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De Marco G, Billè B, Brandão F, Galati M, Pereira P, Cappello T, Pacheco M. Differential Cell Metabolic Pathways in Gills and Liver of Fish (White Seabream Diplodus sargus) Coping with Dietary Methylmercury Exposure. TOXICS 2023; 11:181. [PMID: 36851056 PMCID: PMC9961322 DOI: 10.3390/toxics11020181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/10/2023] [Accepted: 02/12/2023] [Indexed: 06/18/2023]
Abstract
Mercury (Hg) is a dangerous and persistent trace element. Its organic and highly toxic form, methylmercury (MeHg), easily crosses biological membranes and accumulates in biota. Nevertheless, understanding the mechanisms of dietary MeHg toxicity in fish remains a challenge. A time-course experiment was conducted with juvenile white seabreams, Diplodus sargus (Linnaeus, 1758), exposed to realistic levels of MeHg in feed (8.7 μg g-1, dry weight), comprising exposure (E; 7 and 14 days) and post-exposure (PE; 28 days) periods. Total Hg levels increased with time in gills and liver during E and decreased significantly in PE (though levels of control fish were reached only for gills), with liver exhibiting higher levels (2.7 times) than gills. Nuclear magnetic resonance (NMR)-based metabolomics revealed multiple and often differential metabolic changes between fish organs. Gills exhibited protein catabolism, disturbances in cholinergic neurotransmission, and changes in osmoregulation and lipid and energy metabolism. However, dietary MeHg exposure provoked altered protein metabolism in the liver with decreased amino acids, likely for activation of defensive strategies. PE allowed for the partial recovery of both organs, even if with occurrence of oxidative stress and changes of energy metabolism. Overall, these findings support organ-specific responses according to their sensitivity to Hg exposure, pointing out that indications obtained in biomonitoring studies may depend also on the selected organ.
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Affiliation(s)
- Giuseppe De Marco
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy
| | - Barbara Billè
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy
| | - Fátima Brandão
- Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Mariachiara Galati
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy
| | - Patrícia Pereira
- Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Tiziana Cappello
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy
| | - Mário Pacheco
- Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, 3810-193 Aveiro, Portugal
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2
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Ronchetti GZ, Simões MR, Schereider IRG, Leal MAS, Peçanha GAW, Padilha AS, Vassallo DV. Oxidative Stress Induced by 30 Days of Mercury Exposure Accelerates Hypertension Development in Prehypertensive Young SHRs. Cardiovasc Toxicol 2022; 22:929-939. [DOI: 10.1007/s12012-022-09769-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 10/20/2022] [Indexed: 11/16/2022]
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3
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Barfuss DW, Buchanan JT, Joshee L, Pittman EH, D'Souza N, Matta KE, Brownlee RT, Bridges CC. Hepatic Processing of Mercuric Ions Facilitates Delivery to Renal Proximal Tubules. Toxicol Lett 2022; 359:1-9. [DOI: 10.1016/j.toxlet.2022.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 12/16/2021] [Accepted: 01/18/2022] [Indexed: 11/25/2022]
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4
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Gochfeld M, Burger J. Mercury interactions with selenium and sulfur and the relevance of the Se:Hg molar ratio to fish consumption advice. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:18407-18420. [PMID: 33507504 PMCID: PMC8026698 DOI: 10.1007/s11356-021-12361-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 01/02/2021] [Indexed: 05/20/2023]
Abstract
Eating fish is often recommended as part of a healthful diet. However, fish, particularly large predatory fish, can contain significant levels of the highly toxic methylmercury (MeHg). Ocean fish in general also contain high levels of selenium (Se), which is reported to confer protection against toxicity of various metals including mercury (Hg). Se and Hg have a high mutual binding affinity, and each can reduce the toxicity of the other. This is an evolving area of extensive research and controversy with variable results in the animal and epidemiologic literature. MeHg is toxic to many organ systems through high affinity for -SH (thiol) ligands on enzymes and microtubules. Hg toxicity also causes oxidative damage particularly to neurons in the brain. Hg is a potent and apparently irreversible inhibitor of the selenoenzymes, glutathione peroxidases (GPX), and thioredoxin reductases (TXNRD) that are important antioxidants, each with a selenocysteine (SeCys) at the active site. Hg binding to the SeCys inhibits these enzymes, accounting in part for the oxidative damage that is an important manifestation of Hg toxicity, particularly if there is not a pool of excess Se to synthesize new enzymes. A molar excess of Se reflected in an Se:Hg molar ratio > 1 is often invoked as evidence that the Hg content can be discounted. Some recent papers now suggest that if the Se:Hg molar ratio exceeds 1:1, the fish is safe and the mercury concentration can be ignored. Such papers suggested that the molar ratio rather than the Hg concentration should be emphasized in fish advisories. This paper examines some of the limitations of current understanding of the Se:Hg molar ratio in guiding fish consumption advice; Se is certainly an important part of the Hg toxicity story, but it is not the whole story. We examine how Hg toxicity relates also to thiol binding. We suggest that a 1:1 molar ratio cannot be relied on because not all of the Se in fish or in the fish eater is available to interact with Hg. Moreover, in some fish, Se levels are sufficiently high to warrant concern about Se toxicity.
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Affiliation(s)
- Michael Gochfeld
- Rutgers Biomedical and Health Sciences, School of Public Health, Piscataway, NJ, USA.
- Environmental and Occupational Health Sciences Institutes, Rutgers University, Piscataway, NJ, 08854, USA.
| | - Joanna Burger
- Environmental and Occupational Health Sciences Institutes, Rutgers University, Piscataway, NJ, 08854, USA
- Division of Life Science, Rutgers University, 604 Allison Road, Piscataway, NJ, 08854, USA
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Jang JW, Lee S, Lee BJ, Hur SW, Son MH, Kim KW, Kim KD, Han HS. A comparative study of effects of dietary mercuric chloride and methylmercury chloride on growth performance, tissue accumulation, stress and immune responses, and plasma measurements in Korean rockfish, Sebastes schlegeli. CHEMOSPHERE 2020; 260:127611. [PMID: 32758780 DOI: 10.1016/j.chemosphere.2020.127611] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 07/02/2020] [Accepted: 07/03/2020] [Indexed: 06/11/2023]
Abstract
Mercury (Hg) is known as a highly toxic heavy metal, and its toxicity varies depending on its form due to different toxicokinetics between inorganic and organic Hg. Limited information on comparison of Hg toxicity concerning its chemical form by oral exposure is currently available in cultured fishes. Therefore, we conducted a comparative study to have a better understanding of distinct toxic effects between mercuric chloride (HgCl2) and methylmercury chloride (CH3HgCl) in Korean rockfish. The 12-weeks dietary exposure of HgCl2 and CH3HgCl with its graded levels (0.4-6.4 ppm) (2 × 5 factorial design) in the young-of-the-year rockfish (initial weight: 82 ± 0.3 g) resulted in neither interactive nor main effects on whole-organism responses, including growth, feed utilization, and survival. However, the distinct pattern of Hg accumulation between the two forms in dorsal muscle, brain, liver and kidney tissues was observed, showing that the rockfish fed the CH3HgCl-contained diets exhibited the dose-dependent accumulation throughout the sampling points (1, 2, 4, 8, and 12 weeks post feeding), whereas those fed the HgCl2-contained diets did not show such response. The CH3HgCl exposure induced higher oxidative stress and immunotoxicity, reflected by the elevated plasma superoxide dismutase and lysozyme activities, respectively. In addition, the CH3HgCl-induced alteration in plasma measurements, including the plasma aspartate transaminase activity and total protein level was found. Taken together, the dietary exposure of methylmercury chloride had more pronounced toxic effects than mercuric chloride in the young-of-year rockfish, needed to be taken into consideration for regulation of maximum allowed levels for Hg by its chemical form.
