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Ke T, Santamaria A, Junior FB, Rocha JBT, Bowman AB, Aschner M. Methylmercury exposure-induced reproductive effects are mediated by dopamine in Caenorhabditis elegans. Neurotoxicol Teratol 2022; 93:107120. [PMID: 35987454 DOI: 10.1016/j.ntt.2022.107120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 08/09/2022] [Accepted: 08/11/2022] [Indexed: 11/28/2022]
Abstract
Methylmercury (MeHg) is a neurotoxicant that exists in the natural environment, which level can be greatly increased because of human activity. MeHg exposures have the risk of being detrimental to the development of the nervous system. Studies on MeHg toxicity have largely focused on the mechanisms of its neurotoxicity following developmental exposures. Additionally, reproductive toxicity of developmental MeHg exposures has been noted in rodent models. The model organism Caenorhabditis elegans (C. elegans) is a self-fertilizing animal which has a short lifespan around 20 days. Most C. elegans are hermaphrodites that can generate both sperm and oocytes. To investigate the effects of developmental MeHg exposures on the reproduction in C. elegans, larvae stage 1 worms were exposed to MeHg (0, 0.01 or 0.05 μM) for 24 h. The laid eggs and oocytes were compared during each day at adult stages for 6 days. We showed that MeHg exposure significantly induced an increased number of eggs in day 1 adults without an effect on the timing of egg laying or the total number of eggs or oocytes over the 6-day period. The expression of dat-1 and cat-2 and dopamine levels were increased in worms exposed to MeHg. Supplementation with 100 μM dopamine recapitulated the effect of MeHg on the number of eggs present in day 1 adults. Furthermore, the effect of MeHg on the number of eggs was abrogated in the cat-2 mutant worms CB1112. The number of oocytes in the 6-day adult stages was decreased by MeHg in the dat-1 mutant RM2702. MeHg exposures did not change the mating rate or the number of offspring from mating. Combined, these novel findings show that developmental exposure to low levels of MeHg has limited effects on the reproduction in C. elegans. Furthermore, our data support a modulatory role of dopamine in MeHg-induced effects on reproduction in this model system.
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Affiliation(s)
- Tao Ke
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, United States
| | - Abel Santamaria
- Laboratorio de Aminoácidos Excitadores/Laboratorio de Neurofarmacología Molecular y Nanotecnología, Instituto Nacional de Neurología y Neurocirugía, 14269 Mexico City, Mexico
| | - Fernando Barbosa Junior
- Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP 14040-900, Brazil
| | - João B T Rocha
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, 97105900 Santa Maria, RS, Brazil
| | - Aaron B Bowman
- School of Health Sciences, Purdue University, West Lafayette, IN 47907-2051, United States
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, United States.
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2
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Nguyen HD, Oh H, Hoang NHM, Jo WH, Kim MS. Environmental science and pollution research role of heavy metal concentrations and vitamin intake from food in depression: a national cross-sectional study (2009-2017). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:4574-4586. [PMID: 34414543 PMCID: PMC8376242 DOI: 10.1007/s11356-021-15986-w] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 08/11/2021] [Indexed: 04/16/2023]
Abstract
Little is known about associations between depression and serum heavy metal levels, dietary vitamin intakes. Thus, we sought to determine the nature of these associations and to predict risks of depression using marginal effects. A data set of 16,371 individuals aged ≥10 years that participated in Korea National Health and Nutrition Examination Surveys (KNHANES) conducted from 2009 to 2017 (excluding 2014 and 2015) was used to obtain information on sociodemographics, family histories, lifestyles, serum heavy metal levels, food intakes, and depression. Serum cadmium (Cd) and lead (Pb) levels were analyzed by graphite furnace atomic absorption spectrometry and mercury (Hg) levels using a mercury analyzer. Daily vitamin intakes were calculated by 24-h dietary recall. The results obtained showed that females are at higher risk of depression than males. A doubling of serum Cd was associated with a 21% increase in depression (AOR 1.21, 95% CI: 1.07-1.37, p = 0.002), whereas twofold increases in daily vitamin B1, B3 and vitamin A intakes reduced the risk of depression by 17% (0.83, 95% CI: 0.73-0.95, p = 0.005), 20% (0.80, 95% CI: 0.70-0.91, p = 0.001), and 8% (0.92, 95% CI: 0.85-0.99, p = 0.020), respectively. Interactions between heavy metals, vitamin intakes, and sex did not influence the risk of depression. The result shows that increased daily dietary vitamin intake might protect the public against depression. Further studies are needed to reduce the risks posed by heavy metals and to determine more comprehensively the effects of daily dietary vitamin intake on depression.
