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Panzenhagen AC, Petry FDS, Alves-Teixeira A, Santos L, Carazza-Kessler FG, Gelain DP, Moreira JCF. Biomarkers of methylmercury neurotoxicity and neurodevelopmental features: A systematic review. Food Chem Toxicol 2024; 191:114851. [PMID: 38986832 DOI: 10.1016/j.fct.2024.114851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 07/02/2024] [Accepted: 07/04/2024] [Indexed: 07/12/2024]
Abstract
The issue of MeHg contamination is a significant concern due to its detrimental impact on the environment. This study aimed to thoroughly investigate the effects of MeHg on neurodevelopmental biomarkers, as there is a lack of systematic reviews in this area. We conducted a comprehensive search of three databases (PubMed, Scopus, and Web of Science) and found 522 records, which were then meticulously reviewed by two independent reviewers. A total of 66 studies were included, with biomarkers related to oxidative stress, neurotransmission, inflammation, epigenetics, and apoptosis being the most prominent. The results of both in vitro and in vivo models indicate that antioxidant enzymes and other oxidative stress-related markers are indeed, altered following MeHg exposure. Moreover, MeHg exposure causes significant disruptions to neurotransmitter levels, activities of neurotransmitter synthesis enzymes, receptor densities, and proteins involved in synaptic function. Proinflammatory biomarkers are consistently overexpressed in both MeHg-treated cells and the brains of exposed rats. Furthermore, studies on DNA methylation and biomarker activity suggest that MeHg exposure may lead to neurotoxicity and neurodevelopmental issues via perturbations to epigenetic markers and the apoptosis pathway.
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Affiliation(s)
- Alana Castro Panzenhagen
- Centro de Estudos Em Estresse Oxidativo, Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, Brazil.
| | - Fernanda Dos Santos Petry
- Centro de Estudos Em Estresse Oxidativo, Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, Brazil
| | - Alexsander Alves-Teixeira
- Centro de Estudos Em Estresse Oxidativo, Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, Brazil
| | - Lucas Santos
- Centro de Estudos Em Estresse Oxidativo, Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, Brazil
| | - Flávio Gabriel Carazza-Kessler
- Centro de Estudos Em Estresse Oxidativo, Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, Brazil
| | - Daniel Pens Gelain
- Centro de Estudos Em Estresse Oxidativo, Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, Brazil
| | - José Cláudio Fonseca Moreira
- Centro de Estudos Em Estresse Oxidativo, Programa de Pós-Graduação Em Ciências Biológicas: Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal Do Rio Grande Do Sul, Porto Alegre, Brazil
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Starnes HM, Rock KD, Jackson TW, Belcher SM. A Critical Review and Meta-Analysis of Impacts of Per- and Polyfluorinated Substances on the Brain and Behavior. FRONTIERS IN TOXICOLOGY 2022; 4:881584. [PMID: 35480070 PMCID: PMC9035516 DOI: 10.3389/ftox.2022.881584] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 03/14/2022] [Indexed: 01/09/2023] Open
Abstract
Per- and polyfluoroalkyl substances (PFAS) are a class of structurally diverse synthetic organic chemicals that are chemically stable, resistant to degradation, and persistent in terrestrial and aquatic environments. Widespread use of PFAS in industrial processing and manufacturing over the last 70 years has led to global contamination of built and natural environments. The brain is a lipid rich and highly vascularized organ composed of long-lived neurons and glial cells that are especially vulnerable to the impacts of persistent and lipophilic toxicants. Generally, PFAS partition to protein-rich tissues of the body, primarily the liver and blood, but are also detected in the brains of humans, wildlife, and laboratory animals. Here we review factors impacting the absorption, distribution, and accumulation of PFAS in the brain, and currently available evidence for neurotoxic impacts defined by disruption of neurochemical, neurophysiological, and behavioral endpoints. Emphasis is placed on the neurotoxic potential of exposures during critical periods of development and in sensitive populations, and factors that may exacerbate neurotoxicity of PFAS. While limitations and inconsistencies across studies exist, the available body of evidence suggests that the neurobehavioral impacts of long-chain PFAS exposures during development are more pronounced than impacts resulting from exposure during adulthood. There is a paucity of experimental studies evaluating neurobehavioral and molecular mechanisms of short-chain PFAS, and even greater data gaps in the analysis of neurotoxicity for PFAS outside of the perfluoroalkyl acids. Whereas most experimental studies were focused on acute and subchronic impacts resulting from high dose exposures to a single PFAS congener, more realistic exposures for humans and wildlife are mixtures exposures that are relatively chronic and low dose in nature. Our evaluation of the available human epidemiological, experimental, and wildlife data also indicates heightened accumulation of perfluoroalkyl acids in the brain after environmental exposure, in comparison to the experimental studies. These findings highlight the need for additional experimental analysis of neurodevelopmental impacts of environmentally relevant concentrations and complex mixtures of PFAS.
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Albers JL, Steibel JP, Klingler RH, Ivan LN, Garcia-Reyero N, Carvan MJ, Murphy CA. Altered Larval Yellow Perch Swimming Behavior Due to Methylmercury and PCB126 Detected Using Hidden Markov Chain Models. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:3514-3523. [PMID: 35201763 DOI: 10.1021/acs.est.1c07505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Fish swimming behavior is a commonly measured response in aquatic ecotoxicology because behavior is considered a whole organism-level effect that integrates many sensory systems. Recent advancements in animal behavior models, such as hidden Markov chain models (HMM), suggest an improved analytical approach for toxicology. Using both new and traditional approaches, we examined the sublethal effects of PCB126 and methylmercury on yellow perch (YP) larvae (Perca flavescens) using three doses. Both approaches indicate larvae increase activity after exposure to either chemical. The middle methylmercury-dosed larvae showed multiple altered behavior patterns. First, larvae had a general increase in activity, typically performing more behavior states, more time swimming, and more swimming bouts per second. Second, when larvae were in a slow or medium swimming state, these larvae tended to switch between these states more often. Third, larvae swam slower during the swimming bouts. The upper PCB126-dosed larvae exhibited a higher proportion and a fast swimming state, but the total time spent swimming fast decreased. The middle PCB126-dosed larvae transitioned from fast to slow swimming states less often than the control larvae. These results indicate that developmental exposure to very low doses of these neurotoxicants alters YP larvae overall swimming behaviors, suggesting neurodevelopment alteration.
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Affiliation(s)
- Janice L Albers
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, Michigan 48824, United States
| | - Juan P Steibel
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, Michigan 48824, United States
| | - Rebekah H Klingler
- School of Freshwater Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53204, United States
| | - Lori N Ivan
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, Michigan 48824, United States
| | - Natàlia Garcia-Reyero
- Environmental Laboratory, US Army Engineer Research and Development Center, Vicksburg, Mississippi, 39180, United States
| | - Michael J Carvan
- School of Freshwater Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53204, United States
| | - Cheryl A Murphy
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, Michigan 48824, United States
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Pistollato F, de Gyves EM, Carpi D, Bopp SK, Nunes C, Worth A, Bal-Price A. Assessment of developmental neurotoxicity induced by chemical mixtures using an adverse outcome pathway concept. Environ Health 2020; 19:23. [PMID: 32093744 PMCID: PMC7038628 DOI: 10.1186/s12940-020-00578-x] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 02/11/2020] [Indexed: 05/25/2023]
Abstract
BACKGROUND In light of the vulnerability of the developing brain, mixture risk assessment (MRA) for the evaluation of developmental neurotoxicity (DNT) should be implemented, since infants and children are co-exposed to more than one chemical at a time. One possible approach to tackle MRA could be to cluster DNT chemicals in a mixture on the basis of their mode of action (MoA) into 'similar' and 'dissimilar', but still contributing to the same adverse outcome, and anchor DNT assays to common key events (CKEs) identified in DNT-specific adverse outcome pathways (AOPs). Moreover, the use of human in vitro models, such as induced pluripotent stem cell (hiPSC)-derived neuronal and glial cultures would enable mechanistic understanding of chemically-induced adverse effects, avoiding species extrapolation. METHODS HiPSC-derived neural progenitors differentiated into mixed cultures of neurons and astrocytes were used to assess the effects of acute (3 days) and repeated dose (14 days) treatments with single chemicals and in mixtures belonging to different classes (i.e., lead(II) chloride and methylmercury chloride (heavy metals), chlorpyrifos (pesticide), bisphenol A (organic compound and endocrine disrupter), valproic acid (drug), and PCB138 (persistent organic pollutant and endocrine disrupter), which are associated with cognitive deficits, including learning and memory impairment in children. Selected chemicals were grouped based on their mode of action (MoA) into 'similar' and 'dissimilar' MoA compounds and their effects on synaptogenesis, neurite outgrowth, and brain derived neurotrophic factor (BDNF) protein levels, identified as CKEs in currently available AOPs relevant to DNT, were evaluated by immunocytochemistry and high content imaging analysis. RESULTS Chemicals working through similar MoA (i.e., alterations of BDNF levels), at non-cytotoxic (IC20/100), very low toxic (IC5), or moderately toxic (IC20) concentrations, induce DNT effects in mixtures, as shown by increased number of neurons, impairment of neurite outgrowth and synaptogenesis (the most sensitive endpoint as confirmed by mathematical modelling) and increase of BDNF levels, to a certain extent reproducing autism-like cellular changes observed in the brain of autistic children. CONCLUSIONS Our findings suggest that the use of human iPSC-derived mixed neuronal/glial cultures applied to a battery of assays anchored to key events of an AOP network represents a valuable approach to identify mixtures of chemicals with potential to cause learning and memory impairment in children.
