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Liu X, Ge P, Lu Z, Cao M, Chen W, Yan Z, Chen M, Wang J. Ecotoxicity induced by total, water soluble and insoluble components of atmospheric fine particulate matter exposure in Caenorhabditis elegans. CHEMOSPHERE 2023; 316:137672. [PMID: 36587918 DOI: 10.1016/j.chemosphere.2022.137672] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/19/2022] [Accepted: 12/24/2022] [Indexed: 06/17/2023]
Abstract
Although PM2.5 could cause toxicity in environmental organisms, the toxicity difference of PM2.5 under different solubilities is still poorly understood. To acquire a better knowledge of the ecotoxicity of PM2.5 under different solubilities, the model animal Caenorhabditis elegans (C. elegans) was exposed to Total-PM2.5, water insoluble components of PM2.5 (WIS-PM2.5) and water soluble components of PM2.5 (WS-PM2.5). The physiological (growth, locomotion behavior, and reproduction), biochemical (germline apoptosis, and reactive oxygen species (ROS) production) indices, and the related gene expression were examined. According to the findings, acute exposure to these three components caused adverse physiological effects on growth and locomotion behavior, and significantly induced germline apoptosis or ROS production. In contrast, prolonged exposure showed stronger adverse effects than acute exposure. Additionally, the results of multiple toxicological endpoints showed that the toxicity effects of WIS-PM2.5 are more intense than WS-PM2.5, which means that insoluble components contributed more to the toxicity of PM2.5. Prolonged exposure to 1000 mg/L WS-PM2.5, WIS-PM2.5, and Total-PM2.5 dramatically altered the expression of stress-related genes, which further indicated that apoptosis, DNA damage and oxidative stress play a crucial part in toxicity induced by PM2.5.
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Affiliation(s)
- Xiaoming Liu
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, 210044, China
| | - Pengxiang Ge
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, 210044, China
| | - Zhenyu Lu
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, 210044, China
| | - Maoyu Cao
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, 210044, China
| | - Wankang Chen
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, 210044, China
| | - Zhansheng Yan
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, 210044, China
| | - Mindong Chen
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, 210044, China.
| | - Junfeng Wang
- Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, 210044, China.
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Impacts of a perinatal exposure to manganese coupled with maternal stress in rats: Tests of untrained behaviors. Neurotoxicol Teratol 2022; 91:107088. [PMID: 35278630 PMCID: PMC9133146 DOI: 10.1016/j.ntt.2022.107088] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 03/01/2022] [Accepted: 03/06/2022] [Indexed: 11/21/2022]
Abstract
Manganese (Mn), an element that naturally occurs in the environment, has been shown to produce neurotoxic effects on the developing young when levels exceed physiological requirements. To evaluate the effects of this chemical in combination with non-chemical factors pregnant Long-Evans rats were treated with 0, 2, or 4 mg/mL Mn in their drinking water from gestational day (GD) 7 to postnatal day (PND) 22. Half of the dams received a variable stress protocol from GD13 to PND9, that included restraint, small cage with reduced bedding, exposure to predator odor, intermittent intervals of white noise, lights on for 24 h, intermittent intervals of lights on during dark cycle and cages with grid floors and reduced bedding. One male and one female offspring from each litter were tested to assess untrained behavior. Ultrasonic vocalizations (USV) were recorded from PND13 pups while they were isolated from the litter. Locomotor activity (MA) was measured in figure-eight mazes at PND 17, 29, and 79 (different set of rats at each time point). Social approach (SA) was tested at PND48. Acoustic startle response (ASR) and pre-pulse inhibition (PPI) were measured starting at PND58. At PND53 a sweetness preference for a chocolate flavored milk solution was assessed. There were sex related differences on several parameters for the USVs. There was also a Mn by stress by sex interaction with the females from the 4 mg/mL stressed dams having more frequency modulated (FM) call elements than the 4 mg/mL non-stressed group. There was an effect of Mn on motor activity but only at PND29 with the 2 mg/mL group having higher counts than the 0 mg/mL group. The social approach test showed sex differences for both the habituation and test phase. There was an effect of Mn, with the 4 mg/mL males having a greater preference for the stimulus rat than did the 0 mg/mL males. There was also a stress by sex interaction. The ASR and PPI had only a sex effect. Thus, with only the FM call elements having a Mn by stress effect, and the PND29 MA and SA preference index having a Mn effect but at different doses requires further investigation.
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Kamata S, Hashiyama R, Hana-Ika H, Ohkubo I, Saito R, Honda A, Anan Y, Akahoshi N, Noguchi K, Kanda Y, Ishii I. Cytotoxicity comparison of 35 developmental neurotoxicants in human induced pluripotent stem cells (iPSC), iPSC-derived neural progenitor cells, and transformed cell lines. Toxicol In Vitro 2020; 69:104999. [PMID: 32949729 DOI: 10.1016/j.tiv.2020.104999] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 08/05/2020] [Accepted: 09/09/2020] [Indexed: 11/27/2022]
Abstract
The Organization for Economic Co-operation and Development (OECD) test guideline 426 for developmental neurotoxicity (DNT) of industrial/environmental chemicals depends primarily on animal experimentation. This requirement raises various critical issues, such as high cost, long duration, the sacrifice of large numbers of animals, and interspecies differences. This study demonstrates an alternative protocol that is simple, quick, less expensive, and standardized to evaluate DNT of many chemicals using human induced pluripotent stem cells (iPSC) and their differentiation to neural progenitor cells (NPC). Initially, concentration-dependent cytotoxicity of 35 DNT chemicals, including industrial materials, insecticides, and clinical drugs, were compared among iPSC, NPC, and two transformed cells, Cos-7 and HepG2, using tetrazolium dye (MTS)-reducing colorimetric and ATP luciferase assays, and IC50 values were calculated. Next, inhibitory effects of the 14 representative chemicals (mainly insecticides) on iPSC differentiation to NPC were evaluated by measuring altered expression of neural differentiation and undifferentiation marker genes. Results show that both iPSC and NPC were much more sensitive to most DNT chemicals than the transformed cells, and 14 chemicals induced differential patterns of marker gene expression, highlighting the validity and utility of the protocol for evaluation and classification of DNT chemicals and preclinical DNT tests for safety assessment.