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Affiliation(s)
- Ji-Won Jang
- Aquafeed Research Center, National Institute of Fisheries Science, Pohang, 37517, South Korea
| | - Seunghyung Lee
- Aquafeed Research Center, National Institute of Fisheries Science, Pohang, 37517, South Korea.
| | - Bong-Joo Lee
- Aquafeed Research Center, National Institute of Fisheries Science, Pohang, 37517, South Korea
| | - Sang-Woo Hur
- Aquafeed Research Center, National Institute of Fisheries Science, Pohang, 37517, South Korea
| | - Maeng-Hyun Son
- Aquafeed Research Center, National Institute of Fisheries Science, Pohang, 37517, South Korea
| | - Kang-Woong Kim
- Aquafeed Research Center, National Institute of Fisheries Science, Pohang, 37517, South Korea
| | - Kyoung-Duck Kim
- Fisheries Research & Development, East Sea Fisheries Research Institute, National Institute of Fisheries Science, Gangneung, 25435, South Korea
| | - Hyon-Sob Han
- College of Ocean Science and Technology, Kunsan National University, Kusan, 54150, South Korea
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6
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Methylmercury Poisoning Induces Cardiac Electrical Remodeling and Increases Arrhythmia Susceptibility and Mortality. Int J Mol Sci 2020; 21:ijms21103490. [PMID: 32429059 PMCID: PMC7279040 DOI: 10.3390/ijms21103490] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/13/2020] [Accepted: 05/14/2020] [Indexed: 11/21/2022] Open
Abstract
This study aims to investigate the cardiac electrical remodeling associated with intoxication by methylmercury (MeHg). We evaluated the chronic effects of MeHg on in vivo electrocardiograms and on ex vivo action potentials and depolarizing (ICa-L) and repolarizing (Ito) currents. The acute effect of MeHg was evaluated on HEK293 cells expressing human ERG, Kv4.3 and KCNQ1/KCNE1 channels. Chronic MeHg treatment increased QTc and Tpeak–Tend interval duration, prolonged action potential duration and decreased amplitude of Ito and ICa-L. In addition, heterologously expressed IhKv4.3, IhERG or IhKCNQ1/KCNE1 decreased after acute exposure to MeHg at subnanomolar range. The introduction of the in vitro effects of MeHg in a computer model of human ventricular action potentials triggered early afterdepolarizations and arrhythmia. In conclusion, cardiac electrical remodeling induced by MeHg poisoning is related to the reduction of Ito and ICa-L. The acute effect of MeHg on hKv4.3; hERG and hKCNQ1/KCNE1 currents and their transposition to in silico models show an association between MeHg intoxication and acquired Long QT Syndrome in humans. MeHg can exert its high toxicity either after chronic or acute exposure to concentrations as low as picomolar.
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7
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Li W, Wang WX. In vivo oral bioavailability of fish mercury and comparison with in vitro bioaccessibility. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 683:648-658. [PMID: 31150885 DOI: 10.1016/j.scitotenv.2019.05.290] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 04/17/2019] [Accepted: 05/20/2019] [Indexed: 06/09/2023]
Abstract
Fish consumption is considered to be a major human exposure route for mercury (Hg), but assessing the actual Hg bioavailability from consumed fish is challenging. In this study, we conducted both in vivo bioavailability (using a mouse model) and in vitro bioaccessibility (using various gastrointestinal digestion methods) assessments of Hg from consumed fish. Lyophilized fish muscles which already absorbed Hg through natural incorporation were introduced to mice by active feeding. Assimilation efficiency (AE) was measured as a short-term kinetic parameter, while a 7-day accumulation of Hg in mice blood, liver and kidney was determined. The AEs of Hg in mice ranged between 82 and 96% and showed a positive relationship with MeHg in fish independent of the fish species. For long-term bioavailability tests in which the Hg retention in organs was measured after a 7-day exposure, most Hg was found to be accumulated in liver and kidney, resulting in a strong correlation between Hg dosage and accumulation in mice organs. The long-term absolute bioavailability of mice was comparable between the liver and kidney, but much lower in the blood. The calculated absolute total Hg bioavailability ranged between 38% and 99% and decreased as the Hg dosage increased. Results of bioaccessibility tests varied considerably among different methods, illustrating that there were limitations for the in vitro bioaccessibility assay to predict the digestive dynamics of Hg in mammalian gastrointestinal tract. Our study strongly demonstrated the expediency of direct determination of Hg bioavailability, but more bioaccessibility assessments should be explored and optimized as an alternative to traditional animal experimentation.
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Affiliation(s)
- Wanze Li
- Shenzhen Key Laboratory of Edible and Medicinal Bioresources, HKUST Shenzhen Research Institute, Shenzhen 518057, Department of Ocean Science, Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, China
| | - Wen-Xiong Wang
- Shenzhen Key Laboratory of Edible and Medicinal Bioresources, HKUST Shenzhen Research Institute, Shenzhen 518057, Department of Ocean Science, Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, Hong Kong, China.
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8
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Botelho T, Marques VB, Simões MR, do Val Lima PR, Simões FV, Vassallo DV, dos Santos L. Impaired participation of potassium channels and Na+
/K+
-ATPase in vasodilatation due to reduced nitric oxide bioavailability in rats exposed to mercury. Basic Clin Pharmacol Toxicol 2018; 124:190-198. [DOI: 10.1111/bcpt.13113] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 08/13/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Tatiani Botelho
- Department of Physiological Sciences; Federal University of Espirito Santo; Vitória Brazil
| | - Vinícius B. Marques
- Department of Physiological Sciences; Federal University of Espirito Santo; Vitória Brazil
| | - Maylla R. Simões
- Department of Physiological Sciences; Federal University of Espirito Santo; Vitória Brazil
| | | | - Fabiana V. Simões
- Department of Physiological Sciences; Federal University of Espirito Santo; Vitória Brazil
| | - Dalton V. Vassallo
- Department of Physiological Sciences; Federal University of Espirito Santo; Vitória Brazil
- Health Science Center of Vitória-EMESCAM; Vitória Brazil
| | - Leonardo dos Santos
- Department of Physiological Sciences; Federal University of Espirito Santo; Vitória Brazil
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9
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Oliveira CS, Nogara PA, Ardisson-Araújo DMP, Aschner M, Rocha JBT, Dórea JG. Neurodevelopmental Effects of Mercury. ADVANCES IN NEUROTOXICOLOGY 2018; 2:27-86. [PMID: 32346667 PMCID: PMC7188190 DOI: 10.1016/bs.ant.2018.03.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The toxicology of mercury (Hg) is of concern since this metal is ubiquitously distributed in the environment, and living organisms are routinely exposed to Hg at low to high levels. The toxic effects of Hg are well studied and it is known that they may differ depending on the Hg chemical species. In this chapter, we emphasize the neurotoxic effects of Hg during brain development. The immature brain is more susceptible to Hg exposure, since all the Hg chemical forms, not only the organic ones, can harm it. The possible consequences of Hg exposure during the early stages of development, the additive effects with other co-occurring neurotoxicants, and the known mechanisms of action and targets will be addressed in this chapter.
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Affiliation(s)
- Cláudia S Oliveira
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Pablo A Nogara
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Daniel M P Ardisson-Araújo
- Programa de Pós-graduação em Ciências Biológicas: Bioquímica Toxicológica, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
- Laboratório de Virologia de Insetos, Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, NY, USA
| | - João B T Rocha
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - José G Dórea
- Professor Emeritus, Faculdade de Ciências da Saúde, Universidade de Brasília, Brasília, DF, Brazil
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10
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Liu CB, Qu GB, Cao MX, Liang Y, Hu LG, Shi JB, Cai Y, Jiang GB. Distinct toxicological characteristics and mechanisms of Hg 2+ and MeHg in Tetrahymena under low concentration exposure. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2017; 193:152-159. [PMID: 29096088 DOI: 10.1016/j.aquatox.2017.10.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Revised: 10/18/2017] [Accepted: 10/20/2017] [Indexed: 06/07/2023]
Abstract
Inorganic divalent mercury complexes (Hg2+) and monomethylmercury complexes (MeHg) are the main mercury species in aquatic systems and their toxicity to aquatic organisms is of great concern. Tetrahymena is a type of unicellular eukaryotic protozoa located at the bottom of food chain that plays a fundamental role in the biomagnification of mercury. In this work, the dynamic accumulation properties, toxicological characteristics and mechanisms of Hg2+ and MeHg in five Tetrahymena species were evaluated in detail. The results showed that both Hg2+ and MeHg were ingested and exhibited inhibitory effects on the proliferation or survival of Tetrahymena species. However, the ingestion rate of MeHg was significantly higher than that of Hg2+. The mechanisms responsible for the toxicity of MeHg and Hg2+ were different, although both chemicals altered mitochondrial membrane potential (MMP). MeHg disrupted the integrity of membranes while Hg2+ had detrimental effects on Tetrahymena as a result of the increased generation of reactive oxygen species (ROS). In addition, the five Tetrahymena species showed different capacities in accumulating Hg2+ and MeHg, with T. corlissi exhibiting the highest accumulations. The study also found significant growth-promoting effect on T. corlissi under low concentration exposure (0.003 and 0.01μg Hg/mL (15 and 50nM)), suggesting different effect and mechanism that should be more closely examined when assessing the bioaccumulation and toxicity of mercury in aquatic ecosystems.
