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Bjørklund G, Antonyak H, Polishchuk A, Semenova Y, Lesiv M, Lysiuk R, Peana M. Effect of methylmercury on fetal neurobehavioral development: an overview of the possible mechanisms of toxicity and the neuroprotective effect of phytochemicals. Arch Toxicol 2022; 96:3175-3199. [PMID: 36063174 DOI: 10.1007/s00204-022-03366-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 08/17/2022] [Indexed: 11/25/2022]
Abstract
Methylmercury (MeHg) is a global environmental pollutant with neurotoxic effects. Exposure to MeHg via consumption of seafood and fish can severely impact fetal neurobehavioral development even when MeHg levels in maternal blood are as low as about 5 μg/L, which the mother tolerates well. Persistent motor dysfunctions and cognitive deficits may result from trans-placental exposure. The present review summarizes current knowledge on the mechanisms of MeHg toxicity during the period of nervous system development. Although cerebellar Purkinje cells are MeHg targets, the actions of MeHg on thiol components in the neuronal cytoskeleton as well as on mitochondrial enzymes and induction of disturbances of glutamate signaling can impair extra-cerebellar functions, also at levels well tolerated by adult individuals. Numerous herbal substances possess neuroprotective effects, predominantly represented by natural polyphenolic molecules that might be utilized to develop natural drugs to alleviate neurotoxicity symptoms caused by MeHg or other Hg compounds.
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Affiliation(s)
- Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Toften 24, 8610, Mo i Rana, Norway.
| | | | | | | | - Marta Lesiv
- Ivan Franko National University of Lviv, Lviv, Ukraine
| | - Roman Lysiuk
- Danylo Halytsky Lviv National Medical University, Lviv, Ukraine
- CONEM Ukraine Life Science Research Group, Danylo Halytsky Lviv National Medical University, Lviv, Ukraine
| | - Massimiliano Peana
- Department of Chemical, Physics, Mathematics and Natural Sciences, University of Sassari, Sassari, Italy
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Alattar A, Alvi AM, Rashid S, Hussain N, Gul M, Ikram M, Khalil AAK, Alshaman R, Shah FA, Li S, Li J. RETRACTED: Carveol ameliorates mercury-induced oxidative stress, neuroinflammation, and neurodegeneration in a mouse brain. Neurotoxicology 2022; 92:212-226. [PMID: 35963490 DOI: 10.1016/j.neuro.2022.08.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 07/26/2022] [Accepted: 08/09/2022] [Indexed: 11/25/2022]
Abstract
This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editors-in-Chief. Sections of panels from Figure 7B appear similar to each other. Also, inconsistencies have been noticed between the text of the subsection 2.5.4. ‘Morris Water Maze (MWM) test’ and Figure 6E. The journal records indicated that the names of the authors Sajid Rashid, Nadia Hussain, Mehreen Gul, Muhammad Ikram and Jingbo Li were added to the revised version of the article without exceptional approval by the handling Editor, which is contrary to the journal policy on changes to authorship.
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Affiliation(s)
- Abdullah Alattar
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Tabuk, Tabuk, Saudi Arabia.
| | - Arooj Mohsin Alvi
- Riphah Institute of Pharmaceutical Sciences, Riphah International University, Islamabad, Pakistan.
| | - Sajid Rashid
- National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
| | - Nadia Hussain
- Department of Pharmaceutical Sciences, College of Pharmacy, Al Ain University, Al Ain, UAE; AAU Health and Biomedical Research center, Al Ain University, Abu Dhabi, UAE
| | - Mehreen Gul
- National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
| | - Muhammad Ikram
- Institute of Pharmaceutical Sciences, Khyber Medical University, Peshawar, Pakistan.
| | - Atif Ali Khan Khalil
- Institute of Pharmacy, Faculty of Pharmaceutical and Allied Health Sciences, Lahore College for Women University, Lahore, Pakistan.
| | - Reem Alshaman
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, University of Tabuk, Tabuk, Saudi Arabia.
| | - Fawad Ali Shah
- Riphah Institute of Pharmaceutical Sciences, Riphah International University, Islamabad, Pakistan.
| | - Shupeng Li
- State Key Laboratory of Oncogenomics, School of Chemical Biology and Biotechnology, Shenzhen Graduate School, Peking University, Shenzhen, China
| | - Jingbo Li
- Health Management Center, Shenzhen University General Hospital, Shenzhen University Clinical Medical Academy, Shenzhen University, Shenzhen, China.
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Kamarudin AA, Sayuti NH, Saad N, Razak NAA, Esa NM. Induction of apoptosis by Eleutherine bulbosa (Mill.) Urb. bulb extracted under optimised extraction condition on human retinoblastoma cancer cells (WERI-Rb-1). JOURNAL OF ETHNOPHARMACOLOGY 2022; 284:114770. [PMID: 34688803 DOI: 10.1016/j.jep.2021.114770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 10/11/2021] [Accepted: 10/19/2021] [Indexed: 06/13/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The bulb of Eleutherine bulbosa (Mill.) Urb. is an indigenous medicinal plant traditionally used among Dayak people for the management of diabetes, breast cancer, hypertension, stroke, and fertility problems in women. The bulb has been reported with a potent cytotoxic potential but with limited underlying mechanisms. AIM OF THE STUDY This study aimed to investigate the cytotoxic properties of E. bulbosa ethanolic bulb extracted under optimised extraction condition on retinoblastoma cancer cells (WERI-Rb-1) through in vitro cell culture bioassays. The optimised extraction condition has been determined in the previous reports. MATERIALS AND METHODS Cytotoxic assay was analysed through MTT assay. Comparison between non-optimised and optimised extraction condition from E. bulbosa ethanolic bulb extract was evaluated. Morphological assessment of apoptotic cells was conducted through acridine orange propidium iodide (AOPI) staining using fluorescence microscopy. Apoptosis assay was carried out through Annexin V-FITC and cell cycle analysis through PI staining. The effect of varying concentrations (IC25, IC50, IC75) of the optimised E. bulbosa ethanolic bulb extract was observed. The mRNA expression was also conducted to confirm the underlying mechanism. RESULTS The optimised E. bulbosa ethanolic bulb extract markedly suppressed the proliferation of retinoblastoma cancer cells significantly with an IC50 value of 15.7 μg/mL as compared to non-optimised extract (p < 0.01). Fluorescence microscopy revealed that retinoblastoma cancer cells manifested early features of apoptosis-like membrane blebbing, chromatin condensation and formation of apoptotic bodies in a dose-dependent manner. The number of apoptotic cells were greatly observed in early and late apoptosis through Annexin V-FITC and the extract also induced cell arrestment as compared to the untreated group. The apoptosis was confirmed with the upregulation of Bax, Bad, p53, Caspase 3, Caspase 8, and Caspase 9 genes meanwhile, Bcl-2, BcL-xL, Nrf-2, and HO-1 genes were downregulated. CONCLUSION The optimised E. bulbosa ethanolic bulb extract induced a significant cell death and cell cycle arrestment on retinoblastoma cancer cells. It could be suggested that the induction of apoptosis in retinoblastoma cancer cells may be due to the synergistic effect of the bioactive compounds extracted under optimised extraction condition. Our findings indicated that E. bulbosa bulb could be promising chemotherapeutic potential to treat retinoblastoma cancer cells.