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Affiliation(s)
- Shotaro Kamata
- Department of Health Chemistry, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | - Reina Hashiyama
- Department of Health Chemistry, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | - Hiroto Hana-Ika
- Department of Health Chemistry, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | - Issei Ohkubo
- Department of Health Chemistry, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | - Ryota Saito
- Department of Health Chemistry, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | - Akihiro Honda
- Department of Health Chemistry, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | - Yasumi Anan
- Department of Health Chemistry, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | - Noriyuki Akahoshi
- Department of Health Chemistry, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan
| | - Kohji Noguchi
- Laboratory of Molecular Target Therapy, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Noda, Chiba 278-8510, Japan
| | - Yasunari Kanda
- Division of Pharmacology, National Institute of Health Sciences, Kawasaki, Kanagawa 210-9501, Japan.
| | - Isao Ishii
- Department of Health Chemistry, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan.
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Abreu-Villaça Y, Levin ED. Developmental neurotoxicity of succeeding generations of insecticides. ENVIRONMENT INTERNATIONAL 2017; 99:55-77. [PMID: 27908457 PMCID: PMC5285268 DOI: 10.1016/j.envint.2016.11.019] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 11/17/2016] [Accepted: 11/17/2016] [Indexed: 05/19/2023]
Abstract
Insecticides are by design toxic. They must be toxic to effectively kill target species of insects. Unfortunately, they also have off-target toxic effects that can harm other species, including humans. Developmental neurotoxicity is one of the most prominent off-target toxic risks of insecticides. Over the past seven decades several classes of insecticides have been developed, each with their own mechanisms of effect and toxic side effects. This review covers the developmental neurotoxicity of the succeeding generations of insecticides including organochlorines, organophosphates, pyrethroids, carbamates and neonicotinoids. The goal of new insecticide development is to more effectively kill target species with fewer toxic side effects on non-target species. From the experience with the developmental neurotoxicity caused by the generations of insecticides developed in the past advice is offered how to proceed with future insecticide development to decrease neurotoxic risk.
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Affiliation(s)
- Yael Abreu-Villaça
- Departamento de Ciências Fisiologicas, Universidade do Estado do Rio de Janeiro (UERJ), RJ, Brazil
| | - Edward D Levin
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA.
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He X, Gao J, Dong T, Chen M, Zhou K, Chang C, Luo J, Wang C, Wang S, Chen D, Zhou Z, Tian Y, Xia Y, Wang X. Developmental Neurotoxicity of Methamidophos in the Embryo-Larval Stages of Zebrafish. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2016; 14:ijerph14010023. [PMID: 28036051 PMCID: PMC5295274 DOI: 10.3390/ijerph14010023] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/20/2016] [Accepted: 12/26/2016] [Indexed: 12/02/2022]
Abstract
Methamidophos is a representative organophosphate insecticide. The knowledge of its developmental neurotoxicity is limited, especially for zebrafish in the early stages of their life. Four hour post-fertilization (hpf) zebrafish embryos were exposed to several environmentally relevant concentrations of methamidophos (0, 25, and 500 μg/L) for up to 72 hpf. Locomotor behavior was then studied in the zebrafish larvae at this timepoint. Acridine orange (AO) staining was carried out in the zebrafish larvae, and the mRNA levels of genes associated with neural development (mbp and syn2a) were analyzed by reverse transcription-polymerase chain reaction (RT-PCR). The number of escape responders for mechanical stimulation was significantly decreased in exposed groups. AO staining showed noticeable signs of apoptosis mainly in the brain. In addition, the mRNA levels of mbp and syn2a were both significantly down-regulated in exposed groups. Our study provides the first evidence that methamidophos exposure can cause developmental neurotoxicity in the early stages of zebrafish life, which may be caused by the effect of methamidophos on neurodevelopmental genes and the activation of cell apoptosis in the brain.
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Affiliation(s)
- Xiaowei He
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Jiawei Gao
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Tianyu Dong
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Minjian Chen
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Wuxi Maternal and Child Health Hospital, Nanjing Medical University, Wuxi 214002, China.
| | - Kun Zhou
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Chunxin Chang
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Jia Luo
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Chao Wang
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Shoulin Wang
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Daozhen Chen
- Wuxi Maternal and Child Health Hospital, Nanjing Medical University, Wuxi 214002, China.
| | - Zuomin Zhou
- State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China.
| | - Ying Tian
- MOE and Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200092, China.
- Department of Environmental Health, School of Public Health, Shanghai Jiao Tong University, Shanghai 200025, China.
| | - Yankai Xia
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Xinru Wang
- State Key Laboratory of Reproductive Medicine, Institute of Toxicology, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
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Pei Y, Peng J, Behl M, Sipes NS, Shockley KR, Rao MS, Tice RR, Zeng X. Comparative neurotoxicity screening in human iPSC-derived neural stem cells, neurons and astrocytes. Brain Res 2016; 1638:57-73. [PMID: 26254731 PMCID: PMC5032144 DOI: 10.1016/j.brainres.2015.07.048] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 07/24/2015] [Accepted: 07/28/2015] [Indexed: 12/14/2022]
Abstract
Induced pluripotent stem cells (iPSC) and their differentiated derivatives offer a unique source of human primary cells for toxicity screens. Here, we report on the comparative cytotoxicity of 80 compounds (neurotoxicants, developmental neurotoxicants, and environmental compounds) in iPSC as well as isogenic iPSC-derived neural stem cells (NSC), neurons, and astrocytes. All compounds were tested over a 24-h period at 10 and 100 μM, in duplicate, with cytotoxicity measured using the MTT assay. Of the 80 compounds tested, 50 induced significant cytotoxicity in at least one cell type; per cell type, 32, 38, 46, and 41 induced significant cytotoxicity in iPSC, NSC, neurons, and astrocytes, respectively. Four compounds (valinomycin, 3,3',5,5'-tetrabromobisphenol, deltamethrin, and triphenyl phosphate) were cytotoxic in all four cell types. Retesting these compounds at 1, 10, and 100 μM using the same exposure protocol yielded consistent results as compared with the primary screen. Using rotenone, we extended the testing to seven additional iPSC lines of both genders; no substantial difference in the extent of cytotoxicity was detected among the cell lines. Finally, the cytotoxicity assay was simplified by measuring luciferase activity using lineage-specific luciferase reporter iPSC lines which were generated from the parental iPSC line. This article is part of a Special Issue entitled SI: PSC and the brain.
