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Soares MV, Mesadri J, Gonçalves DF, Cordeiro LM, Franzen da Silva A, Obetine Baptista FB, Wagner R, Dalla Corte CL, Soares FAA, Ávila DS. Neurotoxicity induced by toluene: In silico and in vivo evidences of mitochondrial dysfunction and dopaminergic neurodegeneration. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 298:118856. [PMID: 35033616 DOI: 10.1016/j.envpol.2022.118856] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/21/2021] [Accepted: 01/12/2022] [Indexed: 06/14/2023]
Abstract
Toluene is an air pollutant widely used as an organic solvent in industrial production and emitted by fossil fuel combustion, in addition to being used as a drug of abuse. Its toxic effects in the central nervous system have not been well established, and how and which neurons are affected remains unknown. Hence, this study aimed to fill this gap by investigating three central questions: 1) How does toluene induce neurotoxicity? 2) Which neurons are affected? And 3) What are the long-term effects induced by airborne exposure to toluene? To this end, a Caenorhabditis elegans model was employed, in which worms at the fourth larval stage were exposed to toluene in the air for 24 h in a vapor chamber to simulate four exposure scenarios. After the concentration-response curve analysis, we chose scenarios 3 (E3: 792 ppm) and 4 (E4: 1094 ppm) for the following experiments. The assays were performed 1, 48, or 96 h after removal from the exposure environments, and an irreversible reduction in neuron fluorescence and morphologic alterations were observed in different neurons of exposed worms, particularly in the dopaminergic neurons. Moreover, a significant impairment in a dopaminergic-dependent behavior was also associated with negative effects in healthspan endpoints, and we also noted that mitochondria may be involved in toluene-induced neurotoxicity since lower adenosine 5'-triphosphate (ATP) levels and mitochondrial viability were observed. In addition, a reduction of electron transport chain activity was evidenced using ex vivo protocols, which were reinforced by in silico and in vitro analysis, demonstrating toluene action in the mitochondrial complexes. Based on these findings model, it is plausible that toluene neurotoxicity can be initiated by complex I inhibition, triggering a mitochondrial dysfunction that may lead to irreversible dopaminergic neuronal death, thus impairing neurobehavioral signaling.
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Affiliation(s)
- Marcell Valandro Soares
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Programa de Pós-graduação em Ciências Biológicas, Bioquímica Toxicológica, Universidade Federal de Santa Maria, Camobi, 97105-900, Santa Maria, RS, Brazil; Grupo de Pesquisa em Bioquímica e Toxicologia em Caenorhabditis elegans (GBToxCe), Universidade Federal do Pampa - UNIPAMPA, CEP 97500-970, Uruguaiana, RS, Brazil
| | - Juliana Mesadri
- Departamento: Tecnologia e Ciência dos Alimentos, Centro de Ciência Rurais, Programa de Pós-graduação em Ciência e Tecnologia dos Alimentos, Universidade Federal de Santa Maria, RS, Brazil
| | - Débora Farina Gonçalves
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Programa de Pós-graduação em Ciências Biológicas, Bioquímica Toxicológica, Universidade Federal de Santa Maria, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Larissa Marafiga Cordeiro
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Programa de Pós-graduação em Ciências Biológicas, Bioquímica Toxicológica, Universidade Federal de Santa Maria, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Aline Franzen da Silva
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Programa de Pós-graduação em Ciências Biológicas, Bioquímica Toxicológica, Universidade Federal de Santa Maria, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Fabiane Bicca Obetine Baptista
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Programa de Pós-graduação em Ciências Biológicas, Bioquímica Toxicológica, Universidade Federal de Santa Maria, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Roger Wagner
- Departamento: Tecnologia e Ciência dos Alimentos, Centro de Ciência Rurais, Programa de Pós-graduação em Ciência e Tecnologia dos Alimentos, Universidade Federal de Santa Maria, RS, Brazil
| | - Cristiane Lenz Dalla Corte
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Programa de Pós-graduação em Ciências Biológicas, Bioquímica Toxicológica, Universidade Federal de Santa Maria, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Félix Alexandre Antunes Soares
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Programa de Pós-graduação em Ciências Biológicas, Bioquímica Toxicológica, Universidade Federal de Santa Maria, Camobi, 97105-900, Santa Maria, RS, Brazil
| | - Daiana Silva Ávila
- Grupo de Pesquisa em Bioquímica e Toxicologia em Caenorhabditis elegans (GBToxCe), Universidade Federal do Pampa - UNIPAMPA, CEP 97500-970, Uruguaiana, RS, Brazil.
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Shahy EM, Ibrahim KS, Mahdy-Abdallah H, Taha MM, Saad-Hussien A, Hafez SF. Neurotoxicity of organic solvents with emphasis on the role of iron. JOURNAL OF COMPLEMENTARY & INTEGRATIVE MEDICINE 2021; 18:527-533. [PMID: 33544507 DOI: 10.1515/jcim-2019-0103] [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: 04/14/2019] [Accepted: 07/19/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND Exposure to organic solvents (OS) adversely affects different body systems, the central and peripheral nervous systems being the most susceptible ones. OBJECTIVES This study investigated the role of iron in association with some neurotransmitters for diagnosis of neurotoxicity of OS. METHODS The study included 90 workers, 50 occupationally exposed to OS and 40 representing control group. Blood samples were collected from the included subjects for determination of serum iron, total iron binding capacity (TIBC), serotonin and gamma-aminobutyric acid (GABA). RESULTS Revealed reduction in serotonin level and serum iron. However, the elevation in GABA and TIBC was observed. The duration of exposure was significantly correlated with iron and serotonin while it was positively correlated with GABA and TIBC. CONCLUSIONS Elevated GABA and TIBC with decreased serotonin and serum iron can be used as early diagnostic measures to detect the neurotoxic effects of OS.
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Affiliation(s)
- Eman M Shahy
- Environmental Biochemistry and Molecular Biology, Environmental & Occupational Medicine Department, National Research Centre, Cairo, Egypt
| | - Khadiga S Ibrahim
- Environmental Biochemistry and Molecular Biology, Environmental & Occupational Medicine Department, National Research Centre, Cairo, Egypt
| | - Heba Mahdy-Abdallah
- Industrial Medicine, Environmental & Occupational Medicine Department, National Research Centre, Cairo, Egypt
| | - Mona M Taha
- Environmental Biochemistry and Molecular Biology, Environmental & Occupational Medicine Department, National Research Centre, Cairo, Egypt
| | - Amal Saad-Hussien
- Environmental & Preventive Medicine, Environmental & Occupational Medicine Department, National Research Centre, Cairo, Egypt
| | - Salwa F Hafez
- Industrial Medicine, Environmental & Occupational Medicine Department, National Research Centre, Cairo, Egypt
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