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Muza PM, Pérez M, Noy S, Kurosawa M, Katsouri L, Tybulewicz VLJ, Fisher EMC, West SJ. Affordable optical clearing and immunolabelling in mouse brain slices. BMC Res Notes 2023; 16:246. [PMID: 37777793 PMCID: PMC10543858 DOI: 10.1186/s13104-023-06511-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 09/15/2023] [Indexed: 10/02/2023] Open
Abstract
Traditional histological analysis is conducted on thin tissue sections, limiting the data capture from large tissue volumes to 2D profiles, and requiring stereological methods for 3D assessment. Recent advances in microscopical and tissue clearing methods have facilitated 3D reconstructions of tissue structure. However, staining of large tissue blocks remains a challenge, often requiring specialised and expensive equipment to clear and immunolabel tissue. Here, we present the Affordable Brain Slice Optical Clearing (ABSOC) method: a modified iDISCO protocol which enables clearing and immunolabeling of mouse brain slices up to 1 mm thick using inexpensive reagents and equipment, with no intensive expert training required. We illustrate the use of ABSOC in 1 mm C57BL/6J mouse coronal brain slices sectioned through the dorsal hippocampus and immunolabelled with an anti-calretinin antibody. The ABSOC method can be readily used for histological studies of mouse brain in order to move from the use of very thin tissue sections to large volumes of tissue - giving more representative analysis of biological samples, without the need for sampling of small regions only.
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Affiliation(s)
- Phillip M Muza
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, Queen Square, London, WC1N 3BG, UK
| | - Marta Pérez
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, Queen Square, London, WC1N 3BG, UK
| | - Suzanna Noy
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, Queen Square, London, WC1N 3BG, UK
| | - Miyu Kurosawa
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, Queen Square, London, WC1N 3BG, UK
| | - Loukia Katsouri
- Sainsbury Wellcome Centre, University College London, 25 Howland Street, London, W1T 4JG, UK
| | | | - Elizabeth M C Fisher
- Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London, Queen Square, London, WC1N 3BG, UK
| | - Steven J West
- Sainsbury Wellcome Centre, University College London, 25 Howland Street, London, W1T 4JG, UK.
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2
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Knowles JK, Xu H, Soane C, Batra A, Saucedo T, Frost E, Tam LT, Fraga D, Ni L, Villar K, Talmi S, Huguenard JR, Monje M. Maladaptive myelination promotes generalized epilepsy progression. Nat Neurosci 2022; 25:596-606. [PMID: 35501379 PMCID: PMC9076538 DOI: 10.1038/s41593-022-01052-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 03/14/2022] [Indexed: 12/18/2022]
Abstract
Activity-dependent myelination can fine-tune neural network dynamics. Conversely, aberrant neuronal activity, as occurs in disorders of recurrent seizures (epilepsy), could promote maladaptive myelination, contributing to pathogenesis. In this study, we tested the hypothesis that activity-dependent myelination resulting from absence seizures, which manifest as frequent behavioral arrests with generalized electroencephalography (EEG) spike-wave discharges, promote thalamocortical network hypersynchrony and contribute to epilepsy progression. We found increased oligodendrogenesis and myelination specifically within the seizure network in two models of generalized epilepsy with absence seizures (Wag/Rij rats and Scn8a+/mut mice), evident only after epilepsy onset. Aberrant myelination was prevented by pharmacological seizure inhibition in Wag/Rij rats. Blocking activity-dependent myelination decreased seizure burden over time and reduced ictal synchrony as assessed by EEG coherence. These findings indicate that activity-dependent myelination driven by absence seizures contributes to epilepsy progression; maladaptive myelination may be pathogenic in some forms of epilepsy and other neurological diseases.
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Affiliation(s)
- Juliet K Knowles
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.
| | - Haojun Xu
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
- Ph.D. Program in Human Biology, School of Integrative and Global Majors, University of Tsukuba, Tsukuba, Japan
| | - Caroline Soane
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Ankita Batra
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Tristan Saucedo
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Eleanor Frost
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Lydia T Tam
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Danielle Fraga
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Lijun Ni
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Katlin Villar
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Sydney Talmi
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - John R Huguenard
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.
| | - Michelle Monje
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA.