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Affiliation(s)
- Ying Pei
- XCell Science Inc., Novato, CA, USA
| | - Jun Peng
- Buck Institute for Research on Aging, Novato, CA, USA
| | - Mamta Behl
- National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27713, USA
| | - Nisha S Sipes
- National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27713, USA
| | - Keith R Shockley
- National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27713, USA
| | | | - Raymond R Tice
- National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27713, USA
| | - Xianmin Zeng
- XCell Science Inc., Novato, CA, USA; Buck Institute for Research on Aging, Novato, CA, USA.
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Tian Y, Liu Y, Zhou Y, Liu Y, Lü G, Zheng X, Xu D. Effect of Aldicarb Exposure on Cellular Immunity and Antioxidant Capacity in Kun-ming Mice. Health (London) 2015. [DOI: 10.4236/health.2015.77098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Environmental- and growth stage-related differences in the susceptibility of terrestrial isopods to UV radiation. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2013; 126:60-71. [DOI: 10.1016/j.jphotobiol.2013.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Revised: 06/19/2013] [Accepted: 07/02/2013] [Indexed: 01/03/2023]
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Lima CS, Dutra-Tavares AC, Nunes F, Nunes-Freitas AL, Ribeiro-Carvalho A, Filgueiras CC, Manhães AC, Meyer A, Abreu-Villaça Y. Methamidophos exposure during the early postnatal period of mice: immediate and late-emergent effects on the cholinergic and serotonergic systems and behavior. Toxicol Sci 2013; 134:125-39. [PMID: 23596261 DOI: 10.1093/toxsci/kft095] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Organophosphates (OPs) are among the most used pesticides. Although some OPs have had their use progressively more restricted, other OPs are being used without sufficient investigation of their effects. Here, we investigated the immediate neurochemical and delayed neurochemical and behavioral actions of the OP methamidophos to verify whether there are concerns regarding exposure during early postnatal development. From the third to the nineth postnatal day (PN), Swiss mice were sc injected with methamidophos (1mg/kg). At PN10, we assessed cholinergic and serotonergic biomarkers in the cerebral cortex and brainstem. From PN60 to PN63, mice were submitted to a battery of behavioral tests and subsequently to biochemical analyses. At PN10, the effects were restricted to females and to the cholinergic system: Methamidophos promoted increased choline transporter binding in the brainstem. At PN63, in the brainstem, there was a decrease in choline transporter, a female-only decrease in 5HT1A and a male-only increase in 5HT2 receptor binding. In the cortex, choline acetyltransferase activity was decreased and 5HT2 receptor binding was increased both in males and females. Methamidophos elicited behavioral alterations, suggestive of increased depressive-like behavior and impaired decision making. There were no significant alterations on anxiety-related measures and on memory/learning. Methamidophos elicited cholinergic and serotonergic alterations that depended on brain region, sex, and age of the animals. These outcomes, together with the behavioral effects, indicate that this OP is deleterious to the developing brain and that alterations are indeed identified long after the end of exposure.
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Affiliation(s)
- Carla S Lima
- Departamento de Ciências Fisiológicas, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
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Comparison of neurobehavioral effects of methylmercury exposure in older and younger adult zebrafish (Danio rerio). Neurotoxicology 2012; 33:1212-8. [PMID: 22796261 PMCID: PMC8803049 DOI: 10.1016/j.neuro.2012.06.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Revised: 06/21/2012] [Accepted: 06/29/2012] [Indexed: 12/24/2022]
Abstract
It is widely recognized that the nature and severity of responses to toxic exposure are age-dependent. Using active avoidance conditioning as the behavioral paradigm, the present study examined the effect of short-term methylmercury (MeHg) exposure on two adult age classes, 1- and 2-year-olds to coincide with zebrafish in relatively peak vs. declining health conditions. In Experiment 1, 2-year-old zebrafish were randomly divided into groups and were exposed to no MeHg, 0.15% ethanol (EtOH), 0.01, 0.03, 0.1, or 0.3 μM of MeHg (in 0.15% ethanol) for 2 weeks. The groups were then trained and tested for avoidance responses. The results showed that older zebrafish exposed to no MeHg or EtOH learned and retained avoidance responses. However, 0.01 μM or higher concentrations of MeHg exposure impaired avoidance learning in a dose-dependent manner with 0.3 μM of MeHg exposure producing death during the exposure period or shortly after the exposure but before the avoidance training. In Experiment 2, 1-year-old zebrafish were randomly divided into groups and were exposed to the same concentrations of MeHg used in Experiment 1 for 2 weeks. The groups were then trained and tested for avoidance responses. The results showed that younger zebrafish exposed to no MeHg, EtOH, or 0.01 μM of MeHg learned and retained avoidance responses, while 0.1 or 0.3 μM of MeHg exposure impaired avoidance learning in a dose-dependent manner. The study suggested that MeHg exposure produced learning impairments at a much lower concentration of MeHg exposure and more severely in older adult compared against younger adult zebrafish even after short exposure times.
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Moser VC. Age-related differences in acute neurotoxicity produced by mevinphos, monocrotophos, dicrotophos, and phosphamidon. Neurotoxicol Teratol 2011; 33:451-7. [DOI: 10.1016/j.ntt.2011.05.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 05/03/2011] [Accepted: 05/26/2011] [Indexed: 11/24/2022]
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Grignard E, Guéguen Y, Grison S, Dublineau I, Gourmelon P, Souidi M. Testicular steroidogenesis is not altered by 137 cesium Chernobyl fallout, following in utero or post-natal chronic exposure. C R Biol 2010; 333:416-23. [PMID: 20451883 DOI: 10.1016/j.crvi.2010.02.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 01/22/2010] [Accepted: 02/12/2010] [Indexed: 02/02/2023]
Abstract
The testis is especially sensitive to pollutants, including radionuclides. Following the Chernobyl nuclear power plant accident, several of these radionuclides were emitted and spread in the environment. Subsequently, children presented some disruptions of the endocrine system. To determine whether these disruptions were due to 137 cesium ((137)Cs) exposure, the effects of chronic contamination with low doses of (137)Cs in utero or from birth on testicular steroidogenesis in rats were studied. Contamination was continued for 9 months. No modification was observed in circulating level of hormones (17beta-estradiol, testosterone, follicle-stimulating hormone, luteinizing hormone) following in utero or post-natal contamination. Expression of several genes involved in testicular steroidogenesis was affected (cyp19a1, fxr, sf-1), without modification of protein expression or activity. Our results suggest that growing organisms may be affected at the molecular level by (137)Cs contamination at this post-accidental dose.