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Affiliation(s)
- Ammar Akram Kamarudin
- Natural Medicines and Product Research Laboratory (NaturMeds), Institute of Bioscience, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
| | - Nor Hafiza Sayuti
- Natural Medicines and Product Research Laboratory (NaturMeds), Institute of Bioscience, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
| | - Norazalina Saad
- UPM-MAKNA Cancer Research Laboratory (CANRES), Institute of Bioscience, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
| | - Nor Asma Ab Razak
- Natural Medicines and Product Research Laboratory (NaturMeds), Institute of Bioscience, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
| | - Norhaizan Mohd Esa
- Natural Medicines and Product Research Laboratory (NaturMeds), Institute of Bioscience, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia; Department of Nutrition, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
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Kamarudin AA, Sayuti NH, Saad N, Razak NAA, Esa NM. Eleutherine bulbosa (Mill.) Urb. Bulb: Review of the Pharmacological Activities and Its Prospects for Application. Int J Mol Sci 2021; 22:ijms22136747. [PMID: 34201683 PMCID: PMC8268349 DOI: 10.3390/ijms22136747] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/19/2021] [Accepted: 06/21/2021] [Indexed: 01/09/2023] Open
Abstract
Natural product is an excellent candidate for alternative medicine for disease management. The bulb of E. bulbosa is one of the notable Iridaceae family with a variety therapeutic potential that is widely cultivated in Southeast Asia. The bulb has been used traditionally among the Dayak community as a folk medicine to treat several diseases like diabetes, breast cancer, nasal congestion, and fertility problems. The bulb is exceptionally rich in phytochemicals like phenolic and flavonoid derivatives, naphthalene, anthraquinone, and naphthoquinone. The electronic database was searched using various keywords, i.e., E. bulbosa, E. americana, E. palmifolia, E. platifolia, and others due to the interchangeably used scientific names of different countries. Scientific investigations revealed that various pharmacological activities were recorded from the bulb of E. bulbosa including anti-cancer, anti-diabetic, anti-bacterial, anti-fungi, anti-viral, anti-inflammatory, dermatological problems, anti-oxidant, and anti-fertility. The potential application of the bulb in the food industry and in animal nutrition was also discussed to demonstrate its great versatility. This is a compact study and is the first study to review the extensive pharmacological activities of the E. bulbosa bulb and its potential applications. The development of innovative food and pharma products from the bulb of E. bulbosa is of great interest.
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Affiliation(s)
- Ammar Akram Kamarudin
- Natural Medicine and Product Research Laboratory (NaturMeds), Institute of Bioscience, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (A.A.K.); (N.H.S.); (N.A.A.R.)
| | - Nor Hafiza Sayuti
- Natural Medicine and Product Research Laboratory (NaturMeds), Institute of Bioscience, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (A.A.K.); (N.H.S.); (N.A.A.R.)
| | - Norazalina Saad
- Laboratory of Cancer Research UPM-MAKNA (CANRES), Institute of Bioscience, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia;
| | - Nor Asma Ab. Razak
- Natural Medicine and Product Research Laboratory (NaturMeds), Institute of Bioscience, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (A.A.K.); (N.H.S.); (N.A.A.R.)
| | - Norhaizan Mohd. Esa
- Natural Medicine and Product Research Laboratory (NaturMeds), Institute of Bioscience, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; (A.A.K.); (N.H.S.); (N.A.A.R.)
- Department of Nutrition, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia
- Correspondence:
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Chang J, Zhou Y, Wang Q, Aschner M, Lu R. Plant components can reduce methylmercury toxication: A mini-review. Biochim Biophys Acta Gen Subj 2019; 1863:129290. [DOI: 10.1016/j.bbagen.2019.01.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 12/15/2018] [Accepted: 01/21/2019] [Indexed: 12/19/2022]
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Maqbool F, Bahadar H, Hassani S, Niaz K, Baeeri M, Rahimifard M, Ghasemi-Niri SF, Abdollahi M. Biochemical evidence on the potential role of methyl mercury in hepatic glucose metabolism through inflammatory signaling and free radical pathways. J Cell Biochem 2019; 120:16195-16205. [PMID: 31081130 DOI: 10.1002/jcb.28899] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 03/12/2019] [Accepted: 03/22/2019] [Indexed: 12/18/2022]
Abstract
Methylmercury (MeHg) is an extremely important environmental toxicant posing serious health risks to human health and a big source of environmental pollutant. Numerous evidence available showing a link between nervous system toxicity and MeHg exposure. Other forms of mercury are reason of metabolic toxic effects and alteration of DNA in the human body. The sources of exposure could be occupational or other environmental settings. In the present study MeHg was orally gavaged to mice, at doses of 2.5, 5, and 10 mg/kg for 4 weeks. Fasting hyperglycemia, activity of hepatic phoshphoenolpyruvate carboxykinase and glucose 6-phoshphate were reported high as compared to control group. Inflammatory markers like, tumor necrosis factor α, the actual end product of inflammatory mediators' cascade pathway was also raised in comparison to control group. Hyperinsulinemia observed in serum showed clear understanding of mercury induced insulin resistance. Moreover, tissue damage due to increased oxidative stress markers like, hepatic lipid peroxidation, 8-deoxygunosine, reactive oxygen species, and carbonyl groups was significantly higher as compared to control group. MeHg caused a significant reduction in antioxidant markers like ferric reducing antioxidant power and total thiol molecules. The present study highlighted that activity of key enzymes involved in glucose metabolism is changed, owing to MeHg induced toxicity in the liver. Induction of similar toxic effects assumed to be stimulated by the production of high quantity free radicals.