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Affiliation(s)
- Hai Duc Nguyen
- Department of Pharmacy, College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Sunchon, 57922, Jeonnam, Republic of Korea
| | - Hojin Oh
- Department of Pharmacy, College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Sunchon, 57922, Jeonnam, Republic of Korea
| | - Ngoc Hong Minh Hoang
- Department of Pharmacy, College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Sunchon, 57922, Jeonnam, Republic of Korea
| | - Won Hee Jo
- Department of Pharmacy, College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Sunchon, 57922, Jeonnam, Republic of Korea
| | - Min-Sun Kim
- Department of Pharmacy, College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Sunchon, 57922, Jeonnam, Republic of Korea.
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3
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Garcia MS, Orcini WA, Peruquetti RL, Perobelli JE. New approach for reproductive toxicity assessment: chromatoid bodies as a target for methylmercury and polychlorinated biphenyls in prepubertal male rats. Reprod Fertil Dev 2021; 32:914-922. [PMID: 32586421 DOI: 10.1071/rd19447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 05/04/2020] [Indexed: 11/23/2022] Open
Abstract
This study investigated the reproductive toxicity of methylmercury (MeHg) and Aroclor (Sigma-Aldrich), alone or in combination, following exposure of prepubertal male rats considering the chromatoid body (CB) as a potential target. The CB is an important molecular regulator of mammalian spermatogenesis, primarily during spermatid cytodifferentiation. Male Wistar rats were exposed to MeHg and/or Aroclor , according the following experimental design: control group, which was administered in corn oil (vehicle) only; MeHg-treated group, which was administered 0.5mg kg-1 day-1 MeHg; Aroclor-treated group, which was administered 1mg kg-1 day-1 Aroclor; Mix-LD, group which was administered a low-dose mixture of MeHg (0.05mg kg-1 day-1) and Aroclor (0.1mg kg-1 day-1); and Mix-HD group, which was administered a high-dose mixture of MeHg (0.5mg kg-1 day-1) and Aroclor (1.0mg kg-1 day-1). MeHg was diluted in distilled water and Aroclor was made up in corn oil (volume 1mL kg-1). Rats were administered the different treatments from PND23 to PND53 by gavage, . The morphophysiology of CBs was analysed, together with aspects of steroid hormones status and regulation, just after the last treatment on PND53. In addition, the long-term effects on sperm parameters were assessed in adult animals. MeHg exposure increased mouse VASA homologue (MVH) protein levels in seminiferous tubules, possibly affecting the epigenetic status of germ cells. Aroclor produced morphological changes to CB assembly, which may explain the observed morphological defects to the sperm flagellum and the consequent decrease in sperm motility. There were no clear additive or synergistic effects between MeHg and Aroclor when administered in combination. In conclusion, this study demonstrates that MeHg and Aroclor have independent deleterious effects on the developing testis, causing molecular and morphological changes in CBs. To the best of our knowledge, this is the first study to show that CBs are targets for toxic agents.
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Affiliation(s)
- M S Garcia
- School of Health Sciences, Sagrado Coração University, Rua Irmã Arminda, 10-50, Jd., Brasil, 17011-160, Bauru, São Paulo, Brazil; and Experimental Toxicology Laboratory, Department of Marine Sciences, Federal University of São Paulo, Campus Baixada Santista, Rua Dr Carvalho de Mendonça, 144, Encruzilhada, 11070-102 Santos, SP, Brazil
| | - W A Orcini
- Molecular Biology and Cytogenetics Laboratory, Sagrado Coração University, Rua Irmã Arminda, 10-50, Jd., Brasil, 17011-160, Bauru, São Paulo, Brazil
| | - R L Peruquetti
- School of Health Sciences, Sagrado Coração University, Rua Irmã Arminda, 10-50, Jd., Brasil, 17011-160, Bauru, São Paulo, Brazil; and Molecular Biology and Cytogenetics Laboratory, Sagrado Coração University, Rua Irmã Arminda, 10-50, Jd., Brasil, 17011-160, Bauru, São Paulo, Brazil; and Office of the Associate Dean of Graduate Studies and Research, Sagrado Coração University, Rua Irmã Arminda, 10-50, Jd., Brasil, 17011-160, Bauru, São Paulo, Brazil
| | - J E Perobelli
- Experimental Toxicology Laboratory, Department of Marine Sciences, Federal University of São Paulo, Campus Baixada Santista, Rua Dr Carvalho de Mendonça, 144, Encruzilhada, 11070-102 Santos, SP, Brazil; and Corresponding author.
