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Ribeiro RM, da Silveira EP, Santos VC, Teixeira LL, Santos GS, Galvão IN, Hamoy MKO, da Silva Tiago AC, de Araújo DB, Muto NA, Lopes DCF, Hamoy M. Dexamethasone attenuates low-frequency brainwave disturbances following acute seizures induced by pentylenetetrazol in Wistar rats. Exp Mol Pathol 2024; 139:104921. [PMID: 39096892 DOI: 10.1016/j.yexmp.2024.104921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 07/09/2024] [Accepted: 07/22/2024] [Indexed: 08/05/2024]
Abstract
Seizures are neurological disorders triggered by an imbalance in the activity of excitatory and inhibitory neurotransmitters in the brain. When triggered chronically, this imbalance can lead to epilepsy. Critically, many of the affected individuals are refractory to treatment. Given this, anti-inflammatory drugs, in particular glucocorticoids, have been considered as a potential antiepileptogenic therapy. Glucocorticoids are currently used in the treatment of refractory patients, although there have been contradictory results in terms of their use in association with antiepileptic drugs, which reinforces the need for a more thorough investigation of their effects. In this context, the present study evaluated the effects of dexamethasone (DEX, 0.6 mg/kg) on the electroencephalographic (EEG) and histopathological parameters of male Wistar rats submitted to acute seizure induced by pentylenetetrazol (PTZ). The EEG monitoring revealed that DEX reduced the total brainwave power, in comparison with PTZ, in 12 h after the convulsive episode, exerting this effect in up to 36 h (p < 0.05 for all comparisons). An increase in the accommodation of the oscillations of the delta, alpha, and gamma frequencies was also observed from the first 12 h onwards, with the accommodation of the theta frequency occurring after 36 h, and that of the beta frequency 24 h after the seizure. The histopathological analyses showed that the CA3 region and hilum of the hippocampus suffered cell loss after the PTZ-induced seizure (control vs. PTZ, p < 0.05), although DEX was not able to protect these regions against cell death (PTZ vs. DEX + PTZ, p > 0.05). While DEX did not reverse the cell damage caused by PTZ, the data indicate that DEX has beneficial properties in the EEG analysis, which makes it a promising candidate for the attenuation of the epileptiform wave patterns that can precipitate refractory seizures.
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Affiliation(s)
- Rafaella Marques Ribeiro
- Laboratory of the Pharmacology and Toxicology of Natural Products, Biological Sciences Institute, Federal University of Pará, Rua Augusto Corrêa, 01, Guamá, Belém, Pará 66075-110, Brazil
| | - Esther Padilha da Silveira
- Laboratory of Experimental Neuropathology, João de Barros Barreto University Hospital, Federal University of Pará, Rua dos Munducurus, 4487, Guamá, Belém, Pará 66073-000, Brazil
| | - Vitoria Corrêa Santos
- Laboratory of Experimental Neuropathology, João de Barros Barreto University Hospital, Federal University of Pará, Rua dos Munducurus, 4487, Guamá, Belém, Pará 66073-000, Brazil
| | - Leonan Lima Teixeira
- Laboratory of Experimental Neuropathology, João de Barros Barreto University Hospital, Federal University of Pará, Rua dos Munducurus, 4487, Guamá, Belém, Pará 66073-000, Brazil
| | - Gisely Santiago Santos
- Laboratory of the Pharmacology and Toxicology of Natural Products, Biological Sciences Institute, Federal University of Pará, Rua Augusto Corrêa, 01, Guamá, Belém, Pará 66075-110, Brazil
| | - Izabela Nascimento Galvão
- Laboratory of the Pharmacology and Toxicology of Natural Products, Biological Sciences Institute, Federal University of Pará, Rua Augusto Corrêa, 01, Guamá, Belém, Pará 66075-110, Brazil
| | - Maria Klara Otake Hamoy
- Laboratory of the Pharmacology and Toxicology of Natural Products, Biological Sciences Institute, Federal University of Pará, Rua Augusto Corrêa, 01, Guamá, Belém, Pará 66075-110, Brazil
| | - Allan Carlos da Silva Tiago