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Affiliation(s)
- Faheem Maqbool
- Toxicology and Diseases Group, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran.,Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Haji Bahadar
- Toxicology and Diseases Group, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran.,Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.,Department of Pharmacology, Institute of Basic Medical Sciences, Khyber Medical University, Peshawar, Pakistan
| | - Shokoufeh Hassani
- Toxicology and Diseases Group, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran.,Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Kamal Niaz
- Toxicology and Diseases Group, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran.,Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Baeeri
- Toxicology and Diseases Group, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran.,Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahban Rahimifard
- Toxicology and Diseases Group, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran.,Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Seyedeh Farnaz Ghasemi-Niri
- Toxicology and Diseases Group, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran.,Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Abdollahi
- Toxicology and Diseases Group, The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran.,Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
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Teixeira FB, de Oliveira ACA, Leão LKR, Fagundes NCF, Fernandes RM, Fernandes LMP, da Silva MCF, Amado LL, Sagica FES, de Oliveira EHC, Crespo-Lopez ME, Maia CSF, Lima RR. Exposure to Inorganic Mercury Causes Oxidative Stress, Cell Death, and Functional Deficits in the Motor Cortex. Front Mol Neurosci 2018; 11:125. [PMID: 29867340 PMCID: PMC5962769 DOI: 10.3389/fnmol.2018.00125] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/29/2018] [Indexed: 02/04/2023] Open
Abstract
Mercury is a toxic metal that can be found in the environment in three different forms – elemental, organic and inorganic. Inorganic mercury has a lower liposolubility, which results in a lower organism absorption and reduced passage through the blood–brain barrier. For this reason, exposure models that use inorganic mercury in rats in order to evaluate its effects on the central nervous system are rare, especially in adult subjects. This study investigated if a chronic exposure to low doses of mercury chloride (HgCl2), an inorganic form of mercury, is capable of promoting motor alterations and neurodegenerative in the motor cortex of adult rats. Forty animals were exposed to a dose of 0.375 mg/kg/day, for 45 days. They were then submitted to motor evaluation and euthanized to collect the motor cortex. Measurement of mercury deposited in the brain parenchyma, evaluation of oxidative balance, quantification of cellular cytotoxicity and apoptosis and density of mature neurons and astrocytes of the motor cortex were performed. It was observed that chronic exposure to inorganic mercury caused a decrease in balance and fine motor coordination, formation of mercury deposits and oxidative stress verified by the increase of lipoperoxidation and nitrite concentration and a decrease of the total antioxidant capacity. In addition, we found that this model of exposure to inorganic mercury caused cell death by cytotoxicity and induction of apoptosis with a decreased number of neurons and astrocytes in the motor cortex. Our results provide evidence that exposure to inorganic mercury in low doses, even in spite of its poor ability to cross biological barriers, is still capable of inducing motor deficits, cell death by cytotoxicity and apoptosis, and oxidative stress in the motor cortex of adult rats.
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Affiliation(s)
- Francisco B Teixeira
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, Brazil
| | - Ana C A de Oliveira
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, Brazil
| | - Luana K R Leão
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, Brazil
| | - Nathália C F Fagundes
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, Brazil
| | - Rafael M Fernandes
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, Brazil
| | - Luanna M P Fernandes
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, Brazil
| | - Márcia C F da Silva
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, Brazil
| | - Lilian L Amado
- Laboratory of Ecotoxicology, Institute of Biological Sciences, Federal University of Pará, Belém, Brazil
| | - Fernanda E S Sagica
- Laboratório de Cultura de Tecidos e Citogenética, SAMAM, Instituto Evandro Chagas, Ananindeua, Brazil
| | - Edivaldo H C de Oliveira
- Laboratório de Cultura de Tecidos e Citogenética, SAMAM, Instituto Evandro Chagas, Ananindeua, Brazil
| | - Maria E Crespo-Lopez
- Laboratory of Molecular Pharmacology, Institute of Biological Sciences, Federal University of Pará, Belém, Brazil
| | - Cristiane S F Maia
- Laboratory of Inflammation and Behavior Pharmacology, Pharmacy Faculty, Institute of Health Science, Federal University of Pará, Belém, Brazil
| | - Rafael R Lima
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, Brazil
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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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Pinho AI, Oliveira CS, Lovato FL, Waczuk EP, Piccoli BC, Boligon AA, Leite NF, Coutinho HDM, Posser T, Da Rocha JBT, Franco JL. Antioxidant and mercury chelating activity of Psidium guajava var. pomifera L. leaves hydroalcoholic extract. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2017; 80:1301-1313. [PMID: 29020526 DOI: 10.1080/15287394.2017.1382408] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Mercury (Hg) is widely distributed in the environment and is known to produce several adverse effects in organisms. The aim of the present study was to examine the in vitro antioxidant activity and Hg chelating ability of the hydroalcoholic extract of Psidium guajava leaves (HEPG). In addition, the potential protective effects of HEPG against Hg(II) were evaluated using a yeast model (Saccharomyces cerevisiae). HEPG was found to exert significant antioxidant activity in 2,2-diphenyl-1-picrylhydrazyl scavenger and inhibition of lipid peroxidation induced by Fe(II) assays in a concentration-dependent manner. The extract also exhibited significant Hg(II) chelating activity. In yeast, Hg(II) induced a significant decrease in cell viability. In contrast, HEPG partially prevented the fall in cell viability induced by Hg(II). In conclusion, HEPG exhibited protective effects against Hg(II)-mediated toxicity, which may be related to both antioxidant and Hg(II)-chelating activities.
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Affiliation(s)
- Antonio Ivanildo Pinho
- a Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica . Universidade Federal de Santa Maria , Santa Maria , RS , Brazil
| | - Cláudia Sirlene Oliveira
- a Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica . Universidade Federal de Santa Maria , Santa Maria , RS , Brazil
| | - Fabricio Luís Lovato
- a Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica . Universidade Federal de Santa Maria , Santa Maria , RS , Brazil
| | - Emily Pansera Waczuk
- a Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica . Universidade Federal de Santa Maria , Santa Maria , RS , Brazil
| | - Bruna Candia Piccoli
- a Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica . Universidade Federal de Santa Maria , Santa Maria , RS , Brazil
| | - Aline Augusti Boligon
- b Departamento de Farmácia Industrial , Universidade Federal de Santa Maria , Santa Maria , RS , Brazil
| | - Nadghia Figueredo Leite
- c Laboratório de Microbiologia e Biologia Molecular , Universidade Regional do Cariri , Crato , CE , Brazil
| | | | - Thais Posser
- a Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica . Universidade Federal de Santa Maria , Santa Maria , RS , Brazil
- d Centro Interdisciplinar de Pesquisas em Biotecnologia (CIPBIOTEC) , Universidade Federal do Pampa , São Gabriel , RS , Brazil
| | - João Batista Teixeira Da Rocha
- a Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica . Universidade Federal de Santa Maria , Santa Maria , RS , Brazil
| | - Jeferson Luis Franco
- a Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica . Universidade Federal de Santa Maria , Santa Maria , RS , Brazil
- d Centro Interdisciplinar de Pesquisas em Biotecnologia (CIPBIOTEC) , Universidade Federal do Pampa , São Gabriel , RS , Brazil
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Bellante A, D'Agostino F, Traina A, Piazzese D, Milazzo MF, Sprovieri M. Hg and Se exposure in brain tissues of striped dolphin (Stenella coeruleoalba) and bottlenose dolphin (Tursiops truncatus) from the Tyrrhenian and Adriatic Seas. ECOTOXICOLOGY (LONDON, ENGLAND) 2017; 26:250-260. [PMID: 28108889 DOI: 10.1007/s10646-017-1759-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 01/03/2017] [Indexed: 06/06/2023]
Abstract
In this study we analyzed Hg and Se concentrations in dolphin brain tissues of fifteen specimens of striped dolphin (Stenella coeruleoalba) and eight specimens of bottlenose dolphin (Tursiops truncatus) stranded in the Tyrrhenian and Adriatic Seas, in order to assess the toxicological risks associated with Hg exposure. High Hg concentrations were found in brain tissues of both analyzed specie (1.86-243 mg/kg dw for striped dolphin and 2.1-98.7 mg/kg dw for bottlenose dolphin), exceeding levels associated with marine mammals neurotoxicity. Althougth the results clearly suggest that the protective effects of Se against Hg toxicity occur in cetaceans' brain tissues, a molar excess of mercury with respect to selenium was found, particularly in adult specimens of Stenella coeruleoalba. On contrary, negligible neurotoxicological risks were found for Tursiops truncatus specimens, due to detoxification processes. Data obtained allowed to prove a more marked neurotoxicological risk for adult specimens of Stenella coeruleoalba in both Tyrrhenian and Adriatic Seas.
