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Shetty SS, D D, S H, Sonkusare S, Naik PB, Kumari N S, Madhyastha H. Environmental pollutants and their effects on human health. Heliyon 2023; 9:e19496. [PMID: 37662771 PMCID: PMC10472068 DOI: 10.1016/j.heliyon.2023.e19496] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 08/23/2023] [Accepted: 08/24/2023] [Indexed: 09/05/2023] Open
Abstract
Numerous environmental contaminants significantly contribute to human disease, affecting climate change and public and individual health, resulting in increased mortality and morbidity. Because of the scarcity of information regarding pollution exposure from less developed nations with inadequate waste management, higher levels of poverty, and limited adoption of new technology, the relationship between pollutants and health effects needs to be investigated more. A similar situation is present in many developed countries, where solutions are only discovered after the harm has already been done and the necessity for safeguards has subsided. The connection between environmental toxins and health needs to be better understood due to difficulties in quantifying exposure levels and a lack of systematic monitoring. Different pollutants are to blame for both chronic and acute disorders. Additionally, research becomes challenging when disease problems are seen after prolonged exposure. This review aims to discuss the present understanding of the association between environmental toxins and human health in bridging this knowledge gap. The genesis of cancer and the impact of various environmental pollutants on the human body's cardiovascular, respiratory, reproductive, prenatal, and neural health are discussed in this overview.
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Affiliation(s)
- Shilpa S. Shetty
- CentralResearch laboratory, Cellomics Laboratory, K. S. Hegde Medical Academy, Nitte (Deemed to be University), Mangaluru., Karnataka, India
| | - Deepthi D
- CentralResearch laboratory, Cellomics Laboratory, K. S. Hegde Medical Academy, Nitte (Deemed to be University), Mangaluru., Karnataka, India
| | - Harshitha S
- CentralResearch laboratory, Cellomics Laboratory, K. S. Hegde Medical Academy, Nitte (Deemed to be University), Mangaluru., Karnataka, India
| | - Shipra Sonkusare
- Department of Obstetrics and Gynecology, K. S. Hegde Medical Academy, Mangaluru, 576018, Karnataka, India
| | - Prashanth B. Naik
- Department of Pediatrics, K. S. Hegde Medical Academy, Mangaluru, 576018, Karnataka, India
| | - Suchetha Kumari N
- CentralResearch laboratory, Cellomics Laboratory, K. S. Hegde Medical Academy, Nitte (Deemed to be University), Mangaluru., Karnataka, India
- Department of Biochemistry, K. S. Hegde Medical Academy, Mangaluru, 576018, Karnataka, India
| | - Harishkumar Madhyastha
- Department of Cardiovascular Physiology, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
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Jung CC, Chou CCK, Huang YT, Chang SY, Lee CT, Lin CY, Cheung HC, Kuo WC, Chang CW, Chang SC. Isotopic signatures and source apportionment of Pb in ambient PM2.5. Sci Rep 2022; 12:4343. [PMID: 35288600 PMCID: PMC8921186 DOI: 10.1038/s41598-022-08096-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 03/02/2022] [Indexed: 11/09/2022] Open
Abstract
Particulate lead (Pb) is a primary air pollutant that affects society because of its health impacts. This study investigates the source sectors of Pb associated with ambient fine particulate matter (PM2.5) over central-western Taiwan (CWT) with new constraints on the Pb-isotopic composition. We demonstrate that the contribution of coal-fired facilities is overwhelming, which is estimated to reach 35 ± 16% in the summertime and is enhanced to 57 ± 24% during the winter monsoon seasons. Moreover, fossil-fuel vehicles remain a major source of atmospheric Pb, which accounts for 12 ± 5%, despite the current absence of a leaded gasoline supply. Significant seasonal and geographical variations in the Pb-isotopic composition are revealed, which suggest that the impact of East Asian (EA) pollution outflows is important in north CWT and drastically declines toward the south. We estimate the average contribution of EA outflows as accounting for 35 ± 15% (3.6 ± 1.5 ng/m3) of the atmospheric Pb loading in CWT during the winter monsoon seasons.
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Gade M, Comfort N, Re DB. Sex-specific neurotoxic effects of heavy metal pollutants: Epidemiological, experimental evidence and candidate mechanisms. ENVIRONMENTAL RESEARCH 2021; 201:111558. [PMID: 34224706 PMCID: PMC8478794 DOI: 10.1016/j.envres.2021.111558] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/14/2021] [Accepted: 06/17/2021] [Indexed: 05/19/2023]
Abstract
The heavy metals lead (Pb), mercury (Hg), and cadmium (Cd) are ubiquitous environmental pollutants and are known to exert severe adverse impacts on the nervous system even at low concentrations. In contrast, the heavy metal manganese (Mn) is first and foremost an essential nutrient, but it becomes neurotoxic at high levels. Neurotoxic metals also include the less prevalent metalloid arsenic (As) which is found in excessive concentrations in drinking water and food sources in many regions of the world. Males and females often differ in how they respond to environmental exposures and adverse effects on their nervous systems are no exception. Here, we review the different types of sex-specific neurotoxic effects, such as cognitive and motor impairments, that have been attributed to Pb, Hg, Mn, Cd, and As exposure throughout the life course in epidemiological as well as in experimental toxicological studies. We also discuss differential vulnerability to these metals such as distinctions in behaviors and occupations across the sexes. Finally, we explore the different mechanisms hypothesized to account for sex-based differential susceptibility including hormonal, genetic, metabolic, anatomical, neurochemical, and epigenetic perturbations. An understanding of the sex-specific effects of environmental heavy metal neurotoxicity can aid in the development of more efficient systematic approaches in risk assessment and better exposure mitigation strategies with regard to sex-linked susceptibilities and vulnerabilities.
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Affiliation(s)
- Meethila Gade
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Nicole Comfort
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Diane B Re
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA; NIEHS Center of Northern Manhattan, Columbia University, New York, NY, USA; Motor Neuron Center for Biology and Disease, Columbia University, New York, NY, USA.
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Goodchild CG, Beck ML, VanDiest I, Czesak FN, Lane SJ, Sewall KB. Male zebra finches exposed to lead (Pb) during development have reduced volume of song nuclei, altered sexual traits, and received less attention from females as adults. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 210:111850. [PMID: 33421715 DOI: 10.1016/j.ecoenv.2020.111850] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 12/18/2020] [Accepted: 12/21/2020] [Indexed: 06/12/2023]
Abstract
Lead (Pb) is a pervasive global contaminant that interferes with sensitive windows for neurological development and causes oxidative damage to tissues. The effects of moderate and high exposure to Pb have been well-studied in birds, but whether low-level early-life exposure to Pb influences adult phenotype remains unclear. Female songbirds use a male's song and coloration to discriminate between high- and low-quality males. Therefore, if early-life exposure to Pb disrupts song learning ability or shifts the allocation of antioxidant pigments away from colorful secondary sexual traits, male birds exposed to Pb may be less attractive to females. We exposed developing zebra finches (Taeniopygia guttata) to Pb-contaminated drinking water (100 or 1000 parts per billion [ppb]) after hatching (days 0-100). Once male finches reached adulthood (120-150 days post hatch), we measured song learning ability, coloration of bill and cheek patches, and volume of song nuclei in the brain. We also measured female preference for Pb-exposed males relative to control males. Finally, we measured motoric and spatial cognitive performance in male and female finches to assess whether cognitive traits differed in their sensitivity to Pb exposure. Male zebra finches exposed to 1000 ppb Pb had impaired song learning ability, reduced volume of song nuclei, bills with less redness and received less attention from females. Additionally, Pb exposure impaired motoric performance in both male and female finches but did not affect performance in a spatial cognitive task. Adult finches exposed to Pb-contaminated water had higher blood-Pb levels, though in all cases blood-Pb levels were below 7.0 µg dL-1. This study suggests that low-level exposure to Pb contributes to cognitive deficits that persist into adulthood and may indirectly influence fitness by altering secondary sexual traits and reducing male attractiveness.
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Affiliation(s)
- Christopher G Goodchild
- Virgina Tech, Dept. of Biology, Blacksburg, VA, USA; University of Central Oklahoma, Dept. of Biology, Edmond, OK, USA.
| | - Michelle L Beck
- Virgina Tech, Dept. of Biology, Blacksburg, VA, USA; Rivier University, Dept. of Biology, Nashua, NH, USA
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Sex-Dependent Effects of Developmental Lead Exposure in Wistar Rats: Evidence from Behavioral and Molecular Correlates. Int J Mol Sci 2020; 21:ijms21082664. [PMID: 32290408 PMCID: PMC7216048 DOI: 10.3390/ijms21082664] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/06/2020] [Accepted: 04/09/2020] [Indexed: 12/11/2022] Open
Abstract
Lead (Pb) exposure in early life affects brain development resulting in cognitive and behavioral deficits. Epidemiologic and experimental evidence of sex as an effect modifier of developmental Pb exposure is emerging. In the present study, we investigated Pb effects on behavior and mechanisms of neuroplasticity in the hippocampus and potential sex differences. To this aim, dams were exposed, from one month pre-mating to offspring weaning, to Pb via drinking water at 5 mg/kg body weight per day. In the offspring of both sexes, the longitudinal assessment of motor, emotional, and cognitive end points was performed. We also evaluated the expression and synaptic distribution of N-methyl-D-Aspartate receptor (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits at post-natal day (pnd) 23 and 70 in the hippocampus. Neonatal motor patterns and explorative behavior in offspring were affected in both sexes. Pb effects in emotional response and memory retention were observed in adult females only, preceded by increased levels of GluN2A and GluA1 subunits at the post-synapse at pnd 23. These data suggest that Pb exposure during development affects glutamatergic receptors distribution at the post-synaptic spine in females. These effects may contribute to alterations in selected behavioral domains.
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Meyer DN, Crofts EJ, Akemann C, Gurdziel K, Farr R, Baker BB, Weber D, Baker TR. Developmental exposure to Pb 2+ induces transgenerational changes to zebrafish brain transcriptome. CHEMOSPHERE 2020; 244:125527. [PMID: 31816550 PMCID: PMC7015790 DOI: 10.1016/j.chemosphere.2019.125527] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 11/27/2019] [Accepted: 11/30/2019] [Indexed: 05/24/2023]
Abstract
Lead (Pb2+) is a major public health hazard for urban children, with profound and well-characterized developmental and behavioral implications across the lifespan. The ability of early Pb2+ exposure to induce epigenetic changes is well-established, suggesting that Pb2+-induced neurobehavioral deficits may be heritable across generations. Understanding the long-term and multigenerational repercussions of lead exposure is crucial for clarifying both the genotypic alterations behind these behavioral outcomes and the potential mechanism of heritability. To study this, zebrafish (Danio rerio) embryos (<2 h post fertilization; EK strain) were exposed for 24 h to waterborne Pb2+ at a concentration of 10 μM. This exposed F0 generation was raised to adulthood and spawned to produce the F1 generation, which was subsequently spawned to produce the F2 generation. Previous avoidance conditioning studies determined that a 10 μM Pb2+ dose resulted in learning impairments persisting through the F2 generation. RNA was extracted from control- and 10 μM Pb2+-lineage F2 brains, (n = 10 for each group), sequenced, and transcript expression was quantified utilizing Quant-Seq. 648 genes were differentially expressed in the brains of F2 lead-lineage fish versus F2 control-lineage fish. Pathway analysis revealed altered genes in processes including synaptic function and plasticity, neurogenesis, endocrine homeostasis, and epigenetic modification, all of which are implicated in lead-induced neurobehavioral deficits and/or their inheritance. These data will inform future investigations to elucidate the mechanism of adult-onset and transgenerational health effects of developmental lead exposure.
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Affiliation(s)
- Danielle N Meyer
- Department of Pharmacology, School of Medicine, Wayne State University, Detroit, MI, USA; Institute of Environmental Health Sciences, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Emily J Crofts
- Institute of Environmental Health Sciences, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Camille Akemann
- Department of Pharmacology, School of Medicine, Wayne State University, Detroit, MI, USA; Institute of Environmental Health Sciences, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Katherine Gurdziel
- Applied Genome Technology Center, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Rebecca Farr
- Department of Pharmacology, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Bridget B Baker
- Institute of Environmental Health Sciences, School of Medicine, Wayne State University, Detroit, MI, USA; Division of Laboratory Animal Resources, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Daniel Weber
- Children's Environmental Health Sciences Core Center, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Tracie R Baker
- Department of Pharmacology, School of Medicine, Wayne State University, Detroit, MI, USA; Institute of Environmental Health Sciences, School of Medicine, Wayne State University, Detroit, MI, USA.