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4
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Montagner GFFDS, Barbisan F, Ledur PC, Bolignon A, Motta JDR, Ribeiro EE, Praia RDS, Azzolin VF, Cadoná FC, Machado AK, Barcelos RP, da Cruz IBM. In Vitro Biological Properties of Solanum sessiliflorum (Dunal), an Amazonian Fruit. J Med Food 2020; 23:978-987. [PMID: 32598197 DOI: 10.1089/jmf.2019.0193] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Solanum sessiliflorum is an Amazonian fruit (cubiu) that has been domesticated since pre-Colombian era. It is also used in folk medicine to treat some clinical conditions. This investigation chemically characterized and analyzed the in vitro antioxidant and antitumoral effect of a cubiu pulp/seed hydroalcoholic extract. Cubiu extract was chemically characterized by high-performance liquid chromatography with diode array detector (HPLC-DAD), its antioxidant capacity measured by 2.2-diphenyl-1-picrylhydrazyl (DPPH) assay, and the following complementary in vitro protocols were performed: (1) cytoprotective effect of cubiu on human peripheral blood mononuclear cells (PBMCs) exposed to H2O2, a genotoxic and procarcinogen molecule; (2) effect of cubiu on low density lipoproteins oxidation; and (3) cytotoxic and antiproliferative effect on breast (MCF-7) and colorectal (HT-29) cancer cell lines. Biochemical and flow cytometry analyses were conducted in these protocols. Cubiu extract presented high concentrations of caffeic and gallic acids, beta-carotene, catechin, quercetin, and rutin, and its antioxidant capacity was confirmed. Cubiu attenuated H2O2 cytotoxicity on PBMCs, presented lowering effect on LDL oxidation, and induced mortality and proliferative inhibition of colorectal cancer cells. In cancer cells, cubiu extract at 10 μg/mL showed similar effects to 5-fluorouracil chemo drug reducing its viability and frequency of S-phase, indicating that cells are undergoing mitosis. In summary, despite the limitations of in vitro protocols, our results suggest that cubiu has several biological properties that affect human health.
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Affiliation(s)
| | - Fernanda Barbisan
- Graduate Program in Gerontology, Federal University of Santa Maria (UFSM), Santa Maria, Brazil.,Graduate Program in Pharmacology, Federal University of Santa Maria (UFSM), Santa Maria, Brazil
| | - Pauline Christ Ledur
- Graduate Program in Pharmacology, Federal University of Santa Maria (UFSM), Santa Maria, Brazil
| | - Aline Bolignon
- Federal University of Santa Maria (UFSM), Santa Maria, Brazil
| | - Jéssica de Rosso Motta
- Graduate Program in Gerontology, Federal University of Santa Maria (UFSM), Santa Maria, Brazil
| | - Euler Esteves Ribeiro
- Foundation of the State University of Amazonas (Funati), Amazonas State University, Manaus, Brazil
| | - Raquel de Souza Praia
- Foundation of the State University of Amazonas (Funati), Amazonas State University, Manaus, Brazil
| | - Verônica Farina Azzolin
- Graduate Program in Gerontology, Federal University of Santa Maria (UFSM), Santa Maria, Brazil
| | | | | | | | - Ivana Beatrice Mânica da Cruz
- Graduate Program in Gerontology, Federal University of Santa Maria (UFSM), Santa Maria, Brazil.,Graduate Program in Pharmacology, Federal University of Santa Maria (UFSM), Santa Maria, Brazil
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5
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Crespo-López ME, Soares ES, Macchi BDM, Santos-Sacramento L, Takeda PY, Lopes-Araújo A, Paraense RSDO, Souza-Monteiro JR, Augusto-Oliveira M, Luz DA, Maia CDSF, Rogez H, Lima MDO, Pereira JP, Oliveira DC, Burbano RR, Lima RR, do Nascimento JLM, Arrifano GDP. Towards Therapeutic Alternatives for Mercury Neurotoxicity in the Amazon: Unraveling the Pre-Clinical Effects of the Superfruit Açaí ( Euterpe oleracea, Mart.) as Juice for Human Consumption. Nutrients 2019; 11:nu11112585. [PMID: 31717801 PMCID: PMC6893510 DOI: 10.3390/nu11112585] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/19/2019] [Accepted: 10/23/2019] [Indexed: 12/16/2022] Open
Abstract