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Affiliation(s)
- Cheng-Bin Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guang-Bo Qu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Meng-Xi Cao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Institute of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Yong Liang
- Institute of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Li-Gang Hu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Jian-Bo Shi
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; Institute of Environment and Health, Jianghan University, Wuhan 430056, China.
| | - Yong Cai
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Institute of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Gui-Bin Jiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
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11
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Farias-Junior PMA, Teixeira FB, Fagundes NCF, Miranda GHN, Oliveira Bittencourt L, de Oliveira Paraense RS, Silva MCF, Sagica FDES, de Oliveira EH, Crespo-López ME, Lima RR. Chronic intoxication by methylmercury leads to oxidative damage and cell death in salivary glands of rats. Metallomics 2017; 9:1778-1785. [PMID: 29082389 DOI: 10.1039/c7mt00168a] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Methylmercury (MeHg) is one of the most toxic species of mercury, causing several systemic damages; however, its effect on the salivary glands has rarely been explored to date. This study was aimed at analyzing the mercury deposit, oxidative stress markers, and cell viability in parotid and submandibular rat salivary glands after chronic methylmercury intoxication. Herein, forty male Wistar rats (40 days old) were used in the experiment. The animals of the experimental group were intoxicated by intragastric gavage with MeHg at a dose of 0.04 mg per kg body weight per day for 35 days, whereas the control group received only corn oil, a diluent. After the period of intoxication, the glands were obtained for evaluation of total mercury deposit, cell viability, and the malondialdehyde (MDA) and the nitrite levels. Our results indicated mercury deposits in salivary glands, with a decrease in cell viability, higher levels of MDA in both glands of intoxicated animals, and a higher concentration of nitrite only in the submandibular gland of the mercury group. Thus, the intoxication by MeHg was able to generate deposits and oxidative stress in salivary glands that resulted in a decrease in cell viability in both types of glands.
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Affiliation(s)
- Paulo Mecenas Alves Farias-Junior
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Street Augusto Corrêa N. 01, Guamá, Belém, Pará 66075-900, Brazil.
| | - Francisco Bruno Teixeira
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Street Augusto Corrêa N. 01, Guamá, Belém, Pará 66075-900, Brazil.
| | - Nathalia Carolina Fernandes Fagundes
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Street Augusto Corrêa N. 01, Guamá, Belém, Pará 66075-900, Brazil.
| | - Giza Hellen Nonato Miranda
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Street Augusto Corrêa N. 01, Guamá, Belém, Pará 66075-900, Brazil.
| | - Leonardo Oliveira Bittencourt
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Street Augusto Corrêa N. 01, Guamá, Belém, Pará 66075-900, Brazil.
| | | | - Márcia Cristina Freitas Silva
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Street Augusto Corrêa N. 01, Guamá, Belém, Pará 66075-900, Brazil.
| | | | - Edivaldo Herculano de Oliveira
- Laboratory of Tissue Culture and Cytogenetics, Evandro Chagas Institute, Ananindeua, Pará, Brazil and College of Natural Sciences, Institute of Natural Sciences, Federal University of Pará, Pará, Belém, Pará, Brazil
| | - Maria Elena Crespo-López
- Laboratory of Molecular Pharmacology, Institute of Biological Sciences, Federal University of Pará, Pará, Belém, Pará, Brazil
| | - Rafael Rodrigues Lima
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Street Augusto Corrêa N. 01, Guamá, Belém, Pará 66075-900, Brazil.
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12
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Tamm C, Ceccatelli S. Mechanistic insight into neurotoxicity induced by developmental insults. Biochem Biophys Res Commun 2017; 482:408-418. [DOI: 10.1016/j.bbrc.2016.10.087] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 10/23/2016] [Indexed: 12/31/2022]
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13
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Kumagai Y, Abiko Y. Environmental Electrophiles: Protein Adducts, Modulation of Redox Signaling, and Interaction with Persulfides/Polysulfides. Chem Res Toxicol 2016; 30:203-219. [DOI: 10.1021/acs.chemrestox.6b00326] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Yoshito Kumagai
- Environmental Biology Section, Faculty
of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Yumi Abiko
- Environmental Biology Section, Faculty
of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
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14
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Affiliation(s)
- J.R. Mackert
- Dental Materials Medical College of Georgia Augusta, Georgia 30912
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15
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Puga S, Pereira P, Pinto-Ribeiro F, O'Driscoll NJ, Mann E, Barata M, Pousão-Ferreira P, Canário J, Almeida A, Pacheco M. Unveiling the neurotoxicity of methylmercury in fish (Diplodus sargus) through a regional morphometric analysis of brain and swimming behavior assessment. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 180:320-333. [PMID: 27780124 DOI: 10.1016/j.aquatox.2016.10.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 10/11/2016] [Accepted: 10/14/2016] [Indexed: 06/06/2023]
Abstract
The current study aims to shed light on the neurotoxicity of MeHg in fish (white seabream - Diplodus sargus) by the combined assessment of: (i) MeHg toxicokinetics in the brain, (ii) brain morphometry (volume and number of neurons plus glial cells in specific brain regions) and (iii) fish swimming behavior (endpoints associated with the motor performance and the fear/anxiety-like status). Fish were surveyed for all the components after 7 (E7) and 14 (E14) days of dietary exposure to MeHg (8.7μgg-1), as well as after a post-exposure period of 28days (PE28). MeHg was accumulated in the brain of D. sargus after a short time (E7) and reached a maximum at the end of the exposure period (E14), suggesting an efficient transport of this toxicant into fish brain. Divalent inorganic Hg was also detected in fish brain along the experiment (indicating demethylation reactions), although levels were 100-200 times lower than MeHg, which pinpoints the organic counterpart as the great liable for the recorded effects. In this regard, a decreased number of cells in medial pallium and optic tectum, as well as an increased hypothalamic volume, occurred at E7. Such morphometric alterations were followed by an impairment of fish motor condition as evidenced by a decrease in the total swimming time, while the fear/anxiety-like status was not altered. Moreover, at E14 fish swam a greater distance, although no morphometric alterations were found in any of the brain areas, probably due to compensatory mechanisms. Additionally, although MeHg decreased almost two-fold in the brain during post-exposure, the levels were still high and led to a loss of cells in the optic tectum at PE28. This is an interesting result that highlights the optic tectum as particularly vulnerable to MeHg exposure in fish. Despite the morphometric alterations reported in the optic tectum at PE28, no significant changes were found in fish behavior. Globally, the effects of MeHg followed a multiphasic profile, where homeostatic mechanisms prevented circumstantially morphometric alterations in the brain and behavioral shifts. Although it has become clear the complexity of matching brain morphometric changes and behavioral shifts, motor-related alterations induced by MeHg seem to depend on a combination of disruptions in different brain regions.