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Zhu J, Zhang Z, Jia J, Wang L, Yang Q, Wang Y, Chen C. Sevoflurane Induces Learning and Memory Impairment in Young Mice Through a Reduction in Neuronal Glucose Transporter 3. Cell Mol Neurobiol 2019; 40:879-895. [PMID: 31884568 PMCID: PMC7295720 DOI: 10.1007/s10571-019-00779-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 12/17/2019] [Indexed: 12/12/2022]
Abstract
Sevoflurane, which is widely used in paediatric anaesthesia, induces neural apoptosis in the developing brain and cognitive impairment in young mammals. Glucose hypometabolism is the key pathophysiological modulator of cognitive dysfunction. However, the effects and mechanism of sevoflurane on cerebral glucose metabolism after its use as an anaesthetic and its complete elimination are still unknown. We therefore investigated the influence of sevoflurane on neuronal glucose transporter isoform 3 (GLUT3) expression, glucose metabolism and apoptosis in vivo and in vitro and on neurocognitive function in young mice 24 h after the third exposure to sevoflurane. Postnatal day 14 (P14) mice and neural cells were exposed to 3% sevoflurane 2 h daily for three days. We found that sevoflurane anaesthesia decreased GLUT3 gene and protein expression in the hippocampus and temporal lobe, consistent with a decrease in glucose metabolism in the hippocampus and temporal lobe observed by [18F] fluorodeoxyglucose positron emission tomography (18F-FDG PET). Moreover, sevoflurane anaesthesia increased the number of TUNEL-positive cells and the levels of Bax, cleaved caspase 3 and cleaved PARP and reduced Bcl-2 levels in the hippocampus and temporal lobe. Young mice exposed to sevoflurane multiple times also showed learning and memory impairment. In addition, sevoflurane inhibited GLUT3 expression in primary hippocampal neurons and PC12 cells. GLUT3 overexpression in cultured neurons ameliorated the sevoflurane-induced decrease in glucose utilization and increase in the apoptosis rate. These data indicate that GLUT3 deficiency may contribute to sevoflurane-induced learning and memory deficits in young mice.
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Affiliation(s)
- Jinpiao Zhu
- Department of Anaesthesiology, Zhongnan Hospital, Wuhan University, East Lake Road, Wuhan, 430071, Hubei, China
| | - Zongze Zhang
- Department of Anaesthesiology, Zhongnan Hospital, Wuhan University, East Lake Road, Wuhan, 430071, Hubei, China
| | - Junke Jia
- Department of Anaesthesiology, Zhongnan Hospital, Wuhan University, East Lake Road, Wuhan, 430071, Hubei, China
| | - Lirong Wang
- Department of Anaesthesiology, Zhongnan Hospital, Wuhan University, East Lake Road, Wuhan, 430071, Hubei, China
| | - Qiuyue Yang
- Department of Anaesthesiology, Zhongnan Hospital, Wuhan University, East Lake Road, Wuhan, 430071, Hubei, China
| | - Yanlin Wang
- Department of Anaesthesiology, Zhongnan Hospital, Wuhan University, East Lake Road, Wuhan, 430071, Hubei, China
| | - Chang Chen
- Department of Anaesthesiology, Zhongnan Hospital, Wuhan University, East Lake Road, Wuhan, 430071, Hubei, China.
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Arakawa H. Sensorimotor developmental factors influencing the performance of laboratory rodents on learning and memory. Behav Brain Res 2019; 375:112140. [PMID: 31401145 PMCID: PMC6741784 DOI: 10.1016/j.bbr.2019.112140] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 02/08/2023]
Abstract
Behavioral studies in animal models have advanced our knowledge of brain function and the neural mechanisms of human diseases. Commonly used laboratory rodents, such as mice and rats, provide a useful tool for studying the behaviors and mechanisms associated with learning and memory processes which are cooperatively regulated by multiple underlying factors, including sensory and motor performance and emotional/defense innate components. Each of these factors shows unique ontogeny and governs the sustainment of behavioral performance in learning tasks, and thus, understanding the integrative processes of behavioral development are crucial in the accurate interpretation of the functional meaning of learning and memory behaviors expressed in commonly employed behavioral test paradigms. In this review, we will summarize the major findings in the developmental processes of rodent behavior on the basis of the emergence of fundamental components for sustaining learning and memory behaviors. Briefly, most sensory modalities (except for vision) and motor abilities are functional at the juvenile stage, in which several defensive components, including active and passive defensive strategies and risk assessment behavior, emerge. Sex differences are detectable from the juvenile stage through adulthood and are considerable factors that influence behavioral tests. The test paradigms addressed in this review include associative learning (with an emphasis on fear conditioning), spatial learning, and recognition. This basic background information will aid in accurately performing behavioral studies in laboratory rodents and will therefore contribute to reducing inappropriate interpretations of behavioral data and further advance research on learning and memory in rodent models.
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Affiliation(s)
- Hiroyuki Arakawa
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn St. HSF2/S251, Baltimore, MD, 21201, USA.
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Li L, Li H, Qu P, Xiao M, Zhang G, Zhang Q, Cai Y, Jin C, Yang J, Wu S, Lu X. An Antagonism Joint Action of Lead and Di-2-Ethylhexyl Phthalate Explains an Improved Ability of Learning and Memory after Combined Exposure in Weaning Rats. Biol Trace Elem Res 2019; 191:126-134. [PMID: 30523571 DOI: 10.1007/s12011-018-1586-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 11/19/2018] [Indexed: 12/30/2022]
Abstract
Lead and di-2-ethylhexyl phthalate (DEHP) are widely distributed in the environment, and their neurotoxicity has caused a widespread concern. The complexity of environmental exposure provides the possibility of their combined exposure. The present study aims to describe a joint neurotoxicity and clarify the potential mechanism after combined exposure to lead and DEHP. A 2 × 3 factorial design was used to analyze either single effects or their interaction by a subchronic lead and DEHP exposure model of the male weaning rats. Similar to the previous study, lead or DEHP single exposure showed an increased neurotoxicity. Interestingly, our neurobehavioral test showed the rats in the combined exposure groups had a better ability of learning and memory compared with the single-exposure ones. It seemed to reflect an antagonism joint action in neurotoxicity after combined exposure. The content of dehydroepiandrosterone (DHEA) in serum and the mRNA level of brain-derived neurotrophic factor (Bdnf) in the hippocampus showed a similar trend to the ability of learning and memory. However, there was insufficient evidence to support the joint action on some indexes of oxidative stress such as malondialdehyde (MDA), the ratio of reduced glutathione(GSH) to oxidized glutathione(GSSG), γglutamylcysteine synthetase (γ-GCS), glutathione-s transferase (GST), and nuclear factor E2-related factor 2 (Nrf2) mRNA expression in the hippocampus. In a word, our current study reminded a unique antagonism joint action of neurotoxicity after combined exposure to lead and DEHP, which may contribute to understanding some shallow mechanism of the joint toxicity due to the complexity of environmental pollutant exposure.
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Affiliation(s)
- Liuli Li
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China
| | - Hao Li
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China
| | - Peng Qu
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China
| | - Mingyang Xiao
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China
| | - Guopei Zhang
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China
| | - Qianye Zhang
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China
| | - Yuan Cai
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China
| | - Cuihong Jin
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China
| | - Jinghua Yang
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China
| | - Shengwen Wu
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China
| | - Xiaobo Lu
- Department of Toxicology, School of Public Health, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning Province, People's Republic of China.
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Garcia EM, da Silva Júnior FMR, Baisch PRM, Soares MCF, Muccillo-Baisch AL. Effect of mixing two environmental stressors, pH and metal contaminants, on offspring of rats exposed during gestation and lactation. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:35555-35561. [PMID: 30353427 DOI: 10.1007/s11356-018-3495-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 10/16/2018] [Indexed: 06/08/2023]
Abstract
In large urban centers, the toxicity of metal mixtures may be enhanced by physicochemical factors and environmental variables, including pH. Rio Grande, a municipality located in the extreme south of Brazil, has soils with high levels of contamination due to urban and industrial activities and a high prevalence of acid rain events. Previous studies have shown that contact with elutriate of these soils can cause physiological and reproductive changes. Thus, the objective of the present study was to evaluate, through animal experimentation, the effects of a metal-contaminated soil, acidified by hydrofluoric acid at two different pH values (5.2 and 3.6), on the health of offspring of rats exposed during gestation and lactation. Female Wistar rats were gavaged daily for 42 days (gestation and breastfeeding) with soil elutriate contaminated with metals, using solvent with different pH values (6.0, 5.2, and 3.6). The following parameters were evaluated in their offspring: body and organ weight, length, appearance of developmental characteristics, and swimming. Experimental groups in which the progenitors were exposed to the solution at pH 3.6 exhibited a delayed increase in weight as well as motor deficit, with a decreased weight (onset) and length (beginning and end), while exposure in association with soil was an aggravating factor for the damages to the body. Exposure to the solution at pH 5.2 decreased the initial weight of the animals, impaired some parameters of weight development, and caused motor deficit on the 14th day. These novel findings reveal that the exposure of progenitors to environmental stressors can compromise the health of the offspring. Special attention should be given to populations living in areas with high prevalence of acid rain.
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Affiliation(s)
- Edariane Menestrino Garcia
- Laboratório de Ensaios Farmacológicos e Toxicológicos - LEFT, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande do Sul - FURG, Av. Itália, km 8, Campus Carreiros, Rio Grande, RS, CEP 96203-900, Brazil
| | - Flavio Manoel Rodrigues da Silva Júnior
- Laboratório de Ensaios Farmacológicos e Toxicológicos - LEFT, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande do Sul - FURG, Av. Itália, km 8, Campus Carreiros, Rio Grande, RS, CEP 96203-900, Brazil.
- Programa de Pós Graduação em Ciências da Saúde, Universidade Federal do Rio Grande (FURG), Rua Visconde de Paranaguá 102 Centro, Rio Grande, RS, CEP 96203-900, Brazil.
| | - Paulo Roberto Martins Baisch
- Laboratório de Oceanografia Geológica, Instituto de Oceanografia, Universidade Federal do Rio Grande do Sul-FURG, Av. Itália, km 8, Campus Carreiros, Rio Grande, RS, CEP 96201-900, Brazil
| | - Maria Cristina Flores Soares
- Programa de Pós Graduação em Ciências da Saúde, Universidade Federal do Rio Grande (FURG), Rua Visconde de Paranaguá 102 Centro, Rio Grande, RS, CEP 96203-900, Brazil
| | - Ana Luíza Muccillo-Baisch
- Laboratório de Ensaios Farmacológicos e Toxicológicos - LEFT, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande do Sul - FURG, Av. Itália, km 8, Campus Carreiros, Rio Grande, RS, CEP 96203-900, Brazil
- Programa de Pós Graduação em Ciências da Saúde, Universidade Federal do Rio Grande (FURG), Rua Visconde de Paranaguá 102 Centro, Rio Grande, RS, CEP 96203-900, Brazil
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Sobolewski M, Varma G, Adams B, Anderson DW, Schneider JS, Cory-Slechta DA. Developmental Lead Exposure and Prenatal Stress Result in Sex-Specific Reprograming of Adult Stress Physiology and Epigenetic Profiles in Brain. Toxicol Sci 2018; 163:478-489. [PMID: 29481626 PMCID: PMC5974781 DOI: 10.1093/toxsci/kfy046] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Developmental exposure to lead (Pb) and prenatal stress (PS) both impair cognition, which could derive from their joint targeting of the hypothalamic-pituitary-adrenal axis and the brain mesocorticolimbic (MESO) system, including frontal cortex (FC) and hippocampus (HIPP). Glucocorticoids modulate both FC and HIPP function and associated mediation of cognitive and other behavioral functions. This study sought to determine whether developmental Pb ± PS exposures altered glucocorticoid-related epigenetic profiles in brain MESO regions in offspring of female mice exposed to 0 or 100 ppm Pb acetate drinking water from 2 mos prior to breeding until weaning, with half further exposed to prenatal restraint stress from gestational day 11-18. Overall, changes in females occured in response to Pb exposure. In males, however, Pb-induced neurotoxicity was modulated by PS. Changes in serum corticosterone levels were seen in males, while glucocorticoid receptor changes were seen in both sexes. In contrast, both Pb and PS broadly impacted brain DNA methyltransferases and binding proteins, particularly DNMT1, DNMT3a and methyl-CpG-binding protein 2, with patterns that differed by sex and brain regions. Specifically, in males, effects on FC epigenetic modifiers were primarily influenced by Pb, whereas extensive changes in HIPP were produced by PS. In females, Pb exposure and not PS primarily altered epigenetic modifiers in both FC and HIPP. Collectively, these findings indicate that epigenetic mechanisms may underlie associated neurotoxicity of Pb and of PS, particularly associated cognitive deficits. However, mechanisms by which this may occur will be different in males versus females.
