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Nascimento PC, Aragão WAB, Bittencourt LO, Silva MCF, Crespo-Lopez ME, Lima RR. Salivary parameters alterations after early exposure to environmental methylmercury: A preclinical study in offspring rats. J Trace Elem Med Biol 2021; 68:126820. [PMID: 34293649 DOI: 10.1016/j.jtemb.2021.126820] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 06/02/2021] [Accepted: 07/14/2021] [Indexed: 01/18/2023]
Abstract
BACKGROUND Methylmercury (MeHg) is still considered a global pollutant of major concern; thus, it becomes relevant to investigate and validate alternative diagnostic methods to track early-life human exposure. This study aimed to evaluate the salivary parameters and to characterize potential mechanisms of oxidative damage on the salivary glands (SG) of offspring rats after pre- and postnatal environmental-experimental MeHg exposure. METHODS Pregnant Wistar rats were daily exposed to 40 μg/kg MeHg during both gestational and lactation periods. Then, the saliva of offspring rats was analyzed in terms of flow rate, amylase activity, and total protein concentration. The SG of the offspring rats were dissected to perform the oxidative biochemistry analyses of antioxidant capacity against peroxyl radicals (ACAP), lipid peroxidation (LPO), and nitrite levels. RESULTS Exposure to MeHg significantly decreased the ACAP, increased LPO and nitrite levels, decreased salivary flow rate, amylase activity, and total protein concentration. CONCLUSION Saliva analyses can predict damages induced by early-life MeHg exposure and may be used as an auxiliary diagnostic method.
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Affiliation(s)
- Priscila Cunha Nascimento
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Belém, PA, Brazil
| | - Walessa Alana Bragança Aragão
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Belém, PA, Brazil
| | - Leonardo Oliveira Bittencourt
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Belém, PA, Brazil
| | - Marcia Cristina Freitas Silva
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Belém, PA, Brazil
| | - Maria Elena Crespo-Lopez
- Laboratory of Molecular Pharmacology, Institute of Biological Sciences, Federal University of Para, Belém, PA, Brazil
| | - Rafael Rodrigues Lima
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Belém, PA, Brazil.
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Eiró LG, Ferreira MKM, Bittencourt LO, Aragão WAB, Souza MPCD, Silva MCF, Dionizio A, Buzalaf MAR, Crespo-López ME, Lima RR. Chronic methylmercury exposure causes spinal cord impairment: Proteomic modulation and oxidative stress. Food Chem Toxicol 2020; 146:111772. [DOI: 10.1016/j.fct.2020.111772] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/18/2020] [Accepted: 09/21/2020] [Indexed: 12/19/2022]
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Bittencourt LO, Dionizio A, Nascimento PC, Puty B, Leão LKR, Luz DA, Silva MCF, Amado LL, Leite A, Buzalaf MR, Crespo-Lopez ME, Maia CSF, Lima RR. Proteomic approach underlying the hippocampal neurodegeneration caused by low doses of methylmercury after long-term exposure in adult rats. Metallomics 2020; 11:390-403. [PMID: 30525157 DOI: 10.1039/c8mt00297e] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Methylmercury (MeHg) is an important toxicant that causes cognitive dysfunctions in humans. This study aimed to investigate the proteomic and biochemical alterations of the hippocampus associated with behavioural consequences of low doses of MeHg in a long-term exposure model, and to realistically mimic in vivo the result of human exposure to this toxicant. Adult Wistar male rats were exposed to a dose of MeHg at 0.04 mg kg-1 day-1 by gavage for 60 days. Total mercury (Hg) content was significantly increased in the hippocampal parenchyma. The increase in the Hg levels was capable of reducing neuron and astrocyte cell density in the CA1, CA3, hilus and dentate gyrus regions, increasing both malondialdehyde and nitrite levels and decreasing antioxidant capacity against peroxyl radicals. The proteomic analysis detected 1041 proteins with altered expression due to MeHg exposure, including 364 proteins with no expression, 295 proteins with de novo expression and 382 proteins with up- or down-regulated expression. This proteomic approach revealed alterations in pathways related to chemical synapses, metabolism, amino acid transport, cell energy, neurodegenerative processes and myelin maintenance. Therefore, even at low doses of MeHg exposure, it is possible to cause hippocampal damage in adult rats at many organisational levels, triggering oxidative stress and proteome misbalance, featuring a neurodegenerative process and culminating in long- and short-term memory and learning deficits.