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Affiliation(s)
| | | | - Donatella Carpi
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | | | - Carolina Nunes
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Andrew Worth
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Anna Bal-Price
- European Commission, Joint Research Centre (JRC), Ispra, Italy
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Mohammed DAE, Ahmed RR, Ahmed RG. Maternal lithium chloride exposure alters the neuroendocrine-cytokine axis in neonatal albino rats. Int J Dev Neurosci 2020; 80:123-138. [PMID: 31994228 DOI: 10.1002/jdn.10010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/16/2020] [Accepted: 01/20/2020] [Indexed: 01/09/2023] Open
Abstract
The aim of this work was to clarify whether maternal lithium chloride (LiCl) exposure disrupts the neonatal neuroendocrine-cytokine axis. Pregnant Wistar rats were orally administrated 50 mg LiCl/kg b.wt. from gestational day (GD) 1 to postpartum day 28. Maternal administration of LiCl induced a hypothyroid state in both dams and their neonates compared to the control dams and neonates at lactation days (LDs) 14, 21 and 28, where the levels of serum free triiodothyronine (FT3) and free thyroxin (FT4) were decreased and the level of serum thyrotropin (TSH) level was increased. A noticeable depression in maternal body weight gain, neonatal body weight and neonatal serum growth hormone (GH) was observed on all examined postnatal days (PNDs; 14, 21 and 28). A single abortion case was recorded at GD 17, and three dead neonates were noted at birth in the LiCl-treated group. Maternal administration of LiCl disturbed the levels of neonatal serum tumor necrosis factor-alpha (TNF-α), transforming growth factor-beta (TGF-β), interleukin-1 beta (IL-1β), interferon-gamma (INF-γ), leptin, adiponectin and resistin at all tested PNDs compared to the control group. This administration produced a stimulatory action on the level of neonatal cerebral serotonin (5-HT) at PND 14 and on the level of neonatal cerebral norepinephrine (NE) at PNDs 21 and 28. However, this administration produced an inhibitory action on the level of neonatal cerebral dopamine (DA) at all examined PNDs and on the level of neonatal cerebral NE at PND 14 and the level of neonatal cerebral 5-HT at PNDs 21 and 28 compared to the corresponding control group. Thus, maternal LiCl exposure-induced hypothyroidism disrupts the neonatal neuroendocrine-cytokine system, which delay cerebral development.
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Affiliation(s)
- Dena A-E Mohammed
- Division of Anatomy and Embryology, Zoology Department, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt
| | - Rasha R Ahmed
- Division of Histology and Cytology, Zoology Department, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt
| | - R G Ahmed
- Division of Anatomy and Embryology, Zoology Department, Faculty of Science, Beni-Suef University, Beni-Suef, Egypt
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Reardon AJF, Karathra J, Ribbenstedt A, Benskin JP, MacDonald AM, Kinniburgh DW, Hamilton TJ, Fouad K, Martin JW. Neurodevelopmental and Metabolomic Responses from Prenatal Coexposure to Perfluorooctanesulfonate (PFOS) and Methylmercury (MeHg) in Sprague-Dawley Rats. Chem Res Toxicol 2019; 32:1656-1669. [PMID: 31340646 DOI: 10.1021/acs.chemrestox.9b00192] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Methylmercury (MeHg) and perfluorooctanesulfonate (PFOS) are major contaminants of human blood that are both common in dietary fish, thereby raising questions about their combined impact on human development. Here, pregnant Sprague-Dawley rats ingested a daily dose, from gestational day 1 through to weaning, of either 1 mg/kg bw PFOS (PFOS-only), 1 mg/kg MeHg (MeHg-only), a mixture of 0.1 mg/kg PFOS and 1 mg/kg MeHg (Low-Mix), or of 1 mg/kg of PFOS and 1 mg/kg MeHg (High-Mix). Newborns were monitored for physical milestones and reflexive developmental responses, and in juveniles the spontaneous activity, anxiety, memory, and cognition were assessed. Targeted metabolomics of 199 analytes was applied to sectioned brain regions of juvenile offspring. Newborns in the High-Mix group had decreased weight gain as well as delayed reflexes and innate behavioral responses compared to controls and individual chemical groups indicating a toxicological interaction on early development. In juveniles, cumulative mixture effects increased in a dose-dependent manner in tests of anxiety-like behavior. However, other developmental test results suggested antagonism, as PFOS-only and MeHg-only juveniles had increased hyperactivity and thigmotaxic behavior, respectively, but fewer effects in Low-Mix and High-Mix groups. Consistent with these behavioral observations, a pattern of antagonism was also observed in neurochemicals measured in rat cortex, as PFOS-only and MeHg-only juveniles had altered concentrations of metabolites (e.g., lipids, amino acids, and biogenic amines), while no changes were evident in the combined exposures. The cortical metabolites altered in PFOS-only and MeHg-only exposed groups are involved in inhibitory and excitatory neurotransmission. These proof-of-principle findings at relatively high doses indicate the potential for toxicological interaction between PFOS and MeHg, with developmental-stage specific effects. Future mixture studies at lower doses are warranted, and prospective human birth cohorts should consider possible confounding effects from PFOS and mercury exposure on neurodevelopment.
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Affiliation(s)
- Anthony J F Reardon
- Department of Laboratory Medicine and Pathology , University of Alberta , Edmonton , Alberta T6G 2G3 , Canada
| | - Jacqueline Karathra
- Department of Laboratory Medicine and Pathology , University of Alberta , Edmonton , Alberta T6G 2G3 , Canada
| | - Anton Ribbenstedt
- Department of Environmental Science and Analytical Chemistry (ACES) , Stockholm University , Stockholm SE-11418 , Sweden
| | - Jonathan P Benskin
- Department of Environmental Science and Analytical Chemistry (ACES) , Stockholm University , Stockholm SE-11418 , Sweden
| | - Amy M MacDonald
- Alberta Centre for Toxicology , University of Calgary , Calgary , Alberta T2N 1N4 , Canada
| | - David W Kinniburgh
- Alberta Centre for Toxicology , University of Calgary , Calgary , Alberta T2N 1N4 , Canada
| | - Trevor J Hamilton
- Department of Psychology , MacEwan University , Edmonton , Alberta T5J 4S2 , Canada
| | - Karim Fouad
- Department of Physical Therapy , University of Alberta , Edmonton , Alberta T6G 2G4 , Canada
| | - Jonathan W Martin
- Department of Laboratory Medicine and Pathology , University of Alberta , Edmonton , Alberta T6G 2G3 , Canada.,Department of Environmental Science and Analytical Chemistry (ACES) , Stockholm University , Stockholm SE-11418 , Sweden
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Wang X, Xu Y, Song X, Jia Q, Zhang X, Qian Y, Qiu J. Analysis of glycerophospholipid metabolism after exposure to PCB153 in PC12 cells through targeted lipidomics by UHPLC-MS/MS. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 169:120-127. [PMID: 30445242 DOI: 10.1016/j.ecoenv.2018.11.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 10/01/2018] [Accepted: 11/01/2018] [Indexed: 06/09/2023]
Abstract
Polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) that have neurotoxicity, reproductive toxicity, hepatotoxicity and immunotoxicity in both animals and humans. Few studies have focused on the changes to endogenous glycerophospholipid metabolism caused by PCB153. To evaluate the relationships between exposure to PCB153 and specific endogenous glycerophospholipid metabolism, an ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was implemented in this study. Twenty-two endogenous glycerophospholipids in PC12 cells were analyzed after exposure to PCB153 at dosages of 0.05 μg mL-1, 0.5 μg mL-1 or 20 μg mL-1 for 120 h. PC(14:0/14:0), PE(16:0/18:1), PE(16:0/18:2), PS(18:0/18:1) and PI(16:0/18:1) were identified as potential biomarkers under the rules of t-test (P) value < 0.05 and variable importance at projection (VIP) value > 1. It was also found that the alterations at 0.05 μg mL-1 and 20 μg mL-1 PCB153 were similar at 120 h, while 0.5 μg mL-1 PCB153 presented an opposite trend. Additionally, significant upregulation of PC, PE and PS with the same fatty acid chains of 18:0/18:2 was found after exposure to 0.05 μg mL-1 and 20 μg mL-1 PCB153 at 120 h. This study revealed that PCB153 exposure modulated 22 endogenous glycerophospholipids in PC12 cells and provided the basis for the further study of PCB153 on the effects of glycerophospholipids on PC12 cells.
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Affiliation(s)
- Xinlu Wang
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China
| | - Yanyang Xu
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China
| | - Xiao Song
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China
| | - Qi Jia
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China
| | - Xining Zhang
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China
| | - Yongzhong Qian
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China.
| | - Jing Qiu
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China.