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Vargas-Rodríguez I, Reyes-Castro LA, Pacheco-López G, Lomas-Soria C, Zambrano E, Díaz-Ruíz A, Diaz-Cintra S. POSTNATAL EXPOSURE TO LIPOPOLYSACCHARIDE COMBINED WITH HIGH-FAT DIET CONSUMPTION INDUCES IMMUNE TOLERANCE WITHOUT PREVENTION IN SPATIAL WORKING MEMORY IMPAIRMENT. Behav Brain Res 2022; 423:113776. [PMID: 35120930 DOI: 10.1016/j.bbr.2022.113776] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 01/21/2022] [Accepted: 01/30/2022] [Indexed: 02/05/2023]
Abstract
High-fat diet (HFD) consumption has been related to metabolic alterations, such as obesity and cardiovascular problems, and has pronounced effects on brain plasticity and memory impairment. HFD exposure has a pro-inflammatory effect associated with microglial cell modifications in the hippocampus, a region involved in the working memory process. Immune tolerance can protect from inflammation in periphery induced by HFD consumption, when the immune response is desensitized in development period with lipopolysaccharide (LPS) exposure, maybe this previously state can change the course of the diseases associated to HFDs but is not known if can protect the hippocampus's inflammatory response. In the present study, male mice were injected with LPS (100μg.kg-1 body weight) on postnatal day 3 and fed with HFD for 16 weeks after weaning. Ours results indicated that postnatal exposure to LPS in the early postnatal developmental stage combined with HFD consumption prevented glycemia, insulin, HOMA-IR, microglial process, and increased pro-inflammatory cytokines mRNA expression, without changes in body weight gain and spatial working memory with respect vehicle + HFD group. These findings suggest that HFD consumption after postnatal LPS exposure induces hippocampal immune tolerance, without prevention in spatial working memory impairment on male mice.
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Affiliation(s)
- Isaac Vargas-Rodríguez
- Departamento de Neurobiología del Desarrollo y Neurofisiología. Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, C.P. 76230, México
| | - Luis Antonio Reyes-Castro
- Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición, Salvador Zubirán, México 14080
| | - Gustavo Pacheco-López
- División de Ciencias de Biológicas y de la Salud, Universidad Autónoma Metropolitana, Unidad Lerma, Estado de México, C.P. 52005, México
| | - Consuelo Lomas-Soria
- Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición, Salvador Zubirán, México 14080; CONACyT-Cátedras, Departamento de Biología de la Reproducción. Instituto Nacional de Ciencias Médicas y Nutrición, Salvador Zubirán, México 14080
| | - Elena Zambrano
- Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición, Salvador Zubirán, México 14080
| | - Araceli Díaz-Ruíz
- Departamento de Neuroquímica, Instituto Nacional de Neurologı́a y Neurocirugı́a, Manuel Velasco Suárez S.S.A, México, CP, 14269, México
| | - Sofía Diaz-Cintra
- Departamento de Neurobiología del Desarrollo y Neurofisiología. Instituto de Neurobiología, Universidad Nacional Autónoma de México, Querétaro, C.P. 76230, México.
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Shin S, Kim D, Song JY, Jeong H, Hyeon SJ, Kowall NW, Ryu H, Pae AN, Lim S, Kim YK. Visualization of soluble tau oligomers in TauP301L-BiFC transgenic mice demonstrates the progression of tauopathy. Prog Neurobiol 2020; 187:101782. [PMID: 32105751 DOI: 10.1016/j.pneurobio.2020.101782] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 02/16/2020] [Accepted: 02/21/2020] [Indexed: 11/30/2022]
Abstract
Accumulation of abnormal tau aggregates in the brain is a pathological hallmark of multiple neurodegenerative disorders including Alzheimer's disease. Increasing evidence suggests that soluble tau aggregates play a key role in tau pathology as neurotoxic species causing neuronal cell death and act as prion-like seeds mediating tau propagation. Despite the pathological relevance, there is a paucity of methods to monitor tau oligomerization in the brain. As a tool to monitor tau self-assembly in the brain, we generated a novel tau transgenic mouse, named TauP301L-BiFC. By introducing bimolecular fluorescence complementation technique to human tau containing a P301L mutation, we were able to monitor and quantify tau self-assembly, represented by BiFC fluorescence in the brains of transgenic TauP301L-BiFC mice. TauP301L-BiFC mice showed soluble tau oligomerization from 3 months, showing significantly enriched BiFC fluorescence in the brain. Then, massive tau fragmentation occured at 6 months showing dramatically decreased TauP301L-BiFC fluorescence. The fragmented tau species served as a seed for insoluble tau aggregation. In a result, insoluble TauP301L-BiFC aggregates coaggregated with endogenous mouse tau accumulated in the brain, showing subsequently increased BiFC fluorescence from 9 months. Neuronal degeneration and cognitive deficits were observed from 12 months of age. TauP301L-BiFC mouse model demonstrated that methylene blue reduced the amount of soluble tau oligomers in the brain, resulting in the prevention of cognitive impairments. We assure that TauP301L-BiFC mice are a bona-fide animal tool to monitor pathological tau oligomerization in AD and other tauopathies.