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Affiliation(s)
- Sónia Puga
- Life and Health Sciences Research Institute (ICVS), School of Medicine, Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Patrícia Pereira
- Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Filipa Pinto-Ribeiro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Nelson J O'Driscoll
- Department of Earth and Environmental Science, Center for Analytical Research on the Environment, K.C. Irving Center, Acadia University, Wolfville, Nova Scotia, Canada
| | - Erin Mann
- Department of Earth and Environmental Science, Center for Analytical Research on the Environment, K.C. Irving Center, Acadia University, Wolfville, Nova Scotia, Canada
| | - Marisa Barata
- IPMA - Aquaculture Research Station, 8700-005 Olhão, Portugal
| | | | - João Canário
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Armando Almeida
- Life and Health Sciences Research Institute (ICVS), School of Medicine, Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Mário Pacheco
- Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
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Hassan SA, Farouk SM, Abbott LC. Transmission electron microscopic evaluation of neuronal changes in methylmercury-exposed zebrafish embryos (Danio rerio). Ultrastruct Pathol 2016; 40:333-341. [DOI: 10.1080/01913123.2016.1234529] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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17
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Tong J, Wang Y, Lu Y. In vitro evaluation of inorganic and methyl mercury mediated cytotoxic effect on neural cells derived from different animal species. J Environ Sci (China) 2016; 41:138-145. [PMID: 26969059 DOI: 10.1016/j.jes.2015.04.036] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/24/2015] [Accepted: 04/15/2015] [Indexed: 05/15/2023]
Abstract
To extend the current understanding of the mercury-mediated cytotoxic effect, five neural cell lines established from different animal species were comparatively analyzed using three different endpoint bioassays: thiazolyl blue tetrazolium bromide, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay (MTT), neutral red uptake assay (NRU), and Coomassie blue assay (CB). Following a 24-hr exposure to selected concentrations of mercury chloride (HgCl2) and methylmercury (II) chloride (MeHgCl), the cytotoxic effect on test cells was characterized by comparing their 50% inhibition concentration (IC50) values. Experimental results indicated that both these forms of mercury were toxic to all the neural cells, but at very different degrees. The IC50 values of MeHgCl among these cell lines ranged from 1.15±0.22 to 10.31±0.70μmol/L while the IC50 values for HgCl2 were much higher, ranging from 6.44±0.36 to 160.97±19.63μmol/L, indicating the more toxic nature of MeHgCl. The IC50 ratio between HgCl2 and MeHgCl ranged from 1.75 to 96.0, which confirms that organic mercury is much more toxic to these neural cells than inorganic mercury. Among these cell lines, HGST-BR and TriG44 derived from marine sea turtles showed a significantly high tolerance to HgCl2 as compared to the three mammalian neural cells. Among these neural cells, SK-N-SH represented the most sensitive cells to both chemical forms of mercury.
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Affiliation(s)
- Jing Tong
- Institute of TCM & Natural Products, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China; Department of Public Health Sciences, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Youwei Wang
- Institute of TCM & Natural Products, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
| | - Yuanan Lu
- Global Health Center, School of Public Health, Wuhan University, Wuhan 430071, China; Department of Public Health Sciences, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
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Estévez-Hernández O, Duque J, Rodríguez-Hernández J, Reguera E. Dinuclear and polymeric Hg(II) complexes with 1-(2-furoyl)thiourea derivatives: Their crystal structure and related properties. Polyhedron 2015. [DOI: 10.1016/j.poly.2015.05.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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19
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Wei L, Xue R, Zhang P, Wu Y, Li X, Pei F. (1)H NMR-Based Metabolomics and Neurotoxicity Study of Cerebrum and Cerebellum in Rats Treated with Cinnabar, a Traditional Chinese Medicine. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2015; 19:490-8. [PMID: 26110755 DOI: 10.1089/omi.2015.0042] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Cinnabar, an important traditional Chinese mineral medicine, has been widely used as a Chinese patent medicine ingredient for sedative therapy. Nevertheless, the neurotoxic effects of cinnabar have also been noted. In this study, (1)H NMR-based metabolomics, combined with multivariate pattern recognition, were applied to investigate the neurotoxic effects of cinnabar after intragastrical administration (dosed at 2 and 5 g/kg body weight) on male Wistar rats. The metabolite variations induced by cinnabar were characterized by increased levels of glutamate, glutamine, myo-inositol, and choline, as well as decreased levels of GABA, taurine, NAA, and NAAG in tissue extracts of the cerebellum and cerebrum. These findings suggested that cinnabar induced glutamate excitotoxicity, neuronal cell loss, osmotic state changes, membrane fluidity disruption, and oxidative injury in the brain. We also show here that there is a dose- and time-dependent neurotoxicity of cinnabar, and that cerebellum was more sensitive to cinnabar induction than cerebrum. This work illustrates the utility and reliability of (1)H NMR-based metabolomics approach for examining the potential neurotoxic effects of cinnabar and other traditional Chinese medicines.
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Affiliation(s)
- Lai Wei
- Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun, People's Republic of China
| | - Rong Xue
- Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun, People's Republic of China
| | - Panpan Zhang
- Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun, People's Republic of China
| | - Yijie Wu
- Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun, People's Republic of China
| | - Xiaojing Li
- Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun, People's Republic of China
| | - Fengkui Pei
- Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun, People's Republic of China
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Shao Y, Chan HM. Effects of methylmercury on dopamine release in MN9D neuronal cells. Toxicol Mech Methods 2015; 25:637-44. [DOI: 10.3109/15376516.2015.1053654] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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21
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García-Sevillano M, García-Barrera T, Navarro F, Abril N, Pueyo C, López-Barea J, Gómez-Ariza J. Combination of direct infusion mass spectrometry and gas chromatography mass spectrometry for toxicometabolomic study of red blood cells and serum of mice Mus musculus after mercury exposure. J Chromatogr B Analyt Technol Biomed Life Sci 2015; 985:75-84. [DOI: 10.1016/j.jchromb.2015.01.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 12/27/2014] [Accepted: 01/17/2015] [Indexed: 10/24/2022]
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Makino K, Okuda K, Sugino E, Nishiya T, Toyama T, Iwawaki T, Fujimura M, Kumagai Y, Uehara T. Correlation Between Attenuation of Protein Disulfide Isomerase Activity Through S-Mercuration and Neurotoxicity Induced by Methylmercury. Neurotox Res 2014; 27:99-105. [DOI: 10.1007/s12640-014-9494-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 09/22/2014] [Accepted: 09/29/2014] [Indexed: 10/24/2022]
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Lee J, Lee SJ, Lim KT. Preventive effects of ZPDC glycoprotein (24 kDa) on hepatotoxicity induced by mercury chloride in vitro and in vivo. Cell Biochem Funct 2014; 32:520-9. [PMID: 25043152 DOI: 10.1002/cbf.3046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 06/18/2014] [Accepted: 06/19/2014] [Indexed: 12/23/2022]
Abstract
Mercury is a potent environmental contaminant that exerts toxic effect on various vital organs in the human body. Recently, we isolated glycoprotein from Zanthoxylum piperitum DC (ZPDC), which has antioxidant and anticancer effects. In the present study, we determined the preventive effects of ZPDC glycoprotein on hepatic damage induced by mercury chloride (HgCl2 ). We evaluated the activities of lactate dehydrogenase (LDH), alanine aminotransferase (ALT), antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)], extracellular signal-regulated kinase (ERK)1/2, p38 mitogen-activated protein kinase (MAPK), cyclo-oxygenase (COX-2), inducible nitric oxide synthetase (iNOS), and activator protein (AP-1) and the quantitative expressions of nuclear factor E2-related factor (Nrf2), heme oxygenase (HO-1), metallothionein (MT) and reduced glutathione (GSH) in mercury-chloride-exposed (50 μM and 10 mg/kg body weight) primary cultured hepatocytes and ICR mice, using biochemical assays, radioactivity and immunoblot analysis. The results demonstrated that ZPDC glycoprotein decreased the levels of LDH, ALT, HO-1 and MT, whereas it increased the activities of hepatic antioxidant enzymes (SOD, CAT and GPx) and reduced GSH in mercury-chloride-exposed primary cultured hepatocytes. Also, it suppressed arachidonic acid release and expression of ERK, p38 MAPK, COX-2, iNOS, AP-1 and Nrf-2 in primary cultured hepatocytes and ICR mice exposed to mercury chloride. Collectively, ZPDC glycoprotein may have potential applications to prevent hepatotoxicity induced by mercury chloride.