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Affiliation(s)
- Antonio Bellante
- Dipartimento di Scienze della Terra e del Mare (DiSTeM), Università degli Studi di Palermo, CoNISMa -Palermo, Via Archirafi, 26, 90123, Palermo, Italy.
| | - Fabio D'Agostino
- CNR-Istituto per l'Ambiente Marino Costiero, Via del Mare 3, Capo Granitola, Campobello di Mazara, TP, 91021, Italy
| | - Anna Traina
- CNR-Istituto per l'Ambiente Marino Costiero, Via del Mare 3, Capo Granitola, Campobello di Mazara, TP, 91021, Italy
| | - Daniela Piazzese
- Dipartimento di Scienze della Terra e del Mare (DiSTeM), Università degli Studi di Palermo, CoNISMa -Palermo, Via Archirafi, 26, 90123, Palermo, Italy
| | - Maria Francesca Milazzo
- Dipartimento di Ingegneria (Dip.Inge.), Università degli Studi di Messina, Contrada Di Dio, 98166, Messina, Italy
| | - Mario Sprovieri
- CNR-Istituto per l'Ambiente Marino Costiero, Via del Mare 3, Capo Granitola, Campobello di Mazara, TP, 91021, Italy
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11
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Leão LKR, Herculano AM, Maximino C, Brasil Costa A, Gouveia A, Batista EO, Rocha FF, Crespo-Lopez ME, Borges R, Oliveira K. Mauritia flexuosa L. protects against deficits in memory acquisition and oxidative stress in rat hippocampus induced by methylmercury exposure. Nutr Neurosci 2016; 20:297-304. [PMID: 26869022 DOI: 10.1080/1028415x.2015.1133030] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
OBJECTIVE Methylmercury (MeHg) is the most toxic form of mercury that can affect humans through the food chain by bioaccumulation. Human organism is capable of triggering visual and cognitive disorders, neurodegeneration, as well as increased production of reactive species of O2 and depletion of natural anti-oxidant agents. In this context, Mauritia flexuosa L., a fruit rich in compounds with anti-oxidant properties, emerged as an important strategy to prevent the MeHg damages. So, this work has aimed to elucidate the protective effect of Mauritia flexuosa L. on the damage caused by the exposure of rats to MeHg. METHODS In order to evaluate the effect of MeHg on rat aversive memory acquisition and panic-like behavior, we have used elevated T-maze apparatus and after behavioral test, the hippocampus was removed to perfom lipid peroxidation. RESULTS Our results demonstrated that the exposure to MeHg caused deficits in inhibitory avoidance acquisition (aversive conditioning) and in the learning process, and increased levels of lipid peroxidation in hippocampus tissue. However, the pretreatment with feed enriched with Mauritia flexuosa L. showed a protective effect against cognitive deficits caused by MeHg and also prevented the occurrence of cytoplasmic membrane damage induced by lipid peroxidation in the hippocampal region. DISCUSSION Therefore, this study suggests that Mauritia flexuosa L. represents an important strategy to prevent neurocytotoxics and behavioral effects of MeHg.
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Affiliation(s)
- Luana K R Leão
- a Laboratório de Neuroendocrinologia, Instituto de Ciências Biológicas , Universidade Federal do Pará , Brazil
| | - Anderson M Herculano
- a Laboratório de Neuroendocrinologia, Instituto de Ciências Biológicas , Universidade Federal do Pará , Brazil
| | - Caio Maximino
- a Laboratório de Neuroendocrinologia, Instituto de Ciências Biológicas , Universidade Federal do Pará , Brazil
| | - Alódia Brasil Costa
- a Laboratório de Neuroendocrinologia, Instituto de Ciências Biológicas , Universidade Federal do Pará , Brazil
| | - Amauri Gouveia
- b Laboratório de Neurociências e Comportamento, Núcleo de Teoria e Pesquisa do Comportamento , Universidade Federal do Pará , Brazil
| | - Evander O Batista
- c Laboratório de Protozoologia, Núcleo de Medicina Tropical , Universidade Federal do Pará , Brazil
| | - Fernando F Rocha
- d Laboratório de Neurofisiologia Eduardo Oswaldo Cruz, Instituto de Ciências Biológicas , Universidade Federal do Pará , Brazil
| | - Maria Elena Crespo-Lopez
- e Laboratório de Farmacologia Molecular, Instituto de Ciências Biológicas , Universidade Federal do Pará , Brazil
| | - Rosivaldo Borges
- f Laboratório de Química Farmacêutica, Faculdade de Farmácia, Instituto de Ciências da Saúde , Universidade Federal do Pará , Brazil
| | - Karen Oliveira
- a Laboratório de Neuroendocrinologia, Instituto de Ciências Biológicas , Universidade Federal do Pará , Brazil
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Sulforaphane Prevents Methylmercury-Induced Oxidative Damage and Excitotoxicity Through Activation of the Nrf2-ARE Pathway. Mol Neurobiol 2016; 54:375-391. [PMID: 26742517 DOI: 10.1007/s12035-015-9643-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 12/16/2015] [Indexed: 12/29/2022]
Abstract
Methylmercury (MeHg) is a prominent environmental neurotoxicant, which induces oxidative damage and an indirect excitotoxicity caused by altered glutamate (Glu) metabolism. However, the interaction between oxidative damage and excitotoxicity in MeHg-exposed rats has not been fully recognized. Here, we explored the interaction between oxidative damage and excitotoxicity and evaluated the preventive effects of sulforaphane (SFN) on MeHg-induced neurotoxicity in rat cerebral cortex. Seventy-two rats were randomly assigned to four groups: control group, MeHg-treated groups (4 and 12 μmol/kg), and SFN pretreatment group. After treatment (28 days), the rats were killed and the cerebral cortex was analyzed. Then, Hg, glutathione (GSH), malondialdehyde (MDA), protein sulfhydryl, protein carbonyl, 8-hydroxy-2-deoxyguanosine (8-OHdG), and the levels of reactive oxygen species (ROS) and apoptosis were examined. Glu and glutamine (Gln) levels, glutamine synthetase (GS), phosphate-activated glutaminase (PAG), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), Na+-K+-ATPase and Ca2+-ATPase activities, intracellular Ca2+ levels, and the mRNA and protein expressions of Nrf2, Nrf2-regulated gene products, and N-methyl-D-aspartate receptors (NMDARs) were investigated in rat cerebral cortex. In our study, MeHg exposure not only induced Hg accumulation, apoptosis, ROS formation, GSH depletion, inhibition of antioxidant enzyme activities, and activation of Nrf2-ARE pathway signaling but also caused lipid, protein, and DNA peroxidative damage in a dose-dependent manner in rat cerebral cortex. Moreover, MeHg treatment significantly altered Gln/Glu cycling and NMDAR expression and resulted in calcium overloading. Furthermore, the present study also indicated that SFN pretreatment significantly reinforced the activation of the Nrf2-ARE pathway, which could prevent the toxic effects of MeHg exposure. Collectively, MeHg initiates multiple additive or synergistic disruptive mechanisms that lead to oxidative damage and excitotoxicity in rat cerebral cortex; pretreatment with SFN might prevent the MeHg-induced neurotoxicity by reinforcing the activation of the Nrf2-ARE pathway and then downregulating the interaction between oxidative damage and excitotoxicity pathways.