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Affiliation(s)
- Seulgi Shin
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea; Division of Bio-Medical Science & Technology, KIST School, University of Science and Technology (UST), Seoul, 02792, Republic of Korea
| | - Dohee Kim
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Ji Yeon Song
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Hyeanjeong Jeong
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea; Department of Life Sciences, School of Life Sciences and Biotechnology, Korea University, Seoul, 02841, Republic of Korea
| | - Seung Jae Hyeon
- Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Neil W Kowall
- Boston University Alzheimer's Disease Center and Department of Neurology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Hoon Ryu
- Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea; Boston University Alzheimer's Disease Center and Department of Neurology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Ae Nim Pae
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea; Division of Bio-Medical Science & Technology, KIST School, University of Science and Technology (UST), Seoul, 02792, Republic of Korea
| | - Sungsu Lim
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea.
| | - Yun Kyung Kim
- Convergence Research Center for Diagnosis, Treatment and Care System of Dementia, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea; Division of Bio-Medical Science & Technology, KIST School, University of Science and Technology (UST), Seoul, 02792, Republic of Korea.
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5
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Gasser J, Pereira de Vasconcelos A, Cosquer B, Boutillier AL, Cassel JC. Shifting between response and place strategies in maze navigation: Effects of training, cue availability and functional inactivation of striatum or hippocampus in rats. Neurobiol Learn Mem 2020; 167:107131. [DOI: 10.1016/j.nlm.2019.107131] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 11/15/2019] [Accepted: 11/25/2019] [Indexed: 11/24/2022]
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Kuruba R, Wu X, Reddy DS. Benzodiazepine-refractory status epilepticus, neuroinflammation, and interneuron neurodegeneration after acute organophosphate intoxication. Biochim Biophys Acta Mol Basis Dis 2018; 1864:2845-2858. [PMID: 29802961 PMCID: PMC6066461 DOI: 10.1016/j.bbadis.2018.05.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 04/30/2018] [Accepted: 05/22/2018] [Indexed: 12/19/2022]
Abstract
Nerve agents and some pesticides such as diisopropylfluorophosphate (DFP) cause neurotoxic manifestations that include seizures and status epilepticus (SE), which are potentially lethal and carry long-term neurological morbidity. Current antidotes for organophosphate (OP) intoxication include atropine, 2-PAM and diazepam (a benzodiazepine for treating seizures and SE). There is some evidence for partial or complete loss of diazepam anticonvulsant efficacy when given 30 min or later after exposure to an OP; this condition is known as refractory SE. Effective therapies for OP-induced SE are lacking and it is unclear why current therapies do not work. In this study, we investigated the time-dependent efficacy of diazepam in the nerve agent surrogate DFP model of OP intoxication on seizure suppression and neuroprotection in rats, following an early and late therapy. Diazepam (5 mg/kg, IM) controlled seizures when given 10 min after DFP exposure ("early"), but it was completely ineffective at 60 or 120 min ("late") after DFP. DFP-induced neuronal injury, neuroinflammation, and neurodegeneration of principal cells and GABAergic interneurons were significantly reduced by early but not late therapy. These findings demonstrate that diazepam failed to control seizures, SE and neuronal injury when given 60 min or later after DFP exposure, confirming the benzodiazepine-refractory SE and brain damage after OP intoxication. In addition, this study indicates that degeneration of inhibitory interneurons and inflammatory glial activation are potential mechanisms underlying these morbid outcomes of OP intoxication. Therefore, novel anticonvulsant and neuroprotectant antidotes, superior to benzodiazepines, are desperately needed for controlling nerve agent-induced SE and brain injury.
