 70803, USA
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20
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Wong CK, Yeung HY, Woo PS, Wong MH. Specific expression of cytochrome P4501A1 gene in gill, intestine and liver of tilapia exposed to coastal sediments. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2001; 54:69-80. [PMID: 11451427 DOI: 10.1016/s0166-445x(00)00173-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Toxicological effects of persistent organic pollutants (POPs) in aquatic ecosystems lead to the deterioration of water quality and adversely affect fish and human health. The highly lipophilic nature of these pollutants may enter fish through the diet or by water-borne exposure. In monitoring contamination in aquatic systems, induction of the cytochrome P450 1A1 (CYP1A1) gene of fish has been evaluated as a sensitive, "early warning" method. The objective of the present study was to characterize the induction of the gene in fish upon exposure to coastal sediments and to determine its specific expression in liver and extrahepatic organs (i.e. gill and intestine) in which the toxicological effects to the corresponding tissues could be addressed. Sediment samples were collected from different sites, including Victoria Harbour (VS), Ma Wan (MW), Tsim Bei Tsui (TBT) and Mai Po (MP). The samples were analyzed for polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). CYP1A1 mRNA expression was measured in juvenile tilapia exposed experimentally to coastal sediment for 3 and 7 days. A negative control group of fish maintained in seawater was used. Using the primer dropping polymerase chain reaction technique, gill, intestinal and hepatic CYP1A1 mRNAs were quantified. Chemical analysis shows that the samples from VS contaminated with the highest concentration of PCBs (45.24 p.p.b.) and PAHs (1663.7 p.p.b.), followed by MW (16.01 and 347.7 p.p.b.), TBT (14.48 and 235.2 p.p.b.) and MP (14.60 and 242.2 p.p.b.). Fish exposed to sediments were contaminated with various levels of PCBs (VS, 64.14-72.06 p.p.b.; MP, 27.06-31.62 p.p.b.; TBT, 27.29-33.92 p.p.b.; MW, 16.05-17.76 p.p.b.) and PAHs (VS, 124.7-304.9 p.p.b.; MP, 97.57-164.1 p.p.b.; TBT, 25.38-98 p.p.b.; MW, 24.07-68.13 p.p.b.). The control fish displayed moderate expression of CYP1A1 mRNA in liver (1.45 arbitrary units), gill (1.21 arbitrary units) and intestine (0.56 arbitrary units). Following sediment exposure, there was a large increase in CYP1A1 mRNA in intestine and liver but no significant changes in gill tissues. In the first 3 days, there was anywhere from 34-96 and 69-156% induction of the CYP1A1 transcripts in intestine and liver, respectively. Following 7 days of exposure, a continued induction of high level of CYP1A1 mRNA in intestine (73-157%) was observed. The induction of CYP1A1 in liver and intestine provided a defensive mechanism against POPs entering from the external environment.
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Affiliation(s)
- C K Wong
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong.
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21
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Livingstone DR. The fate of organic xenobiotics in aquatic ecosystems: quantitative and qualitative differences in biotransformation by invertebrates and fish. Comp Biochem Physiol A Mol Integr Physiol 1998; 120:43-9. [PMID: 9773498 DOI: 10.1016/s1095-6433(98)10008-9] [Citation(s) in RCA: 335] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Biotransformation of natural and man-made foreign compounds (xenobiotics) proceeds via introduction of a functional group (phase I metabolism) and subsequent attachment of a polar moiety to the group (phase II metabolism). The biotransformation fate of xenobiotics depends on the activities, complement and inducibility of the biotransformation enzymes. Previous analysis of the dependence of in vivo rates of biotransformation on tissue parent compound concentration for marine invertebrates revealed that hydrocarbons are metabolised more slowly than xenobiotics already containing functional groups, and crustaceans metabolise both types of xenobiotics faster than molluscs (Livingstone D.R., Persistent pollutants in marine ecosystems, pp. 3-34, Pergamon, Oxford). Use of the same approach showed that fish metabolise pentachlorophenol (PCP) and benzo[a]pyrene (BaP) faster than certain aquatic invertebrates, viz. rates of biotransformation to total metabolites (pmol min-1 g-1 wet wt.) at a tissue parent compound concentration of 10 nmol g-1 were, respectively, 19.2 +/- 3.7 (Carassius auratus) and 4.8 +/- 6.6 (molluscan species) (PCP), and 19.1 +/- 6.3 (fish species) and 2.1 +/- 0.2 (crustacean species) (BaP). The higher rate of biotransformation of BaP in fish is consistent with higher levels of total cytochrome P450 and inducible cytochrome P4501A (CYP1A) activity. The similar rate of metabolism of a hydrocarbon (BaP) (requires initial metabolism by cytochrome P450) and a functional group compound (PCP) by fish may also be due to the high levels of cytochrome P450, compared with the situation in invertebrates where rate-limiting cytochrome P450 may be responsible for the lower rates of hydrocarbon compared with functional group compound metabolism.