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Affiliation(s)
- Marissa Sobolewski
- Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, New York,To whom correspondence should be addressed at Department of Environmental Medicine, University of Rochester School of Medicine, University of Rochester Medical Center, Box EHSC, Rochester, NY 14642. Fax: 585-256-2591; E-mail:
| | - Garima Varma
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Beth Adams
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - David W Anderson
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Jay S Schneider
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Deborah A Cory-Slechta
- Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, New York
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12
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Sobolewski M, Conrad K, Marvin E, Allen JL, Cory-Slechta DA. Endocrine active metals, prenatal stress and enhanced neurobehavioral disruption. Horm Behav 2018; 101:36-49. [PMID: 29355495 PMCID: PMC5970043 DOI: 10.1016/j.yhbeh.2018.01.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 01/05/2018] [Accepted: 01/14/2018] [Indexed: 11/24/2022]
Abstract
Metals, including lead (Pb), methylmercury (MeHg) and arsenic (As), are long-known developmental neurotoxicants. More recently, environmental context has been recognized to modulate metals toxicity, including nutritional state and stress exposure. Modulation of metal toxicity by stress exposure can occur through shared targeting of endocrine systems, such as the hypothalamic-pituitary-adrenal axis (HPA). Our previous rodent research has identified that prenatal stress (PS) modulates neurotoxicity of two endocrine active metals (EAMs), Pb and MeHg, by altering HPA and CNS systems disrupting behavior. Here, we review this research and further test the hypothesis that prenatal stress modulates metals neurotoxicity by expanding to test the effect of developmental As ± PS exposure. Serum corticosterone and behavior was assessed in offspring of dams exposed to As ± PS. PS increased female offspring serum corticosterone at birth, while developmental As exposure decreased adult serum corticosterone in both sexes. As + PS induced reductions in locomotor activity in females and reduced response rates on a Fixed Interval schedule of reinforcement in males, with the latter suggesting unique learning deficits only in the combined exposure. As-exposed males showed increased time in the open arms of an elevated plus maze and decreased novel object recognition whereas females did not. These data further confirm the hypothesis that combined exposure to chemical (EAMs) and non-chemical (PS) stressors results in enhanced neurobehavioral toxicity. Given that humans are exposed to multiple environmental risk factors that alter endocrine function in development, such models are critical for risk assessment and public health protection, particularly for children.
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Affiliation(s)
- Marissa Sobolewski
- Dept. of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY, United States. marissa:
| | - Katherine Conrad
- Dept. of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY, United States
| | - Elena Marvin
- Dept. of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY, United States
| | - Joshua L Allen
- Dept. of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY, United States
| | - Deborah A Cory-Slechta
- Dept. of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY, United States
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13
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Sprowles JLN, Amos-Kroohs RM, Braun AA, Sugimoto C, Vorhees CV, Williams MT. Developmental manganese, lead, and barren cage exposure have adverse long-term neurocognitive, behavioral and monoamine effects in Sprague-Dawley rats. Neurotoxicol Teratol 2018; 67:50-64. [PMID: 29631003 DOI: 10.1016/j.ntt.2018.04.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 03/30/2018] [Accepted: 04/04/2018] [Indexed: 12/17/2022]
Abstract
Developmental stress, including low socioeconomic status (SES), can induce dysregulation of the hypothalamic-pituitary-adrenal axis and result in long-term changes in stress reactivity. Children in lower SES households experience more stress and are more likely to be exposed to environmental neurotoxins such as lead (Pb) and manganese (Mn) than children in higher SES households. Co-exposure to stress, Pb, and Mn during early development may increase the risk of central nervous system dysfunction compared with unexposed children. To investigate the potential interaction of these factors, Sprague-Dawley rats were bred, and litters born in-house were culled on postnatal day (P)1 to 6 males and 6 females. One male and female within each litter were assigned to one of the following groups: 0 (vehicle), 10 mg/kg Pb, 100 mg/kg Mn, or 10 mg/kg Pb + 100 mg/kg Mn (PbMn), water gavage, and handled only from P4-28 with half the litters reared in cages with standard bedding (29 litters) and half with no bedding (Barren; 27 litters). Mn and PbMn groups had decreased anxiety, reduced acoustic startle, initial open-field hypoactivity, increased activity following (+)-methamphetamine, deficits in egocentric learning in the Cincinnati water maze (CWM), and deficits in latent inhibition conditioning. Pb increased anxiety and reduced open-field activity. Barren-reared rats had decreased anxiety, CWM deficits, increased startle, and initial open-field hyperactivity. Mn, PbMn, Pb Barren-reared groups had impaired Morris water maze performance. Pb altered neostriatal serotonin and norepinephrine, Mn increased hippocampal serotonin in males, Mn + Barren-rearing increased neostriatal serotonin, and Barren-rearing decreased neostriatal dopamine in males. At the doses used here, most effects were in the Mn and PbMn groups. Few interactions between Mn, Pb, and rearing stress were found, indicating that the interaction of these three variables is not as impactful as hypothesized.
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Affiliation(s)
- Jenna L N Sprowles
- Department of Pediatrics, University of Cincinnati College of Medicine, Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, United States; Rhodes College, Department of Psychology, 2000 North Parkway, Memphis, TN 38112, United States.
| | - Robyn M Amos-Kroohs
- Department of Pediatrics, University of Cincinnati College of Medicine, Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, United States; Virginia Department of Forensic Science, 700 North Fifth St, Richmond, VA 23219, United States
| | - Amanda A Braun
- Department of Pediatrics, University of Cincinnati College of Medicine, Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, United States
| | - Chiho Sugimoto
- Department of Pediatrics, University of Cincinnati College of Medicine, Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, United States.
| | - Charles V Vorhees
- Department of Pediatrics, University of Cincinnati College of Medicine, Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, United States.
| | - Michael T Williams
- Department of Pediatrics, University of Cincinnati College of Medicine, Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, United States.
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14
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Singh G, Singh V, Sobolewski M, Cory-Slechta DA, Schneider JS. Sex-Dependent Effects of Developmental Lead Exposure on the Brain. Front Genet 2018; 9:89. [PMID: 29662502 PMCID: PMC5890196 DOI: 10.3389/fgene.2018.00089] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 03/02/2018] [Indexed: 11/23/2022] Open
Abstract
The role of sex as an effect modifier of developmental lead (Pb) exposure has until recently received little attention. Lead exposure in early life can affect brain development with persisting influences on cognitive and behavioral functioning, as well as, elevated risks for developing a variety of diseases and disorders in later life. Although both sexes are affected by Pb exposure, the incidence, manifestation, and severity of outcomes appears to differ in males and females. Results from epidemiologic and animal studies indicate significant effect modification by sex, however, the results are not consistent across studies. Unfortunately, only a limited number of human epidemiological studies have included both sexes in independent outcome analyses limiting our ability to draw definitive conclusions regarding sex-differentiated outcomes. Additionally, due to various methodological differences across studies, there is still not a good mechanistic understanding of the molecular effects of lead on the brain and the factors that influence differential responses to Pb based on sex. In this review, focused on prenatal and postnatal Pb exposures in humans and animal models, we discuss current literature supporting sex differences in outcomes in response to Pb exposure and explore some of the ideas regarding potential molecular mechanisms that may contribute to sex-related differences in outcomes from developmental Pb exposure. The sex-dependent variability in outcomes from developmental Pb exposure may arise from a combination of complex factors, including, but not limited to, intrinsic sex-specific molecular/genetic mechanisms and external risk factors including sex-specific responses to environmental stressors which may act through shared epigenetic pathways to influence the genome and behavioral output.
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Affiliation(s)
- Garima Singh
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Vikrant Singh
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Marissa Sobolewski
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY, United States
| | - Deborah A Cory-Slechta
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY, United States
| | - Jay S Schneider
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, United States
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15
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Cucarián JD, León LA, Luna GA, Torres MR, Corredor K, Cardenas P. F. CARACTERIZACIÓN TEMPORO-ESPACIAL DEL PATRÓN DE MARCHA EN ROEDORES COMO MODELO ANIMAL DE LESIÓN CEREBRAL CEREBROVASCULAR. ACTA BIOLÓGICA COLOMBIANA 2017. [DOI: 10.15446/abc.v22n3.65244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
En la investigación sobre movimiento, la experimentación animal ha proporcionado fundamentación científica para la investigación clínica, mejorando procedimientos diagnósticos y de rehabilitación. Lesiones cerebrales en roedores pueden ser usadas para modelar síntomas locomotores, sensoriales y/o cognitivos. Con el propósito de determinar la funcionalidad locomotriz y sensorial en roedores, se han propuesto varios métodos de evaluación y pronóstico clínico para identificar y evaluar adaptaciones estructurales y mecanismos de neuro-recuperación. Esto ha permitido que métodos de intervención terapéutica, como el ejercicio físico, sean utilizados para restaurar funciones sensitivo-motoras y cognitivas en roedores y humanos. La extrapolación (translación) de los resultados de investigaciones en ciencias básicas a áreas clínicas supone la continua cooperación y retroalimentación entre investigadores y profesionales de la salud, favoreciendo la formulación de intervenciones terapéuticas más eficaces basadas en resultados obtenidos de la experimentación animal. El objetivo de esta revisión es exponer las principales deficiencias motoras y los métodos empleados para determinar la dificultad motriz en la marcha en roedores con lesión cerebrovascular, para lo cual se realizó una revisión de literatura, sobre términos definidos (MeSH), en las bases de datos PsychINFO, Medline y Web of Science, entre enero de 2000 y enero de 2017. Se excluyeron artículos de carácter cualitativo o narrativo, sin revisión por pares, disertaciones, tesis o trabajos de grado y resúmenes de conferencias. Se revisan algunas manifestaciones clínicas, su efecto en la locomotricidad en roedores, algunas metodologías usadas para generar lesiones y para estudiar la función motriz, los principales métodos de medición y algunos aspectos translacionales.
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16
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Varma G, Sobolewski M, Cory-Slechta DA, Schneider JS. Sex- and brain region- specific effects of prenatal stress and lead exposure on permissive and repressive post-translational histone modifications from embryonic development through adulthood. Neurotoxicology 2017; 62:207-217. [PMID: 28712943 DOI: 10.1016/j.neuro.2017.07.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 07/03/2017] [Indexed: 12/19/2022]
Abstract
Developmental exposure to prenatal stress (PS) and lead (Pb) can affect brain development and adversely influence behavior and cognition. Epigenetic-based gene regulation is crucial for normal brain development and mis-regulation, in any form, can result in neurodevelopmental disorders. Post-translational histone modifications (PTHMs) are an integral and dynamic component of the epigenetic machinery involved in gene regulation. Exposures to Pb and/or PS may alter PTHM profiles, promoting lifelong alterations in brain function observed following Pb±PS exposure. Here we examined the effects of Pb±PS on global levels of activating marks H3K9Ac and H3K4Me3 and repressive marks H3K9Me2 and H3K27Me3 at different developmental stages: E18, PND0, PND6 and PND60. Dams were exposed to 0 or 100ppm Pb beginning 2 months prior to breeding followed by no PS (NS) or PS resulting in 4 offspring treatment groups per sex: 0-NS (control), 0-PS, 100-NS and 100-PS. Global levels of PTHMs varied from E18 through adulthood even in control mice, and were influenced by sex and brain-region. The developmental trajectory of these PTHM levels was further modified by Pb±PS in a sex-, brain region- and age-dependent manner. Females showed a preferential response to Pb alone in frontal cortex (FC) and differentially to PS alone and combined Pb+PS in hippocampus (HIPP). In males, PS-induced increases in PTHM levels in FC, whereas PS produced reductions in HIPP. Pb±PS-based changes in PTHM levels continued to be observed in adulthood (PND60), demonstrating the lasting effect of these early life environmental events on these histone marks. These results indicate that epigenetic consequences of Pb±PS and their contribution to mechanisms of toxicity are sex dependent. Additional studies will assist in understanding the functional significance of these changes in PTHM levels on expression of individual genes, functional pathways, and ultimately, their behavioral consequences.
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Affiliation(s)
- G Varma
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, United States
| | - M Sobolewski
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester NY, United States
| | - D A Cory-Slechta
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester NY, United States
| | - J S Schneider
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, United States.
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17
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Soleimani E, Goudarzi I, Abrari K, Lashkarbolouki T. Maternal administration of melatonin prevents spatial learning and memory deficits induced by developmental ethanol and lead co-exposure. Physiol Behav 2017; 173:200-208. [PMID: 28209536 DOI: 10.1016/j.physbeh.2017.02.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 02/10/2017] [Accepted: 02/11/2017] [Indexed: 10/20/2022]
Abstract
Melatonin is a radical scavenger with the ability to remove reactive oxidant species. There is report that co-exposure to lead and ethanol during developmental stages induces learning and memory deficits and oxidative stress. Here, we studied the effect of melatonin, with strong antioxidant properties, on memory deficits induced by lead and ethanol co-exposure and oxidative stress in hippocampus. Pregnant rats in lead and ethanol co-exposure group received lead acetate of 0.2% in distilled drinking water and ethanol (4g/kg) by oral gavages once daily from the 5th day of gestation until weaning. Rats received 10mg/kg melatonin by oral gavages. On postnatal days (PD) 30, rats trained with six trials per day for 6 consecutive days in the water maze. On day 37, a probe test was done and oxidative stress markers in the hippocampus were evaluated. Results demonstrated lead and ethanol co-exposed rats exhibited higher escape latency during training trials and reduced time spent in target quadrant, higher escape location latency in probe trial test and had significantly higher malondialdehyde (MDA) levels, significantly lower superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities in the hippocampus. Melatonin treatment could improve memory deficits, antioxidants activity and reduced MDA levels in the hippocampus. We conclude, co-exposure to lead and ethanol impair memory and melatonin can prevent from it by oxidative stress modulation.