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Affiliation(s)
- Elise Grignard
- Institute for Radiological Protection and Nuclear Safety, Radiological Protection and Human Health Division, Radiobiology and Epidemiology Department, Laboratory of Experimental Toxicology, BP 17, 92262 Fontenay-aux-Roses cedex, France
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13
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Moser VC, McDaniel KL, Phillips PM, Lowit AB. Time-Course, Dose-Response, and Age Comparative Sensitivity of N-Methyl Carbamates in Rats. Toxicol Sci 2009; 114:113-23. [DOI: 10.1093/toxsci/kfp286] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Xing X, Rui Q, Wang D. Lethality toxicities induced by metal exposure during development in nematode Caenorhabditis elegans. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2009; 83:530-536. [PMID: 19588066 DOI: 10.1007/s00128-009-9816-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Accepted: 06/25/2009] [Indexed: 05/28/2023]
Abstract
Lethality changes were investigated during development in 4 h metal exposed Caenorhabditis elegans. Exposure to examined metals caused severe lethality toxicities in L1- and L2-larvae, in L3-larvae exposed to examined metals at concentrations of 50 and 100 microM and to Pb, Hg, and Cr at the concentration of 2.5 microM, in L4-larvae exposed to examined metals at concentrations of 50 and 100 microM, and in adults exposed to Pb, Hg, and Cr at the concentration of 100 microM. Moreover, the lethality toxicities induced by Pb and Hg in L1 larvae for 4 h could be largely comparable to those in young adults for 24 h.
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Affiliation(s)
- X Xing
- Key Laboratory of Developmental Genes and Human Disease in Ministry of Education, Department of Genetics and Developmental Biology, Southeast University, Nanjing 210009, China
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Xing X, Guo Y, Wang D. Using the larvae nematode Caenorhabditis elegans to evaluate neurobehavioral toxicity to metallic salts. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2009; 72:1819-1823. [PMID: 19573919 DOI: 10.1016/j.ecoenv.2009.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 03/03/2009] [Accepted: 06/11/2009] [Indexed: 05/28/2023]
Abstract
In this study, we investigated the locomotion behavior changes at different developmental stages in Caenorhabditis elegans exposed to metals for 4h. No obvious differences could be observed in young adults exposed to examined metals, and only exposure to 100 microM of examined metals could significantly decrease the locomotion behaviors of L4 larvae. In contrast, exposure to 50 and 100 microM of examined metals induced noticeable repression of locomotion behaviors at L1-L3 larval stages, and a significant decrease of locomotion behaviors could be observed in L1 larvae exposed to Pb and Hg, and in L2 larvae exposed to Hg at the concentration of 2.5 microM. Moreover, the L1-, L2-, and L3-larvae exposed to metals for 4h exhibited similar neurobehavioral toxicity manner to L4-larvae exposed to metals for 24h. Therefore, younger larvae showed more severe deficits in neurobehavioral phenotypes than L4 larvae and young adults in metal-exposed nematodes.
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Affiliation(s)
- Xiaojuan Xing
- Key Laboratory of Developmental Genes and Human Disease in Ministry of Education, Department of Genetics and Developmental Biology, Southeast University Medical School, Nanjing 210009, China
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16
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Howd RA. Considering changes in exposure and sensitivity in an early life cumulative risk assessment. Int J Toxicol 2009; 29:71-7. [PMID: 19710296 DOI: 10.1177/1091581809344436] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A cumulative risk assessment is generally intended to address concurrent exposure by all exposure routes to a group of chemicals that share a common mechanism of toxicity. However, the contribution of different exposure routes will change over time. This is most critical when estimating risks to infants and children because their exposure sources change rapidly during the first few years of life because of dietary and behavioral changes. In addition, there may be changes in sensitivity to toxicants during this time period, associated with various developmental stages. Traditional risk assessments do not address this progression. Examples of how these factors might be incorporated into an early life risk assessment are provided for lead, dioxins and furans, and organophosphate pesticides. The same concepts may apply to other potentially susceptible subpopulations, such as the elderly.
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Affiliation(s)
- Robert A Howd
- Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, Oakland, CA 94612, USA.
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17
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Exposure to methamidophos at adulthood elicits depressive-like behavior in mice. Neurotoxicology 2009; 30:471-8. [DOI: 10.1016/j.neuro.2009.01.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2008] [Revised: 12/19/2008] [Accepted: 01/24/2009] [Indexed: 11/18/2022]
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18
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Gomes J, Lloyd OL. Oral exposure of mice to formulations of organophosphorous pesticides: gestational and litter outcomes. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2009; 19:125-137. [PMID: 19370463 DOI: 10.1080/09603120802415818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The purpose of this study was to examine gestational and litter outcomes in mice models from oral exposure to a mixture of formulations of organophosphorous pesticides used in local vegetable production. Male and female mice were exposed to premating and preconception, respectively, to a mixture of organophosphorous pesticide formulations for a period of 7 weeks. The pregnant dams were monitored during gestation and delivered by Caesarean section pre-partum. The percentages of resorptions and the resorptions/implantations ratios, in all the exposed groups, were significantly higher than the reference and the control groups. Percentages of litters with one or more lost embryos were observed in all the exposed groups and were significantly higher than the comparison groups. Fetal weights were significantly lower and the maternal weight gains per live fetus were significantly higher in the medium-dose-exposed groups than the control group. Percentages of fetuses with intra-uterine growth retardation at one standard deviation were significantly higher in all the exposed groups than the comparison groups.
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Affiliation(s)
- James Gomes
- Department of Health Sciences, University of Ottawa, Ontario, Canada.