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Guo Z, Xie HQ, Zhang P, Luo Y, Xu T, Liu Y, Fu H, Xu L, Valsami-Jones E, Boksa P, Zhao B. Dioxins as potential risk factors for autism spectrum disorder. ENVIRONMENT INTERNATIONAL 2018; 121:906-915. [PMID: 30347373 DOI: 10.1016/j.envint.2018.10.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 10/14/2018] [Accepted: 10/14/2018] [Indexed: 06/08/2023]
Abstract
Autism spectrum disorder (ASD) has emerged as a major public health concern due to its fast-growing prevalence in recent decades. Environmental factors are thought to contribute substantially to the variance in ASD. Interest in environmental toxins as causes of ASD has arisen due to the high sensitivity of the developing human brain to toxic chemicals, particularly to dioxin and certain dioxin-like compounds (dioxins). As a group of typical persistent organic pollutants, dioxins have been found to exert adverse effects on human brain development. In this paper, we review the evidence for association of exposure to dioxins with neurodevelopmental abnormalities related to ASD based on both human epidemiological and animal studies. It has been documented that exposure to dioxins during critical developmental periods increased risk for ASD. This notion has been demonstrated in different populations exposed to high or background level of dioxins. Furthermore, the effects and mechanisms of action of dioxins relevant to the pathophysiology and pathogenesis of ASD are summarized, describing potential underlying mechanisms linking dioxin exposure with ASD onset. Further studies focusing on effects of prenatal/perinatal exposure to individual dioxin congeners or to mixtures of dioxins on ASD-associated behavioral and neurobiological consequences in animal models, and on the mechanisms of actions of dioxins, are needed in order to better understand how dioxin exposure might contribute to increased risk for ASD.
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Affiliation(s)
- Zhiling Guo
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Heidi Qunhui Xie
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Peng Zhang
- University of Birmingham, School of Geography, Earth and Environmental Sciences, Birmingham B15 2TT, UK
| | - Yali Luo
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tuan Xu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yiyun Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hualing Fu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Li Xu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Eugenia Valsami-Jones
- University of Birmingham, School of Geography, Earth and Environmental Sciences, Birmingham B15 2TT, UK
| | - Patricia Boksa
- Department of Psychiatry, McGill University, 6875 LaSalle Boulevard, Montreal, QC, Canada; Neuroscience Division, Douglas Mental Health University Institute, Montreal, QC, Canada.
| | - Bin Zhao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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9
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Olguín N, Müller ML, Rodríguez-Farré E, Suñol C. Neurotransmitter amines and antioxidant agents in neuronal protection against methylmercury-induced cytotoxicity in primary cultures of mice cortical neurons. Neurotoxicology 2018; 69:278-287. [PMID: 30075218 DOI: 10.1016/j.neuro.2018.07.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 07/26/2018] [Accepted: 07/30/2018] [Indexed: 12/23/2022]
Abstract
Methylmercury (MeHg) is an environmental toxicant with detrimental effects on the developing brain and adult nervous system. The main mechanisms identified include oxidative stress, changes in intracellular calcium, mitochondrial changes, inhibition of glutamate uptake, of protein synthesis and disruption of microtubules. However, little is known about mechanisms of protection against MeHg neurotoxicity. We found that resveratrol (10 μM) and ascorbic acid (200 μM) protected MeHg-induced cell death in primary cultures of cortical neurons. In this work, we aimed at finding additional targets that may be related to MeHg mode of action in cell toxicity with special emphasis in cell protection. We wonder whether neurotransmitters may affect the MeHg effects on neuronal death. Our findings show that neurons exposed to low MeHg concentrations exhibit less mortality if co-exposed to 10 μM dopamine (DA). However, DA metabolites, HVA (homovanillic acid) and DOPAC (3,4-dihydroxyphenylacetic acid) are not responsible for such protection. Furthermore, both DA D1 and D2 receptors agonists showed a protective effect against MeHg toxicity. It is striking though that DA receptor antagonists SKF83566 (10 μM) and haloperidol (10 μM) did not inhibit DA protection against MeHg. In addition, the protective effect of 10 μM DA against MeHg-induced toxicity was not affected by additional organochlorine pollutants exposure. Our results also demonstrate that cells exposed to MeHg in presence of 100 μM acetylcholine (ACh), show an increase in cell mortality at the "threshold value" of 100 nM MeHg. Finally, norepinephrine (10 μM) and serotonin (20 μM) also had an effect on cell protection. Altogether, we propose to further investigate the additional mechanisms that may be playing an important role in MeHg-induced cytotoxicity.
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Affiliation(s)
- Nair Olguín
- Institut d'Investigacions Biomèdiques de Barcelona (IIBB), CSIC - IDIBAPS, CIBER de Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain
| | - Marie-Lena Müller
- Institut d'Investigacions Biomèdiques de Barcelona (IIBB), CSIC - IDIBAPS, CIBER de Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain
| | - Eduard Rodríguez-Farré
- Institut d'Investigacions Biomèdiques de Barcelona (IIBB), CSIC - IDIBAPS, CIBER de Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain
| | - Cristina Suñol
- Institut d'Investigacions Biomèdiques de Barcelona (IIBB), CSIC - IDIBAPS, CIBER de Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain.
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10
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Pan L, Sun J, Le XC, Zhu L. Effect of copper on the translocation and transformation of polychlorinated biphenyls in rice. CHEMOSPHERE 2018; 193:514-520. [PMID: 29169126 DOI: 10.1016/j.chemosphere.2017.11.054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 11/09/2017] [Accepted: 11/12/2017] [Indexed: 06/07/2023]
Abstract
Contamination of organic pollutants in the environment is usually accompanied by heavy metals. However, a little information on the influences of heavy metals on the uptake, translocation and transformation of organic pollutants in plants is available. In this study, ten-day hydroponic exposure was conducted to explore the influence of copper (Cu) on the bioaccumulation and biotransformation of polychlorinated biphenyls (PCBs) in intact young rice (Oryza sativa L.). Low dose of Cu (≤100 μmol/L) increased the accumulation of CB-61 in rice plants, while excess concentrations of Cu (>100 μmol/L) inhibited uptake and translocation of CB-61. Effect of Cu on the uptake of CB-61 was attributed to the Cu-triggered damage to the roots of rice plants. The presence of a moderate dose of Cu (50 μmol/L) enhanced the formation of hydroxylated polychlorinated biphenyls (OH-PCBs) and methoxylated polychlorinated biphenyls (MeO-PCBs), whereas excess concentrations of Cu (250 μmol/L) inhibited the metabolism of CB-61. The effect of Cu on the interconversion between 4'-OH-CB-61 and 4'-MeO-CB-61 was also concentration dependent: the biotransformation was promoted by a moderate concentration of Cu but inhibited by excess concentrations of Cu. The activities of Cytochrome P450 (CYP450) and S-adenosyl-l-methionine (SAM)-dependent methyltransferase in the roots of rice plants exposed to Cu and CB-61 or its derivatives were consistent with the pattern and trend of the metabolites observed in rice roots. These results could provide valuable insights into the interactions and combined effects of PCBs and heavy metals in plants.
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Affiliation(s)
- Lili Pan
- Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, Zhejiang, 310058, China
| | - Jianteng Sun
- Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, Zhejiang, 310058, China
| | - X Chris Le
- Department of Chemistry and Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, T6G 2G3, Canada
| | - Lizhong Zhu
- Department of Environmental Science, Zhejiang University, Hangzhou, Zhejiang, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, Zhejiang, 310058, China.
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11
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Elnar AA, Desor F, Marin F, Soulimani R, Nemos C. Lactational exposure to low levels of the six indicator non-dioxin-like polychlorinated biphenyls induces DNA damage and repression of neuronal activity, in juvenile male mice. Toxicology 2014; 328:57-65. [PMID: 25510870 DOI: 10.1016/j.tox.2014.12.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 12/09/2014] [Accepted: 12/10/2014] [Indexed: 10/24/2022]
Abstract
Previously, we evaluated the effects of lactational exposure to a representative mixture of the six indicator non-dioxin-like polychlorinated biphenyls (∑6 NDL-PCBs) at low levels on the neurobiological changes and developmental/behavioral performances in mice. In this study, we analyzed the global gene expression profile in cerebellar neurons isolated from male mice presenting the most significant induction of anxiety-like behavior in our previous study (10 ng/kg ∑6 NDL-PCBs). Our results revealed changes in the expression of 16658 genes in the neurons of the exposed mice. Among these, 693 upregulated [fold change (FC)>2; p<0.05] and 665 downregulated (FC<2; p<0.05) genes were statistically linked to gene ontology terms (GO). Overexpressed genes belonged to GO terms involved with the cell cycle, DNA replication, cell cycle checkpoint, response to DNA damage stimulus, regulation of RNA biosynthetic processes, and microtubule cytoskeleton organization. Downregulated genes belonged to terms involved with the transmission of nerve impulses, projection neurons, synapse hands, cell junctions, and regulation of RNA biosynthetic processes. Using qPCR, we quantified gene expression related to DNA damage and validated the transcriptomic study, as a significant overexpression of Atm-Atr Bard1, Brca2, Fancd2, Figf, Mycn, p53 and Rad51 was observed between groups (p<0.001). Finally, using immunoblots we determined the expression level of six selected proteins. We found that changes in the protein expression of Atm Brca1, p53, Kcnma1, Npy4r and Scn1a was significant between exposed and control groups (p<0.05), indicating that the expression pattern of these proteins agreed with the expression pattern of their genes by qPCR, further validating our transcriptomic findings. In conclusion, our study showed that early life exposure of male mice to a low level of ∑6 NDL-PCBs induced p53-dependent responses to cellular stress and a decrease in the expression of proteins involved in the generation, conduction, and transmission of electrical signals in neurons.