- Laboratory of the Pharmacology and Toxicology of Natural Products, Biological Sciences Institute, Federal University of Pará, Rua Augusto Corrêa, 01, Guamá, Belém, Pará 66075-110, Brazil
| | - Daniella Bastos de Araújo
- Laboratory of the Pharmacology and Toxicology of Natural Products, Biological Sciences Institute, Federal University of Pará, Rua Augusto Corrêa, 01, Guamá, Belém, Pará 66075-110, Brazil
| | - Nilton Akio Muto
- Centre for the Valorization of Amazonian Bioactive Compounds (CVACBA), Federal University of Pará, Rua Augusto Corrêa, 01, Guamá, Belém, Pará 66075-110, Brazil
| | - Dielly Catrina Favacho Lopes
- Laboratory of Experimental Neuropathology, João de Barros Barreto University Hospital, Federal University of Pará, Rua dos Munducurus, 4487, Guamá, Belém, Pará 66073-000, Brazil
| | - Moisés Hamoy
- Laboratory of the Pharmacology and Toxicology of Natural Products, Biological Sciences Institute, Federal University of Pará, Rua Augusto Corrêa, 01, Guamá, Belém, Pará 66075-110, Brazil.
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Lehner A, Hoffmann L, Rampp S, Coras R, Paulsen F, Frischknecht R, Hamer H, Walther K, Brandner S, Hofer W, Pieper T, Reisch L, Bien CG, Blumcke I. Age-dependent increase of perineuronal nets in the human hippocampus and precocious aging in epilepsy. Epilepsia Open 2024; 9:1372-1381. [PMID: 38845524 PMCID: PMC11296138 DOI: 10.1002/epi4.12963] [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: 11/23/2023] [Revised: 04/24/2024] [Accepted: 04/29/2024] [Indexed: 08/03/2024] Open
Abstract
OBJECTIVE Perineuronal nets (PNN) are specialized extracellular matrix (ECM) components of the central nervous system, frequently accumulating at the surface of inhibitory GABAergic interneurons. While an altered distribution of PNN has been observed in neurological disorders including Alzheimer's disease, schizophrenia and epilepsy, their anatomical distribution also changes during physiological brain maturation and aging. Such an age-dependent shift was experimentally associated also with hippocampal engram formation during brain maturation. Our aim was to histopathologically assess PNN in the hippocampus of adult and pediatric patients with temporal lobe epilepsy (TLE) compared to age-matched post-mortem control subjects and to compare PNN-related changes with memory impairment observed in our patient cohort. METHODS Sixty-six formalin-fixed and paraffin-embedded tissue specimens of the human hippocampus were retrieved from the European Epilepsy Brain Bank. Twenty-nine patients had histopathologically confirmed hippocampal sclerosis (HS), and eleven patients suffered from TLE without HS. PNN were immunohistochemically visualized using an antibody directed against aggrecan and manually counted from hippocampus subfields and the subiculum. RESULTS PNN density increased with age in both human controls and TLE patients. However, their density was significantly higher in all HS patients compared to age-matched controls. Intriguingly, TLE patients presented presurgically with better memory when their hippocampal PNN density was higher (p < 0.05). SIGNIFICANCE Our results were compatible with age-dependent ECM specialization in the human hippocampus and its precocious aging in the epileptic condition. These observations confirm recent experimental animal models and also support the notion that PNN play a role in memory formation in the human brain. PLAIN LANGUAGE SUMMARY "Perineuronal nets" (PNN) are a specialized compartment of the extracellular matrix (ECM), especially surrounding highly active neurons of the mammalian brain. There is evidence that PNN play a role in memory formation, brain maturation, and in some pathologies like Alzheimer's disease, schizophrenia or epilepsy. In this study, we investigated the role of PNN in patients suffering from drug-resistant focal epilepsy compared to controls. We found that with increasing age, more neurons are surrounded by PNN. Similarly, all epilepsy patients but especially patients with better memory performance also had more PNN. This study raises further interest in studying ECM molecules in the human brain under physiological and pathophysiological conditions.