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19
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Ali BH, Al-Moundhri M, Tageldin M, Al Husseini IS, Mansour MA, Nemmar A, Tanira MO. Ontogenic aspects of cisplatin-induced nephrotoxicity in rats. Food Chem Toxicol 2008; 46:3355-9. [PMID: 18790000 DOI: 10.1016/j.fct.2008.07.030] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 07/07/2008] [Accepted: 07/17/2008] [Indexed: 10/21/2022]
Abstract
A multi-age rat model was evaluated to identify a potential age-related difference in kidney injury following administration of cisplatin (CP). Different age groups of Wistar rats (aged 3, 7, 11 and 24 weeks) were given CP intraperitoneally (6 mg/kg) and sacrificed 6 days thereafter. CP-induced nephrotoxicity caused significant decreases in body weight, creatinine clearance, urine osmolality, plasma total anti-oxidant status, cortical glutathione (GSH) concentration and superoxide dismutase activity. It increased kidney weight and plasma concentrations of creatinine and urea. It increased urinary N-acetyl-beta-D-glucosaminidase activity and protein concentration. Most of the above actions were more marked as the animals advanced in age, except for the changes in GSH, which were similar in all age groups. CP produced necrosis in renal tubules and epithelial vacuolization, the extent of which was more evident as the rats grew older. Renal CP concentration was increased with the increased age of the animal, and the cortical CP concentration in 3 week-old rats was nearly half that of 24 week-old rats. This study showed that the vulnerability profile of each age group was different, suggesting that a multi-age pediatric/geriatric animal model is appropriate to assess, more completely, age-dependent changes in drug toxicity.
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Affiliation(s)
- B H Ali
- Department of Pharmacology and Clinical Pharmacy, Sultan Qaboos University, P.O. Box 35, Al Khod, Postal code 123, Oman.
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20
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Gomes J, Lloyd OL, Hong Z. Oral exposure of male and female mice to formulations of organophosphorous pesticides: congenital malformations. Hum Exp Toxicol 2008; 27:231-40. [DOI: 10.1177/0960327108090266] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Birth outcome was studied in pre-partum litters of mice exposed to oral doses of organophosphorous pesticides at low and high concentrations before mating. Exposed and unexposed pregnant dams were delivered by Caesarean section 1 day before partum, the fetuses were collected, counted and weighed, and the numbers of resorptions were recorded. Live litter sizes were non-significantly higher in all the exposed groups compared with the control group. The numbers of resorptions were significantly higher in all the exposed groups than in the comparison groups. The incidence of intra-uterine growth retardation was significantly higher in all the exposed groups than in the comparison groups. The incidences of congenital malformations were significantly higher in the exposed groups than in one or more of the comparison groups for the defects of the ears, eyes, jaws, brain, and tongue in all the exposed groups. Low set microtia, cataract or open eyelids, microcephaly or anencephaly, maxillary or mandibular hypoplasia, and protruding tongue were observed in all groups, but the numbers were significantly higher in the exposed groups compared with one or more of the comparison groups. Curled or missing tail and intra-auricular septal or intra-ventricular septal defects were observed in higher numbers in the groups in which both the males and the females were exposed than in the comparison groups. Male:female sex ratios were significantly higher in the groups in which males only and females only were exposed.
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Affiliation(s)
- J Gomes
- Health Sciences Program, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada; McLaughlin Centre for Population Health Risk Assessment, Institute of Population Health, University of Ottawa, Ottawa, Ontario, Canada; Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa, Ontario, Canada; Centre for Advanced Research in Environmental Genomics (CAREG), University of Ottawa, Ottawa, Ontario, Canada
| | - OL Lloyd
- Formerly Department of Community Medicine, Faculty of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Z Hong
- Blood Safety Surveillance Division, Centre for Infectious Disease Prevention and Control, Public Health Agency of Canada, Ottawa, Ontario, Canada
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21
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Adaptation of the Behavioral Assessment and Research System (BARS) for evaluating neurobehavioral performance in Filipino children. Neurotoxicology 2007; 29:143-51. [PMID: 18067971 DOI: 10.1016/j.neuro.2007.10.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2007] [Revised: 09/13/2007] [Accepted: 10/15/2007] [Indexed: 11/23/2022]
Abstract
Neurobehavioral tests have long been used to assess health effects in exposed working adult populations. The heightened concern over the potential impact of environmental exposures on neurological functioning in children has led to the development of test batteries for use with children. There is a need for reliable, easy-to-administer batteries to assess neurotoxic exposure in children. One such test battery previously validated with Spanish- and English-speaking children ages 4 and older, combines computerized tests from the Behavioral Assessment and Research System (BARS) with non-computerized tests. The goal of the present study was to determine the feasibility of using standardized neurobehavioral tests in preschool and school-aged Filipino children. Test instructions were translated into the vernacular, Tagalog or Tagalog-English ("Taglish") and some instructions and materials were modified to be appropriate for the target populations. The battery was administered to 4-6-year-old Filipino children (N=50). The performance of the Filipino children was compared to data previously collected from Spanish- and English-speaking children tested in the US. The majority of children had no difficulty completing the tests in the battery with the exception of the Symbol-Digit test and Digit Span-reverse. The three groups showed similar patterns of performance on the tests and the older children performed better than the younger children on all of the tests. The findings from this study demonstrate the utility of using this test battery to assess cognitive and motor performance in Filipino children. Tests in the battery assess a range of functions and the measures are sensitive to age differences. The current battery has been utilized in several cultures and socio-economic status classes, with only minor modifications needed. This study demonstrates the importance of pilot testing the methods before use in a new population, to ensure that the test is valid for that culture.
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Kousba AA, Poet TS, Timchalk C. Age-Related Brain Cholinesterase Inhibition Kinetics following In Vitro Incubation with Chlorpyrifos-Oxon and Diazinon-Oxon. Toxicol Sci 2006; 95:147-55. [PMID: 17018647 DOI: 10.1093/toxsci/kfl123] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Chlorpyrifos and diazinon are two commonly used organophosphorus insecticides (OPs), and their primary mechanism of action involves the inhibition of acetylcholinesterase by their metabolites chlorpyrifos-oxon (CPO) and diazinon-oxon (DZO), respectively. The study objectives were to assess the in vitro age-related inhibition kinetics of neonatal rat brain cholinesterase (ChE) for CPO and DZO by estimating the bimolecular inhibitory rate constant (k(i)) values. Brain ChE inhibition and k(i) values following CPO and DZO incubation with neonatal Sprague-Dawley rat brain homogenates were determined at postnatal day (PND) 5, 12, and 17 and compared with the corresponding inhibition and k(i) values obtained in the adult rat. A modified Ellman method was utilized for measuring the ChE activity. CPO caused a greater ChE inhibition than DZO as evidenced from the estimated k(i) values of both compounds. Neonatal brain ChE inhibition kinetics exhibited a marked age-related sensitivity to CPO, with the order of ChE inhibition being PND 5 > PND 7 > PND 17 with k(i) values of 0.95, 0.50, and 0.22 nM(-1)hr(-1), respectively. In contrast, DZO ChE inhibition was not age related in the neonatal brain, and the estimated k(i) value at all PND ages was 0.02 nM(-1)hr(-1). These results demonstrated an age- and OP-selective inhibition of rat brain ChE, which may be critically important in understanding the potential sensitivity of juveniles to specific OPs exposures.
