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Jung GL, McDaniel KL, LoPachin RM, Geohagen BC, Smith A, Huffstickler M, Herr DW. IN VIVO NEUROPHYSIOLOGICAL ASSESSMENT OF IN SILICO PREDICTIONS OF NEUROTOXICITY: CITRONELLAL, 3,4-DICHLORO-1-BUTENE, AND BENZYL BROMOACETATE. Neurotoxicology 2022; 90:48-61. [PMID: 35227730 PMCID: PMC9133174 DOI: 10.1016/j.neuro.2022.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 02/02/2022] [Accepted: 02/21/2022] [Indexed: 11/29/2022]
Abstract
Neurotoxicants may be widespread in the environment and can produce serious health impacts in the human population. Screening programs that use in vitro methods have generated data for thousands of chemicals. However, these methods often do not evaluate repeated or prolonged exposures, which are required for many neurotoxic outcomes. Additionally, the data produced by such screening methods may not include mechanisms which play critical biological roles necessary for in vivo neurotoxicity. The Hard and Soft Acids and Bases (HSAB) in silico model focuses on chemical structure and electrophilic properties which are important to the formation of protein adducts. A group of structurally diverse chemicals have been evaluated with an in silico screening approach incorporating HSAB parameters. However, the predictions from the expanded chemical space have not been evaluated using in vivo methods. Three chemicals predicted to be cumulative toxicants were selected for in vivo neurotoxicological testing. Adult male Long-Evans rats were treated orally with citronellal (CIT), 3,4-dichloro-1-butene (DCB), or benzyl bromoacetate (BBA) for 8 weeks. Behavioral observations were recorded weekly to assess motor function. Peripheral neurophysiological measurements were derived from nerve excitability (NE) tests which involved compound muscle action potentials (CMAPs) in the tail and foot, and mixed nerve action potentials (MNAPs) in the tail. Compound nerve action potentials (CNAPs) and nerve conduction velocity (NCV) in the tail were also quantified. Peripheral inputs into the central nervous system were examined using somatosensory evoked potentials recorded from the cortex (SEPCTX) and cerebellum (SEPCEREB). CIT or BBA did not result in significant alterations to peripheral nerve or somatosensory function. DCB reduced grip-strength and altered peripheral nerve function. The MNAPs required less current to reach 50% amplitude and had a lower calculated rheobase, suggesting increased excitability. Increased CNAP amplitudes and greater NCV were also observed. Novel changes were found in the SEPCTX with an abnormal peak forming in the early portion of the waveforms of treated rats, and decreased latencies and increased amplitudes were observed in SEPCEREB recordings. These data contribute to testing an expanded chemical space from an in silico HSAB model for predicting cumulative neurotoxicity and may assist with prioritizing chemicals to protect human health.
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Affiliation(s)
- Garyn L Jung
- Center for Public Health and Environmental Assessment, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
| | - Katherine L McDaniel
- Center for Public Health and Environmental Assessment, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
| | - Richard M LoPachin
- Professor Emeritus in the Department of Anesthesiology, Albert Einstein College of Medicine, 111 E. 210th St, Bronx, NY 10467, USA.
| | - Brian C Geohagen
- Department of Anesthesiology, Montefiore Medical Center, Albert Einstein College of Medicine, 111 E. 210th St, Bronx, NY 10467, USA.
| | - Alicia Smith
- Oak Ridge Institute for Science Education, Oak Ridge, Tennessee 37830, USA.
| | | | - David W Herr
- Center for Public Health and Environmental Assessment, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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da Silva TD, Barnabé V, Ricci-Vitor AL, Papapostolou V, Tagle M, Henriquez A, Lawrence J, Ferguson S, Wolfson JM, Koutrakis P, Oyola P, Ferreira C, de Abreu LC, Monteiro CBDM, Godleski JJ. Secondary particles formed from the exhaust of vehicles using ethanol-gasoline blends increase the production of pulmonary and cardiac reactive oxygen species and induce pulmonary inflammation. ENVIRONMENTAL RESEARCH 2019; 177:108661. [PMID: 31442789 DOI: 10.1016/j.envres.2019.108661] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 07/08/2019] [Accepted: 08/12/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Ethanol vehicles release exhaust gases that contribute to the formation of secondary organic aerosols (SOA). OBJECTIVE To determine in vivo toxicity resulting from exposure to SOA derived from vehicles using different ethanol-gasoline blends (E0, E10, E22, E85W, E85S, E100). METHODS Exhaust emissions from vehicles using ethanol blends were delivered to a photochemical chamber and reacted to produce SOA. The aerosol samples were collected on filters, extracted, and dispersed in an aqueous solutions and intratracheally instilled into Sprague Dawley rats in doses of 700 μg/0.2 ml. After 45 min and 4 h pulmonary and cardiac chemiluminescence (CL) was measured to estimate the amount of reactive oxygen species (ROS) produced in the lungs and heart. Inflammation was measured by differential cell count in bronchoalveolar lavages (BAL). RESULTS Statistically and biologically significant differences in response to secondary particles from the different fuel formulations were detected. Compared to the control group, animals exposed to SOA from gasoline (E0) showed a significantly higher average CL in the lungs at 45 min. The highest CL averages in the heart were observed in the groups exposed to SOA from E10 and pure ethanol (E100) at 45 min. BAL of animals exposed to SOA from E0 and E85S had a significant increased number of macrophages at 45 min. BAL neutrophil count was increased in the groups exposed to E85S (45 min) and E0 (4 h). Animals exposed to E0 and E85W had increased BAL lymphocyte count compared to the control and the other exposed groups. DISCUSSION Our results suggest that SOA generated by gasoline (E0), followed by ethanol blends E85S and E85W, substantially induce oxidative stress measured by ROS generation and pulmonary inflammation measured by the recruitment of white blood cells in BAL.
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Affiliation(s)
- Talita Dias da Silva
- Harvard T. H. Chan School of Public Health, Harvard University, Boston, MA, USA; Paulista School of Medicine, Federal University of São Paulo, São Paulo, SP, Brazil.
| | - Viviani Barnabé
- Harvard T. H. Chan School of Public Health, Harvard University, Boston, MA, USA; Medical School, University City of São Paulo, São Paulo, SP, Brazil
| | - Ana Laura Ricci-Vitor
- Harvard T. H. Chan School of Public Health, Harvard University, Boston, MA, USA; Paulista School of Medicine, Federal University of São Paulo, São Paulo, SP, Brazil
| | | | - Matias Tagle
- Mario Molina Center for Strategic Studies in Energy and Environment, Santiago, Chile
| | - Andres Henriquez
- Oak Ridge Institute for Science and Education, Research Triangle Park, NC, United States
| | - Joy Lawrence
- Harvard T. H. Chan School of Public Health, Harvard University, Boston, MA, USA
| | - Stephen Ferguson
- Harvard T. H. Chan School of Public Health, Harvard University, Boston, MA, USA
| | - J Mikhail Wolfson
- Harvard T. H. Chan School of Public Health, Harvard University, Boston, MA, USA
| | - Petros Koutrakis
- Harvard T. H. Chan School of Public Health, Harvard University, Boston, MA, USA
| | - Pedro Oyola
- Mario Molina Center for Strategic Studies in Energy and Environment, Santiago, Chile
| | - Celso Ferreira
- Paulista School of Medicine, Federal University of São Paulo, São Paulo, SP, Brazil
| | | | | | - John J Godleski
- Harvard T. H. Chan School of Public Health, Harvard University, Boston, MA, USA
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