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Affiliation(s)
- Ramkumar Kuruba
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of Medicine, Bryan, TX 77807, USA
| | - Xin Wu
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of Medicine, Bryan, TX 77807, USA
| | - Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of Medicine, Bryan, TX 77807, USA.
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Napper RMA. Total Number Is Important: Using the Disector Method in Design-Based Stereology to Understand the Structure of the Rodent Brain. Front Neuroanat 2018; 12:16. [PMID: 29556178 PMCID: PMC5844935 DOI: 10.3389/fnana.2018.00016] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 02/15/2018] [Indexed: 12/15/2022] Open
Abstract
The advantages of using design-based stereology in the collection of quantitative data, have been highlighted, in numerous publications, since the description of the disector method by Sterio (1984). This review article discusses the importance of total number derived with the disector method, as a key variable that must continue to be used to understand the rodent brain and that such data can be used to develop quantitative networks of the brain. The review article will highlight the huge impact total number has had on our understanding of the rodent brain and it will suggest that neuroscientists need to be aware of the increasing number of studies where density, not total number, is the quantitative measure used. It will emphasize that density can result in data that is misleading, most often in an unknown direction, and that we run the risk of this type of data being accepted into the collective neuroscience knowledge database. It will also suggest that design-based stereology using the disector method, can be used alongside recent developments in electron microscopy, such as serial block-face scanning electron microscopy (SEM), to obtain total number data very efficiently at the ultrastructural level. Throughout the article total number is discussed as a key parameter in understanding the micro-networks of the rodent brain as they can be represented as both anatomical and quantitative networks.
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Affiliation(s)
- Ruth M A Napper
- Brain Health Research Centre, Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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8
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Puga S, Pereira P, Pinto-Ribeiro F, O'Driscoll NJ, Mann E, Barata M, Pousão-Ferreira P, Canário J, Almeida A, Pacheco M. Unveiling the neurotoxicity of methylmercury in fish (Diplodus sargus) through a regional morphometric analysis of brain and swimming behavior assessment. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 180:320-333. [PMID: 27780124 DOI: 10.1016/j.aquatox.2016.10.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 10/11/2016] [Accepted: 10/14/2016] [Indexed: 06/06/2023]
Abstract
The current study aims to shed light on the neurotoxicity of MeHg in fish (white seabream - Diplodus sargus) by the combined assessment of: (i) MeHg toxicokinetics in the brain, (ii) brain morphometry (volume and number of neurons plus glial cells in specific brain regions) and (iii) fish swimming behavior (endpoints associated with the motor performance and the fear/anxiety-like status). Fish were surveyed for all the components after 7 (E7) and 14 (E14) days of dietary exposure to MeHg (8.7μgg-1), as well as after a post-exposure period of 28days (PE28). MeHg was accumulated in the brain of D. sargus after a short time (E7) and reached a maximum at the end of the exposure period (E14), suggesting an efficient transport of this toxicant into fish brain. Divalent inorganic Hg was also detected in fish brain along the experiment (indicating demethylation reactions), although levels were 100-200 times lower than MeHg, which pinpoints the organic counterpart as the great liable for the recorded effects. In this regard, a decreased number of cells in medial pallium and optic tectum, as well as an increased hypothalamic volume, occurred at E7. Such morphometric alterations were followed by an impairment of fish motor condition as evidenced by a decrease in the total swimming time, while the fear/anxiety-like status was not altered. Moreover, at E14 fish swam a greater distance, although no morphometric alterations were found in any of the brain areas, probably due to compensatory mechanisms. Additionally, although MeHg decreased almost two-fold in the brain during post-exposure, the levels were still high and led to a loss of cells in the optic tectum at PE28. This is an interesting result that highlights the optic tectum as particularly vulnerable to MeHg exposure in fish. Despite the morphometric alterations reported in the optic tectum at PE28, no significant changes were found in fish behavior. Globally, the effects of MeHg followed a multiphasic profile, where homeostatic mechanisms prevented circumstantially morphometric alterations in the brain and behavioral shifts. Although it has become clear the complexity of matching brain morphometric changes and behavioral shifts, motor-related alterations induced by MeHg seem to depend on a combination of disruptions in different brain regions.