Methylmercury (MeHg) exposure is a serious problem of public health, especially in the Amazon. Exposure in riverine populations is responsible for neurobehavioral abnormalities. It was hypothesized that consumption of Amazonian fruits could protect by reducing mercury accumulation. This work analyzed the effects of commercial samples of Euterpe oleracea (EO) for human consumption (10 μL/g) against MeHg i.p. exposure (2.5 mg/Kg), using neurobehavioral (open field, rotarod and pole tests), biochemical (lipid peroxidation and nitrite levels), aging-related (telomerase reverse transcriptase (TERT) mRNA expression) and toxicokinetic (MeHg content) parameters in mice. Both the pole and rotarod tests were the most sensitive tests accompanied by increased lipid peroxidation and nitrite levels in brains. MeHg reduced TERT mRNA about 50% demonstrating a strong pro-aging effect. The EO intake, similar to that of human populations, prevented all alterations, without changing the mercury content, but avoiding neurotoxicity and premature aging of the Central Nervous System (CNS). Contrary to the hypothesis found in the literature on the possible chelating properties of Amazonian fruits consumption, the effect of EO would be essentially pharmacodynamics, and possible mechanisms are discussed. Our data already support the regular consumption of EO as an excellent option for exposed Amazonian populations to have additional protection against MeHg intoxication.
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Affiliation(s)
| | - Ericks Sousa Soares
- Laboratory of Molecular Pharmacology, Federal University of Pará, Belém-PA 66075-110, Brazil
- Laboratory of Neurochemical Investigation, Center of Biological Sciences, Federal University of Santa, Catarina, Florianópolis-SC 88040-900, Brazil
| | - Barbarella de Matos Macchi
- Laboratory of Molecular and Cellular Neurochemistry, Federal University of Pará, Belém-PA 66075-110, Brazil
| | | | - Priscila Yuki Takeda
- Laboratory of Molecular Pharmacology, Federal University of Pará, Belém-PA 66075-110, Brazil
| | - Amanda Lopes-Araújo
- Laboratory of Molecular Pharmacology, Federal University of Pará, Belém-PA 66075-110, Brazil
| | | | | | - Marcus Augusto-Oliveira
- Laboratory of Molecular Pharmacology, Federal University of Pará, Belém-PA 66075-110, Brazil
- Laboratory of Experimental Neuropathology, Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Diandra Araújo Luz
- Laboratory of Pharmacology of Inflammation and Behavior and Federal University of Pará, Belém-PA 66075-110, Brazil
| | | | - Hervé Rogez
- Centre for Valorisation of Amazonian Bioactive Compounds (CVACBA) and Federal University of Pará, Belém-PA 66075-110, Brazil
| | | | - João Paulo Pereira
- Evandro Chagas Institute, Secretary of Sanitary Surveillance, Belém-PA 66093-020, Brazil
| | | | | | - Rafael Rodrigues Lima
- Laboratory of Functional and Structural Biology, Federal University of Pará, Belém-PA 66075-110, Brazil
| | | | - Gabriela de Paula Arrifano
- Laboratory of Molecular Pharmacology, Federal University of Pará, Belém-PA 66075-110, Brazil
- Laboratory of Experimental Neuropathology, Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
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6
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Medicinal plants and natural products can play a significant role in mitigation of mercury toxicity. Interdiscip Toxicol 2019; 11:247-254. [PMID: 31762676 PMCID: PMC6853017 DOI: 10.2478/intox-2018-0024] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 08/11/2018] [Indexed: 12/18/2022] Open
Abstract
Mercury is a heavy metal of considerable toxicity. Scientific literature reveals various plants and plant derived natural products, i.e., phytochemicals, which can alleviate experimentally induced mercury toxicity in animals. The present review attempts to collate those experimental studies on medicinal plants and phytochemicals with ameliorative effects on mercury toxicity. A literature survey was carried out by using Google, Scholar Google, Scopus and Pub-Med. Only the scientific journal articles found in the internet for the last two decades (1998–2018) were considered. Minerals and semi-synthetic or synthetic analogs of natural products were excluded. The literature survey revealed that in pre-clinical studies 27 medicinal plants and 27 natural products exhibited significant mitigation from mercury toxicity in experimental animals. Clinical investigations were not found in the literature. Admissible research in this area could lead to development of a potentially effective agent from the plant kingdom for clinical management of mercury toxicity in humans.