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Affiliation(s)
- Ahmed A Kousba
- Department of Pharmaceutical Property Assessments, TargeGen Inc., San Diego, California 92121, USA.
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23
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Moser VC, Simmons JE, Gennings C. Neurotoxicological interactions of a five-pesticide mixture in preweanling rats. Toxicol Sci 2006; 92:235-45. [PMID: 16611628 DOI: 10.1093/toxsci/kfj189] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The estimation of risk following exposure to mixtures is an important feature of pesticide risk assessment. Also of concern is the potential for increased sensitivity of the young to pesticide toxicity. We have conducted interaction studies using a mixture of five organophosphorus (OP) pesticides (chlorpyrifos, diazinon, dimethoate, acephate, and malathion) in both adult (published previously) and preweanling rats using a fixed-ratio ray design. In the present study, cholinesterase inhibition and behavioral changes (motor activity, gait, and tail-pinch response) were measured in 17-day-old Long-Evans male rats following acute exposure to the OPs. The ratio of pesticides in the mixture reflected the relative dietary exposure estimates projected by the U.S. Environmental Protection Agency Dietary Exposure Evaluation Model. Dose-response data were collected for each OP alone, which were used (alone or in conjunction with the mixture data) to build an additivity model to predict the effects of the pesticide mixture along a ray of increasing total doses, using the same fixed ratio of components. The mixture data (full ray) were similarly modeled and statistically compared to the additivity model along the ray. Since malathion has been shown to produce synergistic interactions with certain OPs, it was of interest to evaluate the influence of malathion in this study. A second pesticide mixture, without malathion (reduced ray), was tested using the same dose levels of the remaining four OPs. Analysis of the full ray revealed significant greater-than-additive responses for all endpoints. The magnitude of this shift ranged from two- to threefold for estimates of the ED(20) and ED(50). The deviation from additivity was also detected in the reduced ray for all but two endpoints (motor activity and tail-pinch response); however, for all endpoints, the reduced ray was significantly different from the full ray. Thus, greater-than-additive responses were detected in preweanling rats with this OP mixture, and this effect can only partially be attributed to the malathion in the mixture.
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Affiliation(s)
- Virginia C Moser
- Neurotoxicology Division, National Health and Environmental Effects Research Laboratory/Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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24
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Chang PA, Wu YJ, Li W, Leng XF. Effect of carbamate esters on neurite outgrowth in differentiating human SK-N-SH neuroblastoma cells. Chem Biol Interact 2006; 159:65-72. [PMID: 16256972 DOI: 10.1016/j.cbi.2005.09.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2005] [Revised: 09/27/2005] [Accepted: 09/27/2005] [Indexed: 11/16/2022]
Abstract
Carbamate esters are widely used as pesticides and can cause neurotoxicity in humans and animals; the exact mechanism is still unclear. In the present investigation, the effects of carbamates at sublethal concentration on neurite outgrowth and cytoskeleton as well as activities of acetylcholinesterase (AChE) and neuropathy target esterase (NTE) in differentiating human SK-N-SH neuroblastoma cells were studied. The results showed that 50 microM of either aldicarb or carbaryl significantly decreased neurite length in the retinoic acid-induced differentiation of the neuroblastoma cells, compared to cells treated with vehicle. Western blot analyses revealed that neither carbamate had significant effects on the levels of actin, or total neurofilament high molecular proteins (NF-H). However, increased NF-H phosphorylation was observed following carbamate treatment. These changes may represent a useful in vitro marker of carbamate neurotoxicity within a simple model of neuronal cell differentiation. Furthermore, activity of AChE, but not NTE, was significantly inhibited by aldicarb and carbaryl in differentiating cells, which suggested that cytoskeletal protein changes induced by carbamate esters in differentiating cells was associated with inhibition of AChE but not NTE.
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Affiliation(s)
- Ping-An Chang
- Laboratory of Molecular Toxicology, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100080, PR China
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25
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Padilla S, Sung HJ, Moser VC. Further assessment of an in vitro screen that may help identify organophosphorus pesticides that are more acutely toxic to the young. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2004; 67:1477-1489. [PMID: 15371233 DOI: 10.1080/15287390490483836] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Some, but not all, organophosphorus pesticides are more acutely toxic to the young as compared to adults. We have developed an in vitro assay that measures the detoxification potential (via carboxylesterase and A-esterases) of tissues. Previous results using this in vitro screen correlated with the marked in vivo sensitivity of the young to chlorpyrifos and also correlated with the equal sensitivity of the young and adult to methamidophos (Padilla et al., 2000). We have now extended these observations to two other pesticides that have already been shown in the literature to be more toxic to the young: parathion (paraoxon) and malathion (malaoxon). In our in vitro assay, liver or plasma from 7-d-old rats were much less efficacious than adult tissues at detoxification of the active metabolites of these two pesticides. Using our in vitro assay we also tested the active metabolite of diazinon, diazoxon, and again found that young liver or plasma possessed much less detoxification capability than adult tissues. From these results, we predicted that young animals would be more sensitive to diazinon, which, in fact, was the case: When postnatal day (PND) 17 or adult rats were given a dosage of 75 mg/kg diazinon, adult brain cholinesterase (ChE) was only inhibited 38%, while the brain ChE in the PND 17 animals showed much more inhibition (75%). We conclude that our in vitro screen may prove to be a useful, quick, convenient test for identifying which organophosphorus pesticides may be more acutely toxic to the young as compared to adults.
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Affiliation(s)
- S Padilla
- Neurotoxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, North Carolina 27711, USA.