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Ansar S. Effect of Selenium on the Levels of Cytokines and Trace Elements in Toxin-Mediated Oxidative Stress in Male Rats. Biol Trace Elem Res 2016; 169:129-33. [PMID: 26089086 DOI: 10.1007/s12011-015-0403-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 06/08/2015] [Indexed: 10/23/2022]
Abstract
Selenium is an essential cofactor in the key enzymes involved in cellular antioxidant defense. This study was designed to investigate the protective effects of selenium on mercury chloride (HgCl2)-induced toxicity. Male Wistar rats were randomly divided into four groups of six animals each. The first group was control; the second group was treated with mercuric chloride (HgCl2: 50 mg/kg/bw). The third group was treated with sodium selenite (Se 0.2 mg/kg/bw), and the fourth group received Se (0.2 mg/kg/bw) plus HgCl2 (50 mg/kg for 24 h). The influence of Se on mercury induced levels of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) and zinc, copper, and iron in serum of rats were observed. The serum MDA, SOD, zinc, and iron concentrations were found to be statistically different among the control and toxin-treated group. The serum levels of IL-6, IL-10, and TNF-α were also measured. There was a significant decrease in the levels of TNF-α, IL-6, and IL-10 in toxin-treated group II compared with that of the control group (p < 0.05). A significant increase in the serum levels of inflammatory cytokines IL-6, TNF-α, and IL-10 after administration of Se seemed to counteract some of the damage, as indicated by differences in the serum concentrations of major elements.
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Affiliation(s)
- S Ansar
- Department of Clinical Laboratory Sciences, College of Applied Medical Science, King Saud University, Riyadh, Saudi Arabia.
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Abdel Moneim AE. The neuroprotective effect of berberine in mercury-induced neurotoxicity in rats. Metab Brain Dis 2015; 30:935-42. [PMID: 25600690 DOI: 10.1007/s11011-015-9652-6] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 01/13/2015] [Indexed: 01/05/2023]
Abstract
The central nervous system is one of the most vulnerable organs affected by mercury toxicity. Both acute and chronic exposure to mercury is also known to cause a variety of neurological or psychiatric disorders. Here, the neuroprotective effect of berberine (BN; 100 mg/kg bwt) on mercuric chloride (HgCl2; 0.4 mg/kg bwt) induced neurotoxicity and oxidative stress was examined in rats. Adult male albino Wistar rats were injected with HgCl2 for 7 days. HgCl2 treatment induced oxidative stress by increasing lipid peroxidation (LPO) and nitrite/nitrate (nitric oxide; NO) production along with a concomitant decrease in glutathione (GSH) and various antioxidant enzymes, namely superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase. Pre-treatment of rats with BN inhibited LPO and NO production, whereas it increased GSH content. Activities of antioxidant enzymes were also restored concomitantly when compared to the control rats after BN administration. Berberine also caused decrease in TNF-α level and caspase-3 activity which was higher with HgCl2. Furthermore, treatment with BN inhibited apoptosis, as indicated by the reduction of Bax/Bcl-2 ratio in brain tissue. These data indicated that BN augments antioxidant defense with anti-inflammatory and anti-apoptotic activities against HgCl2-induced neurotoxicity and provides evidence that it has a therapeutic potential as neuroprotective agent.
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Affiliation(s)
- Ahmed E Abdel Moneim
- Zoology and Entomology Department, Faculty of Science, Helwan University, Cairo, Egypt,
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15
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Kim W, Kim DW, Yoo DY, Jung HY, Kim JW, Kim DW, Choi JH, Moon SM, Yoon YS, Hwang IK. Antioxidant effects of Dendropanax morbifera Léveille extract in the hippocampus of mercury-exposed rats. Altern Ther Health Med 2015. [PMID: 26201852 PMCID: PMC4511420 DOI: 10.1186/s12906-015-0786-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Background Dendropanax morbifera Léveille has been employed for the treatment of infectious diseases using folk medicine. In this study, we evaluated the antioxidant effects of a leaf extract of Dendropanax morbifera Léveille in the hippocampus of mercury-exposed rats. Methods Seven-week-old Sprague–Dawley rats received a daily intraperitoneal injection of 5 μg/kg dimethylmercury and/or oral Dendropanax morbifera Léveille leaf extract (100 mg/kg) for 4 weeks. Animals were sacrificed 2 h after the last dimethylmercury and/or leaf extract treatment. Mercury levels were measured in homogenates of hippocampal tissue, a brain region that is vulnerable to mercury toxicity. In addition, we measured reactive oxygen species production, lipid peroxidation levels, and antioxidant levels in these hippocampal homogenates. Results Treatment with Dendropanax morbifera Léveille leaf extract significantly reduced mercury levels in hippocampal homogenates and attenuated the dimethylmercury-induced increase in the production of reactive oxygen species and formation of malondialdehyde. In addition, this leaf extract treatment significantly reversed the dimethylmercury-induced reduction in the hippocampal activities of Cu, Zn-superoxide dismutase, catalase, glutathione peroxidase, and glutathione-S-transferase. Conclusion These results suggest that a leaf extract of Dendropanax morbifera Léveille had strong antioxidant effects in the hippocampus of mercury-exposed rats.
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Feng S, Xu Z, Liu W, Li Y, Deng Y, Xu B. Preventive effects of dextromethorphan on methylmercury-induced glutamate dyshomeostasis and oxidative damage in rat cerebral cortex. Biol Trace Elem Res 2014; 159:332-45. [PMID: 24819089 DOI: 10.1007/s12011-014-9977-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 04/10/2014] [Indexed: 12/29/2022]
Abstract
Methylmercury (MeHg) is a well-known environmental pollutant leading to neurotoxicant associated with aberrant central nervous system (CNS) functions, but its toxic mechanisms have not yet been fully recognized. In the present study, we tested the hypothesis that MeHg induces neuronal injury via glutamate (Glu) dyshomeostasis and oxidative damage mechanisms and that these effects are attenuated by dextromethorphan (DM), a low-affinity and noncompetitive N-methyl-D-aspartate receptor (NMDAR) antagonist. Seventy-two rats were randomly divided into four groups of 18 animals in each group: control group, MeHg-treated group (4 and 12 μmol/kg), and DM-pretreated group. After the 4-week treatment, we observed that the administration of MeHg at a dose of 12 μmol/kg significantly increased in total mercury (Hg) levels, disrupted Glu metabolism, overexcited NMDARs, and led to intracellular calcium overload in the cerebral cortex. We also found that MeHg reduced nonenzymatic and enzymatic antioxidants, enhanced neurocyte apoptosis, induced reactive oxygen species (ROS), and caused lipid, protein, and DNA peroxidative damage in the cerebral cortex. Moreover, glutamate/aspartate transporter (GLAST) and glutamate transporter-1 (GLT-1) appeared to be inhibited by MeHg exposure. These alterations were significantly prevented by the pretreatment with DM at a dose of 13.5 μmol/kg. In conclusion, these findings strongly implicate that DM has potential to protect the brain from Glu dyshomeostasis and oxidative damage resulting from MeHg-induced neurotoxicity in rat.