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Auharek SA, Carollo CA, Oliveira RJ, Cunha-Laura AL, Monreal ACD, Siqueira JM, Costa DS, de Paiva Condé TR, Wollf DIL, Aloysio Amaral E. Evaluation of the testis function of mice exposed in utero and during lactation to Pfaffia glomerata (Brazilian ginseng). Andrologia 2019; 51:e13328. [PMID: 31145510 DOI: 10.1111/and.13328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/25/2019] [Accepted: 05/05/2019] [Indexed: 11/28/2022] Open
Abstract
Pfaffia glomerata (Spreng.) Pedersen, popularly known as "Brazilian ginseng," is used as medicinal plant in Brazil to treat inflammatory diseases in general. Previous studies showed that its extract increases the nitric oxide (NO) levels. Knowing that NO downregulates steroidogenesis and that alterations in the action/production of androgens during perinatal life could alter testis development, the present studies sought to investigate the reproductive toxicity of Pfaffia glomerata on male mice exposed to hydroalcoholic extract in utero and during lactation. The present study shows that P. glomerata extract does not alter body weight, tubular diameter and testis function in male mice. Although a reduction in the testis weight was observed in the animals that received the highest dose directly in early post-natal life, our findings show clearly that P. glomerata may not act as an endocrine disruptor, and it is not an "antiandrogenic" compound that could lead to testicular dysgenesis syndrome.
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Affiliation(s)
- Sarah Alves Auharek
- Faculdade de Medicina do Mucuri (FAMMUC), Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Teófilo Otoni, Brazil
| | - Carlos Alexandre Carollo
- Programa de pós-graduação em Farmácia, Centro de Ciências Biológicas e da Saúde (CCBS), Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, Brazil
| | - Rodrigo Juliano Oliveira
- Programa de pós-graduação em Farmácia, Centro de Ciências Biológicas e da Saúde (CCBS), Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, Brazil.,Centro de Estudos em Células Tronco, Terapia Celular e Genética Toxicológica (CeTroGen), Núcleo de Hospital Universitário (NHU), Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, Brazil
| | - Andréa Luiza Cunha-Laura
- Programa de pós-graduação em Farmácia, Centro de Ciências Biológicas e da Saúde (CCBS), Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, Brazil
| | - Antônio Carlos Duenhas Monreal
- Programa de pós-graduação em Farmácia, Centro de Ciências Biológicas e da Saúde (CCBS), Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, Brazil
| | - João Máximo Siqueira
- Universidade Federal de São João Del-Rei (UFSJ), Divinópolis, Minas Gerais, Brazil
| | - Deiler Sampaio Costa
- Faculdade de Medicina Veterinária e Zootecnia (FAMEZ), Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, Brazil
| | - Tammy Reis de Paiva Condé
- Faculdade de Medicina do Mucuri (FAMMUC), Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Teófilo Otoni, Brazil
| | - Dayhanne Isa Langkammer Wollf
- Faculdade de Medicina do Mucuri (FAMMUC), Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Teófilo Otoni, Brazil
| | - Ernani Aloysio Amaral
- Faculdade de Medicina do Mucuri (FAMMUC), Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), Teófilo Otoni, Brazil
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Farina M, Aschner M. Glutathione antioxidant system and methylmercury-induced neurotoxicity: An intriguing interplay. Biochim Biophys Acta Gen Subj 2019; 1863:129285. [PMID: 30659883 DOI: 10.1016/j.bbagen.2019.01.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 12/09/2018] [Accepted: 01/09/2019] [Indexed: 01/20/2023]
Abstract