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26
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Vidair CA. Age dependence of organophosphate and carbamate neurotoxicity in the postnatal rat: extrapolation to the human. Toxicol Appl Pharmacol 2004; 196:287-302. [PMID: 15081274 DOI: 10.1016/j.taap.2003.12.016] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2003] [Accepted: 12/18/2003] [Indexed: 10/26/2022]
Abstract
One important aspect of risk assessment for the organophosphate and carbamate pesticides is to determine whether their neurotoxicity occurs at lower dose levels in human infants compared to adults. Because these compounds probably exert their neurotoxic effects through the inhibition of acetylcholinesterase (AChE), the above question can be narrowed to whether the cholinesterase inhibition and neurotoxicity they produce is age-dependent, both in terms of the effects produced and potency. The rat is the animal model system most commonly used to address these issues. This paper first discusses the adequacy of the postnatal rat to serve as a model for neurodevelopment in the postnatal human, concluding that the two species share numerous pathways of postnatal neurodevelopment, and that the rat in the third postnatal week is the neurodevelopmental equivalent of the newborn human. Then, studies are discussed in which young and adult rats were dosed by identical routes with organophosphates or carbamates. Four pesticides were tested in rat pups in their third postnatal week: aldicarb, chlorpyrifos, malathion, and methamidophos. The first three, but not methamidophos, caused neurotoxicity at dose levels that ranged from 1.8- to 5.1-fold lower (mean 2.6-fold lower) in the 2- to 3-week-old rat compared to the adult. This estimate in the rat, based on a limited data set of three organophosphates and a single carbamate, probably represents the minimum difference in the neurotoxicity of an untested cholinesterase-inhibiting pesticide that should be expected between the human neonate and adult. For the organophosphates, the greater sensitivity of postnatal rats, and, by analogy, that expected for human neonates, is correlated with generally lower levels of the enzymes involved in organophosphate deactivation.
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Affiliation(s)
- Charles A Vidair
- Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, Oakland, CA 94612, USA.
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27
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Smulders CJGM, Bueters TJH, Van Kleef RGDM, Vijverberg HPM. Selective effects of carbamate pesticides on rat neuronal nicotinic acetylcholine receptors and rat brain acetylcholinesterase. Toxicol Appl Pharmacol 2003; 193:139-46. [PMID: 14644616 DOI: 10.1016/j.taap.2003.07.011] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Effects of commonly used carbamate pesticides on rat neuronal nicotinic acetylcholine receptors expressed in Xenopus laevis oocytes have been investigated using the two-electrode voltage clamp technique. The potencies of these effects have been compared to the potencies of the carbamates to inhibit rat brain acetylcholinesterase. The potency order of six carbamates to inhibit alpha4beta4 nicotinic receptors is fenoxycarb > EPTC > carbaryl, bendiocarb > propoxur > aldicarb with IC50 values ranging from 3 microM for fenoxycarb to 165 microM for propoxur and >1 mM for aldicarb. Conversely, the potency order of these carbamates to inhibit rat brain acetylcholinesterase is bendiocarb > propoxur, aldicarb > carbaryl > EPTC, fenoxycarb with IC50 values ranging from 1 microM for bendiocarb to 17 microM for carbaryl and > mM for EPTC and fenoxycarb. The alpha4beta2, alpha3beta4, and alpha3beta2 nicotinic acetylcholine receptors are inhibited by fenoxycarb, EPTC, and carbaryl with potency orders similar to that for alpha4beta4 receptors. Comparing the potencies of inhibition of the distinct subtypes of nicotinic acetylcholine receptors shows that the alpha3beta2 receptor is less sensitive to inhibition by fenoxycarb and EPTC. The potency of inhibition depends on the carbamate as well as on a combination of alpha and beta subunit properties. It is concluded that carbamate pesticides affect different subtypes of neuronal nicotinic receptors independently of acetylcholinesterase inhibition. This implicates that neuronal nicotinic receptors are additional targets for some carbamate pesticides and that these receptors may contribute to carbamate pesticide toxicology, especially after long-term exposure.
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Affiliation(s)
- Chantal J G M Smulders
- Institute for Risk Assessment Sciences, Utrecht University, P.O. Box 80176, NL-3508 TD Utrecht, The Netherlands
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28
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Levin ED, Christopher NC. Persistence of nicotinic agonist RJR 2403-induced working memory improvement in rats. Drug Dev Res 2002. [DOI: 10.1002/ddr.10024] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Sharma R, Kodavanti PRS. In vitro effects of polychlorinated biphenyls and hydroxy metabolites on nitric oxide synthases in rat brain. Toxicol Appl Pharmacol 2002; 178:127-36. [PMID: 11858728 DOI: 10.1006/taap.2001.9328] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nitric oxide synthases (NOS) play a key role in motor activity in the cerebellum, hormonal regulation in the hypothalamus, and long-term potentiation (LTP), learning, and memory processes in the hippocampus. Developmental exposure to polychlorinated biphenyls (PCBs) has been shown to affect psychomotor functions, learning and memory processes, and to inhibit LTP. We hypothesized that PCBs may disrupt the regulation of such neurological functions by altering NOSs. We have studied the in vitro effects of several PCB congeners and some hydroxy PCBs on NOS activity in cytosolic (presumably neuronal NOS [nNOS]) and membrane (presumably endothelial NOS [eNOS]) fractions in different brain regions of young and adult rats. Among the two selected dichloro PCBs, the ortho-PCB, 2,2'-dichlorobiphenyl (DCB), inhibited both cytosolic and membrane NOS activity at low micromolar concentrations (3-10 microM) in the selected brain regions of all age groups while the non-ortho-PCB, 4,4'-DCB, did not. 2,2'-DCB inhibited cytosolic NOS to a greater extent than membrane NOS. Pentachloro-PCBs (PeCBs) and hexachloro-PCBs (HCBs) did not have a significant effect on adult cerebellar cytosolic or membrane NOS. However, mono- and dihydroxy derivatives of HCBs significantly decreased cytosolic NOS (IC50s: 16.33 +/- 0.47 and 33.65 +/- 4.33 microM, respectively) but resulted in a marginal effect on membrane NOS in the cerebellum. Among three adult rat brain regions, the hypothalamic cytosolic NOS was the most sensitive to 2,2'-DCB. Also, cytosolic NOS in the cerebellum and hypothalamus of young rats was less sensitive than in the older rats. In summary, these results indicate that only di-ortho-PCB inhibited both NOS and hydroxy substitution of one or more chlorine molecules significantly increased the potency of both ortho- and non-ortho-HCBs. The selective sensitivity of NOS to dichloro- ortho-PCB and hydroxy metabolites suggests that the inhibition of NOS could play a role in the neuroendocrine effects as well as learning and memory deficits caused by exposure to PCBs.