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Affiliation(s)
- Arpiné Ardzivian Elnar
- Université de Lorraine, Neurotoxicologie Alimentaire et Bioactivité, MRCA/UR AFPA/INRA, BP 4102, 57040 Metz, France.
| | - Frédéric Desor
- Université de Lorraine, Neurotoxicologie Alimentaire et Bioactivité, MRCA/UR AFPA/INRA, BP 4102, 57040 Metz, France
| | - Fabian Marin
- Université de Lorraine, UMR INSERM-954 Nutrition - Génétique et exposition aux risques environnementaux, Faculté de médecine de Nancy, 54511 Vandœuvre-Lès-Nancy, France
| | - Rachid Soulimani
- Université de Lorraine, Neurotoxicologie Alimentaire et Bioactivité, MRCA/UR AFPA/INRA, BP 4102, 57040 Metz, France
| | - Christophe Nemos
- Université de Lorraine, UMR INSERM-954 Nutrition - Génétique et exposition aux risques environnementaux, Faculté de médecine de Nancy, 54511 Vandœuvre-Lès-Nancy, France; CHU de Nancy, Unité de foetoplacentologie, Maternité régionale Universitaire, 54000 Nancy, France
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12
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Biamonte F, Latini L, Giorgi FS, Zingariello M, Marino R, De Luca R, D'Ilio S, Majorani C, Petrucci F, Violante N, Senofonte O, Molinari M, Keller F. Associations among exposure to methylmercury, reduced Reelin expression, and gender in the cerebellum of developing mice. Neurotoxicology 2014; 45:67-80. [PMID: 25305366 DOI: 10.1016/j.neuro.2014.09.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 09/24/2014] [Accepted: 09/28/2014] [Indexed: 12/30/2022]
Abstract
Genetic risk factors acting during pregnancy or early after birth have been proposed to account for the exponential increase of autism diagnoses in the past 20 years. In particular, a potential link with exposure to environmental mercury has been suggested. Male sex constitutes a second risk factor for autism. A third potential genetic risk factor is decreased Reelin expression. Male heterozygous reeler (rl(+/-)) mice show an autism-like phenotype, including Purkinje cells (PCs) loss and behavioral rigidity. We evaluated the complex interactions between 3 risk factors, i.e. genetic status, sex, and exposure to methylmercury (MeHg), in rl(+/-) mice. Mice were exposed to MeHg during the prenatal and early postnatal period, either at a subtoxic dose (2 ppm in Dams' drinking water), or at a toxic dose (6 ppm Dams' drinking water), based on observations in other rodent species and mice strains. We show that: (a) 2 ppm MeHg does not cause PCs loss in the different animal groups, and does not enhance PCs loss in rl(+/-) males; consistent with a lack of overt neurotoxicity, 2 ppm MeHg per se does not cause behavioral alterations (separation-induced ultrasonic calls in newborns, or sociability and social preference in adults); (b) in stark contrast, 6 ppm MeHg causes a dramatic reduction of PCs number in all groups, irrespective of genotype and sex. Cytochrome C release from mitochondria of PCs is enhanced in 6 ppm MeHg-exposed groups, with a concomitant increase of μ-calpain active subunit. At the behavioral level, 6 ppm MeHg exposure strongly increases ultrasonic vocalizations in all animal groups. Notably, 6 ppm MeHg significantly decreases sociability in rl(+/-) male mice, while the 2 ppm group does not show such as decrease. At a subtoxic dose, MeHg does not enhance the autism-like phenotype of male rl(+/-) mice. At the higher MeHg dose, the scenario is more complex, with some "autism-like" features (loss of sociability, preference for sameness) being evidently affected only in rl(+/-) males, while other neuropathological and behavioral parameters being altered in all groups, independently from genotype and sex. Mitochondrial abnormalities appear to play a crucial role in the observed effects.
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Affiliation(s)
- Filippo Biamonte
- Laboratory of Developmental Neuroscience and Neural Plasticity, University Campus Biomedico, Via A. del Portillo 21, 00198 Rome, Italy
| | - Laura Latini
- Santa Lucia Foundation, I.R.C.C.S., Via del Fosso di Fiorano 64, 00143 Rome, Italy
| | - Filippo Sean Giorgi
- Section of Neurology, Department of Clinical and Experimental Medicine, University of Pisa, Via Roma 67, 56126 Pisa, Italy
| | | | - Ramona Marino
- Laboratory of Developmental Neuroscience and Neural Plasticity, University Campus Biomedico, Via A. del Portillo 21, 00198 Rome, Italy
| | - Roberto De Luca
- Laboratory of Developmental Neuroscience and Neural Plasticity, University Campus Biomedico, Via A. del Portillo 21, 00198 Rome, Italy
| | - Sonia D'Ilio
- Istituto Superiore di Sanità, Centro Nazionale Sostanze Chimiche, Viale Regina Elena 299, Rome, Italy
| | - Costanza Majorani
- Istituto Superiore di Sanità, Dipartimento di Ambiente e Prevenzione Primaria, Viale Regina Elena 299, Rome, Italy
| | - Francesco Petrucci
- Istituto Superiore di Sanità, Dipartimento di Ambiente e Prevenzione Primaria, Viale Regina Elena 299, Rome, Italy
| | - Nicola Violante
- Istituto Superiore di Sanità, Dipartimento di Ambiente e Prevenzione Primaria, Viale Regina Elena 299, Rome, Italy
| | - Oreste Senofonte
- Istituto Superiore di Sanità, Dipartimento di Ambiente e Prevenzione Primaria, Viale Regina Elena 299, Rome, Italy
| | - Marco Molinari
- Santa Lucia Foundation, I.R.C.C.S., Via del Fosso di Fiorano 64, 00143 Rome, Italy.
| | - Flavio Keller
- Laboratory of Developmental Neuroscience and Neural Plasticity, University Campus Biomedico, Via A. del Portillo 21, 00198 Rome, Italy.
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13
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Pellacani C, Tagliaferri S, Caglieri A, Goldoni M, Giordano G, Mutti A, Costa LG. Synergistic interactions between PBDEs and PCBs in human neuroblastoma cells. ENVIRONMENTAL TOXICOLOGY 2014; 29:418-27. [PMID: 22434561 DOI: 10.1002/tox.21768] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 01/30/2012] [Accepted: 02/01/2012] [Indexed: 05/03/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) are ubiquitous environmental pollutants. Exposure to these chemicals has been associated with developmental neurotoxicity, endocrine dysfunction, and reproductive disorders. Humans and wildlife are generally exposed to a mixture of these environmental pollutants, highlighting the need to evaluate the potential effects of combined exposures. In this study, we investigated the cytotoxic effects of the combined exposure to two PBDEs and two PCBs in a human neuronal cell line. 2,2',4,4'-Tetrabromodiphenyl ether, 2,2',4,4',5-pentabromodiphenyl ether, PCB-126 (3,3',4,4',5-pentachlorobiphenyl; a dioxin-like PCB), and PCB-153 (2,2',4,4',5,5'-hexachlorobiphenyl; a non-dioxin-like PCB) were chosen, because their concentrations are among the highest in human tissues and the environment. The results suggest that the nature of interactions is related to the PCB structure. Mixtures of PCB-153 and both PBDEs had a prevalently synergistic effect. In contrast, mixtures of each PBDE congener with PCB-126 showed additive effects at threshold concentrations, and synergistic effects at higher concentrations. These results emphasize the concept that the toxicity of xenobiotics may be affected by possible interactions, which may be of significance given the common coexposures to multiple contaminants.
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Affiliation(s)
- C Pellacani
- Department of Human Anatomy, Pharmacology, and Forensic Sciences, University of Parma Medical School, Via Volturno 39, 43100 Parma, Italy
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14
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Iwai-Shimada M, Nakamura T, Sugawara N, Kurokawa N, Nakai K, Satoh H. Increase in accumulation of polychlorinated biphenyls in offspring mouse brain via maternal coexposure to methylmercury and polychlorinated biphenyls. J Toxicol Sci 2014; 38:689-96. [PMID: 24025785 DOI: 10.2131/jts.38.689] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Methylmercury (MeHg) and polychlorinated biphenyls (PCBs) are environmentally persistent neurodevelopmental toxicants. In Japan, the most common source of human exposure is the consumption of contaminated fish and seafood. We investigated the accumulation of MeHg and PCBs in the brains of dams and offspring mice maternally exposed to MeHg and/or PCBs. Pregnant mice (C57BL/6Cr) were assigned to one of four exposure groups: control, MeHg alone (MeHg in diet at 5 mg/kg as Hg), PCB alone (Aroclor1254 by gavage at the dose of 18 mg/kg body weight/3 days) and MeHg+PCB. Levels of MeHg and PCBs were measured in the whole brains of dams and offspring mice on postnatal day 21 (PND21) and at 9 weeks of age. Total mercury, MeHg and PCB congener concentrations were determined by CVAAS, GC-ECD and HRGC/HRMS, respectively. For the mercury concentrations, there were no significant differences between MeHg alone and MeHg+PCB except for pups at 9 weeks. The maternal PCB levels were not significantly different between MeHg+PCB and PCB alone. In pup brain on PND21, MeHg+PCB resulted in a significantly higher PCB level than PCB alone. Although the levels of lightly chlorinated (= 4CBs) homologues were lower for MeHg+PCB than for PCB alone, those of highly chlorinated (>= 5CBs) homologues were significantly higher on PND21 for MeHg+PCB. The PCB composition in dams and pups shifted to higher chlorinated homologues compared with the composition of administered Aroclor1254. For these reasons, further detailed studies are necessary to clarify the interactional effects of PCB metabolism after coexposure to MeHg and PCBs.