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Affiliation(s)
- Jin Lee
- Molecular Biochemistry Laboratory, Biotechnology Research Institute & Center for the Control of Animal Hazards Using Biotechnology (BK21), Chonnam National University, Gwang-ju, Korea
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Affiliation(s)
- J Rooney
- Department of Pharmaceutical and Medicinal Chemistry, Royal College of Surgeons in Ireland, 123, St Stephen's Green, Ireland ; Academic Unit of Neurology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
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The role of the Keap1/Nrf2 pathway in the cellular response to methylmercury. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2013; 2013:848279. [PMID: 23878621 PMCID: PMC3710591 DOI: 10.1155/2013/848279] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 05/26/2013] [Accepted: 06/03/2013] [Indexed: 12/26/2022]
Abstract
Methylmercury (MeHg) is an environmental electrophile that covalently modifies cellular proteins with reactive thiols, resulting in the formation of protein adducts. While such protein modifications, referred to as S-mercuration, are thought to be associated with the enzyme dysfunction and cellular damage caused by MeHg exposure, the current consensus is that (1) there is a cellular response to MeHg through the activation of NF-E2-related factor 2 (Nrf2) coupled to S-mercuration of its negative regulator, Kelch-like ECH-associated protein 1 (Keap1), and (2) the Keap1/Nrf2 pathway protects against MeHg toxicity. In this review, we introduce our findings and discuss the observations of other workers concerning the S-mercuration of cellular proteins by MeHg and the importance of the Keap1/Nrf2 pathway in protection against MeHg toxicity in cultured cells and mice.
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Vignani R, Milanesi C, Di Simplicio P. Disruption of cytoskeleton by methylmercury in cultured CHO cells. Toxicol In Vitro 2012; 6:61-70. [PMID: 20732093 DOI: 10.1016/0887-2333(92)90086-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/1990] [Revised: 02/21/1991] [Indexed: 11/24/2022]
Abstract
The effect of methylmercury (MM) on three main cytoskeletal components [i.e. microtubules (MT), microfilaments (MF) and intermediate filaments (IF)] and on specific biochemical parameters (i.e. glutathione transferase (GST), glutathione reductase (RED), glutathione peroxidase (GSH-Px), glyoxalase 1 (GLY 1) and total -SH groups (TSH) of the cytosolic fraction) was studied in cultured Chinese hamster ovary (CHO) cells. The experiments were conducted with increasing doses of MM (i.e. 1, 4 and 8 mum), using an exposure time of 16 hr; and with a fixed dose of MM (2 mum), using increasing exposure periods (i.e. 0-24 hr). The morphological changes observed by immunofluorescence seemed to indicate that MF were damaged as much as (if not more than) MT after 16 hr of exposure to 4 mum-MM. At a concentration of 1 mum, MM only affected MF. The time-course experiments revealed that IF as well as MF and MT were severely disorganized after 3 and 6 hr of incubation in the presence of 2 mum-MM. However, an obvious reorganization was observed after 24 hr of exposure. In experiments using increasing MM doses, changes in the enzymatic activities were less noticeable than those observed in the morphology; only a modest decrease in TSH and RED activities (<30%) was recorded at the highest dose of MM used (i.e. 8 mum). In contrast, increasing the time of exposure to MM induced changes in both the cytoskeletal structures and the biochemical parameters: the lowest RED activity and TSH were observed after 3-6 hr exposure; control values were obtained after an exposure period of 24 hr. Ultrastructural observations on cells treated with increasing doses of MM showed changes in plasmamembrane profile, cytoskeleton organization and mitochondrion structure. The results confirm that MM causes non-specific damage to CHO cells and suggest that a functional interaction may exist between GSH-dependent enzymes and cytoskeletal structures.
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Affiliation(s)
- R Vignani
- Department of Environmental Biology, Faculty of Science, University of Siena, Via Mattioli 4, 54100 Siena, Italy
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Xu B, Xu ZF, Deng Y, Liu W, Yang HB, Wei YG. Protective effects of MK-801 on methylmercury-induced neuronal injury in rat cerebral cortex: Involvement of oxidative stress and glutamate metabolism dysfunction. Toxicology 2012; 300:112-20. [DOI: 10.1016/j.tox.2012.06.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Revised: 06/07/2012] [Accepted: 06/08/2012] [Indexed: 11/25/2022]
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Falcone G, Foti C, Gianguzza A, Giuffrè O, Napoli A, Pettignano A, Piazzese D. Sequestering ability of some chelating agents towards methylmercury(II). Anal Bioanal Chem 2012; 405:881-93. [DOI: 10.1007/s00216-012-6336-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 07/31/2012] [Accepted: 08/06/2012] [Indexed: 10/27/2022]
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29
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A simple selective protocol for continuous two-stage fluorescent sensing of both MeHg+ and anti-MeHg+ agents in living cells. Tetrahedron Lett 2012. [DOI: 10.1016/j.tetlet.2012.04.113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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30
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Kanda H, Toyama T, Shinohara-Kanda A, Iwamatsu A, Shinkai Y, Kaji T, Kikushima M, Kumagai Y. S-Mercuration of rat sorbitol dehydrogenase by methylmercury causes its aggregation and the release of the zinc ion from the active site. Arch Toxicol 2012; 86:1693-702. [PMID: 22752181 DOI: 10.1007/s00204-012-0893-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 06/12/2012] [Indexed: 11/25/2022]
Abstract
We previously developed a screening method to identify proteins that undergo aggregation through S-mercuration by methylmercury (MeHg) and found that rat arginase I is a target protein for MeHg (Kanda et al. in Arch Toxicol 82:803-808, 2008). In the present study, we characterized another S-mercurated protein from a rat hepatic preparation that has a subunit mass of 42 kDa, thereby facilitating its aggregation. Two-dimensional SDS-polyacrylamide gel electrophoresis and subsequent peptide mass fingerprinting using matrix-assisted laser desorption and ionization time-of-flight mass spectrometry revealed that the 42 kDa protein was NAD-dependent sorbitol dehydrogenase (SDH). With recombinant rat SDH, we found that MeHg is covalently bound to SDH through Cys44, Cys119, Cys129 and Cys164, resulting in the inhibition of its catalytic activity, release of zinc ions and facilitates protein aggregation. Mutation analysis indicated that Cys44, which ligates the active site zinc atom, and Cys129 play a crucial role in the MeHg-mediated aggregation of SDH. Pretreatment with the cofactor NAD, but not NADP or FAD, markedly prevented aggregation of SDH. Such a protective effect of NAD on the aggregation of SDH caused by MeHg is discussed.
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Affiliation(s)
- Hironori Kanda
- Doctoral Program in Biomedical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
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Rescue of neuronal migration deficits in a mouse model of fetal Minamata disease by increasing neuronal Ca2+ spike frequency. Proc Natl Acad Sci U S A 2012; 109:5057-62. [PMID: 22411806 DOI: 10.1073/pnas.1120747109] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In the brains of patients with fetal Minamata disease (FMD), which is caused by exposure to methylmercury (MeHg) during development, many neurons are hypoplastic, ectopic, and disoriented, indicating disrupted migration, maturation, and growth. MeHg affects a myriad of signaling molecules, but little is known about which signals are primary targets for MeHg-induced deficits in neuronal development. In this study, using a mouse model of FMD, we examined how MeHg affects the migration of cerebellar granule cells during early postnatal development. The cerebellum is one of the most susceptible brain regions to MeHg exposure, and profound loss of cerebellar granule cells is detected in the brains of patients with FMD. We show that MeHg inhibits granule cell migration by reducing the frequency of somal Ca(2+) spikes through alterations in Ca(2+), cAMP, and insulin-like growth factor 1 (IGF1) signaling. First, MeHg slows the speed of granule cell migration in a dose-dependent manner, independent of the mode of migration. Second, MeHg reduces the frequency of spontaneous Ca(2+) spikes in granule cell somata in a dose-dependent manner. Third, a unique in vivo live-imaging system for cell migration reveals that reducing the inhibitory effects of MeHg on somal Ca(2+) spike frequency by stimulating internal Ca(2+) release and Ca(2+) influxes, inhibiting cAMP activity, or activating IGF1 receptors ameliorates the inhibitory effects of MeHg on granule cell migration. These results suggest that alteration of Ca(2+) spike frequency and Ca(2+), cAMP, and IGF1 signaling could be potential therapeutic targets for infants with MeHg intoxication.