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Affiliation(s)
- Shu Feng
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, People's Republic of China
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Christinal J, Sumathi T. Effect of Bacopa monniera extract on methylmercury-induced behavioral and histopathological changes in rats. Biol Trace Elem Res 2013; 155:56-64. [PMID: 23872736 DOI: 10.1007/s12011-013-9756-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 07/04/2013] [Indexed: 11/28/2022]
Abstract
Methylmercury (MeHg) is a well-recognized environmental contaminant with established health risk to human beings by fish and marine mammal consumption. Bacopa monniera (BM) is a perennial herb and is used as a nerve tonic in Ayurveda, a traditional medicine system in India. This study was aimed to evaluate the effect of B. monniera extract (BME) on MeHg-induced toxicity in rat cerebellum. Male Wistar rats were administered with MeHg orally at a dose of 5 mg/kg b.w. for 21 days. Experimental rats were given MeHg and also administered with BME (40 mg/kg, orally) 1 h prior to the administration of MeHg for 21 days. After treatment period, MeHg exposure significantly decreases the body weight and also caused the following behavioral changes. Decrease tail flick response, longer immobility time, significant decrease in motor activity, and spatial short-term memory. BME pretreatment reverted the behavioral changes to normal. MeHg exposure decreases the DNA and RNA content in cerebellum and also caused some pathological changes in cerebellum. Pretreatment with BME restored all the changes to near normal. These findings suggest that BME has a potent efficacy to alleviate MeHg-induced toxicity in rat cerebellum.
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Affiliation(s)
- Johnson Christinal
- Department of Medical Biochemistry, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, Tamil Nadu, India
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Patel E, Reynolds M. Methylmercury impairs motor function in early development and induces oxidative stress in cerebellar granule cells. Toxicol Lett 2013; 222:265-72. [DOI: 10.1016/j.toxlet.2013.08.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 07/31/2013] [Accepted: 08/03/2013] [Indexed: 01/20/2023]
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de Paula Martins R, Glaser V, da Luz Scheffer D, de Paula Ferreira PM, Wannmacher CMD, Farina M, de Oliveira PA, Prediger RD, Latini A. Platelet oxygen consumption as a peripheral blood marker of brain energetics in a mouse model of severe neurotoxicity. J Bioenerg Biomembr 2013; 45:449-57. [PMID: 23471523 DOI: 10.1007/s10863-013-9499-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 01/30/2013] [Indexed: 01/12/2023]
Abstract
Interactions of chemicals with cerebral cellular systems are often accompanied by similar changes involving components in non-neural tissues. On this basis, indirect strategies have been developed to investigate neural cell function parameters by methods using accessible cells, including platelets and/or peripheral blood lymphocytes. Therefore, here it was investigated whether peripheral blood markers may be useful for assessing the central toxic effects of methylmercury (MeHg). For this purpose, we investigated platelet mitochondrial physiology in a well-established mouse model of MeHg-induced neurotoxicity, and correlated this peripheral activity with behavioural and central biochemical parameters. In order to characterize the cortical toxicity induced by MeHg (20 and 40 mg/L in drinking water, 21 days), the behavioral parameter namely, short-term object recognition, and the central mitochondrial impairment assessed by measuring respiratory complexes I-IV enzyme activities were determined in MeHg-poisoned animals. Neurotoxicity induced by MeHg exposure provoked compromised cortical activity (memory impairment) and reduced NADH dehydrogenase, complex II and II-III activities in the cerebral cortex. These alterations correlated with impaired systemic platelet oxygen consumption of intoxicated mice, which was characterized by reduced electron transfer activity and uncoupled mitochondria. The data brought here demonstrated that impaired systemic platelet oxygen consumption is a sensitive and non-invasive marker of the brain energy deficits induced by MeHg poisoning. Finally, brain and platelets biochemical alterations significantly correlated with cognitive behavior in poisoned mice. Therefore, it could be proposed the use of platelet oxygen consumption as a peripheral blood marker of brain function in a mouse model MeHg-induced neurotoxicity.
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Affiliation(s)
- Roberta de Paula Martins
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil,
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Lucena GMRS, Matheus FC, Ferreira VM, Tessele PB, Azevedo MS, Cechinel-Filho V, Prediger RD. Effects of Ethanolic Extract and Naphthoquinones Obtained from the Bulbs ofCipura paludosaon Short-Term and Long-Term Memory: Involvement of Adenosine A1and A2AReceptors. Basic Clin Pharmacol Toxicol 2012; 112:229-35. [DOI: 10.1111/bcpt.12022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 09/26/2012] [Indexed: 11/27/2022]
Affiliation(s)
| | - Filipe C. Matheus
- Departamento de Farmacologia, Centro de Ciências Biológicas; Universidade Federal de Santa Catarina (UFSC); Florianópolis; SC; Brazil
| | - Vania M. Ferreira
- Faculdade de Ciências da Saúde; Universidade de Brasília (UnB); Brasília; DF; Brazil
| | - Priscila B. Tessele
- Núcleo de Investigações Químico-Farmacêuticas (NIQFAR); Curso de Farmácia-CCS, Universidade do Vale do Itajaí (UNIVALI); Itajaí; SC; Brazil
| | - Mariangela S. Azevedo
- Departamento de Química, Laboratórios de Fitoquímica; Produtos Naturais e Meio Ambiente, Universidade Federal de Rondônia (Labfito-UNIR); Porto Velho; RO; Brazil
| | - Valdir Cechinel-Filho
- Núcleo de Investigações Químico-Farmacêuticas (NIQFAR); Curso de Farmácia-CCS, Universidade do Vale do Itajaí (UNIVALI); Itajaí; SC; Brazil
| | - Rui D. Prediger
- Departamento de Farmacologia, Centro de Ciências Biológicas; Universidade Federal de Santa Catarina (UFSC); Florianópolis; SC; Brazil
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Farina M, Avila DS, da Rocha JBT, Aschner M. Metals, oxidative stress and neurodegeneration: a focus on iron, manganese and mercury. Neurochem Int 2012; 62:575-94. [PMID: 23266600 DOI: 10.1016/j.neuint.2012.12.006] [Citation(s) in RCA: 357] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Revised: 12/07/2012] [Accepted: 12/10/2012] [Indexed: 02/08/2023]
Abstract
Essential metals are crucial for the maintenance of cell homeostasis. Among the 23 elements that have known physiological functions in humans, 12 are metals, including iron (Fe) and manganese (Mn). Nevertheless, excessive exposure to these metals may lead to pathological conditions, including neurodegeneration. Similarly, exposure to metals that do not have known biological functions, such as mercury (Hg), also present great health concerns. This review focuses on the neurodegenerative mechanisms and effects of Fe, Mn and Hg. Oxidative stress (OS), particularly in mitochondria, is a common feature of Fe, Mn and Hg toxicity. However, the primary molecular targets triggering OS are distinct. Free cationic iron is a potent pro-oxidant and can initiate a set of reactions that form extremely reactive products, such as OH. Mn can oxidize dopamine (DA), generating reactive species and also affect mitochondrial function, leading to accumulation of metabolites and culminating with OS. Cationic Hg forms have strong affinity for nucleophiles, such as -SH and -SeH. Therefore, they target critical thiol- and selenol-molecules with antioxidant properties. Finally, we address the main sources of exposure to these metals, their transport mechanisms into the brain, and therapeutic modalities to mitigate their neurotoxic effects.