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Affiliation(s)
- Miyuki Iwai-Shimada
- Environmental Health Sciences, Tohoku University Graduate School of Medicine
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15
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Xie HQ, Xu HM, Fu HL, Hu Q, Tian WJ, Pei XH, Zhao B. AhR-mediated effects of dioxin on neuronal acetylcholinesterase expression in vitro. ENVIRONMENTAL HEALTH PERSPECTIVES 2013; 121:613-8. [PMID: 23426015 PMCID: PMC3673198 DOI: 10.1289/ehp.1206066] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 02/19/2013] [Indexed: 05/18/2023]
Abstract
BACKGROUND Deficits in cognitive functioning have been reported in humans exposed to dioxins and dioxin-like compounds. Evidence suggests that dioxins induce cholinergic dysfunction mediated by hypothyroidism. However, little is known about direct effects of dioxins on the cholinergic system. OBJECTIVES We investigated the action of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on acetylcholinesterase (AChE), a key enzyme in cholinergic neurotransmission. METHODS We used SK-N-SH human-derived neuronal cells to evaluate the effect of dioxin exposure on AChE. RESULTS We consistently found a significant decrease in enzymatic activity of AChE in cultured neurons treated with TCDD. We also found that, unlike organophosphate pesticides that directly act on the catalytic center of AChE, the suppressive effect of dioxin was through transcriptional regulation. The addition of CH223191, an inhibitor of the aryl hydrocarbon receptor (AhR)-dependent pathway, counteracted the TCDD-induced suppression of AChE, suggesting involvement of the AhR-dependent pathway. The existence of putative dioxin-responsive element (DRE) consensus sequences in the human ACHE promoter region further supported this hypothesis. Consistent with the absence of DRE elements in mouse or rat ACHE promoter regions, suppression of AChE by TCDD did not occur in rat neuronal cells, indicating a potential species-specific effect. CONCLUSIONS In SK-N-SH cells, dioxin suppressed the activity of neuronal AChE via AhR-mediated transcriptional down-regulation. This is the first study to report direct interference by dioxin with the cholinergic neurotransmission system.
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Affiliation(s)
- Heidi Qunhui Xie
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China
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16
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Hassauer M, Kaiser E, Schneider K, Schuhmacher‐Wolz U. Collate the literature on toxicity data on mercury in experimental animals and humans (Part I – Data on organic mercury). ACTA ACUST UNITED AC 2012. [DOI: 10.2903/sp.efsa.2012.en-297] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Martin Hassauer
- Forschungs‐ und Beratungsinstitut Gefahrstoffe GmbH (FoBiG) Freiburg Germany
| | - Eva Kaiser
- Forschungs‐ und Beratungsinstitut Gefahrstoffe GmbH (FoBiG) Freiburg Germany
| | - Klaus Schneider
- Forschungs‐ und Beratungsinstitut Gefahrstoffe GmbH (FoBiG) Freiburg Germany
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17
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Forns J, Torrent M, Garcia-Esteban R, Grellier J, Gascon M, Julvez J, Guxens M, Grimalt JO, Sunyer J. Prenatal exposure to polychlorinated biphenyls and child neuropsychological development in 4-year-olds: an analysis per congener and specific cognitive domain. THE SCIENCE OF THE TOTAL ENVIRONMENT 2012; 432:338-43. [PMID: 22750179 DOI: 10.1016/j.scitotenv.2012.06.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 06/04/2012] [Accepted: 06/05/2012] [Indexed: 05/22/2023]
Abstract
Polychlorinated biphenyls (PCB) are synthetic organochlorine compounds with potential neurotoxic effects. Although negative effects on neuropsychological development have been observed in previous studies on PCB exposure, there are inconsistencies in these effects at current exposure levels of these compounds which are much lower than for previous generations. This study aimed to disentangle the effects of prenatal and postnatal PCB exposure on neuropsychological development at 4 years of age. This study is based on a population-based birth cohort design established in Menorca (Spain) as part of the INMA [Environment and Childhood] Project. We assessed general neuropsychological development using the McCarthy Scales of Children's Abilities (MCSA). A total of 422 4-year old children were assessed with the MCSA. Levels of PCBs were measured in cord blood (n=405) and in blood samples taken at 4 years (n=285). We found no statistically significant effects of the sum of prenatal PCBs on MCSA scores. Nevertheless, individual congener analyses yielded significant detrimental effects of prenatal PCB153 on the majority of MCSA scores, while no effects were reported for other congeners. The levels of PCBs at 4 years of age were not associated with neuropsychological development. Thus, prenatal exposure to low-level concentrations of PCBs, particularly PCB153, was associated with an overall deleterious effect on neuropsychological development at 4 years of age, including negative effects on executive function, verbal functions and visuospatial abilities, but not on motor development.
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Affiliation(s)
- Joan Forns
- Centre for Research in Environmental Epidemiology (CREAL), Doctor Aiguader 88, 08003 Barcelona, Spain.
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18
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Hendriks HS, van Kleef RGDM, Westerink RHS. Modulation of human α4β2 nicotinic acetylcholine receptors by brominated and halogen-free flame retardants as a measure for in vitro neurotoxicity. Toxicol Lett 2012; 213:266-74. [PMID: 22750351 DOI: 10.1016/j.toxlet.2012.06.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 06/18/2012] [Accepted: 06/20/2012] [Indexed: 11/16/2022]
Abstract
Brominated flame retardants (BFRs) are abundant persistent organic pollutants with well-studied toxicity. The toxicological and ecological concern associated with BFRs argues for replacement by safer alternatives. However, the (neuro)toxic potential of alternative halogen-free flame retardants (HFFRs) is unknown. Previous research identified the nervous system as a sensitive target organ for BFRs, with modulation of excitatory nicotinic acetylcholine (nACh) receptors as one of the modes of action. Since it is essential to assess the (neuro)toxic potential of HFFRs before large scale use, we measured the effects of three BFRs and 13 HFFRs on the function of human α(4)β(2) nACh receptors, expressed in Xenopus oocytes, using the two-electrode voltage-clamp technique. The results demonstrate that some BFRs (TBBPA and to a lesser extent BDE-209) and HFFRs (TPP, Alpi, APP, MMT and to a lesser extent ATH, ATO, MHO, MPP, RDP and ZHS) act as nACh receptor antagonists. Contrary, BPS, BDP, DOPO and ZS were unable to modulate nACh receptors. Despite the lack of toxicological data on HFFRs and the need for additional studies to perform a full (neuro)toxic risk assessment, the current data on antagonistic effects on nACh receptors could be an important step in prioritizing viable HFFRs for substitution of BFRs.
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Affiliation(s)
- Hester S Hendriks
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences, Faculty of Veterinary Medicine, Utrecht University, P.O. Box 80.177, NL-3508 TD Utrecht, The Netherlands
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Application of Neurochemical Markers for Assessing Health Effects after Developmental Methylmercury and PCB Coexposure. J Toxicol 2012; 2012:216032. [PMID: 22505887 PMCID: PMC3306999 DOI: 10.1155/2012/216032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Accepted: 10/21/2011] [Indexed: 11/17/2022] Open
Abstract
Cholinergic muscarinic receptors (MRs) and monoamine oxidase activity (MAO-B), expressed both in brain and blood cells, were investigated in animals and exposed subjects to assess (i) MeHg (0.5–1 mg/kg/day GD7-PD7) and/or PCB153 (20 mg/kg/day GD10–GD16) effects on cerebellar MAO-B and MRs, and lymphocyte MRs, in dams and offspring 21 days postpartum; (ii) MAO-B in platelets and MRs in lymphocytes of a Faroese 7-year-old children cohort, prenatally exposed to MeHg/PCBs. Animal Data. MAO-B was altered in male cerebellum by MeHg, PCB153, and their combination (35%, 45%, and 25% decrease, resp.). Cerebellar MRs were enhanced by MeHg alone in dams (87%) and male pups (27%). PCB153 alone and in mixture did not modify cerebellar MRs. Similarly to brain, lymphocyte MRs were enhanced in both dams and offspring by MeHg alone. All changes were caused by 1 MeHg mg/kg/day, the lower dose was ineffective. Human Data. Both biomarkers showed homogeneous distributions within the cohort (MRs, range 0.1–36.78 fmol/million cells; MAO-B, 0.95–14.95 nmol/mg protein/h). No correlation was found between the two biomarkers and neurotoxicant concentrations in blood (pre- and postnatally).
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20
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Berg K, Puntervoll P, Klungsøyr J, Goksøyr A. Brain proteome alterations of Atlantic cod (Gadus morhua) exposed to PCB 153. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2011; 105:206-217. [PMID: 21762652 DOI: 10.1016/j.aquatox.2011.06.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2011] [Revised: 06/02/2011] [Accepted: 06/07/2011] [Indexed: 05/31/2023]
Abstract
Polychlorinated biphenyls (PCBs) are still widespread environmental pollutants that bioaccumulate and biomagnify in the aquatic food chains despite the ban on their production. They constitute a class of 209 possible congeners with different chlorination pattern of the biphenyl ring structure resulting in many different toxicities and mechanisms of toxicity. The neurotoxicity of PCBs is relatively poorly understood, and biomarkers for their neurotoxic effects are lacking. We have carried out a proteomic analysis of brain tissue from Atlantic cod (Gadus morhua) exposed to 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153, ortho-substituted and non-coplanar), a previously demonstrated neurotoxic congener and the most prevalent congener in biological samples. The fish received 0, 0.5, 2 and 8 mg/kg PCB 153 by intraperitoneal injection, half of the dose on the first day and the second half after one week, and were exposed for two weeks in total. Using a 2-DE approach we found 56 protein spots to be 20% or more (≤ 0.8-fold or ≥ 1.2-fold) significantly different between at least one of the three PCB 153-exposed groups and the control group, and 27 of these were identified by MALDI-TOF MS and MS/MS. Approximately 80% of the differentially regulated proteins may be associated with a non stressor-specific response and/or have previously been classified as notoriously differentially regulated in 2-DE/MS based proteomics studies, such as alterations/responses in energy metabolism, cytoskeleton, protein synthesis, protein degradation (ubiquitin-proteasome system), cellular growth, cycle and death (14-3-3 protein), and (surprisingly) axon guidance (dihydropyrimidinase-like 2 (=collapsin response mediator protein 2, CRMP-2)). The six remaining affected proteins include the strongest up-regulated protein, pyridoxal kinase (essential for synthesis of neurotransmitters such as dopamine, serotonin and GABA), nicotinamide phosphoribosyl-transferase (involved in protection against axonal degeneration) and protein phosphatase 1 (controls brain recovery by synaptic plasticity). The last three of these six proteins (deltex, Rab14 and sorting nexin 6) may preliminarily identify involvement of the Notch signaling pathway and endosomal function in PCB 153-induced neurotoxicity. Our findings constitute novel clues for further research on PCB 153 mode of action in brain, and a proper selection of proteins may, following validation, be applicable in a panel of biomarkers for aquatic environmental monitoring.