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Affiliation(s)
- Leonardo Oliveira Bittencourt
- Laboratory of Structural and Functional Biology, Institute of Biological Sciences, Federal University of Pará, No 125, Augusto Corrêa Street N. 01, Guamá, 66075-900, Belém, Pará, Brazil.
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Corrêa MG, Bittencourt LO, Nascimento PC, Ferreira RO, Aragão WAB, Silva MCF, Gomes-Leal W, Fernandes MS, Dionizio A, Buzalaf MR, Crespo-Lopez ME, Lima RR. Spinal cord neurodegeneration after inorganic mercury long-term exposure in adult rats: Ultrastructural, proteomic and biochemical damages associated with reduced neuronal density. Ecotoxicol Environ Saf 2020; 191:110159. [PMID: 31962214 DOI: 10.1016/j.ecoenv.2019.110159] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 12/28/2019] [Accepted: 12/31/2019] [Indexed: 06/10/2023]
Abstract
Mercury chloride (HgCl2) is a chemical pollutant widely found in the environment. This form of mercury is able to promote several damages to the Central Nervous System (CNS), however the effects of HgCl2 on the spinal cord, an important pathway for the communication between the CNS and the periphery, are still poorly understood. The aim of this work was to investigate the effects of HgCl2 exposure on spinal cord of adult rats. For this, animals were exposed to a dose of 0.375 mg/kg/day, for 45 days. Then, they were euthanized, the spinal cord collected and we investigated the mercury concentrations in medullary parenchyma and the effects on oxidative biochemistry, proteomic profile and tissue structures. Our results showed that exposure to this metal promoted increased levels of Hg in the spinal cord, impaired oxidative biochemistry by triggering oxidative stress, mudulated antioxidant system proteins, energy metabolism and myelin structure; as well as caused disruption in the myelin sheath and reduction in neuronal density. Despite the low dose, we conclude that prolonged exposure to HgCl2 triggers biochemical changes and modulates the expression of several proteins, resulting in damage to the myelin sheath and reduced neuronal density in the spinal cord.
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Affiliation(s)
- Márcio Gonçalves Corrêa
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Belém, PA, Brazil
| | - Leonardo Oliveira Bittencourt
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Belém, PA, Brazil
| | - Priscila Cunha Nascimento
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Belém, PA, Brazil
| | - Railson Oliveira Ferreira
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Belém, PA, Brazil
| | - Walessa Alana Bragança Aragão
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Belém, PA, Brazil
| | - Marcia Cristina Freitas Silva
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Belém, PA, Brazil
| | - Walace Gomes-Leal
- Laboratory of Experimental Neuroprotection and Neuroregeneration, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Mileni Silva Fernandes
- Department of Biological Sciences, Bauru Dental School, University of São Paulo, Bauru, SP, Brazil
| | - Aline Dionizio
- Department of Biological Sciences, Bauru Dental School, University of São Paulo, Bauru, SP, Brazil
| | - Marília Rabelo Buzalaf
- Department of Biological Sciences, Bauru Dental School, University of São Paulo, Bauru, SP, Brazil
| | - Maria Elena Crespo-Lopez
- Laboratory of Molecular Pharmacology, Institute of Biological Sciences, Federal University of Para, Belém, PA, Brazil
| | - Rafael Rodrigues Lima
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Belém, PA, Brazil.