Methylmercury (MeHg) is a toxic chemical compound naturally produced mainly in the aquatic environment through the methylation of inorganic mercury catalyzed by aquatic microorganisms. MeHg is biomagnified in the aquatic food chain and, consequently, piscivorous fish at the top of the food chain possess huge amounts of MeHg (at the ppm level). Some populations that have fish as main protein's source can be exposed to exceedingly high levels of MeHg and develop signs of toxicity. MeHg is toxic to several organs, but the central nervous system (CNS) represents a preferential target, especially during development (prenatal and early postnatal periods). Though the biochemical events involved in MeHg-(neuro)toxicity are not yet entirely comprehended, a vast literature indicates that its pro-oxidative properties explain, at least partially, several of its neurotoxic effects. As result of its electrophilicity, MeHg interacts with (and oxidize) nucleophilic groups, such as thiols and selenols, present in proteins or low-molecular weight molecules. It is noteworthy that such interactions modify the redox state of these groups and, therefore, lead to oxidative stress and impaired function of several molecules, culminating in neurotoxicity. Among these molecules, glutathione (GSH; a major thiol antioxidant) and thiol- or selenol-containing enzymes belonging to the GSH antioxidant system represent key molecular targets involved in MeHg-neurotoxicity. In this review, we firstly present a general overview concerning the neurotoxicity of MeHg. Then, we present fundamental aspects of the GSH-antioxidant system, as well as the effects of MeHg on this system.
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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 Molecular Pharmacology, Albert Einstein College of Medicine, New York, USA
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9
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Garcia MS, Constantino DHJ, Silva APG, Perobelli JE. Fish pollutants MeHg and Aroclor cause permanent structural damage in male gonads and kidneys after prepubertal exposure. Int J Exp Pathol 2016; 97:360-368. [PMID: 27917541 PMCID: PMC5206816 DOI: 10.1111/iep.12200] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 08/08/2016] [Indexed: 12/29/2022] Open
Abstract
This study investigated whether or not prepubertal exposure to the fish contaminants methylmercury (MeHg) and the polychlorinated bisphenol Aroclor in low doses interferes with the histomorphometry of the testes, epididymis, liver and kidneys in rats. Wistar male rats, 21 days old, were allocated into the following: control (n = 17, received corn oil), MeHg (n = 17, received MeHg at 0.5 mg/kg/day), Aroclor (n = 17, received Aroclor at 1.0 mg/kg/day), low mix (n = 18, received MeHg at 0.05 mg/kg/day and Aroclor at 0.1 mg/kg/day), high mix (n = 18, received MeHg at 0.5 mg/kg/day and Aroclor at 1.0 mg/kg/day). Dosing continued from post natal day (PND) 23 to 53, by gavage. Euthanasia was performed on PND 53; or, after an interval of 62 days without exposure to chemicals, on PND 115. The degree of maturation of the seminiferous epithelium was delayed in chemical-exposed groups and testicular interstitial oedema was observed at adulthood. The pattern of male gonad organization was changed in the Aroclor group on PND 53 and in all treated groups at adulthood. The animals from Aroclor, low mix and high mix groups showed a reduction in the number of Sertoli cells. Histological evidence of renal injury was observed in all chemical-exposed groups in both ages. A probable target for MeHg and Aroclor in the reproductive system was Sertoli cells, in which possible dysfunctions could be linked to the other testicular alterations. Curiously, the main deleterious effects were late outcomes, along with the absence of synergistic interaction of MeHg and Aroclor in the parameters investigated. In conclusion, fish pollutants MeHg and Aroclor caused permanent structural damage in male gonads and kidneys after prepubertal exposure, without showing clear chemical interactions.
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Affiliation(s)
- Mariana S. Garcia
- Central de Laboratórios de Ciência e Tecnologia AmbientalUniversidade Sagrado Coração, USCBauruSão PauloBrazil
| | - Dulce Helena J. Constantino
- Central de Laboratórios de Ciência e Tecnologia AmbientalUniversidade Sagrado Coração, USCBauruSão PauloBrazil
| | - Ana P. G. Silva
- Programa de Pós‐Gradução Interdisciplinar em Ciências da SaúdeUniversidade Federal de São Paulo, Campus Baixada SantistaSantosSão PauloBrazil
| | - Juliana E. Perobelli
- Departamento de Ciências do MarUniversidade Federal de São Paulo, Campus Baixada SantistaSantosSão PauloBrazil
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