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Affiliation(s)
- Karin Berg
- Department of Molecular Biology, University of Bergen, PB 7803, N-5020 Bergen, Norway.
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21
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Ahmed R. Perinatal TCDD exposure alters developmental neuroendocrine system. Food Chem Toxicol 2011; 49:1276-84. [DOI: 10.1016/j.fct.2011.03.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Revised: 02/26/2011] [Accepted: 03/09/2011] [Indexed: 10/18/2022]
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Mazzariol S, Di Guardo G, Petrella A, Marsili L, Fossi CM, Leonzio C, Zizzo N, Vizzini S, Gaspari S, Pavan G, Podestà M, Garibaldi F, Ferrante M, Copat C, Traversa D, Marcer F, Airoldi S, Frantzis A, Quirós YDB, Cozzi B, Fernández A. Sometimes sperm whales (Physeter macrocephalus) cannot find their way back to the high seas: a multidisciplinary study on a mass stranding. PLoS One 2011; 6:e19417. [PMID: 21673789 PMCID: PMC3097202 DOI: 10.1371/journal.pone.0019417] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 03/29/2011] [Indexed: 11/18/2022] Open
Abstract
Background Mass strandings of sperm whales (Physeter macrocephalus) remain peculiar and rather unexplained events, which rarely occur in the Mediterranean Sea. Solar cycles and related changes in the geomagnetic field, variations in water temperature and weather conditions, coast geographical features and human activities have been proposed as possible causes. In December 2009, a pod of seven male sperm whales stranded along the Adriatic coast of Southern Italy. This is the sixth instance from 1555 in this basin. Methodology/Principal Findings Complete necropsies were performed on three whales whose bodies were in good condition, carrying out on sampled tissues histopathology, virology, bacteriology, parasitology, and screening of veins looking for gas emboli. Furthermore, samples for age determination, genetic studies, gastric content evaluation, stable isotopes and toxicology were taken from all the seven specimens. The animals were part of the same group and determined by genetic and photo-identification to be part of the Mediterranean population. Causes of death did not include biological agents, or the “gas and fat embolic syndrome”, associated with direct sonar exposure. Environmental pollutant tissue concentrations were relatively high, in particular organochlorinated xenobiotics. Gastric content and morphologic tissue examinations showed a prolonged starvation, which likely caused, at its turn, the mobilization of lipophilic contaminants from the adipose tissue. Chemical compounds subsequently entered the blood circulation and may have impaired immune and nervous functions. Conclusions/Significance A multi-factorial cause underlying this sperm whales' mass stranding is proposed herein based upon the results of postmortem investigations as well as of the detailed analyses of the geographical and historical background. The seven sperm whales took the same “wrong way” into the Adriatic Sea, a potentially dangerous trap for Mediterranean sperm whales. Seismic surveys should be also regarded as potential co-factors, even if no evidence of direct impact has been detected.
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Affiliation(s)
- Sandro Mazzariol
- Department of Public Health, Comparative Pathology and Veterinary Hygiene, University of Padua, Legnaro, Italy.
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Developmental exposure to methylmercury and 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB153) affects cerebral dopamine D1-like and D2-like receptors of weanling and pubertal rats. Arch Toxicol 2011; 85:1281-94. [DOI: 10.1007/s00204-011-0660-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Accepted: 01/25/2011] [Indexed: 11/25/2022]
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Long-term effects of developmental exposure to low doses of PCB 126 and methylmercury. Toxicol Lett 2010; 197:38-45. [DOI: 10.1016/j.toxlet.2010.04.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 04/27/2010] [Indexed: 11/23/2022]
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25
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Early developmental effects of separate or combined perinatal exposure to methylmercury (MeHg) and 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153) in the rat. Int J Occup Med Environ Health 2009; 22:89-105. [PMID: 19617190 DOI: 10.2478/v10001-009-0015-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVES Methylmercury (MeHg) and polychlorinated biphenyls (PCBs) are ubiquitous and persistent environmental pollutants and food contaminants. Both are neurotoxic, especially for the developing nervous system. MATERIAL AND METHODS Female rats were exposed from day 7 of pregnancy up to day 21 after the delivery to MeHg in drinking water, PCB 153 per os or MeHg+PCB 153. Assessment of the exposure effects in mothers included food and water intake, body weight and reproduction success. Assessment of the progeny comprised determination of body weight, time of pinna detachment, eye opening, incisor eruption, and the negative geotaxis, grip strength and righting reflex. RESULTS The following effects of the exposures were observed: A) MeHg: 0.5 mg/kg/day - no effect on maternal health status and reproduction. In the progeny: faster incisor eruption and hastened negative geotaxis development. MeHg 2.0 mg/kg/day: In mothers: signs of MeHg toxicity (reduced food intake and body weight, ataxia) during lactation. In the progeny: reduced rate of body weight increase, accelerated incisor eruption but delayed development of the righting reflex. B) PCB 153 exposure: 1.0 mg/kg/day: no effect on maternal health status, reproduction success or morphological and physical development of the progeny; 5.0 mg/kg/day: no effect on maternal health status and reproduction. In the progeny: accelerated growth in females, faster pinna detachment and incisor eruption but delayed development of the grip strength. C) MeHg+PCB153 exposure: none overt effect was noted in mothers or in their progeny. CONCLUSION The results confirm the ability of a low level perinatal exposure to MeHg or PCB 153 to affect the early development in the rat. They have not provided, however, an evidence of a synergistic interaction of these contaminants. To the contrary, the results suggest that, at least under the conditions prevailing in the present study, MeHg and PCB 153 interact antagonistically.
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Shimada M, Kameo S, Sugawara N, Yaginuma-Sakurai K, Kurokawa N, Mizukami-Murata S, Nakai K, Iwahashi H, Satoh H. Gene expression profiles in the brain of the neonate mouse perinatally exposed to methylmercury and/or polychlorinated biphenyls. Arch Toxicol 2009; 84:271-86. [PMID: 20020106 DOI: 10.1007/s00204-009-0493-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Accepted: 11/30/2009] [Indexed: 11/29/2022]
Abstract
Methylmercury (MeHg) and polychlorinated biphenyls (PCBs) are environmentally persistent neurodevelopmental toxicants. The primary source of human exposure is the consumption of contaminated fish, seafood and marine mammals. However, little is known about the molecular mechanisms of MeHg and PCB toxicities and interactions between these contaminants. We investigated the functional profiles of differently expressed genes in the brains of offspring mice perinatally exposed to MeHg and/or PCBs to elucidate how these contaminants interact with each other. Pregnant mice (C57BL/6) were divided into four groups by exposure: (1) vehicle control, (2) MeHg alone, (3) PCBs alone, (4) MeHg + PCBs. Gene expression analysis of the brains of offspring mice was carried out with 4 x 44 K whole mouse genome's microarrays (Agilent) on postnatal day 1. The gene expression pattern of the MeHg exposure-group differed from that of the PCB-exposure group. The MeHg + PCB group expressed a larger number of genes, most of which were not expressed in the MeHg group or PCB group. It was revealed that gene expression was greatly increased, and the most altered genes were found with co-exposure. The genes were related to the functional categories of development, inflammation, calcium ion homeostasis, signal transduction, the ubiquitin-proteasome pathway and detoxication. The ubiquitin-proteasome system and detoxication categories might function for protection against the toxicity induced by co-exposure to MeHg and PCBs. These results suggest that co-exposure does not simply exacerbate the toxicity of MeHg alone or PCB alone, but stimulates a protection system.
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Affiliation(s)
- Miyuki Shimada
- Department of Environmental Health Sciences, Tohoku University Graduate School of Medicine, 2-1 Seiryomachi, Aoba-ku, Sendai 980-8575, Japan.