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Affiliation(s)
- Annika Lehner
- Department of NeuropathologyUniversitätsklinikum Erlangen and FAU Erlangen‐NürnbergErlangenGermany
- Partner of the European Reference Network (ERN) EpiCAREBarcelonaSpain
| | - Lucas Hoffmann
- Department of NeuropathologyUniversitätsklinikum Erlangen and FAU Erlangen‐NürnbergErlangenGermany
- Partner of the European Reference Network (ERN) EpiCAREBarcelonaSpain
| | - Stefan Rampp
- Department of NeuroradiologyUniversitätsklinikum Erlangen and FAU Erlangen‐NürnbergErlangenGermany
- Department of NeurosurgeryUniversitätsklinikum Erlangen and FAU Erlangen‐NürnbergErlangenGermany
| | - Roland Coras
- Department of NeuropathologyUniversitätsklinikum Erlangen and FAU Erlangen‐NürnbergErlangenGermany
- Partner of the European Reference Network (ERN) EpiCAREBarcelonaSpain
| | - Friedrich Paulsen
- Institute of Functional and Clinical Anatomy, FAU Erlangen‐NürnbergErlangenGermany
| | - Renato Frischknecht
- Department of Biology, Animal PhysiologyFriedrich‐Alexander‐Universität Erlangen‐NürnbergErlangenGermany
| | - Hajo Hamer
- Epilepsy Center, Department of NeurologyUniversitätsklinikum Erlangen and FAU Erlangen‐NürnbergErlangenGermany
| | - Katrin Walther
- Epilepsy Center, Department of NeurologyUniversitätsklinikum Erlangen and FAU Erlangen‐NürnbergErlangenGermany
| | - Sebastian Brandner
- Department of NeurosurgeryUniversitätsklinikum Erlangen and FAU Erlangen‐NürnbergErlangenGermany
- Department of NeurosurgeryKlinikum FürthGermany
| | - Wiebke Hofer
- Department of Psychology/Neuropsychology, Center for Pediatric Neurology, Neurorehabilitation, and EpileptologySchön Klinik VogtareuthGermany
| | - Tom Pieper
- Center for Pediatric Neurology, Neurorehabilitation, and EpileptologySchön Klinik VogtareuthGermany
| | - Lea‐Marie Reisch
- Department of Epileptology (Krankenhaus Mara), Medical SchoolBielefeld UniversityBielefeldGermany
| | - Christian G. Bien
- Department of Epileptology (Krankenhaus Mara), Medical SchoolBielefeld UniversityBielefeldGermany
| | - Ingmar Blumcke
- Department of NeuropathologyUniversitätsklinikum Erlangen and FAU Erlangen‐NürnbergErlangenGermany
- Partner of the European Reference Network (ERN) EpiCAREBarcelonaSpain
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Aly EK, Mahmoud HS, Alkhalifah DHM, Shehab GMG, Abuelsaad ASA, Abdel-Rehiem ES, Abdul-Hamid M. Bee venom ameliorates oxidative stress and histopathological changes of hippocampus, liver and testis during status epileptics. Neuropeptides 2023; 101:102368. [PMID: 37562116 DOI: 10.1016/j.npep.2023.102368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/31/2023] [Accepted: 08/01/2023] [Indexed: 08/12/2023]
Abstract
The unrelenting progression of neurodegenerative diseases has a negative impact on affected individuals, their families, and society. Recurrent epileptic seizures are the hallmark of epilepsy, and treating it effectively remains difficult. Clarify and understanding effects of the antiepileptic drugs (AEDs) in epilepsy by comparing the therapeutic effects between rats receiving valproic acid (VPA) and Bee venom (BV) was aimed throughout the present study. Four male Wistar rat groups were included: control, epileptic group receiving pilocarpine (PILO), epileptic group treated with VPA and BV respectively. Cognitive functions were assessed by evaluating latency time in hot plate, despair swim test, grooming, rearing and ambulation frequency in the open field. BV has ameliorative effect on electrolytes balancing, assured by decreasing lipid peroxidation, nitric oxide and increasing catalase, superoxide dismutase and glutathione peroxidase activities. BV enhanced restoration of liver functions indicated by alanine transaminase (ALT) and aspartate transaminase (AST), total proteins, and albumin; hormonal parameters total and free testosterone, follicle stimulating hormone (FSH) and Luteinizing hormone (LH) were preserved by BV with great recovery of hippocampus, liver and testicular histopathology and ultrastructure comparing with the epileptic rats. The present findings suggested that BV and its active components offer fresh options for controlling epilepsy and prospective methods via minimize or manage the severe consequences.