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Santana LNDS, Bittencourt LO, Nascimento PC, Fernandes RM, Teixeira FB, Fernandes LMP, Freitas Silva MC, Nogueira LS, Amado LL, Crespo-Lopez ME, Maia CDSF, Lima RR. Low doses of methylmercury exposure during adulthood in rats display oxidative stress, neurodegeneration in the motor cortex and lead to impairment of motor skills. J Trace Elem Med Biol 2019; 51:19-27. [PMID: 30466930 DOI: 10.1016/j.jtemb.2018.09.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 08/21/2018] [Accepted: 09/10/2018] [Indexed: 12/20/2022]
Abstract
Despite the vast distribution among tissues, the central nervous system (CNS) represents the main target of methylmercury (MeHg) toxicity. However, few studies have evaluated the effects of MeHg exposure on the CNS at equivalent doses to human environmental exposure. In our study, we evaluated the motor cortex, an important area of motor control, in adult rats chronically exposed to MeHg in a concentration equivalent to those found in fish-eating populations exposed to mercury (Hg). The parameters evaluated were total Hg accumulation, oxidative stress, tissue damage, and behavioral assessment in functional actions that involved this cortical region. Our results show in exposed animals a significantly greater level of Hg in the motor cortex; increase of nitrite levels and lipid peroxidation, associated with decreased antioxidant capacity against peroxyl radicals; reduction of neuronal and astrocyte density; and poor coordination and motor learning impairment. Our data showed that chronic exposure at low doses to MeHg is capable of promoting damages to the motor cortex of adult animals, with changes in oxidative biochemistry misbalance, neurodegeneration, and motor function impairment.
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Affiliation(s)
- Luana Nazaré da Silva Santana
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Leonardo Oliveira Bittencourt
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Priscila Cunha Nascimento
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Rafael Monteiro Fernandes
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Francisco Bruno Teixeira
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Luanna Melo Pereira Fernandes
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Marcia Cristina Freitas Silva
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Lygia Sega Nogueira
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Lílian Lund Amado
- Laboratory of Ecotoxicology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Maria Elena Crespo-Lopez
- Laboratory of Molecular Pharmacology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Cristiane do Socorro Ferraz Maia
- Laboratory of Pharmacology of Inflammation and Behavior, Institute of Health Sciences, Federal University of Pará, Belém, PA, Brazil
| | - Rafael Rodrigues Lima
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Belém, PA, Brazil.
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Lima LADO, Bittencourt LO, Puty B, Fernandes RM, Nascimento PC, Silva MCF, Alves-Junior SM, Pinheiro JDJV, Lima RR. Methylmercury Intoxication Promotes Metallothionein Response and Cell Damage in Salivary Glands of Rats. Biol Trace Elem Res 2018; 185:135-142. [PMID: 29332268 DOI: 10.1007/s12011-017-1230-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 12/20/2017] [Indexed: 12/20/2022]
Abstract
Environmental and occupational mercury exposure is considered a major public health issue. Despite being well known that MeHg exposure causes adverse effects in several physiologic functions, MeHg effects on salivary glands still not completely elucidated. Here, we investigated the cellular MeHg-induced damage in the three major salivary glands (parotid, submandibular, and sublingual) of adult rats after chronic, systemic and low doses of MeHg exposure. Rats were exposed by 0.04 mg/kg/day over 60 days. After that, animals were euthanized and all three glands were collected. We evaluated total Hg accumulation, metallothionein I/II (MT I/II), α-smooth muscle actin (α-SMA), and cytokeratin 18 (CK18) immune expression. Our results have showed that MeHg is able to disrupt gland tissue and to induce a protective mechanism by MT I/II expression. We also showed that cell MT production is not enough to protect gland tissue against cellular structural damage seen by reducing marking of cytoskeletal proteins as CK18 and α-SMA. Our data suggest that chronic MeHg exposure in low-daily doses is able to induce cellular damage in rat salivary glands.
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Affiliation(s)
- Leidiane Alencar de Oliveira Lima
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Street Augusto Correa N. 01, Guamá, Belém, Para, 66075-900, Brazil
| | - Leonardo Oliveira Bittencourt
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Street Augusto Correa N. 01, Guamá, Belém, Para, 66075-900, Brazil
| | - Bruna Puty
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Street Augusto Correa N. 01, Guamá, Belém, Para, 66075-900, Brazil
| | - Rafael Monteiro Fernandes
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Street Augusto Correa N. 01, Guamá, Belém, Para, 66075-900, Brazil
| | - Priscila Cunha Nascimento
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Street Augusto Correa N. 01, Guamá, Belém, Para, 66075-900, Brazil
| | - Marcia Cristina Freitas Silva
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Street Augusto Correa N. 01, Guamá, Belém, Para, 66075-900, Brazil
| | | | | | - Rafael Rodrigues Lima
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Para, Street Augusto Correa N. 01, Guamá, Belém, Para, 66075-900, Brazil.