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Affiliation(s)
- Marcelo Farina
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil
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Hassauer M, Kaiser E, Schneider K, Schuhmacher‐Wolz U. Collate the literature on toxicity data on mercury in experimental animals and humans (Part I – Data on organic mercury). ACTA ACUST UNITED AC 2012. [DOI: 10.2903/sp.efsa.2012.en-297] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Martin Hassauer
- Forschungs‐ und Beratungsinstitut Gefahrstoffe GmbH (FoBiG) Freiburg Germany
| | - Eva Kaiser
- Forschungs‐ und Beratungsinstitut Gefahrstoffe GmbH (FoBiG) Freiburg Germany
| | - Klaus Schneider
- Forschungs‐ und Beratungsinstitut Gefahrstoffe GmbH (FoBiG) Freiburg Germany
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Lucena GM, Prediger RD, Silva MV, Santos SN, Silva JFB, Santos ARS, Azevedo MS, Ferreira VM. Ethanolic extract from bulbs of Cipura paludosa reduced long-lasting learning and memory deficits induced by prenatal methylmercury exposure in rats. Dev Cogn Neurosci 2012; 3:1-10. [PMID: 23245215 DOI: 10.1016/j.dcn.2012.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 08/16/2012] [Accepted: 08/17/2012] [Indexed: 01/12/2023] Open
Abstract
Previous studies from our group have indicated important biological properties of the ethanolic extract (EE) and isolated compounds from the bulbs of Cipura paludosa (Iridaceae), a native plant widely distributed in northern Brazil. In the present study, the effects of chronic treatment with the EE on the memory of adult rats exposed to methylmercury (MeHg) during early development were assessed. Pregnant rats were treated by gavage with a single dose of MeHg (8 mg/kg) on gestational day 15, the developmental stage critical for cortical neuron proliferation. Adult offspring were administered orally with the EE of C. paludosa (1, 10 or 100mg/kg) over 14 consecutive days. EE improved short-term social memory in a specific manner and facilitated the step-down inhibitory avoidance of short- and long-term memory. MeHg exposure induced pronounced long-lasting impairments in social recognition memory that were improved by EE. Moreover, EE significantly increased the step-down latencies specifically during the short-term session in prenatal MeHg-exposed rats. These results demonstrate that EE reduced the long-lasting short-term learning and memory deficits induced by MeHg exposure. These findings may encourage further studies evaluating the cognitive enhancing properties of C. paludosa and its components on neuropathological conditions associated with exposure to environmental contaminants.
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Role of calcium and mitochondria in MeHg-mediated cytotoxicity. J Biomed Biotechnol 2012; 2012:248764. [PMID: 22927718 PMCID: PMC3425894 DOI: 10.1155/2012/248764] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 06/12/2012] [Accepted: 06/14/2012] [Indexed: 11/17/2022] Open
Abstract
Methylmercury (MeHg) mediated cytotoxicity is associated with loss of intracellular calcium (Ca2+) homeostasis. The imbalance in Ca2+ physiology is believed to be associated with dysregulation of Ca2+ intracellular stores and/or increased permeability of the biomembranes to this ion. In this paper we summarize the contribution of glutamate dyshomeostasis in intracellular Ca2+ overload and highlight the mitochondrial dysfunctions induced by MeHg via Ca2+ overload. Mitochondrial disturbances elicited by Ca2+ may involve several molecular events (i.e., alterations in the activity of the mitochondrial electron transport chain complexes, mitochondrial proton gradient dissipation, mitochondrial permeability transition pore (MPTP) opening, thiol depletion, failure of energy metabolism, reactive oxygen species overproduction) that could culminate in cell death. Here we will focus on the role of oxidative stress in these phenomena. Additionally, possible antioxidant therapies that could be effective in the treatment of MeHg intoxication are briefly discussed.
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Protective Effect of Bacopa monniera on Methyl Mercury-Induced Oxidative Stress in Cerebellum of Rats. Cell Mol Neurobiol 2012; 32:979-87. [DOI: 10.1007/s10571-012-9813-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 02/04/2012] [Indexed: 01/21/2023]
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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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Black P, Niu L, Sachdeva M, Lean D, Poon R, Bowers WJ, Chan HM, Arnason JT, Pelletier G. Modulation of the effects of methylmercury on rat neurodevelopment by co-exposure with Labrador Tea (Rhododendron tomentosum ssp. subarcticum). Food Chem Toxicol 2011; 49:2336-42. [DOI: 10.1016/j.fct.2011.06.035] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 06/14/2011] [Accepted: 06/15/2011] [Indexed: 02/07/2023]
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Farina M, Rocha JBT, Aschner M. Mechanisms of methylmercury-induced neurotoxicity: evidence from experimental studies. Life Sci 2011; 89:555-63. [PMID: 21683713 DOI: 10.1016/j.lfs.2011.05.019] [Citation(s) in RCA: 303] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 04/22/2011] [Accepted: 05/13/2011] [Indexed: 02/08/2023]
Abstract
Neurological disorders are common, costly, and can cause enduring disability. Although mostly unknown, a few environmental toxicants are recognized causes of neurological disorders and subclinical brain dysfunction. One of the best known neurotoxins is methylmercury (MeHg), a ubiquitous environmental toxicant that leads to long-lasting neurological and developmental deficits in animals and humans. In the aquatic environment, MeHg is accumulated in fish, which represent a major source of human exposure. Although several episodes of MeHg poisoning have contributed to the understanding of the clinical symptoms and histological changes elicited by this neurotoxicant in humans, experimental studies have been pivotal in elucidating the molecular mechanisms that mediate MeHg-induced neurotoxicity. The objective of this mini-review is to summarize data from experimental studies on molecular mechanisms of MeHg-induced neurotoxicity. While the full picture has yet to be unmasked, in vitro approaches based on cultured cells, isolated mitochondria and tissue slices, as well as in vivo studies based mainly on the use of rodents, point to impairment in intracellular calcium homeostasis, alteration of glutamate homeostasis and oxidative stress as important events in MeHg-induced neurotoxicity. The potential relationship among these events is discussed, with particular emphasis on the neurotoxic cycle triggered by MeHg-induced excitotoxicity and oxidative stress. The particular sensitivity of the developing brain to MeHg toxicity, the critical role of selenoproteins and the potential protective role of selenocompounds are also discussed. These concepts provide the biochemical bases to the understanding of MeHg neurotoxicity, contributing to the discovery of endogenous and exogenous molecules that counteract such toxicity and provide efficacious means for ablating this vicious cycle.