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Affiliation(s)
- Esraa K Aly
- Cell Biology & Histology Division, Zoology Department, Faculty of Science, Beni-Suef University, Beni-Suef 62521, Egypt
| | - Hanan S Mahmoud
- Ecology Division, Zoology Department, Faculty of Science, Beni-Suef University, Beni-Suef 62521, Egypt
| | - Dalal Hussien M Alkhalifah
- Department of Biology, College of Science, Princess Nourah Bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia
| | - Gaber M G Shehab
- Department of Biochemistry, College of Medicine, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia
| | - Abdelaziz S A Abuelsaad
- Immunology Division, Department of Zoology, Faculty of Science, Beni-Suef University, 62511 Beni-Suef, Egypt
| | - Eman S Abdel-Rehiem
- Molecular Physiology Division, Zoology Department, Faculty of Science, Beni-Suef University, Beni-Suef 62521, Egypt
| | - Manal Abdul-Hamid
- Cell Biology & Histology Division, Zoology Department, Faculty of Science, Beni-Suef University, Beni-Suef 62521, Egypt.
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Woo AM, Sontheimer H. Interactions between astrocytes and extracellular matrix structures contribute to neuroinflammation-associated epilepsy pathology. FRONTIERS IN MOLECULAR MEDICINE 2023; 3:1198021. [PMID: 39086689 PMCID: PMC11285605 DOI: 10.3389/fmmed.2023.1198021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 05/31/2023] [Indexed: 08/02/2024]
Abstract
Often considered the "housekeeping" cells of the brain, astrocytes have of late been rising to the forefront of neurodegenerative disorder research. Identified as crucial components of a healthy brain, it is undeniable that when astrocytes are dysfunctional, the entire brain is thrown into disarray. We offer epilepsy as a well-studied neurological disorder in which there is clear evidence of astrocyte contribution to diseases as evidenced across several different disease models, including mouse models of hippocampal sclerosis, trauma associated epilepsy, glioma-associated epilepsy, and beta-1 integrin knockout astrogliosis. In this review we suggest that astrocyte-driven neuroinflammation, which plays a large role in the pathology of epilepsy, is at least partially modulated by interactions with perineuronal nets (PNNs), highly structured formations of the extracellular matrix (ECM). These matrix structures affect synaptic placement, but also intrinsic neuronal properties such as membrane capacitance, as well as ion buffering in their immediate milieu all of which alters neuronal excitability. We propose that the interactions between PNNs and astrocytes contribute to the disease progression of epilepsy vis a vis neuroinflammation. Further investigation and alteration of these interactions to reduce the resultant neuroinflammation may serve as a potential therapeutic target that provides an alternative to the standard anti-seizure medications from which patients are so frequently unable to benefit.