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27
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Rice DC, Thompson WD, Reeve EA, Onos KD, Assadollahzadeh M, Markowski VP. Behavioral changes in aging but not young mice after neonatal exposure to the polybrominated flame retardant decaBDE. ENVIRONMENTAL HEALTH PERSPECTIVES 2009; 117:1903-11. [PMID: 20049210 PMCID: PMC2799465 DOI: 10.1289/ehp.11814] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2008] [Accepted: 06/17/2009] [Indexed: 05/03/2023]
Abstract
BACKGROUND After several decades of commercial use, the flame-retardant chemicals polybrominated diphenyl ethers (PBDEs) and their metabolites are pervasive environmental contaminants and are detected in the human body. Decabrominated diphenyl ether (decaBDE) is currently the only PBDE in production in the United States. OBJECTIVES Little is known about the health effects of decaBDE. In the present study we examined the effects of neonatal decaBDE exposure on behavior in mice at two ages. METHODS Neonatal male and female C57BL6/J mice were exposed to a daily oral dose of 0, 6, or 20 mg/kg decaBDE from postnatal days 2 through 15. Two age groups were examined: a cohort that began training during young adulthood and an aging cohort of littermates that began training at 16 months of age. Both cohorts were tested on a series of operant procedures that included a fixed-ratio 1 schedule of reinforcement, a fixed-interval (FI) 2-min schedule, and a light-dark visual discrimination. RESULTS We observed minimal effects on the light-dark discrimination in the young cohort, with no effects on the other tasks. The performance of the aging cohort was significantly affected by decaBDE. On the FI schedule, decaBDE exposure increased the overall response rate. On the light-dark discrimination, older treated mice learned the task more slowly, made fewer errors on the first-response choice of a trial but more perseverative errors after an initial error, and had lower latencies to respond compared with controls. Effects were observed in both dose groups and sexes on various measures. CONCLUSIONS These findings suggest that neonatal decaBDE exposure produces effects on behavioral tasks in older but not younger animals. The behavioral mechanisms responsible for the pattern of observed effects may include increased impulsivity, although further research is required.
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Affiliation(s)
- Deborah C. Rice
- Environmental and Occupational Health Program, Maine Center for Disease Control and Prevention, Augusta, Maine, USA
- Maine Center for Toxicology and Environmental Health
| | - W. Douglas Thompson
- Maine Center for Toxicology and Environmental Health
- Department of Applied Medical Sciences and
| | | | - Kristen D. Onos
- Department of Psychology, University of Southern Maine, Portland, Maine, USA
| | | | - Vincent P. Markowski
- Maine Center for Toxicology and Environmental Health
- Department of Psychology, University of Southern Maine, Portland, Maine, USA
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Coccini T, Manzo L, Debes F, Steuerwald U, Weihe P, Grandjean P. No changes in lymphocyte muscarinic receptors and platelet monoamine oxidase-B examined as surrogate central nervous system biomarkers in a Faroese children cohort prenatally exposed to methylmercury and polychlorinated biphenyls. Biomarkers 2009; 14:67-76. [PMID: 19330584 DOI: 10.1080/13547500902783739] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Experimental evidence suggests that monoamine oxidase B (MAO-B) and muscarinic cholinergic receptors (mAChRs) are involved in the pathogenesis of neurotoxicity caused by methylmercury and polychlorinated biphenyls (PCBs). Blood samples from 7-year-old exposed children were analyzed for platelet MAO-B and lymphocyte mAChRs as potential markers of exposure to these neurotoxicants. The blood neurotoxicity biomarkers were compared with prenatal and current exposures and with neuropsychological test results. Both biomarkers showed homogeneous distributions within this cohort (mAChR, range 0.04-36.78 fmol/million cells; MAO-B, 0.95-14.95 nmol mg(-1) protein h(-1)). No correlation was found between the two biomarkers and either blood neurotoxicant concentrations or clinical findings. MAO-B and mAChR sensitivity may not be sufficiently high to assess early, subclinical responses to low/moderate methylmercury and/or PCB exposure, whereas these markers are significantly altered in sustained exposure scenarios, as shown by clinical studies in drug addicts or patients treated with psychopharmacological agents.
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Affiliation(s)
- Teresa Coccini
- IRCCS Salvatore Maugeri Foundation, Toxicology Division, Institute of Pavia, Italy.
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29
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Contribution of methylmercury, polychlorinated biphenyls and organochlorine pesticides to the toxicity of a contaminant mixture based on Canadian Arctic population blood profiles. Toxicol Lett 2009; 184:176-85. [DOI: 10.1016/j.toxlet.2008.11.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Revised: 11/07/2008] [Accepted: 11/10/2008] [Indexed: 11/21/2022]
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Neurobehavioural functions in adult progeny of rat mothers exposed to methylmercury or 2,2', 4,4', 5,5'-hexachlorobiphenyl (PCB 153) alone or their combination during gestation and lactation. Int J Occup Med Environ Health 2009; 22:277-91. [DOI: 10.2478/v10001-009-0020-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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31
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de Oliveira RB, Gomes Leal W, Picanço-Diniz DLW, Torres Neto JB, Lins N, Malm O, Picanço-Diniz CW. Three dimensional morphometric analyses of axon terminals early changes induced by methylmercury intoxication in the adult cat striate cortex. Brain Res 2008; 1244:155-63. [PMID: 18835550 DOI: 10.1016/j.brainres.2008.09.036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Revised: 09/11/2008] [Accepted: 09/12/2008] [Indexed: 10/21/2022]
Abstract
The aim of the present report is to investigate in detail morphometric changes of axon terminals of area 17 of adult cat induced by methylmercury intoxication. Six adult male cats (Felix catus), with 12 h day-light cycle and ad libitum water and food regimen, received a single dose of MeHgCl (6.4 mg/kg) dissolved in milk, whereas control subjects (n=6) received only milk. After 30 days, biocytin iontophoretic injections were done into the area 17, (Horsley-Clark coordinates between AP 3.0-6.0) on the crown of the lateral gyrus, near the border with area 18. MeHg and inorganic Hg (Hgi) concentrations were measured in the brain parenchyma of intoxicated cats and corresponded on average to 1.39+/-0.3 and 6.79+/-0.6 ppm (mean+/-s.e.m.) respectively. Twenty four hours after iontophoresis, aldehyde fixed brain sections (200 microm thick), were processed to reveal biocytin labeled terminals. Axonal microscopic 3D reconstructions using Neurolucida software (Microbright Systems Inc.) allowed estimations of boutons, branching points and segment densities for each terminal. Cluster analysis of morphometric axonal features from control and intoxicated group revealed, two distinct axon families (Type I and II) as described elsewhere. Total density values of boutons, branching points and segment densities of intoxicated group, decreased 81, 59 and 91% respectively, as compared to the control group (ANOVA two-way, Bonferroni a priori test p<0.05). Altered axonal morphology associated with MeHg, appeared early in the disease (30 days after contamination), revealing new aspects of the neuronal pathology of the methylmercury intoxication in the visual cortex.
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Affiliation(s)
- Ricardo Bezerra de Oliveira
- Laboratório de Bioprospecção e Biologia Experimental, Campus de Santarém, Universidade Federal do Pará, Brazil.
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Pradidarcheep W, Labruyère WT, Dabhoiwala NF, Lamers WH. Lack of specificity of commercially available antisera: better specifications needed. J Histochem Cytochem 2008; 56:1099-111. [PMID: 18796405 DOI: 10.1369/jhc.2008.952101] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The ideal antiserum for immunohistochemical (IHC) applications contains monospecific high-affinity antibodies with little nonspecific adherence to sections. Many commercially available antibodies are "affinity" purified, but it is unknown if they meet "hard" specificity criteria, such as absence of staining in tissues genetically deficient for the antigen or a staining pattern that is identical to that of an antibody raised against a different epitope on the same protein. Reviewers, therefore, often require additional characterization. Although the affinity-purified antibodies used in our study on the distribution of muscarinic receptors produced selective staining patterns on sections, few passed the preabsorption test, and none produced bands of the anticipated size on Western blots. More importantly, none showed a difference in staining pattern on sections or Western blots between wild-type and knockout mice. Because these antibodies were used in most studies published thus far, our findings cast doubts on the validity of the extant body of morphological knowledge of the whole family of muscarinic receptors. We formulate requirements that antibody-specification data sheets should meet and propose that journals for which IHC is a core technique facilitate consumer rating of antibodies. "Certified" antibodies could avoid fruitless and costly validation assays and should become the standard of commercial suppliers.
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Affiliation(s)
- Wisuit Pradidarcheep
- AMC Liver Center, Academic Medical Center, University of Amsterdam, Meibergdreef 69-71, 1105 BK Amsterdam, The Netherlands
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Developmental exposure to polychlorinated biphenyls or methylmercury, but not to its combination, impairs the glutamate-nitric oxide-cyclic GMP pathway and learning in 3-month-old rats. Neuroscience 2008; 154:1408-16. [PMID: 18556134 DOI: 10.1016/j.neuroscience.2008.05.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Revised: 05/12/2008] [Accepted: 05/13/2008] [Indexed: 11/21/2022]
Abstract
Prenatal exposure to polychlorinated biphenyls (PCBs) or methylmercury (MeHg) contaminated food may affect brain development, leading to long-term alterations in cognitive function. Both types of contaminants, PCBs and MeHg, are often found together contaminating food, especially fish in some polluted areas. Exposure to combinations of neurotoxicants may exert different effects on the developing nervous system than exposure to individual contaminants. Developmental exposure (during pregnancy and lactation) to PCB126 or PCB153 impairs learning ability when the rats are 3 months old. Impairment of learning seems to be a consequence of impairment of the function of the glutamate-nitric oxide (NO)-cGMP pathway in brain in vivo. The aims of the present work were 1) to assess whether perinatal exposure to MeHg also affects the function of the glutamate-NO-cGMP pathway in brain in vivo analyzed by in vivo brain microdialysis and/or the ability to learn the Y maze task when the rats are 3 months old, and 2) to assess whether perinatal exposure to combinations of MeHg with PCB153 or PCB126 potentiates, decreases or does not modify the effects of the individual neurotoxicants. Perinatal exposure to PCB126, PCB153 or MeHg impaired the function of the glutamate-NO-cGMP pathway in cerebellum and learning ability. However, co-exposure to PCB126+MeHg or PCB153+MeHg inhibits the impairment of the pathway or learning ability. These results support that the function of this pathway modulates learning of the Y maze task. Moreover, they show that co-exposure to these PCBs and MeHg does not exacerbate, but reduces the effects on the ability to learn this task.