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Affiliation(s)
- Sónia Puga
- Life and Health Sciences Research Institute (ICVS), School of Medicine, Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Patrícia Pereira
- Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Filipa Pinto-Ribeiro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Nelson J O'Driscoll
- Department of Earth and Environmental Science, Center for Analytical Research on the Environment, K.C. Irving Center, Acadia University, Wolfville, Nova Scotia, Canada
| | - Erin Mann
- Department of Earth and Environmental Science, Center for Analytical Research on the Environment, K.C. Irving Center, Acadia University, Wolfville, Nova Scotia, Canada
| | - Marisa Barata
- IPMA - Aquaculture Research Station, 8700-005 Olhão, Portugal
| | | | - João Canário
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Armando Almeida
- Life and Health Sciences Research Institute (ICVS), School of Medicine, Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Mário Pacheco
- Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
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Pereira P, Puga S, Cardoso V, Pinto-Ribeiro F, Raimundo J, Barata M, Pousão-Ferreira P, Pacheco M, Almeida A. Inorganic mercury accumulation in brain following waterborne exposure elicits a deficit on the number of brain cells and impairs swimming behavior in fish (white seabream-Diplodus sargus). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 170:400-412. [PMID: 26688460 DOI: 10.1016/j.aquatox.2015.11.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 11/30/2015] [Accepted: 11/30/2015] [Indexed: 06/05/2023]
Abstract
The current study contributes to fill the knowledge gap on the neurotoxicity of inorganic mercury (iHg) in fish through the implementation of a combined evaluation of brain morphometric alterations (volume and total number of neurons plus glial cells in specific regions of the brain) and swimming behavior (endpoints related with the motor activity and mood/anxiety-like status). White seabream (Diplodus sargus) was exposed to realistic levels of iHg in water (2μgL(-1)) during 7 (E7) and 14 days (E14). After that, fish were allowed to recover for 28 days (PE28) in order to evaluate brain regeneration and reversibility of behavioral syndromes. A significant reduction in the number of cells in hypothalamus, optic tectum and cerebellum was found at E7, accompanied by relevant changes on swimming behavior. Moreover, the decrease in the number of neurons and glia in the molecular layer of the cerebellum was followed by a contraction of its volume. This is the first time that a deficit on the number of cells is reported in fish brain after iHg exposure. Interestingly, a recovery of hypothalamus and cerebellum occurred at E14, as evidenced by the identical number of cells found in exposed and control fish, and volume of cerebellum, which might be associated with an adaptive phenomenon. After 28 days post-exposure, the optic tectum continued to show a decrease in the number of cells, pointing out a higher vulnerability of this region. These morphometric alterations coincided with numerous changes on swimming behavior, related both with fish motor function and mood/anxiety-like status. Overall, current data pointed out the iHg potential to induce brain morphometric alterations, emphasizing a long-lasting neurobehavioral hazard.