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Affiliation(s)
- Rashmi Sharma
- National Research Council, National Academy of Sciences, Washington, DC, USA
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30
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Hazarika A, Sarkar SN. Effect of isoproturon pretreatment on the biochemical toxicodynamics of anilofos in male rats. Toxicology 2001; 165:87-95. [PMID: 11522367 DOI: 10.1016/s0300-483x(01)00411-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Anilofos and isoproturon are important herbicides of organophosphorus and substituted phenylurea groups, respectively. Isoproturon is an inducer of hepatic drug-metabolizing enzymes. Animals and humans have the potential to be exposed to the mixture of these intentionally introduced environmental xenobiotics, but toxicological interactions between these herbicides are not known. Effects of isoproturon pretreatment (675 mg/kg/day for 3 consecutive days) on the toxic actions of anilofos administered orally as a single dose (850 mg/kg) were evaluated by determining some biochemical attributes in blood (erythrocyte/plasma), brain and liver of rats. Anilofos or isoproturon alone or in combination failed to produce any noticeable signs of cholinergic hyperactivity and behavioural alterations. Isoproturon did not potentiate the anticholinesterase action of anilofos in blood and liver. Inhibition of brain acetylcholinesterase was significantly protected. No significant alteration in anilofos-mediated production of lipid peroxidation was observed in erythrocyte and brain of isoproturon-pretreated rats, but it was significantly increased in liver. Anilofos did not affect GSH and GST. The isoproturon-mediated increase in GSH levels of brain (threefold) and liver (3.6-fold) was also not affected following combined administration. GST activity was increased in liver of rats given isoproturon alone (fourfold) or in combination with anilofos (2.8-fold). Activities of total ATPase, Mg2+-ATPase and Na+-K+-ATPase were not affected in rats given either anilofos alone or herbicides in sequence. With these treatments, there were no alterations in the protein content of plasma, brain and liver. Overall findings of the study indicate that isoproturon pretreatment does not alter the toxicity of anilofos, the GSH-GST metabolic pathway may not have a significant implication in the detoxification of anilofos and the production of a reactive oxygen species may be a factor in mediating anilofos toxicity.
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Affiliation(s)
- A Hazarika
- Division of Pharmacology and Toxicology, Indian Veterinary Research Institute, Izatnagar-243 122, U.P., India
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31
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de Castro VL, Chiorato SH, Pinto NF. Relevance of developmental testing of exposure to methamidophos during gestation to its toxicology evaluation. Toxicol Lett 2000; 118:93-102. [PMID: 11137314 DOI: 10.1016/s0378-4274(00)00271-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The organophosphate insecticide (OP) are known to be able to promote cholinergic toxicity related to neurobehavioral findings. The measures of cholinesterase activity are the most common index of its action. The influence was evaluated, of the OP methamidophos (1.0 mg/kg), by oral exposure during gestational organogenesis of rats, on maturational and behavioral aspects of offspring development. This dose did not promote evidence of maternal toxicity. The pesticide did not affect body weight gain of the dams and offspring, but interfered with the offspring's physical and maturational development landmarks according to age. The behavioral performance of the offspring with or without a pharmacological challenge was tested at different postnatal days (pnd 14, 21 and 40) in an open-field apparatus. The results showed a large standard deviation that prejudiced the conclusions. There were no observed alterations in the swimming behavior tested also at pnd 7, 14 and 21. As long as the obtained results showed some subtle effects on rat development, the data, as possible additional effect biomarkers for risk analysis, will aid further studies of the embryo-feto-toxic potential of OP exposure.
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Affiliation(s)
- V L de Castro
- Embrapa Environment, Rodovia, Jaguariuna, Sao Paulo 13820-000, Brazil.
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Dam K, Seidler FJ, Slotkin TA. Chlorpyrifos exposure during a critical neonatal period elicits gender-selective deficits in the development of coordination skills and locomotor activity. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2000; 121:179-87. [PMID: 10876030 DOI: 10.1016/s0165-3806(00)00044-4] [Citation(s) in RCA: 187] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The widespread use of chlorpyrifos has raised concern about the potential consequences of fetal and childhood exposure. Previous studies have shown that apparently subtoxic doses of chlorpyrifos are nevertheless capable of affecting brain development by inhibiting mitosis, eliciting apoptosis, and altering neuronal activity and reactivity. To determine whether these biochemical changes elicit behavioral abnormalities, we evaluated coordination skills and open field behaviors in developing rats. Administration of 1 mg/kg s.c. of chlorpyrifos on postnatal (PN) days 1-4 elicited deficits in reflex righting on PN3-4 and in geotaxic responses on PN5-8, an effect that was specific to females. However, the ontogeny of more complex behaviors indicated a subsequent selectivity toward males. In the periweaning period, open-field locomotor activity and rearing were markedly reduced in male rats that had been exposed to chlorpyrifos on PN1-4, whereas no effect was detected in females. The gender-selective behavioral effects were associated with greater sensitivity of males to inhibition of cholinesterase in the first few hours after chlorpyrifos treatment. In contrast to the effects seen after administration on PN1-4, shifting the period of chlorpyrifos exposure to PN11-14 had a much less notable effect, even when higher doses were used: no decreases in locomotor activity and overall increases in rearing and grooming that were not significantly gender-selective. Administration on PN11-14 did not produce differential effects on cholinesterase in males and females. These studies indicate that chlorpyrifos given during a critical neonatal period, even at levels below the threshold for overt toxicity, can elicit both immediate and delayed gender-selective behavioral abnormalities. The ultimate evaluation of the developmental neurotoxicity of chlorpyrifos will thus require long-term assessments of neurobehavioral consequences of exposure during discrete developmental periods.
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Affiliation(s)
- K Dam
- Box 3813 DUMC, Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
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Moser VC. Letter to the editor. Toxicol Appl Pharmacol 1999; 161:303-5. [PMID: 10620489 DOI: 10.1006/taap.1999.8792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- VC Moser
- United States Environmental Protection Agency, Research Triangle Park, North Carolina, 27711, USA
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