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Affiliation(s)
| | - Iran Goudarzi
- Faculty of Biology, Damghan University, Damghan, Iran.
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18
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Karri V, Schuhmacher M, Kumar V. Heavy metals (Pb, Cd, As and MeHg) as risk factors for cognitive dysfunction: A general review of metal mixture mechanism in brain. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2016; 48:203-213. [PMID: 27816841 DOI: 10.1016/j.etap.2016.09.016] [Citation(s) in RCA: 274] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 09/21/2016] [Accepted: 09/24/2016] [Indexed: 05/22/2023]
Abstract
Human exposure to toxic heavy metals is a global challenge. Concurrent exposure of heavy metals, such as lead (Pb), cadmium (Cd), arsenic (As) and methylmercury (MeHg) are particularly important due to their long lasting effects on the brain. The exact toxicological mechanisms invoked by exposure to mixtures of the metals Pb, Cd, As and MeHg are still unclear, however they share many common pathways for causing cognitive dysfunction. The combination of metals may produce additive/synergetic effects due to their common binding affinity with NMDA receptor (Pb, As, MeHg), Na+ - K+ ATP-ase pump (Cd, MeHg), biological Ca+2 (Pb, Cd, MeHg), Glu neurotransmitter (Pb, MeHg), which can lead to imbalance between the pro-oxidant elements (ROS) and the antioxidants (reducing elements). In this process, ROS dominates the antioxidants factors such as GPx, GS, GSH, MT-III, Catalase, SOD, BDNF, and CERB, and finally leads to cognitive dysfunction. The present review illustrates an account of the current knowledge about the individual metal induced cognitive dysfunction mechanisms and analyse common Mode of Actions (MOAs) of quaternary metal mixture (Pb, Cd, As, MeHg). This review aims to help advancement in mixture toxicology and development of next generation predictive model (such as PBPK/PD) combining both kinetic and dynamic interactions of metals.
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Affiliation(s)
- Venkatanaidu Karri
- Center of Environmental Food and Toxicological Technology (TecnATox), Departament d'Enginyeria Química, Universitat Rovira i Virgili, Tarragona, Catalonia, Spain
| | - Marta Schuhmacher
- Center of Environmental Food and Toxicological Technology (TecnATox), Departament d'Enginyeria Química, Universitat Rovira i Virgili, Tarragona, Catalonia, Spain
| | - Vikas Kumar
- Center of Environmental Food and Toxicological Technology (TecnATox), Departament d'Enginyeria Química, Universitat Rovira i Virgili, Tarragona, Catalonia, Spain.
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19
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Soleimani E, Goudarzi I, Abrari K, Lashkarbolouki T. The combined effects of developmental lead and ethanol exposure on hippocampus dependent spatial learning and memory in rats: Role of oxidative stress. Food Chem Toxicol 2016; 96:263-72. [PMID: 27421826 DOI: 10.1016/j.fct.2016.07.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 07/01/2016] [Accepted: 07/11/2016] [Indexed: 01/31/2023]
Abstract
Either developmental lead or ethanol exposure can impair learning and memory via induction of oxidative stress, which results in neuronal damage. we examined the effect of combined exposure with lead and ethanol on spatial learning and memory in offspring and oxidative stress in hippocampus. Rats were exposed to lead (0.2% in drinking water) or ethanol (4 g/kg) either individually or in combination in 5th day gestation through weaning. On postnatal days (PD) 30, rats were trained with six trials per day for 6 consecutive days in the water maze. On day 37, a probe test was done. Also, oxidative stress markers in the hippocampus were also evaluated. Results demonstrated that lead + ethanol co-exposed rats exhibited higher escape latency during training trials and reduced time spent in target quadrant, higher escape location latency and average proximity in probe trial test. There was significant decrease in superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities and increase of malondialdehyde (MDA) levels in hippocampus of animals co-exposed to lead and ethanol compared with their individual exposures. We suggest that maternal consumption of ethanol during lead exposure has pronounced detrimental effects on memory, which may be mediated by oxidative stress.
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Affiliation(s)
| | - Iran Goudarzi
- Faculty of Biology, Damghan University, Damghan, Iran.
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20
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Anderson DW, Mettil W, Schneider JS. Effects of low level lead exposure on associative learning and memory in the rat: Influences of sex and developmental timing of exposure. Toxicol Lett 2016; 246:57-64. [PMID: 26812500 DOI: 10.1016/j.toxlet.2016.01.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 12/23/2015] [Accepted: 01/18/2016] [Indexed: 12/20/2022]
Abstract
Lead (Pb) exposure during development impairs a variety of cognitive, behavioral and neurochemical processes resulting in deficits in learning, memory, attention, impulsivity and executive function. Numerous studies have attempted to model this effect of Pb in rodents, with the majority of studies focusing on hippocampus-associated spatial learning and memory processes. Using a different paradigm, trace fear conditioning, a process requiring coordinated integration of both the medial prefrontal cortex and the hippocampus, we have assessed the effects of Pb exposure on associative learning and memory. The present study examined both female and male long evans rats exposed to three environmentally relevant levels of Pb (150 ppm, 375 ppm and 750 ppm) during different developmental periods: perinatal (PERI; gestation-postnatal day 21), early postnatal (EPN; postnatal days 1-21) and late postnatal (LPN; postnatal days 1-55). Testing began at postnatal day 55 and consisted of a single day of acquisition training, and three post training time points (1, 2 and 10 days) to assess memory consolidation and recall. All animals, regardless of sex, developmental window or level of Pb-exposure, successfully acquired conditioned-unconditioned stimulus association during training. However, there were significant effects of Pb-exposure on consolidation and memory recall at days 1-10 post training. In females, EPN and LPN exposure to 150 ppm Pb (but not PERI exposure) significantly impaired recall. In contrast, only PERI 150 ppm and 750 ppm-exposed males had significant recall deficits. These data suggest a complex interaction between sex, developmental window of exposure and Pb-exposure level on consolidation and recall of associative memories.
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Affiliation(s)
- D W Anderson
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
| | - W Mettil
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - J S Schneider
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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21
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Du Y, Ge MM, Xue W, Yang QQ, Wang S, Xu Y, Wang HL. Chronic Lead Exposure and Mixed Factors of Gender×Age×Brain Regions Interactions on Dendrite Growth, Spine Maturity and NDR Kinase. PLoS One 2015; 10:e0138112. [PMID: 26368815 PMCID: PMC4569283 DOI: 10.1371/journal.pone.0138112] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Accepted: 08/26/2015] [Indexed: 02/01/2023] Open
Abstract
NDR1/2 kinase is essential in dendrite morphology and spine formation, which is regulated by cellular Ca2+. Lead (Pb) is a potent blocker of L-type calcium channel and our recent work showed Pb exposure impairs dendritic spine outgrowth in hippocampal neurons in rats. But the sensitivity of Pb-induced spine maturity with mixed factors (gender×age×brain regions) remains unknown. This study aimed to systematically investigate the effect of Pb exposure on spine maturity in rat brain with three factors (gender×age×brain regions), as well as the NDR1/2 kinase expression. Sprague–Dawley rats were exposed to Pb from parturition to postnatal day 30, 60, 90, respectively. Golgi-Cox staining was used to examine spine maturity. Western blot assay was applied to measure protein expression and real-time fluorescence quantitative PCR assay was used to examine mRNA levels. The results showed chronic Pb exposure significantly decreased dendritic length and impaired spine maturity in both rat hippocampus and medial prefrontal cortex. The impairment of dendritic length induced by Pb exposure tended to adolescence > adulthood, hippocampus > medial prefrontal cortex and female > male. Pb exposure induced significant damage in spine maturity during adolescence and early adult while little damage during adult in male rat brain and female medial prefrontal cortex. Besides, there was sustained impairment from adolescence to adulthood in female hippocampus. Interestingly, impairment of spine maturity followed by Pb exposure was correlated with NDR1/2 kinase. The reduction of NDR1/2 kinase protein expression after Pb exposure was similar to the result of spine maturity. In addition, NDR2 and their substrate Rabin3 mRNA levels were significantly decreased by Pb exposure in developmental rat brain. Taken together, Pb exposure impaired dendrite growth and maturity which was subject to gender×age×brain regions effects and related to NDR1/2 signal expression.
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Affiliation(s)
- Yang Du
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui 230009, P. R. China
| | - Meng-Meng Ge
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui 230009, P. R. China
| | - Weizhen Xue
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui 230009, P. R. China
| | - Qian-Qian Yang
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui 230009, P. R. China
| | - Shuang Wang
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui 230009, P. R. China
| | - Yi Xu
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui 230009, P. R. China
| | - Hui-Li Wang
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui 230009, P. R. China
- * E-mail:
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22
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Using the Morris water maze to assess spatial learning and memory in weanling mice. PLoS One 2015; 10:e0124521. [PMID: 25886563 PMCID: PMC4401674 DOI: 10.1371/journal.pone.0124521] [Citation(s) in RCA: 143] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 03/16/2015] [Indexed: 12/21/2022] Open
Abstract
Mouse models have been indispensable for elucidating normal and pathological processes that influence learning and memory. A widely used method for assessing these cognitive processes in mice is the Morris water maze, a classic test for examining spatial learning and memory. However, Morris water maze studies with mice have principally been performed using adult animals, which preclude studies of critical neurodevelopmental periods when the cellular and molecular substrates of learning and memory are formed. While weanling rats have been successfully trained in the Morris water maze, there have been few attempts to test weanling mice in this behavioral paradigm even though mice offer significant experimental advantages because of the availability of many genetically modified strains. Here, we present experimental evidence that weanling mice can be trained in the Morris water maze beginning on postnatal day 24. Maze-trained weanling mice exhibit significant improvements in spatial learning over the training period and results of the probe trial indicate the development of spatial memory. There were no sex differences in the animals’ performance in these tasks. In addition, molecular biomarkers of synaptic plasticity are upregulated in maze-trained mice at the transcript level. These findings demonstrate that the Morris water maze can be used to assess spatial learning and memory in weanling mice, providing a potentially powerful experimental approach for examining the influence of genes, environmental factors and their interactions on the development of learning and memory.
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23
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Xiao Y, Fu H, Han X, Hu X, Gu H, Chen Y, Wei Q, Hu Q. Role of synaptic structural plasticity in impairments of spatial learning and memory induced by developmental lead exposure in Wistar rats. PLoS One 2014; 9:e115556. [PMID: 25536363 PMCID: PMC4275220 DOI: 10.1371/journal.pone.0115556] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Accepted: 11/24/2014] [Indexed: 11/19/2022] Open
Abstract
Lead (Pb) is found to impair cognitive function. Synaptic structural plasticity is considered to be the physiological basis of synaptic functional plasticity and has been recently found to play important roles in learning and memory. To study the effect of Pb on spatial learning and memory at different developmental stages, and its relationship with alterations of synaptic structural plasticity, postnatal rats were randomly divided into three groups: Control; Pre-weaning Pb (Parents were exposed to 2 mM PbCl2 3 weeks before mating until weaning of pups); Post-weaning Pb (Weaned pups were exposed to 2 mM PbCl2 for 9 weeks). The spatial learning and memory of rats was measured by Morris water maze (MWM) on PND 85–90. Rat pups in Pre-weaning Pb and Post-weaning Pb groups performed significantly worse than those in Control group (p<0.05). However, there was no significant difference in the performance of MWM between the two Pb-exposure groups. Before MWM (PND 84), the number of neurons and synapses significantly decreased in Pre-weaning Pb group, but not in Post-weaning Pb group. After MWM (PND 91), the number of synapses in Pre-weaning Pb group increased significantly, but it was still less than that of Control group (p<0.05); the number of synapses in Post-weaning Pb group was also less than that of Control group (p<0.05), although the number of synapses has no differences between Post-weaning Pb and Control groups before MWM. In both Pre-weaning Pb and Post-weaning Pb groups, synaptic structural parameters such as thickness of postsynaptic density (PSD), length of synaptic active zone and synaptic curvature increased significantly while width of synaptic cleft decreased significantly compared to Control group (p<0.05). Our data demonstrated that both early and late developmental Pb exposure impaired spatial learning and memory as well as synaptic structural plasticity in Wistar rats.