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Affiliation(s)
- Patrícia Pereira
- Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Sónia Puga
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences (ECS), Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Vera Cardoso
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences (ECS), Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Filipa Pinto-Ribeiro
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences (ECS), Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Joana Raimundo
- IPMA-Portuguese Institute for the Sea and Atmosphere, Av. Brasília, 1449-006 Lisbon, Portugal
| | - Marisa Barata
- IPMA-Aquaculture Research Station, 8700-005 Olhão, Portugal
| | | | - Mário Pacheco
- Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Armando Almeida
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences (ECS), Campus of Gualtar, University of Minho, 4750-057 Braga, Portugal; ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
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10
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Golub VM, Brewer J, Wu X, Kuruba R, Short J, Manchi M, Swonke M, Younus I, Reddy DS. Neurostereology protocol for unbiased quantification of neuronal injury and neurodegeneration. Front Aging Neurosci 2015; 7:196. [PMID: 26582988 PMCID: PMC4628120 DOI: 10.3389/fnagi.2015.00196] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 10/02/2015] [Indexed: 01/31/2023] Open
Abstract
Neuronal injury and neurodegeneration are the hallmark pathologies in a variety of neurological conditions such as epilepsy, stroke, traumatic brain injury, Parkinson's disease and Alzheimer's disease. Quantification of absolute neuron and interneuron counts in various brain regions is essential to understand the impact of neurological insults or neurodegenerative disease progression in animal models. However, conventional qualitative scoring-based protocols are superficial and less reliable for use in studies of neuroprotection evaluations. Here, we describe an optimized stereology protocol for quantification of neuronal injury and neurodegeneration by unbiased counting of neurons and interneurons. Every 20th section in each series of 20 sections was processed for NeuN(+) total neuron and parvalbumin(+) interneuron immunostaining. The sections that contain the hippocampus were then delineated into five reliably predefined subregions. Each region was separately analyzed with a microscope driven by the stereology software. Regional tissue volume was determined by using the Cavalieri estimator, as well as cell density and cell number were determined by using the optical disector and optical fractionator. This protocol yielded an estimate of 1.5 million total neurons and 0.05 million PV(+) interneurons within the rat hippocampus. The protocol has greater predictive power for absolute counts as it is based on 3D features rather than 2D images. The total neuron counts were consistent with literature values from sophisticated systems, which are more expensive than our stereology system. This unbiased stereology protocol allows for sensitive, medium-throughput counting of total neurons in any brain region, and thus provides a quantitative tool for studies of neuronal injury and neurodegeneration in a variety of acute brain injury and chronic neurological models.
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Affiliation(s)
- Victoria M. Golub
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of MedicineBryan, TX, USA
| | - Jonathan Brewer
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of MedicineBryan, TX, USA
| | - Xin Wu
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of MedicineBryan, TX, USA
| | - Ramkumar Kuruba
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of MedicineBryan, TX, USA
| | - Jenessa Short
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of MedicineBryan, TX, USA
| | - Maunica Manchi
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of MedicineBryan, TX, USA
| | - Megan Swonke
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of MedicineBryan, TX, USA
| | - Iyan Younus
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of MedicineBryan, TX, USA
| | - Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of MedicineBryan, TX, USA
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Cholvin T, Loureiro M, Cassel R, Cosquer B, Herbeaux K, de Vasconcelos AP, Cassel JC. Dorsal hippocampus and medial prefrontal cortex each contribute to the retrieval of a recent spatial memory in rats. Brain Struct Funct 2014; 221:91-102. [PMID: 25260556 DOI: 10.1007/s00429-014-0894-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 09/19/2014] [Indexed: 01/25/2023]
Abstract
Systems-level consolidation models propose that recent memories are initially hippocampus-dependent. When remote, they are partially or completely dependent upon the medial prefrontal cortex (mPFC). An implication of the mPFC in recent memory, however, is still debated. Different amounts of muscimol (MSCI 0, 30, 50, 80 and 250 ng in 1 µL PBS) were used to assess the impact of inactivation of the dorsal hippocampus (dHip) or the mPFC (targeting the prelimbic cortex) on a 24-h delayed retrieval of a platform location that rats had learned drug-free in a water maze. The two smallest amounts of MSCI (30 and 50 ng) did not affect recall, whatever the region. 80 ng MSCI infused into the dHip disrupted spatial memory retrieval, as did the larger amount. Infusion of MSCI into the mPFC did not alter performance in the 0-80 ng range. At 250 ng, it induced an as dramatic memory impairment as after efficient dHip inactivation. Stereological quantifications showed that 80 ng MSCI in the dHip and 250 ng MSCI in the mPFC induced a more than 80% reduction of c-Fos expression, suggesting that, beyond the amounts infused, it is the magnitude of the neuronal activity decrease which is determinant as to the functional outcome of the inactivation. Because, based on the literature, even 250 ng MSCI is a small amount, our results point to a contribution of the mPFC to the recall of a recently acquired spatial memory and thereby extend our knowledge about the functions of this major actor of cognition.