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Aragão WAB, da Costa NMM, Fagundes NCF, Silva MCF, Alves-Junior SM, Pinheiro JJV, Amado LL, Crespo-López ME, Maia CSF, Lima RR. Chronic exposure to inorganic mercury induces biochemical and morphological changes in the salivary glands of rats. Metallomics 2018; 9:1271-1278. [PMID: 28795724 DOI: 10.1039/c7mt00123a] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mercury exposure is considered to be a public health problem due to the generation of toxic effects on human health as a result of environmental and occupational conditions. The inorganic form of mercury (HgCl2) can cause several biological changes in cells and tissues through its cumulative toxic potential, but little has been experimentally proven about the effects of inorganic mercury on salivary glands, an important modulator organ of oral health. This study analyzes the effects of prolonged low dose exposure to HgCl2 on the salivary glands of rats. Adult animals received a dose of 0.375 mg kg-1 day-1 over a period of 45 days. The parotid and submandibular glands were collected for analysis of the mercury levels and evaluation of oxidative stress, histological parameters and immunomodulation for metallothionein I and II (MT-I/II). In this investigation, biochemical and tissue changes in the salivary glands were verified due to the mercury levels, causing reduction in antioxidant capacity against peroxyl radicals, with consequent cellular lipid peroxidation and an increase in nitrite levels, volumetric changes and cytoskeletal damage in the submandibular glands, with less severe damage to the parotid glands. The results also have shown the occurrence of a cytoprotection mechanism due to increased MT-I/II expression, but not enough to avoid the morphology and oxidative damage. This evidence highlights, for the first time, that inorganic mercury is able to alter the morphology and oxidative biochemistry in salivary glands when exposed for a long time in low doses.
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Affiliation(s)
- W A B Aragão
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Street Augusto Corrêa 1, Guamá, 66075-900, Belém, Pará, Brazil.
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Silva MCF, Zuccherato LW, Soares-Souza GB, Vieira ZM, Cabrera L, Herrera P, Balqui J, Romero C, Jahuira H, Gilman RH, Martins ML, Tarazona-Santos E. Development of two multiplex mini-sequencing panels of ancestry informative SNPs for studies in Latin Americans: an application to populations of the State of Minas Gerais (Brazil). Genet Mol Res 2010; 9:2069-85. [PMID: 20967697 DOI: 10.4238/vol9-4gmr911] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Admixture occurs when individuals from parental populations that have been isolated for hundreds of generations form a new hybrid population. Currently, interest in measuring biogeographic ancestry has spread from anthropology to forensic sciences, direct-to-consumers personal genomics, and civil rights issues of minorities, and it is critical for genetic epidemiology studies of admixed populations. Markers with highly differentiated frequencies among human populations are informative of ancestry and are called ancestry informative markers (AIMs). For tri-hybrid Latin American populations, ancestry information is required for Africans, Europeans and Native Americans. We developed two multiplex panels of AIMs (for 14 SNPs) to be genotyped by two mini-sequencing reactions, suitable for investigators of medium-small laboratories to estimate admixture of Latin American populations. We tested the performance of these AIMs by comparing results obtained with our 14 AIMs with those obtained using 108 AIMs genotyped in the same individuals, for which DNA samples is available for other investigators. We emphasize that this type of comparison should be made when new admixture/population structure panels are developed. At the population level, our 14 AIMs were useful to estimate European admixture, though they overestimated African admixture and underestimated Native American admixture. Combined with more AIMs, our panel could be used to infer individual admixture. We used our panel to infer the pattern of admixture in two urban populations (Montes Claros and Manhuaçu) of the State of Minas Gerais (southeastern Brazil), obtaining a snapshot of their genetic structure in the context of their demographic history.
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Affiliation(s)
- M C F Silva
- Fundação Hemominas, Belo Horizonte, MG, Brasil
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