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Farina M, Aschner M, Rocha JBT. Oxidative stress in MeHg-induced neurotoxicity. Toxicol Appl Pharmacol 2011; 256:405-17. [PMID: 21601588 PMCID: PMC3166649 DOI: 10.1016/j.taap.2011.05.001] [Citation(s) in RCA: 241] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 05/01/2011] [Accepted: 05/02/2011] [Indexed: 12/20/2022]
Abstract
Methylmercury (MeHg) is an environmental toxicant that leads to long-lasting neurological and developmental deficits in animals and humans. Although the molecular mechanisms mediating MeHg-induced neurotoxicity are not completely understood, several lines of evidence indicate that oxidative stress represents a critical event related to the neurotoxic effects elicited by this toxicant. The objective of this review is to summarize and discuss data from experimental and epidemiological studies that have been important in clarifying the molecular events which mediate MeHg-induced oxidative damage and, consequently, toxicity. Although unanswered questions remain, the electrophilic properties of MeHg and its ability to oxidize thiols have been reported to play decisive roles to the oxidative consequences observed after MeHg exposure. However, a close examination of the relationship between low levels of MeHg necessary to induce oxidative stress and the high amounts of sulfhydryl-containing antioxidants in mammalian cells (e.g., glutathione) have led to the hypothesis that nucleophilic groups with extremely high affinities for MeHg (e.g., selenols) might represent primary targets in MeHg-induced oxidative stress. Indeed, the inhibition of antioxidant selenoproteins during MeHg poisoning in experimental animals has corroborated this hypothesis. The levels of different reactive species (superoxide anion, hydrogen peroxide and nitric oxide) have been reported to be increased in MeHg-exposed systems, and the mechanisms concerning these increments seem to involve a complex sequence of cascading molecular events, such as mitochondrial dysfunction, excitotoxicity, intracellular calcium dyshomeostasis and decreased antioxidant capacity. This review also discusses potential therapeutic strategies to counteract MeHg-induced toxicity and oxidative stress, emphasizing the use of organic selenocompounds, which generally present higher affinity for MeHg when compared to the classically studied agents.
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Affiliation(s)
- Marcelo Farina
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Michael Aschner
- Department of Pediatrics and Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - João B. T. Rocha
- Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
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Schiønning JD. Experimental neurotoxicity of mercury Autometallographic and stereologic studies on rat dorsal root ganglion and spinal cord. APMIS 2011. [DOI: 10.1111/j.1600-0463.2000.tb05696.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Alissa EM, Ferns GA. Heavy metal poisoning and cardiovascular disease. J Toxicol 2011; 2011:870125. [PMID: 21912545 PMCID: PMC3168898 DOI: 10.1155/2011/870125] [Citation(s) in RCA: 201] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 06/28/2011] [Indexed: 02/07/2023] Open
Abstract
Cardiovascular disease (CVD) is an increasing world health problem. Traditional risk factors fail to account for all deaths from CVD. It is mainly the environmental, dietary and lifestyle behavioral factors that are the control keys in the progress of this disease. The potential association between chronic heavy metal exposure, like arsenic, lead, cadmium, mercury, and CVD has been less well defined. The mechanism through which heavy metals act to increase cardiovascular risk factors may act still remains unknown, although impaired antioxidants metabolism and oxidative stress may play a role. However, the exact mechanism of CVD induced by heavy metals deserves further investigation either through animal experiments or through molecular and cellular studies. Furthermore, large-scale prospective studies with follow up on general populations using appropriate biomarkers and cardiovascular endpoints might be recommended to identify the factors that predispose to heavy metals toxicity in CVD. In this review, we will give a brief summary of heavy metals homeostasis, followed by a description of the available evidence for their link with CVD and the proposed mechanisms of action by which their toxic effects might be explained. Finally, suspected interactions between genetic, nutritional and environmental factors are discussed.
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Affiliation(s)
- Eman M. Alissa
- Faculty of Medicine, King Abdul Aziz University, P.O. Box 12713, Jeddah 21483, Saudi Arabia
| | - Gordon A. Ferns
- Institute for Science & Technology in Medicine, Faculty of Health, University of Keele, Staffordshire ST4 7QB, UK
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Jin Y, Park JY, Kim J, Kwak J. Oxidation of extracellular cysteines by mercury chloride reduces TRPV1 activity in rat dorsal root ganglion neurons. Anim Cells Syst (Seoul) 2011. [DOI: 10.1080/19768354.2011.604942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
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Vassallo DV, Simões MR, Furieri LB, Fioresi M, Fiorim J, Almeida EAS, Angeli JK, Wiggers GA, Peçanha FM, Salaices M. Toxic effects of mercury, lead and gadolinium on vascular reactivity. Braz J Med Biol Res 2011; 44:939-46. [PMID: 21845340 DOI: 10.1590/s0100-879x2011007500098] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2011] [Accepted: 07/28/2011] [Indexed: 11/21/2022] Open
Abstract
Heavy metals have been used in a wide variety of human activities that have significantly increased both professional and environmental exposure. Unfortunately, disasters have highlighted the toxic effects of metals on different organs and systems. Over the last 50 years, the adverse effects of chronic lead, mercury and gadolinium exposure have been underscored. Mercury and lead induce hypertension in humans and animals, affecting endothelial function in addition to their other effects. Increased cardiovascular risk after exposure to metals has been reported, but the underlying mechanisms, mainly for short periods of time and at low concentrations, have not been well explored. The presence of other metals such as gadolinium has raised concerns about contrast-induced nephropathy and, interestingly, despite this negative action, gadolinium has not been defined as a toxic agent. The main actions of these metals, demonstrated in animal and human studies, are an increase of free radical production and oxidative stress and stimulation of angiotensin I-converting enzyme activity, among others. Increased vascular reactivity, highlighted in the present review, resulting from these actions might be an important mechanism underlying increased cardiovascular risk. Finally, the results described in this review suggest that mercury, lead and gadolinium, even at low doses or concentrations, affect vascular reactivity. Acting via the endothelium, by continuous exposure followed by their absorption, they can increase the production of free radicals and of angiotensin II, representing a hazard for cardiovascular function. In addition, the actual reference values, considered to pose no risk, need to be reduced.
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Affiliation(s)
- D V Vassallo
- Programa de Pós-Graduação em Ciências Fisiológicas, Universidade Federal do Espírito Santo, Vitória, ES, Brasil.
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Chronic HgCl2 treatment increases vasoconstriction induced by electrical field stimulation: role of adrenergic and nitrergic innervation. Clin Sci (Lond) 2011; 121:331-41. [DOI: 10.1042/cs20110072] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In the present study, we have investigated the possible changes in rat mesenteric artery vascular innervation function caused by chronic exposure to low doses of HgCl2 (mercuric chloride), as well as the mechanisms involved. Rats were divided into two groups: (i) control, and (ii) HgCl2-treated rats (30 days; first dose, 4.6 μg/kg of body weight; subsequent dose, 0.07 μg·kg−1 of body weight·day−1, intramuscularly). Vasomotor response to EFS (electrical field stimulation), NA (noradrenaline) and the NO donor DEA-NO (diethylamine NONOate) were studied, nNOS (neuronal NO synthase) and phospho-nNOS protein expression were analysed, and NO, O2− (superoxide anion) and NA release were also determined. EFS-induced contraction was higher in the HgCl2-treated group. Phentolamine (1 μmol/l) decreased the response to EFS to a greater extent in HgCl2-treated rats. HgCl2 treatment increased vasoconstrictor response to exogenous NA and NA release. L-NAME (NG-nitro-L-arginine methyl ester; 0.1 mmol/l) increased the response to EFS in both experimental groups, but the increase was greater in segments from control animals. HgCl2 treatment decreased NO release and increased O2− production. Vasodilator response to DEA-NO was lower in HgCl2-treated animals. Tempol increased DEA-NO-induced relaxation to a greater extent in HgCl2-treated animals. nNOS expression was similar in arteries from both experimental groups, whereas phospho-nNOS was decreased in segments from HgCl2-treated animals. HgCl2 treatment increased vasoconstrictor response to EFS as a result of, in part, reduced NO bioavailability and increased adrenergic function. These findings offer further evidence that mercury, even at low concentrations, is an environmental risk factor for cardiovascular disease.