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Affiliation(s)
- Thibault Cholvin
- Laboratoire de Neurosciences Cognitives et Adaptatives, UMR 7364, CNRS, Université de Strasbourg, Neuropôle de Strasbourg, GDR 2905 du CNRS, Faculté de Psychologie, 12 rue Goethe, 67000, Strasbourg, France
| | - Michaël Loureiro
- Laboratoire de Neurosciences Cognitives et Adaptatives, UMR 7364, CNRS, Université de Strasbourg, Neuropôle de Strasbourg, GDR 2905 du CNRS, Faculté de Psychologie, 12 rue Goethe, 67000, Strasbourg, France
| | - Raphaelle Cassel
- Laboratoire de Neurosciences Cognitives et Adaptatives, UMR 7364, CNRS, Université de Strasbourg, Neuropôle de Strasbourg, GDR 2905 du CNRS, Faculté de Psychologie, 12 rue Goethe, 67000, Strasbourg, France
| | - Brigitte Cosquer
- Laboratoire de Neurosciences Cognitives et Adaptatives, UMR 7364, CNRS, Université de Strasbourg, Neuropôle de Strasbourg, GDR 2905 du CNRS, Faculté de Psychologie, 12 rue Goethe, 67000, Strasbourg, France
| | - Karin Herbeaux
- Laboratoire de Neurosciences Cognitives et Adaptatives, UMR 7364, CNRS, Université de Strasbourg, Neuropôle de Strasbourg, GDR 2905 du CNRS, Faculté de Psychologie, 12 rue Goethe, 67000, Strasbourg, France
| | - Anne Pereira de Vasconcelos
- Laboratoire de Neurosciences Cognitives et Adaptatives, UMR 7364, CNRS, Université de Strasbourg, Neuropôle de Strasbourg, GDR 2905 du CNRS, Faculté de Psychologie, 12 rue Goethe, 67000, Strasbourg, France.
| | - Jean-Christophe Cassel
- Laboratoire de Neurosciences Cognitives et Adaptatives, UMR 7364, CNRS, Université de Strasbourg, Neuropôle de Strasbourg, GDR 2905 du CNRS, Faculté de Psychologie, 12 rue Goethe, 67000, Strasbourg, France
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West MJ. Counting and measuring ultrastructural features of biological samples. Cold Spring Harb Protoc 2013; 2013:593-605. [PMID: 23818664 DOI: 10.1101/pdb.top071886] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Ultrastructural features of cells can be fractions of a micrometer in diameter, and electron microscopy is needed to resolve them to a degree that is compatible with stereological techniques. Because the focal depth of transmission electron microscopy (TEM) images is thousands of times greater than the thickness of the sections used with TEM, virtual sectioning of sections suitable for TEM is not possible, as it is with light microscopy and the optical disector probe. With features the size of neuronal synapses, for example, this necessitates the use of physical sections and physical disectors. Regardless of how the imaging is performed, the design of stereological studies for quantifying ultrastructural features will be essentially the same as that used in the example described here, which uses physically separated ultrathin sections viewed with conventional TEM to estimate the number and size of synapses in a particular brain region.
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West MJ. Optimizing the sampling scheme for a stereological study: how many individuals, sections, and probes should be used. Cold Spring Harb Protoc 2013; 2013:521-32. [PMID: 23734015 DOI: 10.1101/pdb.top071852] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Stereology provides meaningful quantitative descriptions of the geometry of three-dimensional (3D) structures from measurements that are made on two-dimensional (2D) images. A pilot stereological study will provide information that can be used to rationalize how many individuals, sections, and probes should be used to ensure that one is sampling enough, but not too much, to achieve the goal of a study. This general approach is exemplified in the thought experiment described here, which involves a comparison of the means of estimates of the total number of neurons N in two groups, using the simplest of statistical tests, the Student's t-test. It is also applicable to studies involving other estimates of total quantities such as volume, surface, and length obtained from a parallel series of sections.
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Abstract
Length estimates of particular features of biological tissues can be useful in evaluating function. Such estimates have been notoriously difficult to obtain because of the requirement for an isotropic interaction between the area probes and the linear features of cells and tissues, which are most likely not isotropically oriented. For complex embedded structures, such as subdivisions of the brain, the turning of the tissue before sectioning that is needed to ensure an isotropic interaction has made it difficult to delineate many regions of interest and limited the number of unbiased stereological studies of length. The recent development of a virtual isotropic spherical probe, the spaceball, makes it relatively easy for the isotropic interaction between probe and structure to be realized. This article describes the use of the spaceball probe to estimate length, and gives an example of estimating total capillary length in CA1 stratum radiatum of the human hippocampus.
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