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22
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Van Veld PA, Ko U, Vogelbein WK, Westbrook DJ. Glutathione S-transferase in intestine, liver and hepatic lesions of mummichog (Fundulus heteroclitus) from a creosote-contaminated environment. FISH PHYSIOLOGY AND BIOCHEMISTRY 1991; 9:369-76. [PMID: 24213733 DOI: 10.1007/bf02265157] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/01/1991] [Indexed: 05/06/2023]
Abstract
Cytosolic glutathione S-transferase (GSH transferase) activity towards 1-chloro-2,4-dinitrobenzene (CDNB) was elevated approximately three to four-fold in intestine and liver of mummichog (Fundulus heteroclitus) collected from a creosote-contaminated site in the Elizabeth River, Virginia. Intestinal GSH transferase activity at the most heavily contaminated site, at a moderately contaminated site and at a relatively clean site averaged 3.64, 2.83 and 1.11µmoles/min/mg respectively, while values for liver at these sites averaged 2.84, 1.75 and 0.93µmoles/min/mg. In addition, densitometric tracings of sodium dodecylsulfate-polyacrylamide gels of intestine and liver cytosol revealed a similar trend in the staining intensity of a 25.8 kD protein band, which lies within the molecular weight range of GSH transferase subunits. Activity in putative preneoplastic and neoplastic hepatic lesions of fish collected from the creosote-contaminated site was not significantly different from that of adjacent normal tissue. In the laboratory, dietary betanaphthoflavone (ßNF) treatment resulted in a three-fold increase in intestinal GSH transferase. Hepatic GSH transferase activity in the same fish was not affected by dietary ßNF although hepatic monooxygenase activity, measured as ethoxyresorufin O-deethylase (EROD), was. The results of this study indicate a response of the intestinal detoxification system to environmental contaminants and supports previous studies on the importance of intestinal metabolism of foreign compounds. Further, our results indicate the trend towards elevated GSH transferase in liver of feral fish could not be attributed to a cancerous disease state in these fish but indicates chemical induction in this organ as well.