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Affiliation(s)
- Marcelo Farina
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.
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Franco JL, Posser T, Missau F, Pizzolatti MG, dos Santos ARS, Souza DO, Aschner M, Rocha JBT, Dafre AL, Farina M. Structure-activity relationship of flavonoids derived from medicinal plants in preventing methylmercury-induced mitochondrial dysfunction. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2010; 30:272-278. [PMID: 21127717 PMCID: PMC2992974 DOI: 10.1016/j.etap.2010.07.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
In the present study, we investigated the potential protective effects of three flavonoids (myricetin, myricitrin and rutin) derived from medicinal plants against methyl mercury (MeHg)-induced mitochondrial dysfunction in vitro. Incubation of mouse brain mitochondria with MeHg induced a significant decrease in mitochondrial function, which was correlated with decreased glutathione (GSH) levels and increased generation of reactive oxygen species (ROS) and lipid peroxidation. The co-incubation of mouse brain mitochondria with myricetin or myricitrin caused a concentration-dependent decrease of MeHg-induced mitochondrial dysfunction and oxidative stress. The flavonoid rutin was ineffective in counteracting MeHg toxicity. Among the three tested flavonoids, myricetin was the most efficient in protecting against MeHg-induced mitochondrial dysfunction. Moreover, myricetin completely blocked MeHg-induced ROS formation and lipid peroxidation and partially prevented MeHg-induced GSH depletion. The ability of myricetin to attenuate MeHg-induced mitochondrial dysfunction and oxidative stress appears to be related to its higher scavenging capability when compared to myricitrin and rutin. Overall, the results suggest that MeHg-induced mitotoxicity is associated with oxidative stress. The ability of myricetin to prevent MeHg-induced oxidative damage in brain mitochondria renders this flavonoid a promising molecule for further in vivo studies in the search for potential antidotes to counteract MeHg-induced neurotoxicity.
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Affiliation(s)
- Jeferson L. Franco
- Departamento de Bioquímica Centro de Ciências Biológicas Universidade Federal de Santa Catarina, Florianópolis - SC, Brazil
- Campus São Gabriel, Universidade Federal do Pampa, São Gabriel - RS, Brazil
| | - Thais Posser
- Departamento de Bioquímica Centro de Ciências Biológicas Universidade Federal de Santa Catarina, Florianópolis - SC, Brazil
- Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria - RS, Brazil
| | - Fabiana Missau
- Departamento de Química, Centro de Ciências Físicas e Matemáticas, Universidade Federal de Santa Catarina, Florianópolis - SC, Brazil
| | - Moacir G. Pizzolatti
- Departamento de Química, Centro de Ciências Físicas e Matemáticas, Universidade Federal de Santa Catarina, Florianópolis - SC, Brazil
| | - Adair R. S. dos Santos
- Departamento de Ciências Fisiológicas, Centro de Ciências Biológicas Universidade Federal de Santa Catarina, Florianópolis - SC, Brazil
| | - Diogo O. Souza
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre - RS, Brazil
| | - Michael Aschner
- Department of Pediatrics, 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
| | - Alcir L. Dafre
- Departamento de Bioquímica Centro de Ciências Biológicas Universidade Federal de Santa Catarina, Florianópolis - SC, Brazil
| | - Marcelo Farina
- Departamento de Bioquímica Centro de Ciências Biológicas Universidade Federal de Santa Catarina, Florianópolis - SC, Brazil
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Lucena GMRS, Porto FA, Campos EG, Azevedo MS, Cechinel-Filho V, Prediger RDS, Ferreira VMM. Cipura paludosa attenuates long-term behavioral deficits in rats exposed to methylmercury during early development. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2010; 73:1150-1158. [PMID: 20447691 DOI: 10.1016/j.ecoenv.2010.04.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Revised: 04/05/2010] [Accepted: 04/10/2010] [Indexed: 05/29/2023]
Abstract
In the present study, we evaluated the effects of the ethanolic extract (EE) of Cipura paludosa on locomotor, and anxiety- and depression-like behaviors of adult rats exposed to MeHg during early development. Additionally, the antioxidant enzymes catalase (CAT) and selenium-glutathione peroxidase (Se-GPx) were measured in cortical, hippocampal, and cerebellar tissues. Pregnant Wistar rats were treated by gavage with a single dose of MeHg (8 mg/kg) on gestational day 15, the developmental stage critical for cortical neuron proliferation. Moreover, prenatal MeHg exposure inhibited CAT and Se-GPx in the cortex and cerebellum. Chronic treatment with the EE of C. paludosa attenuated these emotional and antioxidant deficits induced by prenatal MeHg toxic exposure. This study provides novel evidence that developmental exposure to MeHg can affect not only cognitive functions but also locomotor, and anxiety- and depression-like behaviors.
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Affiliation(s)
- Greice M R S Lucena
- Faculdade de Ciências da Saúde, Curso de Ciências Farmacêuticas, Universidade de Brasília (UnB), Campus Universitário Darcy Ribeiro (Asa Norte), 70910-900 DF, Brazil
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da Conceição Nascimento Pinheiro M, do Nascimento JLM, de Lima Silveira LC, da Rocha JBT, Aschner M. Mercury and Selenium - A Review on Aspects Related to the Health of Human Populations in the Amazon. ACTA ACUST UNITED AC 2009; 4:222-245. [PMID: 31485199 DOI: 10.1080/15555270903143440] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Mercury (Hg) toxicity is governed by cellular thiol compounds and its capacity to generate reactive oxygen radicals and oxidative stress. Selenium (Se) plays a key role in the prevention of the toxic effects of Hg by modulating the activity of several Se-dependent enzymes, including glutathione peroxidase (GSH-Px). In addition, dietary Se can reduce Hg toxicity by directly interacting with either Hg(II) or methylmercury (MeHg) to form inert products, such as HgSe complexes.. Although experimental and environmental data have indicated a protective role for selenium against Hg toxicity, human data are more limited and somewhat conroversial In the Amazon Region of Brazil, Hg pollution is rampant as a result of gold (Au) mining and other anthropogenic factors, leading to pervasive release of large quantities of metallic Hg0 into the environment. Exposure to Hg in this region is associated with direct occupational exposure in the gold mining industry, as well as consumption by in inhabitants of riverside communities of a diet rich in MeHg-contaminated fish. Human exposure to MeHg in the Amazon through the diet has been monitored by measuring Hg and MeHg in hair samples. In this paper, we review the environmental contamination of Hg in the Amazon and detail human exposures in populations of this region. We conclude with a brief synopsis on Se levels in the Amazon population and provide a brief review of data available on the interaction between Hg and Se in this region. Overall, the literature supports the notion that low environmental Se is linked to susceptibility to Hg toxicity and that Se levels could be used as a bioindicator to monitor the health of Hg exposed subjects. However, in light of the limited human data on this subject, further epidemiological studies are needed to clarify how changes in Se levels modify the toxicity of environmental Hg.
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Affiliation(s)
| | | | - Luiz Carlos de Lima Silveira
- Núcleo de Medicina Tropical, Universidade Federal do Pará, Belém, Pará Brazil.,Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Pará, Brazil
| | | | - Michael Aschner
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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