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38
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Sarma H. Metal Hyperaccumulation in Plants: A Review Focusing on Phytoremediation Technology. ACTA ACUST UNITED AC 2011. [DOI: 10.3923/jest.2011.118.138] [Citation(s) in RCA: 305] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Alhamad T, Rooney J, Nwosu A, MacCombs J, Kim YS, Shukla V. Lessons learned from a fatal case of mercury intoxication. Int Urol Nephrol 2011; 44:647-51. [DOI: 10.1007/s11255-010-9896-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2010] [Accepted: 12/29/2010] [Indexed: 10/18/2022]
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Accidental inorganic mercury chloride poisoning in a 2-year old child. Indian J Pediatr 2010; 77:1153-5. [PMID: 20721700 DOI: 10.1007/s12098-010-0143-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Accepted: 04/23/2010] [Indexed: 10/19/2022]
Abstract
Inorganic mercury poisoning is uncommon, but when it occurs it can result in severe, life threatening features and acute renal failure. A 2-year old well thriving child presented with alleged history of accidental ingestion of inorganic mercury chloride. He presented with evidence of corrosive trauma to the gastrointestinal tract mucosa, but with normal renal function at admission, which was managed with BAL and other supportive treatment. But he developed non-oliguric renal failure after admission, which also improved gradually. On follow-up, two months later, the patient's renal function was normal; indicating that renal failure caused by acute inorganic mercury poisoning produced no permanent renal damage. We have hereby presented a case of mercury intoxication in a 2-year old child, with an excellent clinical improvement and normalization of laboratory results.
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Nichols JW, Bennett RS, Rossmann R, French JB, Sappington KG. A physiologically based toxicokinetic model for methylmercury in female American kestrels. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2010; 29:1854-1867. [PMID: 20821642 DOI: 10.1002/etc.241] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A physiologically based toxicokinetic (PBTK) model was developed to describe the uptake, distribution, and elimination of methylmercury (CH(3)Hg) in female American kestrels. The model consists of six tissue compartments corresponding to the brain, liver, kidney, gut, red blood cells, and remaining carcass. Additional compartments describe the elimination of CH(3)Hg to eggs and growing feathers. Dietary uptake of CH(3)Hg was modeled as a diffusion-limited process, and the distribution of CH(3)Hg among compartments was assumed to be mediated by the flow of blood plasma. To the extent possible, model parameters were developed using information from American kestrels. Additional parameters were based on measured values for closely related species and allometric relationships for birds. The model was calibrated using data from dietary dosing studies with American kestrels. Good agreement between model simulations and measured CH(3)Hg concentrations in blood and tissues during the loading phase of these studies was obtained by fitting model parameters that control dietary uptake of CH(3)Hg and possible hepatic demethylation. Modeled results tended to underestimate the observed effect of egg production on circulating levels of CH(3)Hg. In general, however, simulations were consistent with observed patterns of CH(3)Hg uptake and elimination in birds, including the dominant role of feather molt. This model could be used to extrapolate CH(3)Hg kinetics from American kestrels to other bird species by appropriate reassignment of parameter values. Alternatively, when combined with a bioenergetics-based description, the model could be used to simulate CH(3)Hg kinetics in a long-term environmental exposure.
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Affiliation(s)
- John W Nichols
- U.S. Environmental Protection Agency, Office of Research and Development, Mid-Continent Ecology Division, 6201 Congdon Boulevard, Duluth, Minnesota 55804, USA.
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42
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Effects of inorganic selenium administration in methylmercury‐induced neurotoxicity in mouse cerebral cortex. Int J Dev Neurosci 2010; 28:631-7. [DOI: 10.1016/j.ijdevneu.2010.07.225] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2010] [Revised: 06/19/2010] [Accepted: 07/01/2010] [Indexed: 11/22/2022] Open
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Flora SJ, Pachauri V. Chelation in metal intoxication. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2010; 7:2745-88. [PMID: 20717537 PMCID: PMC2922724 DOI: 10.3390/ijerph7072745] [Citation(s) in RCA: 515] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Revised: 04/22/2010] [Accepted: 05/27/2010] [Indexed: 12/11/2022]
Abstract
Chelation therapy is the preferred medical treatment for reducing the toxic effects of metals. Chelating agents are capable of binding to toxic metal ions to form complex structures which are easily excreted from the body removing them from intracellular or extracellular spaces. 2,3-Dimercaprol has long been the mainstay of chelation therapy for lead or arsenic poisoning, however its serious side effects have led researchers to develop less toxic analogues. Hydrophilic chelators like meso-2,3-dimercaptosuccinic acid effectively promote renal metal excretion, but their ability to access intracellular metals is weak. Newer strategies to address these drawbacks like combination therapy (use of structurally different chelating agents) or co-administration of antioxidants have been reported recently. In this review we provide an update of the existing chelating agents and the various strategies available for the treatment of heavy metals and metalloid intoxications.
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Affiliation(s)
- Swaran J.S. Flora
- Division of Pharmacology and Toxicology, Defence Research and Development Establishment, Jhansi Road, Gwalior474 002, India; E-Mail:
| | - Vidhu Pachauri
- Division of Pharmacology and Toxicology, Defence Research and Development Establishment, Jhansi Road, Gwalior474 002, India; E-Mail:
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Ceccatelli S, Daré E, Moors M. Methylmercury-induced neurotoxicity and apoptosis. Chem Biol Interact 2010; 188:301-8. [PMID: 20399200 DOI: 10.1016/j.cbi.2010.04.007] [Citation(s) in RCA: 215] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 04/06/2010] [Accepted: 04/08/2010] [Indexed: 12/24/2022]
Abstract
Methylmercury is a widely distributed environmental toxicant with detrimental effects on the developing and adult nervous system. Due to its accumulation in the food chain, chronic exposure to methylmercury via consumption of fish and sea mammals is still a major concern for human health, especially developmental exposure that may lead to neurological alterations, including cognitive and motor dysfunctions. Mercury-induced neurotoxicity and the identification of the underlying mechanisms has been a main focus of research in the neurotoxicology field. Three major mechanisms have been identified as critical in methylmercury-induced cell damage including (i) disruption of calcium homeostasis, (ii) induction of oxidative stress via overproduction of reactive oxygen species or reduction of antioxidative defenses and (iii) interactions with sulfhydryl groups. In vivo and in vitro studies have provided solid evidence for the occurrence of neural cell death, as well as cytoarchitectural alterations in the nervous system after exposure to methylmercury. Signaling cascades leading to cell death induced by methylmercury involve the release of mitochondrial factors, such as cytochrome c and AIF with subsequent caspase-dependent or -independent apoptosis, respectively; induction of calcium-dependent proteases calpains; interaction with lysosomes leading to release of cathepsins. Interestingly, several pathways can be activated in parallel, depending on the cell type. In this paper, we provide an overview of recent findings on methylmercury-induced neurotoxicity and cell death pathways that have been described in neural and endocrine cell systems.