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Affiliation(s)
- P A Van Veld
- The College of William and Mary, School of Marine Science, Virginia Institute of Marine Science, 23062, Gloucester Point, Viriginia, USA
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23
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James MO, Schell JD, Boyle SM, Altman AH, Cromer EA. Southern flounder hepatic and intestinal metabolism and DNA binding of benzo[a]pyrene (BaP) metabolites following dietary administration of low doses of BaP, BaP-7,8-dihydrodiol or a BaP metabolite mixture. Chem Biol Interact 1991; 79:305-21. [PMID: 1913975 DOI: 10.1016/0009-2797(91)90111-j] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Certain finfish species living in chemically polluted environments exhibit a high incidence of gastrointestinal tract tumors. Carnivorous fish in such environments are likely to consume invertebrates which contain chemical procarcinogens and the invertebrate biotransformation products of these compounds. The retention in tissues, extent of DNA adduct formation in liver and intestine, and metabolite composition of bile was investigated in southern flounder following gavage with pure [3H]- or [14C]benzo[a]pyrene (BaP), pure [14C]benzo[a]pyrene-7,8-dihydrodiol (BaP-7,8D), or hepatopancreas from spiny lobsters previously dosed with [3H]- or [14C]BaP (Metab.HP). Metab.HP contained mainly polar conjugates of BaP diols, triols and tetraols. BaP-7,8D was retained in fish tissues and bile at 24 h to a greater extent (33.6% of the dose), than either BaP (19.00%) or Metab.HP (6.6%). Hepatic and intestinal DNA isolated from all dosed fish contained covalently bound radioactivity, but exposure to BaP-7,8D or BaP resulted in significantly higher binding in both tissues than exposure to Metab.HP. Hepatic DNA from BaP and BaP-7,8D-dosed flounder contained 0.24 +/- 0.07 and 0.33 +/- 0.06 pmol BaP equivalents/mg DNA respectively (mean +/- S.E.), while hepatic DNA isolated from Metab.HP-dosed flounder contained 0.006 +/- 0.002 pmol BaP equivalents/mg DNA. Binding of radioactivity to intestinal DNA was significantly higher than to hepatic DNA for flounder dosed with Metab.HP (0.026 +/- 0.003) or with BaP (0.76 +/- 0.27) but not for flounder dosed with BaP-7,8D (0.44 +/- 0.09). These studies show that dietary BaP, and metabolites likely to be present in invertebrates, can be absorbed by the southern flounder and form DNA adducts in target organs.
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Affiliation(s)
- M O James
- Department of Medicinal Chemistry, JHMHC, University of Florida, Gainesville 32610
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24
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Dunn BP. Carcinogen adducts as an indicator for the public health risks of consuming carcinogen-exposed fish and shellfish. ENVIRONMENTAL HEALTH PERSPECTIVES 1991; 90:111-6. [PMID: 2050048 PMCID: PMC1519488 DOI: 10.1289/ehp.90-1519488] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
A large variety of environmental carcinogens are metabolically activated to electrophilic metabolites that can bind to nucleic acids and protein, forming covalent adducts. The formation of DNA-carcinogen adducts is thought to be a necessary step in the action of most carcinogens. Recently, a variety of new fluorescence, immunochemical, and radioactive-postlabeling procedures have been developed that allow the sensitive measurement of DNA-carcinogen adducts in organisms exposed to environmental carcinogens. In some cases, similar procedures have been developed for protein-carcinogen adducts. In an organism with active metabolic systems for a given carcinogen, adducts are generally much longer lived than the carcinogens that formed them. Thus, the detection of DNA- or protein-carcinogen adducts in aquatic foodstuffs can act as an indicator of prior carcinogen exposure. The presence of DNA adducts would, in addition, suggest a mutagenic/carcinogenic risk to the aquatic organism itself. Vertebrate fish are characterized by high levels of carcinogen metabolism, low body burdens of carcinogen, the formation of carcinogen-macromolecule adducts, and the occurrence of pollution-related tumors. Shellfish, on the other hand, have low levels of carcinogen metabolism, high body burdens of carcinogen, and have little or no evidence of carcinogen-macromolecule adducts or tumors. The consumption of carcinogen adducts in aquatic foodstuffs is unlikely to represent a human health hazard. There are no metabolic pathways by which protein-carcinogen or DNA-carcinogen adducts could reform carcinogens. Incorporation via salvage pathways of preformed nucleoside-carcinogen adducts from foodstuffs into newly synthesized human DNA is theoretically possible.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- B P Dunn
- British Columbia Cancer Research Center, Vancouver, Canada
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25
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Barrowman JA, Rahman A, Lindstrom MB, Borgstrom B. Intestinal absorption and metabolism of hydrocarbons. Prog Lipid Res 1989; 28:189-203. [PMID: 2694176 DOI: 10.1016/0163-7827(89)90012-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- J A Barrowman
- Faculty of Medicine, Memorial University of Newfoundland St. John's, Canada
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