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Affiliation(s)
- Yongmei Xiao
- Department of Preventive Medicine, School of Public Health, Sun Yat-Sen University, Guangzhou 510080, China
| | - Hongjun Fu
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine 04609, United States of America
| | - Xiaojie Han
- Department of Preventive Medicine, School of Public Health, Sun Yat-Sen University, Guangzhou 510080, China
| | - Xiaoxia Hu
- Department of Preventive Medicine, School of Public Health, Sun Yat-Sen University, Guangzhou 510080, China
| | - Huaiyu Gu
- School of Medicine, Sun Yat-Sen University, Guangzhou 510080, China
| | - Yilin Chen
- Department of Preventive Medicine, School of Public Health, Sun Yat-Sen University, Guangzhou 510080, China
| | - Qing Wei
- Department of Preventive Medicine, School of Public Health, Sun Yat-Sen University, Guangzhou 510080, China
| | - Qiansheng Hu
- Department of Preventive Medicine, School of Public Health, Sun Yat-Sen University, Guangzhou 510080, China
- * E-mail:
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Li J, Bo L, Zhang P, Gao Q, Li L, Tang J, Wu C, Li D, Xiao J, Chen J, Tao J, Mao C, Xu Z. Exposure to nicotine during pregnancy and altered learning and memory in the rat offspring. Nicotine Tob Res 2014; 17:661-6. [PMID: 25239954 DOI: 10.1093/ntr/ntu178] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 08/20/2014] [Indexed: 11/14/2022]
Abstract
INTRODUCTION Prenatal exposure to nicotine can cause many fetal developmental problems. This study determined the influence of nicotine during pregnancy on the development of cognitive behavior in the offspring. METHODS Nicotine was administered to pregnant rats through implanted osmotic mini-pumps at 6mg/kg/day and flow rate of 60 μl/day for whole pregnancy from gestational day 4. Fetal and offspring body and brain weight was measured. Learning and memory were tested in adult offspring with Morris water maze; Learning and memory-related receptors were measured. RESULTS The results showed that exposure to prenatal nicotine (PN) not only caused fetal growth restriction, but also had long-term effects on learning and memory in the offspring. The PN offspring exhibited longer escape latency regardless of sex. The number of passing the platform was significantly less in the PN offspring than that of the control. The expression of messenger RNA (mRNA) and protein of N-methyl-D-aspartic acid receptor (NMDAR) in the hippocampus was significantly increased, whereas alpha7 nicotinic acetylcholine receptor (α7 nAChR) protein was decreased with unchanged α7 nAChR mRNA in the PN offspring. CONCLUSION The data provided novel information on the PN-affected development in learning and memory in the offspring, suggesting that α7 nAChR and NMDAR1 in the hippocampus might be the targets for actions of PN in association with memory impairment.
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Affiliation(s)
- Jiayue Li
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Le Bo
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Pengjie Zhang
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Qinqin Gao
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Lingjun Li
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Jiaqi Tang
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Chonglong Wu
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Dawei Li
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Jianping Xiao
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Jie Chen
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Jianying Tao
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Caiping Mao
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Zhice Xu
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China; Center for Perinatal Biology, Loma Linda University, Loma Linda, CA
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Assessment of attention and inhibitory control in rodent developmental neurotoxicity studies. Neurotoxicol Teratol 2014; 52:78-87. [PMID: 25224214 DOI: 10.1016/j.ntt.2014.09.001] [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: 03/27/2014] [Revised: 08/16/2014] [Accepted: 09/05/2014] [Indexed: 11/20/2022]
Abstract
In designing screens to assess potential neurotoxicants, the paramount goal is that the selected assessment tools detect dysfunction if it exists. This goal is particularly challenging in the case of cognitive assessments. Cognition is not a unitary phenomenon, and indeed there is growing evidence that different aspects of cognitive functioning are subserved by distinct neural systems. As a result, if a particular neurotoxicant selectively damages certain neural systems but not others, it can impair some cognitive, sensory, or affective functions, but leave many others intact. Accordingly, studies with human subjects use batteries of cognitive tests, cognizant of the fact that no one test is capable of detecting all forms of cognitive dysfunction. In contrast, assessment of cognitive functioning in non-human animal developmental neurotoxicity (DNT) studies typically consists of a single, presumably representative, "learning and memory" task that is expected to detect all potential effects on cognitive functioning. Streamlining the cognitive assessment in these studies saves time and money, but these shortcuts can have serious consequences if the aspect of cognitive functioning that is impaired is not tapped by the single selected task. In particular, executive functioning - a constellation of cognitive functions which enables the organism to focus on multiple streams of information simultaneously, and revise plans as necessary - is poorly assessed in most animal DNT studies. The failure to adequately assess these functions - which include attention, working memory, inhibitory control, and planning - is particularly worrisome in light of evidence that the neural systems that subserve these functions may be uniquely vulnerable to early developmental insults. We illustrate the importance of tapping these areas of functioning in DNT studies by describing the pattern of effects produced by early developmental Pb exposure. Rats exposed to lead (Pb) early in development were tested on a series of automated attention tasks, as well as on a radial arm maze task. The lead-exposed rats were not impaired in this demanding radial arm maze task, despite conditions which tapped the limits of both working and long-term memory. In contrast, the automated tests designed to assess rodent executive functioning revealed selective and functionally important deficits in attention and regulation of emotion or negative affect (produced by committing an error or not receiving an expected reward). This example underscores the importance of including tasks to specifically tap executive functioning in DNT batteries. Such tasks are not only sensitive but can also shed light on the specific nature of the dysfunction, and they can implicate dysfunction of specific neural systems, information which can be used to design therapeutic interventions. Although the use of such tasks increases the time and effort needed to complete the battery, the benefits outweigh the cost, in light of the greater sensitivity of the battery and the more complete characterization of effects.
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Cory-Slechta DA, Weston D, Liu S, Allen JL. Brain hemispheric differences in the neurochemical effects of lead, prenatal stress, and the combination and their amelioration by behavioral experience. Toxicol Sci 2013; 132:419-30. [PMID: 23358193 DOI: 10.1093/toxsci/kft015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Brain lateralization, critical to mediation of cognitive functions and to "multitasking," is disrupted in conditions such as attention deficit disorder and schizophrenia. Both low-level lead (Pb) exposure and prenatal stress (PS) have been associated with mesocorticolimbic system-mediated executive-function cognitive and attention deficits. Mesocorticolimbic systems demonstrate significant laterality. Thus, altered brain lateralization could play a role in this behavioral toxicity. This study examined laterality of mesocorticolimbic monoamines (frontal cortex, nucleus accumbens, striatum, midbrain) and amino acids (frontal cortex) in male and female rats subjected to lifetime Pb exposure (0 or 50 ppm in drinking water), PS (restraint stress on gestational days 16-17), or the combination with and without repeated learning behavioral experience. Control males exhibited prominent laterality, particularly in midbrain and also in frontal cortex and striatum; females exhibited less laterality, and this was primarily striatal. Lateralized Pb ± PS induced neurotransmitter changes were assessed only in males because of limited sample sizes of Pb + PS females. In males, Pb ± PS changes occurred in left hemisphere of frontal cortex and right hemisphere of midbrain. Behavioral experience modified the laterality of Pb ± PS-induced neurotransmitter changes in a region-dependent manner. Notably, behavioral experience eliminated Pb ± PS neurotransmitter changes in males. These findings underscore the critical need to evaluate both sexes and brain hemispheres for the mechanistic understanding of sex-dependent differences in neuro- and behavioral toxicity. Furthermore, assessment of central nervous system mechanisms in the absence of behavioral experience, shown here for males, may constitute less relevant models of human health effects.
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Affiliation(s)
- Deborah A Cory-Slechta
- Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, New York 14642, USA.
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Lestaevel P, Bensoussan H, Dhieux B, Delissen O, Vacher CM, Dublineau I, Voisin P, Taouis M. Cerebral cortex and hippocampus respond differently after post-natal exposure to uranium. J Toxicol Sci 2013; 38:803-11. [DOI: 10.2131/jts.38.803] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Philippe Lestaevel
- Institut de RadioProtection et de Sûreté Nucléaire, Pôle de la Radioprotection de l’Homme, Service de Radiobiologie et d’Epidémiologie, Laboratoire de Radiotoxicologie Expérimentale
| | - Hélène Bensoussan
- Institut de RadioProtection et de Sûreté Nucléaire, Pôle de la Radioprotection de l’Homme, Service de Radiobiologie et d’Epidémiologie, Laboratoire de Radiotoxicologie Expérimentale
| | - Bernadette Dhieux
- Institut de RadioProtection et de Sûreté Nucléaire, Pôle de la Radioprotection de l’Homme, Service de Radiobiologie et d’Epidémiologie, Laboratoire de Radiotoxicologie Expérimentale
| | - Olivia Delissen
- Institut de RadioProtection et de Sûreté Nucléaire, Pôle de la Radioprotection de l’Homme, Service de Radiobiologie et d’Epidémiologie, Laboratoire de Radiotoxicologie Expérimentale
| | - Claire-Marie Vacher
- Laboratoire de Neuroendocrinologie Moléculaire de la Prise Alimentaire, UMR 1197 INRA/Université Paris XI
| | - Isabelle Dublineau
- Institut de RadioProtection et de Sûreté Nucléaire, Pôle de la Radioprotection de l’Homme, Service de Radiobiologie et d’Epidémiologie, Laboratoire de Radiotoxicologie Expérimentale
| | - Philippe Voisin
- Institut de RadioProtection et de Sûreté Nucléaire, Pôle de la Radioprotection de l’Homme, Service de Radiobiologie et d’Epidémiologie, Laboratoire de Radiotoxicologie Expérimentale
| | - Mohammed Taouis
- Laboratoire de Neuroendocrinologie Moléculaire de la Prise Alimentaire, UMR 1197 INRA/Université Paris XI
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Betharia S, Maher TJ. Neurobehavioral effects of lead and manganese individually and in combination in developmentally exposed rats. Neurotoxicology 2012; 33:1117-27. [DOI: 10.1016/j.neuro.2012.06.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 05/26/2012] [Accepted: 06/06/2012] [Indexed: 11/26/2022]
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Braun JM, Lucchini R, Bellinger DC, Hoffman E, Nazzaro M, Smith DR, Wright RO. Predictors of virtual radial arm maze performance in adolescent Italian children. Neurotoxicology 2012; 33:1203-11. [PMID: 22771383 DOI: 10.1016/j.neuro.2012.06.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 06/20/2012] [Accepted: 06/29/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND Comparisons between animal and human neurotoxicology studies are a foundation of risk assessment, but are hindered by differences in measured behaviors. The radial arm maze (RAM), a rodent visuospatial learning and memory task, has a computerized version for use in children, which may help improve comparisons between animal and human studies. OBJECTIVE To describe the characteristics and correlates of the virtual radial arm maze (VRAM) in 255 children age 10-15 years from Italy. METHODS We administered the VRAM using a laptop computer and measured children's performance using the latency, distance, and working/reference memory errors during eight trials. Using generalized linear mixed models, we described VRAM performance in relation to demographic factors, child activities, and several standard neuropsychologic tests (Italian translations), including the Conners Parent Rating Scales-Short Version (CPRS), California Verbal Learning Test (CVLT), Wechsler Intelligence Scales for Children, finger tapping speed, reaction time, and motor skills. RESULTS Children's VRAM performance tended to improve between trials 1 and 6 and then plateaued between trials 6 and 8. Males finished the task 14 s faster (95% confidence interval [CI]: -20, -9) than females. Children who played 2+h of video games per day finished 16 s faster (CI: -26, -6) and with 34% (CI: 5, 54%) fewer working memory errors than children who reported not playing video games. Higher IQ and better CVLT scores were associated with better VRAM performance. Higher cognitive/inattention CPRS scores were associated with more working (11%; CI: 1, 22) and reference memory errors (7%; CI: 1, 12). CONCLUSIONS Consistent with animal studies, VRAM performance improved over the course of test trials and males performed better than females. Better VRAM performance was related to higher IQ, fewer inattentive behaviors, and better verbal memory. The VRAM may help to improve the integration and comparison between animal and epidemiological studies of environmental neurotoxicants.
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Affiliation(s)
- Joe M Braun
- Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA.
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Abstract
Endocrine disruptors are substances commonly encountered in every setting and condition in the modern world. It is virtually impossible to avoid the contact with these chemical compounds in our daily life. Molecules defined as endocrine disruptors constitute an extremely heterogeneous group and include synthetic chemicals used as industrial solvents/lubricants and their by-products. Natural chemicals found in human and animal food (phytoestrogens) also act as endocrine disruptors. Different from adults, children are not exposed only to chemical toxins in the environment but may also be exposed during their intrauterine life. Hundreds of toxic substances, which include neuro-immune and endocrine toxic chemical components that may influence the critical steps of hormonal, neurological and immunological development, may affect the fetus via the placental cord and these substances may be excreted in the meconium. Children and especially newborns are more sensitive to environmental toxins compared to adults. Metabolic pathways are immature, especially in the first months of life. The ability of the newborn to metabolize, detoxify and eliminate many toxins is different from that of the adults. Although exposures occur during fetal or neonatal period, their effects may sometimes be observed in later years. Further studies are needed to clarify the effects of these substances on the endocrine system and to provide evidence for preventive measures.