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Affiliation(s)
- Sandra Ceccatelli
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
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Grotto D, Valentini J, Fillion M, Passos CJS, Garcia SC, Mergler D, Barbosa F. Mercury exposure and oxidative stress in communities of the Brazilian Amazon. THE SCIENCE OF THE TOTAL ENVIRONMENT 2010; 408:806-811. [PMID: 19914681 DOI: 10.1016/j.scitotenv.2009.10.053] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Revised: 10/11/2009] [Accepted: 10/16/2009] [Indexed: 05/28/2023]
Abstract
This study was designed to assess possible associations between biomarkers of mercury (Hg) exposure and oxidative stress in fish-eating Amazonian communities. Clinical samples were obtained from riparians living in the Brazilian Amazon. Biomarkers of oxidative stress (glutathione - GSH, glutathione peroxidase - GSH-Px, catalase - CAT, activity and reactivation index of delta-aminolevulinate dehydratase - ALA-D (R%) were determined in blood. Total Hg was measured in whole blood (B-Hg), plasma (P-Hg) and hair (H-Hg). Association between biomarkers of Hg exposure and oxidative stress were examined using multiple regression models, including age, gender, alcohol consumption, smoking status, fish consumption and then stratified for gender. Significant inverse relations were observed between GSH-Px, GSH, CAT, ALA-D activity and B-Hg or H-Hg (p<0.05). ALA-D reactivation index was positively related to B-Hg (p<0.0001). P-Hg was directly related to ALA-D reactivation index and inversely associated with GSH-Px, GSH, and ALA-D activity (p<0.05). When stratified for gender, women showed significant inverse associations between all biomarkers of Hg exposure and CAT (p<0.05) or GSH (p<0.05), while for men only P-Hg showed a significant inverse relation with GSH (p<0.001). Our results clearly demonstrated an association between Hg exposure and oxidative stress. Moreover, for B-Hg, P-Hg and H-Hg gender differences were present.
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Affiliation(s)
- Denise Grotto
- Laboratório de Toxicologia e Essencialidade de Metais, Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo
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Cukurovali A. New Route to Synthesis of Unexpected Pyridoin Derivatives: Their Structure Determination with Spectroscopic and X-Ray Methods. SYNTHETIC COMMUN 2009. [DOI: 10.1080/00397910902906537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Alaaddin Cukurovali
- a Chemistry Department , Faculty of Arts and Sciences, Firat University , Elazig, Turkey
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Are neuropathological conditions relevant to ethylmercury exposure? Neurotox Res 2009; 18:59-68. [PMID: 19756911 DOI: 10.1007/s12640-009-9113-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Revised: 08/31/2009] [Accepted: 09/02/2009] [Indexed: 10/20/2022]
Abstract
Mercury and mercurial compounds are among the environmentally ubiquitous substances most toxic to both wildlife and humans. Once released into the environment from both natural and anthropogenic sources, mercury exists mainly as three different molecular species: elemental, inorganic, and organic. Potential health risks have been reported from exposure to all forms; however, of particular concern for human exposure relate to the potent neurotoxic effects of methylmercury (MeHg), especially for the developing nervous system. The general population is primarily exposed to MeHg by seafood consumption. In addition, some pharmaceuticals, including vaccines, have been, and some continue to be, a ubiquitous source of exposure to mercurials. A significant controversy has been whether the vaccine preservative ethylmercury thiosalicylate, commonly known as thimerosal, could cause the development of autism. In this review, we have discussed the hypothesis that exposure to thimerosal during childhood may be a primary cause of autism. The conclusion is that there are no reliable data indicating that administration of vaccines containing thimerosal is a primary cause of autism. However, one cannot rule out the possibility that the individual gene profile and/or gene-environment interactions may play a role in modulating the response to acquired risk by modifying the individual susceptibility.
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Moors M, Rockel TD, Abel J, Cline JE, Gassmann K, Schreiber T, Schuwald J, Weinmann N, Fritsche E. Human neurospheres as three-dimensional cellular systems for developmental neurotoxicity testing. ENVIRONMENTAL HEALTH PERSPECTIVES 2009; 117:1131-8. [PMID: 19654924 PMCID: PMC2717141 DOI: 10.1289/ehp.0800207] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Accepted: 02/26/2009] [Indexed: 05/04/2023]
Abstract
BACKGROUND Developmental neurotoxicity (DNT) of environmental chemicals is a serious threat to human health. Current DNT testing guidelines propose investigations in rodents, which require large numbers of animals. With regard to the "3 Rs" (reduction, replacement, and refinement) of animal testing and the European regulation of chemicals [Registration, Evaluation, and Authorisation of Chemicals (REACH)], alternative testing strategies are needed in order to refine and reduce animal experiments and allow faster and less expensive screening. OBJECTIVES The goal of this study was to establish a three-dimensional test system for DNT screening based on human fetal brain cells. METHODS We established assays suitable for detecting disturbances in basic processes of brain development by employing human neural progenitor cells (hNPCs), which grow as neurospheres. Furthermore, we assessed effects of mercury and oxidative stress on these cells. RESULTS We found that human neurospheres imitate proliferation, differentiation, and migration in vitro. Exposure to the proapoptotic agent staurosporine further suggests that human neurospheres possess functioning apoptosis machinery. The developmental neurotoxicants methylmercury chloride and mercury chloride decreased migration distance and number of neuronal-like cells in differentiated hNPCs. Furthermore, hNPCs undergo caspase-independent apoptosis when exposed toward high amounts of oxidative stress. CONCLUSIONS Human neurospheres are likely to imitate basic processes of brain development, and these processes can be modulated by developmental neurotoxicants. Thus, this three-dimensional cell system is a promising approach for DNT testing.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Ellen Fritsche
- Address correspondence to E. Fritsche, Institut für Umweltmedizinische Forschung gGmbH an der Heinrich Heine-Universität, Toxicology, Auf’m Hennekamp 50, 40225 Düsseldorf, Germany. Telephone: 00492113389217. Fax: 00492113190910. E-mail:
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Lucu C, Dupcić-Radić I, Tomsić S. Methyl mercury inhibits short-circuit current and Cl- influx across isolated epipodite of European lobster (Homarus gammarus). Comp Biochem Physiol C Toxicol Pharmacol 2009; 149:476-80. [PMID: 19038364 DOI: 10.1016/j.cbpc.2008.11.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2008] [Revised: 11/01/2008] [Accepted: 11/02/2008] [Indexed: 11/30/2022]
Abstract
The effect of methyl mercuric chloride (MeHg) on short-circuit current (I(SC)) was studied in the isolated perfused epipodite preparation from the branchial chamber of European lobster (Homarus gammarus) acclimated to dilute seawater. When applied at the apical surface, 0.2, 1.0 and 3.0 microM MeHg depressed I(SC) by a 26%, 81% and 98%, respectively. The half-maximal inhibitory concentration (IC(50)) of apically applied MeHg was 0.6 microM. Basolaterally added MeHg (3.0 microM) had no effect on I(SC), whereas addition of the specific Na(+),K(+)-ATPase inhibitor ouabain (1.5 mM) reduced I(SC) by approximately 90%. Ouabain effects were reversible, and I(SC) fully recovered upon removal of ouabain. The MeHg-induced block of I(SC) was partially reversed by the reducing agent, 1,4-dithiothreitol, suggesting that the formation of S-Hg-S bridges is important in the inhibitory mechanism. A significant reduction of I(SC) and conductance occurred when low Na(+) and Cl(-) salines were substituted. Furthermore, in the low Na(+) saline, J(Cl)(A-->B) fluxes were reduced by about 50%. In the highly conductive epipodite epithelium, coupling of Na(+) and Cl(-) fluxes was suggested. The effects of MeHg on I(SC) in the lobster epipodite are attributed to inhibition of an apical Cl(-) influx.
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Affiliation(s)
- Cedomil Lucu
- University of Dubrovnik, Department of Aquaculture, Dubrovnik, Croatia.
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DENCKER LENNART. TISSUE LOCALIZATION OF SOME TERATOGWNS AT EARLY AND LATE GESTATION RELATED TO FETAL EFFECTS. ACTA ACUST UNITED AC 2009. [DOI: 10.1111/j.1600-0773.1976.tb03622.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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