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Castoldi AF, Onishchenko N, Johansson C, Coccini T, Roda E, Vahter M, Ceccatelli S, Manzo L. Neurodevelopmental toxicity of methylmercury: Laboratory animal data and their contribution to human risk assessment. Regul Toxicol Pharmacol 2008; 51:215-29. [PMID: 18482784 DOI: 10.1016/j.yrtph.2008.03.005] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Revised: 01/28/2008] [Accepted: 03/18/2008] [Indexed: 11/28/2022]
Abstract
Methylmercury (MeHg) is one of the most significant public health hazards. The clinical findings in the victims of the Japanese and Iraqi outbreaks have disclosed the pronounced susceptibility of the developing brain to MeHg poisoning. This notion has triggered worldwide scientific attention toward the long-term consequences of prenatal exposure on child development in communities with chronic low level dietary exposure. MeHg neurodevelopmental effects have been extensively investigated in laboratory animals under well-controlled exposure conditions. This article provides an updated overview of the main neuromorphological and neurobehavioral changes reported in non-human primates and rodents following developmental exposure to MeHg. Different aspects of MeHg's effects on the immature organism are reported, with particular reference to the delayed onset of symptoms and the persistency of central nervous system (CNS) injury/dysfunction. Particular attention is paid to the comparative toxicity assessment across species, and to the degree of concordance/discordance between human and animal data. The contribution of animal studies to define the role of potential effect modifiers and variables on MeHg dose-response relationships is also addressed. The ultimate goal is to discuss the relevance of laboratory animal results, as a complementary tool to human data, with regard to the human risk assessment process.
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Affiliation(s)
- Anna F Castoldi
- Toxicology Division, University of Pavia, Via Palestro 26, 27100 Pavia, Italy.
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35
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Piedrafita B, Erceg S, Cauli O, Monfort P, Felipo V. Developmental exposure to polychlorinated biphenyls PCB153 or PCB126 impairs learning ability in young but not in adult rats. Eur J Neurosci 2008; 27:177-82. [PMID: 18093177 DOI: 10.1111/j.1460-9568.2007.05988.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Polychlorinated biphenyls (PCBs) are persistent organic pollutants present in the food chain and in human blood and milk. Exposure to PCBs during pregnancy and lactation leads to cognitive impairment in children. The underlying mechanisms remain unclear. Some PCBs are endocrine disrupters. The aim of this work was to assess whether exposure of rats to PCB126 (dioxin-like) or PCB153 (non-dioxin-like) during pregnancy and lactation affects the ability of the pups to learn a Y maze conditional discrimination task and/or the function of the glutamate-nitric oxide (NO)-cGMP pathway in brain in vivo when the rats are young (3 months) or adult (7-8 months). After finishing the learning experiments, the function of the pathway was analysed in the same rats by in vivo brain microdialysis. The results obtained show that perinatal exposure to PCB153 or PCB126: (1) impairs learning ability in young but not in adult rats, (2) impairs the glutamate-NO-cGMP pathway function in cerebellum in vivo in young but not in adult rats and (3) affect these parameters in males and females similarly. PCB126 is around 10 000-fold more potent than PCB153. In control rats the function of the glutamate-NO-cGMP pathway and learning ability are lower in adult than in young rats. These age-related differences are not present in rats exposed to PCBs. The impairment of the glutamate-NO-cGMP pathway function induced at young age by developmental exposure to the PCBs could be one of the mechanisms contributing to the cognitive impairment found in children whose mothers ingested PCB-contaminated food during pregnancy and lactation.
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Affiliation(s)
- Blanca Piedrafita
- Laboratory of Neurobiology, Centro de Investigacion Príncipe Felipe, Avda Autopista del Saler 16, 46013 Valencia, Spain
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36
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Roda E, Coccini T, Acerbi D, Castoldi A, Bernocchi G, Manzo L. Cerebellum cholinergic muscarinic receptor (subtype-2 and -3) and cytoarchitecture after developmental exposure to methylmercury: an immunohistochemical study in rat. J Chem Neuroanat 2008; 35:285-94. [PMID: 18358697 DOI: 10.1016/j.jchemneu.2008.01.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Revised: 01/22/2008] [Accepted: 01/22/2008] [Indexed: 11/27/2022]
Abstract
The developing central nervous system (CNS) is a target of the environmental toxicant methylmercury (MeHg), and the cerebellum seems the most susceptible tissue in response to this neurotoxicant. The cholinergic system is essential for brain development, acting as a modulator of neuronal proliferation, migration and differentiation processes; its muscarinic receptors (MRs) play pivotal roles in regulating important basic physiologic functions. By immunohistochemistry, we investigated the effects of perinatal (GD7-PD21) MeHg (0.5 mg/kg bw/day in drinking water) administration on cerebellum of mature (PD36) and immature (PD21) rats, evaluating the: (i) M2- and M3-MR expression; (ii) presence of gliosis; (iii) cytoarchitecture alterations. Regarding to M2-MRs, we showed that: at PD21, MeHg-treated animals did not display any differences compared to controls, while, at PD36 there was a significant increase of M2-immunopositive Bergmann cells in the molecular layer (ML), suggesting a MeHg-related cytotoxic effect. Similarly to M2-MRs, at PD21 the M3-MRs were not affected by MeHg, while, at PD36 a lacking immunoreactivity of the granular layer (IGL) was observed after MeHg treatment. In MeHg-treated rats, at both developmental points, we showed reactive gliosis, e.g. a significant increase in Bergmann glia of the ML and astrocytes of the IGL, identified by their expression of glial fibrillar acidic protein. No MeHg-related effects on Purkinje cells were detected neither at weaning nor at puberty. These findings suggest: (i) a delayed MeHg exposure-related effect on M2- and M3-MRs, (ii) an overt MeHg-related cytotoxic effect on cerebellar oligodendroglia, e.g. reactive gliosis, (iii) a selective vulnerability of granule cells and Purkinje neurons to MeHg, with the latter that remain unharmed.
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Affiliation(s)
- Elisa Roda
- University of Pavia, Department of Internal Medicine and Therapeutics, Toxicology Division, Pavia, Italy.
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Castoldi AF, Johansson C, Onishchenko N, Coccini T, Roda E, Vahter M, Ceccatelli S, Manzo L. Human developmental neurotoxicity of methylmercury: impact of variables and risk modifiers. Regul Toxicol Pharmacol 2008; 51:201-14. [PMID: 18367301 DOI: 10.1016/j.yrtph.2008.01.016] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Revised: 01/28/2008] [Accepted: 01/30/2008] [Indexed: 11/26/2022]
Abstract
Methylmercury (MeHg) is a widespread environmental and food toxicant which has long been known to affect neurodevelopment in both humans and experimental animals. Risk assessment for MeHg is mainly based on human data coming from the massive episodes of poisoning in Japan and Iraq, as well as from large scale epidemiological studies concerning childhood development and neurotoxicity in relation to in utero exposure in various fish eating communities around the world. Despite the extensive literature and research, the threshold dose for MeHg neurotoxic effects is still unclear, in particular when it comes to subtle effects on neurobehaviour. In this article clinical and epidemiological findings concerning the neurodevelopmental toxicity of MeHg are reviewed. Much attention is focussed on the potential impact of factors, such as diet and nutrition, gender, pattern of exposure and co-exposure to other neurotoxic pollutants, which may modulate MeHg toxic effects. These factors, together with the notion that some symptoms may ensue or exacerbate with aging, contribute to the difficulties in the definition of safe levels for developmental exposure.
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Affiliation(s)
- Anna F Castoldi
- Toxicology Division, University of Pavia, Via Palestro 26, 27100 Pavia, Italy.
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Goldoni M, Caglieri A, Poli D, Vettori MV, Ceccatelli S, Mutti A. Methylmercury at low doses modulates the toxicity of PCB153 on PC12 neuronal cell line in asynchronous combination experiments. Food Chem Toxicol 2007; 46:808-11. [PMID: 17980472 DOI: 10.1016/j.fct.2007.09.104] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Revised: 06/18/2007] [Accepted: 09/14/2007] [Indexed: 10/22/2022]
Abstract
Me-Hg and PCB153 are known neurotoxic contaminants which tend to accumulate in food, particularly in fish. Aim of this study was to perform asynchronous and combined exposure to Me-Hg and PCB153 in a neuronal rat cell line (PC12) to better characterise the antagonism observed at some combination concentrations. PC12 cells were treated with three concentrations of Me-Hg (0.1-0.5-1.0 microM) and PCB153 at one concentration (175 microM) in single and combined asynchronous exposures, using viability (MTT assay) as end-point. At all concentrations used, a statistically significant antagonistic effect was observed when Me-Hg preceded PCB153 exposure, while effect was additive when PCB153 preceded Me-Hg exposure. The antagonism is particularly evident at low concentrations of Me-Hg (0.1 microM). In conclusion, combined asynchronous exposure showed that whereas Me-Hg can modulate PCB153 toxicity, the opposite seems not to be true. Therefore, the use of asynchronous exposure could be a promising approach to study the mechanisms of toxicity of binary mixtures.
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Affiliation(s)
- M Goldoni
- Laboratory of Industrial Toxicology, Department of Clinical Medicine, Nephrology and Health Sciences, University of Parma, Via Gramsci 14, 43100 Parma, Italy.
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