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Affiliation(s)
- Tolga Ünüvar
- T.C. Ministry of Health, İstanbul Kanuni Sultan Süleyman, Training and Research Hospital, Department of Pediatric Endocrinology, İstanbul, Turkey
| | - Atilla Büyükgebiz
- Bilim University Faculty of Medicine, Department of Pediatric Endocrinology, İstanbul, Turkey
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Rahman A, Khan KM, Al-Khaledi G, Khan I, Al-Shemary T. Over activation of hippocampal serine/threonine protein phosphatases PP1 and PP2A is involved in lead-induced deficits in learning and memory in young rats. Neurotoxicology 2012; 33:370-83. [DOI: 10.1016/j.neuro.2012.02.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 02/15/2012] [Accepted: 02/21/2012] [Indexed: 11/27/2022]
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Sex and rearing condition modify the effects of perinatal lead exposure on learning and memory. Neurotoxicology 2012; 33:985-95. [PMID: 22542453 DOI: 10.1016/j.neuro.2012.04.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 04/01/2012] [Accepted: 04/12/2012] [Indexed: 11/20/2022]
Abstract
Developmental lead (Pb) exposure is associated with cognitive impairments in humans and rodents alike. In particular, impaired spatial learning and memory, as assessed using the Morris water maze (MWM), has been noted in developmentally Pb-exposed rats. Although sex and rearing environment can influence MWM performance in normal animals, the interactions of sex and rearing environment on the impact of developmental Pb exposure on hippocampal-dependent processes has not been well characterized. The present study examined the effects of perinatal exposure (i.e., gestation through weaning) to different levels of Pb (250, 750 and 1500 ppm Pb acetate in food) in males and females raised in a non-enriched environment (standard cage with 3 animals and no toys) or an enriched environment (large cage containing a variety of toys that were changed twice weekly). Testing in the MWM began at postnatal day 55. Behavioral outcomes were influenced by sex and rearing environment, with complex interactions with Pb exposure. In non-Pb exposed control animals, beneficial effects of environmental enrichment on spatial learning and memory were observed in males and females, with greater effects in females. Pb exposure in females mitigated at least some of the benefits of enrichment on learning, particularly at the lowest and highest exposure levels. In males, enrichment conferred a modest learning advantage and for the most part, Pb exposure did not affect this. However, in males with the highest Pb exposure, enrichment did help to overcome detrimental effects of Pb on learning. In females, any potential benefit to reference memory contributed by enrichment was muted by exposure to Pb and for the most part, this was not reproduced in males. Thus, there are complex interactions between sex, environment, and Pb exposure on spatial learning and memory. Environmental manipulation is a potential risk modifier of developmental Pb exposure and interacts with other factors including sex and amount of Pb exposure to affect the functional influences of Pb on the brain.
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Nava-Ruiz C, Méndez-Armenta M, Ríos C. Lead neurotoxicity: effects on brain nitric oxide synthase. J Mol Histol 2012; 43:553-63. [PMID: 22526509 DOI: 10.1007/s10735-012-9414-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 04/02/2012] [Indexed: 12/23/2022]
Abstract
Lead (Pb), a ubiquitous and potent neurotoxicant, induces several neurophysiological and behavioural changes, while Pb alters the function of multiple organs and systems, it primarily affects the central nervous system. In human adults, encephalopathy resulting from Pb intoxication is often characterized by sleeplessness, poor attention span, vomiting, convulsions and coma; in children, Pb-induced encephalopathy is associated with mental dullness, vomiting, irritability and anorexia; diminished cognitive function resulting in a mental deficit has been also observed during Prolonged exposure to Pb. Pb can produce oxidative stress, disrupt the blood-brain barrier and alter several Ca(2+)-dependent processes, including physiological processes that involve nitric oxide synthesis on central nervous system in development and adult animals. This review summarizes recent evidence showing that Pb can interfere with the production of nitric oxide and can disrupt the function of nitric oxide synthase. Lead interferes with nitric oxide-related physiological mechanisms, and Pb neurotoxicity may affect processes involved in learning and memory.
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Affiliation(s)
- Concepción Nava-Ruiz
- Lab. Neuropatología Experimental, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Mexico City, Mexico
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Schneider JS, Anderson DW, Sonnenahalli H, Vadigepalli R. Sex-based differences in gene expression in hippocampus following postnatal lead exposure. Toxicol Appl Pharmacol 2011; 256:179-90. [PMID: 21864555 DOI: 10.1016/j.taap.2011.08.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 08/03/2011] [Accepted: 08/05/2011] [Indexed: 11/18/2022]
Abstract
The influence of sex as an effect modifier of childhood lead poisoning has received little systematic attention. Considering the paucity of information available concerning the interactive effects of lead and sex on the brain, the current study examined the interactive effects of lead and sex on gene expression patterns in the hippocampus, a structure involved in learning and memory. Male or female rats were fed either 1500 ppm lead-containing chow or control chow for 30 days beginning at weaning.Blood lead levels were 26.7±2.1 μg/dl and 27.1±1.7 μg/dl for females and males, respectively. The expression of 175 unique genes was differentially regulated between control male and female rats. A total of 167 unique genes were differentially expressed in response to lead in either males or females. Lead exposure had a significant effect without a significant difference between male and female responses in 77 of these genes. In another set of 71 genes, there were significant differences in male vs. female response. A third set of 30 genes was differentially expressed in opposite directions in males vs. females, with the majority of genes expressed at a lower level in females than in males. Highly differentially expressed genes in males and females following lead exposure were associated with diverse biological pathways and functions. These results show that a brief exposure to lead produced significant changes in expression of a variety of genes in the hippocampus and that the response of the brain to a given lead exposure may vary depending on sex.
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Affiliation(s)
- J S Schneider
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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Low Lead Exposure During Foetal and Early Postnatal Life Impairs Passive Avoidance Learning in Adulthood in Rats. Arh Hig Rada Toksikol 2011; 62:147-53. [DOI: 10.2478/10004-1254-62-2011-2070] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Low Lead Exposure During Foetal and Early Postnatal Life Impairs Passive Avoidance Learning in Adulthood in RatsThis follow-up study investigated the effects of low-level lead exposure during prenatal and early postnatal period on learning and memory in rats immediately after exposure has ceased at weaning and later in their adulthood. Male Wistar-derived rats were exposed to lead (as 0.2 % lead acetate solution) through their mothers during pregnancy and lactation until they were weaned. Mothers of control rats were given tap water during pregnancy and lactation. All pups were weaned on tap water at 21 days of age and were followed up until 120 days old. Low-level lead exposure did not affect their body weight at any time during the experiment. Blood lead in the exposed rats was significantly higher on postnatal day 22 and dropped to control values by day 120. Passive avoidance test showed impaired memory retention in the exposed rats on postnatal days 25 and 120. This suggests that exposure to low-lead levels during foetal and early postnatal development of brain tissue can cause memory impairment that lasts into adulthood.
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Graham DL, Grace CE, Braun AA, Schaefer TL, Skelton MR, Tang PH, Vorhees CV, Williams MT. Effects of developmental stress and lead (Pb) on corticosterone after chronic and acute stress, brain monoamines, and blood Pb levels in rats. Int J Dev Neurosci 2010; 29:45-55. [PMID: 20920575 DOI: 10.1016/j.ijdevneu.2010.09.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 09/10/2010] [Accepted: 09/24/2010] [Indexed: 12/28/2022] Open
Abstract
Despite restrictions, exposure to lead (Pb) continues. Moreover, exposure varies and is often higher in lower socioeconomic status (SES) families and remains a significant risk to cognitive development. Stress is another risk factor. Lower SES may be a proxy for stress in humans. When stress and Pb co-occur, risk may be increased. A few previous experiments have combined Pb with intermittent or acute stress but not with chronic stress. To determine if chronic developmental stress affects outcome in combination with Pb, we tested such effects on growth, organ weight, brain monoamines, and response to an acute stressor. Sprague Dawley rats were gavaged with Pb acetate (1 or 10 mg/kg) or vehicle every other day from postnatal day (P)4-29 and reared in standard or barren cages. Subsets were analyzed at different ages (P11, 19, 29). Chronic stress did not alter blood Pb levels but altered HPA axis response during early development whereas Pb did not. Pb treatment and rearing each altered organ-to-body weight ratios, most notably of thymus weights. Both Pb and rearing resulted in age- and region-dependent changes in serotonin and norepinephrine levels and in dopamine and serotonin turnover. The model introduced here may be useful for investigating the interaction of Pb and chronic developmental stress.
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Affiliation(s)
- Devon L Graham
- Division of Neurology, Cincinnati Children's Research Foundation, Cincinnati, OH 45229-3039, USA.
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Yang D, Kim KH, Phimister A, Bachstetter AD, Ward TR, Stackman RW, Mervis RF, Wisniewski AB, Klein SL, Kodavanti PRS, Anderson KA, Wayman G, Pessah IN, Lein PJ. Developmental exposure to polychlorinated biphenyls interferes with experience-dependent dendritic plasticity and ryanodine receptor expression in weanling rats. ENVIRONMENTAL HEALTH PERSPECTIVES 2009; 117:426-35. [PMID: 19337518 PMCID: PMC2661913 DOI: 10.1289/ehp.11771] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2008] [Accepted: 09/11/2008] [Indexed: 05/02/2023]
Abstract
BACKGROUND Neurodevelopmental disorders are associated with altered patterns of neuronal connectivity. A critical determinant of neuronal connectivity is the dendritic morphology of individual neurons, which is shaped by experience. The identification of environmental exposures that interfere with dendritic growth and plasticity may, therefore, provide insight into environmental risk factors for neurodevelopmental disorders. OBJECTIVE We tested the hypothesis that polychlorinated biphenyls (PCBs) alter dendritic growth and/or plasticity by promoting the activity of ryanodine receptors (RyRs). METHODS AND RESULTS The Morris water maze was used to induce experience-dependent neural plasticity in weanling rats exposed to either vehicle or Aroclor 1254 (A1254) in the maternal diet throughout gestation and lactation. Developmental A1254 exposure promoted dendritic growth in cerebellar Purkinje cells and neocortical pyramidal neurons among untrained animals but attenuated or reversed experience-dependent dendritic growth among maze-trained littermates. These structural changes coincided with subtle deficits in spatial learning and memory, increased [3H]-ryanodine binding sites and RyR expression in the cerebellum of untrained animals, and inhibition of training-induced RyR upregulation. A congener with potent RyR activity, PCB95, but not a congener with negligible RyR activity, PCB66, promoted dendritic growth in primary cortical neuron cultures and this effect was blocked by pharmacologic antagonism of RyR activity. CONCLUSIONS Developmental exposure to PCBs interferes with normal patterns of dendritic growth and plasticity, and these effects may be linked to changes in RyR expression and function. These findings identify PCBs as candidate environmental risk factors for neurodevelopmental disorders, especially in children with heritable deficits in calcium signaling.
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Affiliation(s)
- Dongren Yang
- Center for Research on Occupational and Environmental Toxicology, Oregon Health & Science University, Portland, Oregon, USA
| | - Kyung Ho Kim
- Veterinary Molecular Biosciences and Center for Children’s Environmental Health, University of California, Davis, California, USA
| | - Andrew Phimister
- Veterinary Molecular Biosciences and Center for Children’s Environmental Health, University of California, Davis, California, USA
| | - Adam D. Bachstetter
- Neurostructural Research Labs and Center for Aging and Brain Repair, University of South Florida College of Medicine, Tampa, Florida, USA
| | - Thomas R. Ward
- Neurotoxicology Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
| | - Robert W. Stackman
- Department of Psychology, Florida Atlantic University, Boca Raton, Florida, USA
| | - Ronald F. Mervis
- Neurostructural Research Labs and Center for Aging and Brain Repair, University of South Florida College of Medicine, Tampa, Florida, USA
| | - Amy B. Wisniewski
- Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Sabra L. Klein
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Prasada Rao S. Kodavanti
- Neurotoxicology Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
| | - Kim A. Anderson
- Department of Environmental & Molecular Toxicology, Oregon State University, Corvallis, Oregon; USA
| | - Gary Wayman
- Department of Veterinary and Comparative Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - Isaac N. Pessah
- Veterinary Molecular Biosciences and Center for Children’s Environmental Health, University of California, Davis, California, USA
| | - Pamela J. Lein
- Center for Research on Occupational and Environmental Toxicology, Oregon Health & Science University, Portland, Oregon, USA
- Veterinary Molecular Biosciences and Center for Children’s Environmental Health, University of California, Davis, California, USA
- Department of Environmental Health Science, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
- Address correspondence to P.J. Lein, University of California Davis, Department of Molecular Biosciences, 1120 Haring Hall, One Shields Ave., Davis, CA 95616 USA. Telephone: (530) 752-1970. Fax: (530) 752-4698. E-mail:
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Yu F, Liao Y, Jin Y, Zhao Y, Ren Y, Lu C, Li G, Li Y, Yang J. Effects of in utero meso-2,3-dimercaptosuccinic acid with calcium and ascorbic acid on lead-induced fetal development. Arch Toxicol 2007; 82:453-9. [PMID: 18046539 DOI: 10.1007/s00204-007-0267-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2007] [Accepted: 11/13/2007] [Indexed: 11/24/2022]
Abstract
To examine the effects of meso-2,3-dimercaptosuccinic acid (DMSA) on developmental toxicity resulting from exposure to lead in utero, female albino mice were exposed to lead by drinking water contaminated with lead acetate for 4 weeks. After the cessation of lead exposure, female mice were supplemented by gavage with saline solution, DMSA, or DMSA and calcium as well as ascorbic acid from the fourth day of gestation until parturition, respectively. Lead levels (blood, liver, and bone) were measured at birth. Pups were then tested about neural development including surface righting reflex, cliff avoidance and air righting reflex. The markers of physical maturation, such as body weight, pinna unfolding, incisor eruption, and eye opening were also recorded. DMSA treatment decreased blood lead levels of pregnant mice, however, increased lead levels in both liver and bone of fetus, and delayed the early physical and neural development of offspring. Calcium and ascorbic acid reduced the transfer of lead to fetus. In conclusion, DMSA treatment during pregnancy enhances lead-induced fetal developmental toxicity.
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Affiliation(s)
- Fei Yu
- Department of Nutrition and Food Hygiene, School of Public Health, China Medical University, No. 92 Beier Road, Heping District, Shenyang, Liaoning Postal code: 110001, People's Republic of China
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39
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Soodi M, Sharifzadeh M, Naghdi N, Ostad N, Abdollahi M, Roghani A. Systemic and developmental exposure to lead causes spatial memory deficits and a reduction in COX-2 immunoreactivity in the hippocampus of male rats. J Neurosci Res 2007; 85:3183-92. [PMID: 17639600 DOI: 10.1002/jnr.21423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Chronic lead exposure during development is known to produce learning deficits. In the present study, we investigated the effects of developmental exposure to lead on spatial memory, as shown in the Morris water maze, and on expression of inducible cyclooxygenase-2 protein in the hippocampi of male rats. Rats were separated into four groups according to which concentration of lead acetate at which developmental stage they were exposed. One group was exposed maternally to lead acetate at a concentration of 250 parts per million (ppm), one group was exposed continuously to 250 ppm lead, one group was exposed maternally to 750 ppm lead, and one group was exposed continuously to 750 ppm lead. Increases were observed in both average escape latency and traveled distance of the rats in the maternally and continuously 750 ppm lead-exposed groups, indicating significant impairment of spatial memory. Quantitative immunostaining analysis by optical density measurement of brain sections from rats in all lead-exposed groups revealed a significant reduction (P < 0.001) in the intensity of cyclooxygenase-2 immunoreactivity in the Ammon's horn region 1 (CA1) and the dentate gyrus areas of the hippocampus. This reduction was concentration-dependent, with the maximum reduction observed in rats exposed to 750 ppm lead. Taken together, these findings suggest that exposure to lead causes spatial memory deficits in male rats and a significant reduction in cyclooxygenase-2 immunoreactivity in the CA1 and dentate gyrus areas.
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Affiliation(s)
- Maliheh Soodi
- Department of Toxicology and Pharmacology, School of Pharmacy, Pharmaceutical Sciences and Medicinal Plants Research Centers, Tehran University of Medical Sciences, Tehran, Iran
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40
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Kumlin T, Iivonen H, Miettinen P, Juvonen A, van Groen T, Puranen L, Pitkäaho R, Juutilainen J, Tanila H. Mobile Phone Radiation and the Developing Brain: Behavioral and Morphological Effects in Juvenile Rats. Radiat Res 2007; 168:471-9. [PMID: 17903040 DOI: 10.1667/rr1002.1] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Accepted: 05/22/2007] [Indexed: 11/03/2022]
Abstract
The increasing use of mobile phones by children and teenagers has raised concerns about their safety. Addressing such concerns is difficult, because no data are available on possible effects from long-term exposure to radiofrequency (RF) fields during the development of the nervous system. Possible morphological and functional changes were evaluated in the central nervous system of young male Wistar rats exposed to 900 MHz mobile phone signal for 2 h/day on 5 days/week. After 5 weeks of exposure at whole-body average specific energy absorption rates of 0.3 or 3.0 W/kg or sham exposure, six rats per group were examined histologically, and the remaining 18 rats per group were subjected to behavioral tests. No degenerative changes, dying neurons, or effects on the leakage of the blood-brain barrier were detected. No group differences were observed in the open-field test, plus maze test or acoustic startle response tests. In the water maze test, however, significantly improved learning (P = 0.012) and memory (P = 0.01) were detected in rats exposed to RF fields. The results do not indicate a serious threat to the developing brain from mobile phone radiation at intensities relevant to human exposure. However, the interesting finding of improved learning and memory warrants further studies.
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Affiliation(s)
- Timo Kumlin
- University of Kuopio, Department of Environmental Science, Finland.
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41
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Prasanthi RP, Reddy GH, Reddy GR. Calcium or zinc supplementation reduces lead toxicity: assessment of behavioral dysfunction in young and adult mice. Nutr Res 2006. [DOI: 10.1016/j.nutres.2006.09.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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42
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Giza CC, Maria NSS, Hovda DA. N-methyl-D-aspartate receptor subunit changes after traumatic injury to the developing brain. J Neurotrauma 2006; 23:950-61. [PMID: 16774479 PMCID: PMC2531140 DOI: 10.1089/neu.2006.23.950] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Traumatic brain injury (TBI) is a major cause of disability in the pediatric population and can result in abnormal development. Experimental studies conducted in animals have revealed impaired plasticity following developmental TBI, even in the absence of significant anatomical damage. The N-methyl-D-aspartate receptor (NMDAR) is clearly involved in both normal development and in the pathophysiology of TBI. Following lateral fluid percussion injury in postnatal day (PND) 19 rats, we tested the hypothesis that TBI sustained at an early age would result in impaired NMDAR expression. Using immunoblotting and reverse transcriptase-polymerase chain reaction (RT-PCR), protein and RNA levels of NMDAR subunits were measured in the cerebral cortex and hippocampus on post-injury days (PID) 1, 2, 4, and 7 (though the PID7 analysis was only for protein) and compared with age-matched shams. Significant effects of hemisphere (analysis of variance [ANOVA], p<0.01), and interactions between hemisphere and injury (ANOVA, p<0.05) and hemisphere and PID (ANOVA, p<0.05) were found for synaptic protein levels of the NR2A subunit in hippocampus. Specifically, within the ipsilateral hippocampus, NR2A was reduced by 9.9%, 47.9%, 40.8%, and 6.3% on PID1, PID2, PID4, and PID7, respectively. Within the cortex, there was a significant effect of injury (ANOVA, p<0.05) without any hemispheric differences. These bilateral cortical reductions measured 30.5%, 3.2%, 5.7%, and 13.4% at the same timepoints after injury. Injury had no significant main effect on NR1 or NR2B protein levels. RT-PCR analysis showed no significant changes in NR1, NR2A, or NR2B gene expression; however, as a positive control, hsp70 was induced more than twofold in ipsilateral cortex and hippocampus on PID1. It is known that NR2A expression levels increase during normal development, and in response to environmental stimuli. Our data suggest that injury-induced reduction in the expression of NR2A is one likely mechanism for the impaired experience-dependent neuroplasticity seen following traumatic injury to the immature brain.
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Affiliation(s)
- Christopher C Giza
- UCLA Brain Injury Research Center, Division of Neurosurgery/Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA.
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Chang W, Chen J, Wei QY, Chen XM. Effects of Brn-3a protein and RNA expression in rat brain following low-level lead exposure during development on spatial learning and memory. Toxicol Lett 2006; 164:63-70. [PMID: 16384672 DOI: 10.1016/j.toxlet.2005.11.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2005] [Revised: 11/21/2005] [Accepted: 11/21/2005] [Indexed: 11/26/2022]
Abstract
The developing nervous system is preferentially vulnerable to lead exposure with alterations in neuronal and glial cells of the brain. Chronic exposure to lead (Pb2+) causes deficits of learning and memory in children and spatial learning deficits in developing rats. Brn-3a is a member of the Pit-Oct-Unc (POU) family of transcription factors that is expressed predominantly in neuronal cells. It exists in two forms, with the long form containing 84 amino acids at the N-terminus that are lacking in the short form. The N-terminal domain unique to the long form induces expression of the Bcl-2 gene and protects neuronal cells against apoptosis whereas the C-terminal POU domain common to both forms is sufficient for activating a number of other neuronally expressed genes and stimulating neuronal process outgrowth. We examined Brn-3a protein and RNA expression in rat brain following low-level lead exposure during development and subsequent effects on spatial learning and memory. Two groups of rats were investigated: a control group and a lead-exposed group (0.2% lead acetate in the drinking water of the dam from gestational day 15 to postnatal day 21). Levels of Brn-3a were measured in rat cortex, hippocampus and cerebellum by immunohistochemistry and in situ hybridization, both protein and mRNA levels were reduced in lead-exposed group (p < 0.05). In Morris water maze, we found spatial learning deficits in rats of lead-exposed group (p < 0.05). These data suggest that the alteration of Brn-3a may play a key role in the mechanisms underlying lead neurotoxicity.
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Affiliation(s)
- Wei Chang
- Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huanzhong University of Science and Technology, Wuhan, Huibei 430030, PR China
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Moser VC, Barone S, Phillips PM, McDaniel KL, Ehman KD. Evaluation of developmental neurotoxicity of organotins via drinking water in rats: Monomethyl tin. Neurotoxicology 2006; 27:409-20. [PMID: 16442161 DOI: 10.1016/j.neuro.2005.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2005] [Revised: 12/02/2005] [Accepted: 12/06/2005] [Indexed: 02/05/2023]
Abstract
Organotins such as monomethyltin (MMT) are widely used as heat stabilizers in PVC and CPVC piping, which results in their presence in drinking water supplies. Concern for neurotoxicity produced by organotin exposure during development has been raised by published findings of a deficit on a runway learning task in rat pups perinatally exposed to MMT (Noland EA, Taylor DH, Bull RJ. Monomethyl and trimethyltin compounds induce learning deficiencies in young rats. Neurobehav Toxicol Teratol 1982;4:539-44). The objective of these studies was to replicate the earlier publication and further define the dose-response characteristics of MMT following perinatal exposure. In Experiment 1, female Sprague-Dawley rats were exposed via drinking water to MMT (0, 10, 50, 245 ppm) before mating and throughout gestation and lactation (until weaning at postnatal day [PND] 21). Behavioral assessments of the offspring included: a runway test (PND 11) in which the rat pups learned to negotiate a runway for dry suckling reward; motor activity habituation (PNDs 13, 17, and 21); learning in the Morris water maze (as adults). Other endpoints in the offspring included measures of apoptosis (DNA fragmentation) at PND 22 and as adults, as well as brain weights and neuropathological evaluation at PND 2, 12, 22, and as adults. There were no effects on any measure of growth, development, cognitive function, or apoptosis following MMT exposure. There was a trend towards decreased brain weight in the high dose group. In addition, there was vacuolation of the neuropil in a focal area of the cerebral cortex of the adult offspring in all MMT dose groups (1-3 rats per treatment group). In Experiment 2, pregnant rats were exposed from gestational day 6 until weaning to 500 ppm MMT in drinking water. The offspring behavioral assessments again included the runway task (PND 11), motor activity habituation (PND 17), and Morris water maze (as adults). In this second study, MMT-exposed females consumed significantly less water than the controls throughout both gestation and lactation, although neither dam nor pup weights were affected. As in Experiment 1, MMT-exposure did not alter pup runway performance, motor activity, or cognitive function. These results indicate that perinatal exposure to MMT, even at concentrations which decrease fluid intake, does not result in significant neurobehavioral or cognitive deficits. While mild neuropathological lesions were observed in the adult offspring, the biological significance of this restricted finding is unclear.
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Affiliation(s)
- Virginia C Moser
- Neurotoxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711, United States.
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Wang W, Duan B, Xu H, Xu L, Xu TL. Calcium-permeable acid-sensing ion channel is a molecular target of the neurotoxic metal ion lead. J Biol Chem 2005; 281:2497-505. [PMID: 16319075 DOI: 10.1074/jbc.m507123200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Acid-sensing ion channels (ASICs) are emerging as fundamental players in the regulation of neural plasticity and in pathological conditions. Here we showed that lead (Pb2+), a well known neurotoxic metal ion, reversibly and concentration-dependently inhibited ASIC currents in the acutely dissociated spinal dorsal horn and hippocampal CA1 neurons of rats. In vitro expression of ASIC subunits in combination demonstrated that both ASIC1 and -3 subunits were sensitive to Pb2+. Mechanistically, Pb2+ reduced the pH sensitivity of ASICs independent of membrane voltage change. Moreover, Pb2+ inhibited the ASIC-mediated membrane depolarization and the elevation of intracellular Ca2+ concentration. In addition, we compared the effect of Pb2+ with that of Ca2+ or amiloride to explore the possible interactions of Pb2+ and Ca2+ in regulating ASICs, and we found that Pb2+ inhibited ASIC currents independent of the amiloride/Ca2+ blockade. Because ASIC1b and -3 subunits are mainly expressed in peripheral neurons, our data identified ASIC1a-containing Ca2+-permeable ASIC as a novel central target of Pb2+ action, which may contribute to Pb2+ neurotoxicity.
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Affiliation(s)
- Wei Wang
- Institute of Neuroscience and Key Laboratory of Neurobiology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031
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46
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Toscano CD, Guilarte TR. Lead neurotoxicity: From exposure to molecular effects. ACTA ACUST UNITED AC 2005; 49:529-54. [PMID: 16269318 DOI: 10.1016/j.brainresrev.2005.02.004] [Citation(s) in RCA: 243] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2004] [Revised: 02/11/2005] [Accepted: 02/14/2005] [Indexed: 10/25/2022]
Abstract
The effects of lead (Pb(2+)) on human health have been recognized since antiquity. However, it was not until the 1970s that seminal epidemiological studies provided evidence on the effects of Pb(2+) intoxication on cognitive function in children. During the last two decades, advances in behavioral, cellular and molecular neuroscience have provided the necessary experimental tools to begin deciphering the many and complex effects of Pb(2+) on neuronal processes and cell types that are essential for synaptic plasticity and learning and memory in the mammalian brain. In this review, we concentrate our efforts on the effects of Pb(2+) on glutamatergic synapses and specifically on the accumulating evidence that the N-methyl-D-aspartate type of excitatory amino acid receptor (NMDAR) is a direct target for Pb(2+) effects in the brain. Our working hypothesis is that disruption of the ontogenetically defined pattern of NMDAR subunit expression and NMDAR-mediated calcium signaling in glutamatergic synapses is a principal mechanism for Pb(2+)-induced deficits in synaptic plasticity and in learning and memory documented in animal models of Pb(2+) neurotoxicity. We provide an introductory overview of the magnitude of the problem of Pb(2+) exposure to bring forth the reality that childhood Pb(2+) intoxication remains a major public health problem not only in the United States but worldwide. Finally, the latest research offers some hope that the devastating effects of childhood Pb(2+) intoxication in a child's ability to learn may be reversible if the appropriate stimulatory environment is provided.
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MESH Headings
- Animals
- Child
- Humans
- Lead/toxicity
- Lead Poisoning, Nervous System/metabolism
- Lead Poisoning, Nervous System/pathology
- Lead Poisoning, Nervous System/psychology
- Lead Poisoning, Nervous System, Childhood/epidemiology
- Lead Poisoning, Nervous System, Childhood/metabolism
- Lead Poisoning, Nervous System, Childhood/pathology
- Lead Poisoning, Nervous System, Childhood/psychology
- Receptors, N-Methyl-D-Aspartate/biosynthesis
- Receptors, N-Methyl-D-Aspartate/physiology
- Signal Transduction/drug effects
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Affiliation(s)
- Christopher D Toscano
- Department of Environmental Health Sciences, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
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Lim SY, Doherty JD, McBride K, Miller-Ihli NJ, Carmona GN, Stark KD, Salem N. Lead Exposure and (n-3) Fatty Acid Deficiency during Rat Neonatal Development Affect Subsequent Spatial Task Performance and Olfactory Discrimination. J Nutr 2005; 135:1019-26. [PMID: 15867275 DOI: 10.1093/jn/135.5.1019] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Docosahexaenoic acid [22:6(n-3), DHA] is important for optimal infant central nervous system development, and lead (Pb) exposure during development can produce neurological deficits. Long-Evans strain rats were fed either an (n-3) deficient [(n-3) Def] diet to produce brain DHA deficiency, or an adequate [(n-3) Adq] diet through 2 generations. At the birth of the 2nd generation, the dams were subdivided into 4 groups and supplied drinking water containing either 5.27 mmol/L (Pb) or sodium (Na) acetate until weaning. Rats were killed at 3 wk (weaning) and 11 wk (maturity) for brain Pb and fatty acid analysis. Spatial task and olfactory-cued behavioral assessments were initiated at 9 wk. Rats in the (n-3) Def group had a 79% lower concentration of brain DHA compared with the (n-3) Adq group with no effect of Pb exposure. At weaning, Pb concentrations were 7.17 +/- 0.47 nmol Pb/g of brain (wet weight) in the (n-3) Adq-Pb group and 6.49 +/- 0.63 nmol Pb/g of brain (wet weight) in the (n-3) Def-Pb group. At maturity, the brains contained 1.30 +/- 0.22 and 1.07 +/- 0.12 nmol Pb/g (wet weight), respectively. In behavioral testing, significant effects of both Pb and DHA deficiency were observed in the Morris water maze probe trial and in 2-odor olfactory discrimination acquisition and olfactory-based reversal learning tasks. Both lactational Pb exposure and (n-3) fatty acid deficiency led to behavioral deficits with additive effects observed only in the acquisition of 2-odor discriminations.
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Affiliation(s)
- Sun-Young Lim
- Division of Ocean Science, Korea Maritime University, Busan, Korea
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Gilbert ME, Kelly ME, Samsam TE, Goodman JH. Chronic developmental lead exposure reduces neurogenesis in adult rat hippocampus but does not impair spatial learning. Toxicol Sci 2005; 86:365-74. [PMID: 15788721 DOI: 10.1093/toxsci/kfi156] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The dentate granule cell (DG) layer of the hippocampal formation has the distinctive property of ongoing neurogenesis that continues throughout adult life. Although the function of these newly generated neurons and the mechanisms that control their birth are unknown, age, activity, diet and psychosocial stress have all been demonstrated to regulate this type of neurogenesis. Little information on the impact of environmental insults on this process has appeared to date. Developmental lead (Pb) exposure has been well documented to impair cognitive function in children and animals and reduce activity-dependent synaptic plasticity in the hippocampus of rodents. Therefore, we examined the effects of this classic environmental neurotoxicant on hippocampal-dependent learning and adult neurogenesis in the hippocampus. Pregnant rats were exposed to a low level of Pb-acetate (0.2%) via the drinking water from late gestation (GD 16) until weaning on postnatal day 21 (PN 21). At weaning, half of the Pb-exposed animals were weaned to control drinking water and the remainder were maintained on Pb water until termination of the study. Animals were paired- housed and on PN 75 were administered a series of injections of a thymidine analog bromodeoxyuridine (BrdU), a marker of DNA synthesis that labels proliferating cells and their progeny. At 12-h intervals for 12 days, rats received an ip injection of BrdU (50 mg/kg). Subjects were sacrificed and perfused 24 h and 28 days after the last injection. Spatial learning was assessed in an independent group of animals beginning on PN 110 using a Morris water maze. No Pb-induced impairments were evident in water maze learning. Immunohistochemistry for the detection of BrdU-labeled cells was performed on 40-microm coronal sections throughout the hippocampus. Continuous exposure to Pb (Life) reduced the total number of BrdU-positive cells at 28 days without affecting the total number of labeled cells evident 24 h after the last injection. No differences in the number of progenitor cells labeled or surviving were seen between control and treated animals whose Pb exposure was terminated at weaning. Double labeling with BrdU and the glial specific marker, glial acidic fibrillary protein (GFAP) indicated that the bulk of the surviving cells were of a neuronal rather than a glial phenotype. These data reveal that chronic low-level Pb exposure reduces the capacity for neurogenesis in the adult hippocampus. Despite deficits in synaptic plasticity previously reported from our laboratory, and now structural plasticity, no significant impact on spatial learning was detected.
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Affiliation(s)
- M E Gilbert
- Neurotoxicology Division, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.
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Vázquez A, Peña de Ortiz S. Lead (Pb(+2)) impairs long-term memory and blocks learning-induced increases in hippocampal protein kinase C activity. Toxicol Appl Pharmacol 2004; 200:27-39. [PMID: 15451305 DOI: 10.1016/j.taap.2004.03.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2003] [Accepted: 03/18/2004] [Indexed: 11/28/2022]
Abstract
The long-term storage of information in the brain known as long-term memory (LTM) depends on a variety of intracellular signaling cascades utilizing calcium (Ca2+) and cyclic adenosine monophosphate as second messengers. In particular, Ca(+2)/phospholipid-dependent protein kinase C (PKC) activity has been proposed to be necessary for the transition from short-term memory to LTM. Because the neurobehavioral toxicity of lead (Pb(+2)) has been associated to its interference with normal Ca(+2) signaling in neurons, we studied its effects on spatial learning and memory using a hippocampal-dependent discrimination task. Adult rats received microinfusions of either Na+ or Pb(+2) acetate in the CA1 hippocampal subregion before each one of four training sessions. A retention test was given 7 days later to examine LTM. Results suggest that intrahippocampal Pb(+2) did not affect learning of the task, but significantly impaired retention. The effects of Pb(+2) selectively impaired reference memory measured in the retention test, but had no effect on the general performance because it did not affect the latency to complete the task during the test. Finally, we examined the effects of Pb(+2) on the induction of hippocampal Ca(+2)/phospholipid-dependent PKC activity during acquisition training. The results showed that Pb(+2) interfered with the learning-induced activation of Ca(+2)/phospholipid-dependent PKC on day 3 of acquisition. Overall, our results indicate that Pb(+2) causes cognitive impairments in adult rats and that such effects might be subserved by interference with Ca(+2)-related signaling mechanisms required for normal LTM.
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Affiliation(s)
- Adrinel Vázquez
- Department of Biology, University of Puerto Rico, San Juan 00931-3360, Puerto Rico
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Mickley GA, Kenmuir CL, McMullen CA, Snyder A, Yocom AM, Likins-Fowler D, Valentine EL, Weber B, Biada JM. Long-term age-dependent behavioral changes following a single episode of fetal N-methyl-D-Aspartate (NMDA) receptor blockade. BMC Pharmacol 2004; 4:28. [PMID: 15509306 PMCID: PMC528728 DOI: 10.1186/1471-2210-4-28] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2004] [Accepted: 10/28/2004] [Indexed: 11/21/2022] Open
Abstract
Background Administration of the N-methyl-D-aspartate (NMDA) antagonist ketamine during the perinatal period can produce a variety of behavioral and neuroanatomical changes. Our laboratory has reported reliable changes in learning and memory following a single dose of ketamine administered late in gestation. However, the nature of the drug-induced changes depends on the point during embryonic development when ketamine is administered. Embryonic day 18 (E18) rat fetuses pre-treated with ketamine (100 mg/kg, i.p. through the maternal circulation) and taught a conditioned taste aversion (CTA) learn and remember the CTA, whereas E19 fetuses do not. The current study sought to determine if long-term behavioral effects could be detected in animals that received ketamine or a saline control injection on either E18 or E19. Rat behavior was evaluated on two different measures: spontaneous locomotion and water maze learning. Measurements were collected during 2 periods: Juvenile test period [pre-pubertal locomotor test: Postnatal Day 11 (P11); pre-pubertal water maze test: P18] or Young-adult test period [post-pubertal locomotor test: P60; post-pubertal water maze test: P81]. Results Water maze performance of ketamine-treated rats was similar to that of controls when tested on P18. Likewise, the age of the animal at the time of ketamine/saline treatment did not influence learning of the maze. However, the young-adult water maze test (P81) revealed reliable benefits of prenatal ketamine exposure – especially during the initial re-training trial. On the first trial of the young adult test, rats treated with ketamine on E18 reached the hidden platform faster than any other group – including rats treated with ketamine on E19. Swim speeds of experimental and control rats were not significantly different. Spontaneous horizontal locomotion measured during juvenile testing indicated that ketamine-treated rats were less active than controls. However, later in development, rats treated with ketamine on E18 were more active than rats that received the drug on E19. Conclusion These data suggest that both the day in fetal development when ketamine is administered and the timing of post-natal behavioral testing interact to influence behavioral outcomes. The data also indicate that the paradoxical age-dependent effects of early ketamine treatment on learning, previously described in fetuses and neonates, may also be detected later in young adult rats.
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Affiliation(s)
- G Andrew Mickley
- Department of Psychology and the Neuroscience Program, Baldwin-Wallace College, 275 Eastland Road, Berea, OH 44017-2088, USA
| | - Cynthia L Kenmuir
- Department of Psychology and the Neuroscience Program, Baldwin-Wallace College, 275 Eastland Road, Berea, OH 44017-2088, USA
| | - Colleen A McMullen
- Department of Psychology and the Neuroscience Program, Baldwin-Wallace College, 275 Eastland Road, Berea, OH 44017-2088, USA
| | - Alicia Snyder
- Department of Psychology and the Neuroscience Program, Baldwin-Wallace College, 275 Eastland Road, Berea, OH 44017-2088, USA
| | - Anna M Yocom
- Department of Psychology and the Neuroscience Program, Baldwin-Wallace College, 275 Eastland Road, Berea, OH 44017-2088, USA
| | - Deborah Likins-Fowler
- Department of Psychology and the Neuroscience Program, Baldwin-Wallace College, 275 Eastland Road, Berea, OH 44017-2088, USA
| | - Elizabeth L Valentine
- Department of Psychology and the Neuroscience Program, Baldwin-Wallace College, 275 Eastland Road, Berea, OH 44017-2088, USA
| | - Bettina Weber
- Department of Psychology and the Neuroscience Program, Baldwin-Wallace College, 275 Eastland Road, Berea, OH 44017-2088, USA
| | - Jaclyn M Biada
- Department of Psychology and the Neuroscience Program, Baldwin-Wallace College, 275 Eastland Road, Berea, OH 44017-2088, USA
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