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Affiliation(s)
- AnnaLin M. Woo
- Neuroscience Graduate Program, Neuroscience Department, University of Virginia, Charlottesville, VA, United States
| | - Harald Sontheimer
- Neuroscience Department, University of Virginia, Charlottesville, VA, United States
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Fang Q, Zheng S, Chen Q, Chen L, Yang Y, Wang Y, Zhang H, Chen J. The protective effect of inhibiting mitochondrial fission on the juvenile rat brain following PTZ kindling through inhibiting the BCL2L13/LC3 mitophagy pathway. Metab Brain Dis 2023; 38:453-466. [PMID: 36094724 DOI: 10.1007/s11011-022-01077-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 08/30/2022] [Indexed: 02/04/2023]
Abstract
Maintaining the balance of mitochondrial fission and mitochondrial autophagy on seizures is helpful to find a solution to control seizures and reduce brain injuries. The present study is to investigate the protective effect of inhibiting mitochondrial fission on brain injury in juvenile rat epilepsy induced by pentatetrazol (PTZ) by inhibiting the BCL2L13/LC3-mediated mitophagy pathway. PTZ was injected (40 mg/kg) to induce kindling once every other day, for a total of 15 times. In the PTZ + DMSO (DMSO), PTZ + Mdivi-1 (Mdivi-1), and PTZ + WY14643 (WY14643) groups, rats were pretreated with DMSO, Mdivi-1 and WY14643 for half an hour prior to PTZ injection. The seizure attacks of young rats were observed for 30 min after model establishment. The Morris water maze (MWM) was used to test the cognition of experimental rats. After the test, the numbers of NeuN(+) neurons and GFAP(+) astrocytes were observed and counted by immunofluorescence (IF). The protein expression levels of Drp1, BCL2L13, LC3 and caspase 3 in the hippocampus of young rats were detected by immunohistochemistry (IHC) and Western blotting (WB). Compared with the PTZ and DMSO groups, the seizure latency in the Mdivi-1 group was longer (P < 0.01), and the severity degree and frequency of seizures were lower (P < 0.01). The MWM test showed that the incubation periods of crossing the platform in the Mdivi-1 group was significantly shorter. The number of platform crossings, the platform stay time, and the ratio of residence time/total stay time were significantly increased in the Mdivi-1 group (P < 0.01). The IF results showed that the number of NeuN(+) neurons in the Mdivi-1 group was greater, while the number of GFAP(+) astrocytes was lower. IHC and WB showed that the average optical density (AOD) and relative protein expression levels of Drp1, BCL2L13, LC3 and caspase 3 in the hippocampi of rats in the Mdivi-1 group were higher (P < 0.05). The above results in the WY14643 group were opposite to those in the Mdivi-1 group. Inhibition of mitochondrial fission could reduce seizure attacks, protect injured neurons, and improve cognition following PTZ-induced epilepsy by inhibiting mitochondrial autophagy mediated by the BCL2L13/LC3 mitophagy pathway.
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Affiliation(s)
- Qiong Fang
- Department of Pediatrics, Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, 134 East Street, Gulou District, Fuzhou, 350001, Fujian Province, China.
| | - Shaojuan Zheng
- Department of Pediatrics, Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, 134 East Street, Gulou District, Fuzhou, 350001, Fujian Province, China
| | - Qiaobin Chen
- Department of Pediatrics, Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, 134 East Street, Gulou District, Fuzhou, 350001, Fujian Province, China.
| | - Lang Chen
- Department of Pediatrics, Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, 134 East Street, Gulou District, Fuzhou, 350001, Fujian Province, China
| | - Yating Yang
- Department of Pediatrics, Fujian Provincial Hospital, Shengli Clinical Medical College of Fujian Medical University, 134 East Street, Gulou District, Fuzhou, 350001, Fujian Province, China
| | - Ying Wang
- Department of clinical medicine, Fujian Medical University, Fuzhou, 350001, Fujian Province, China
| | - Huixia Zhang
- Department of clinical medicine, Fujian Medical University, Fuzhou, 350001, Fujian Province, China
| | - Jiafan Chen
- Department of clinical medicine, Fujian Medical University, Fuzhou, 350001, Fujian Province, China
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Li S, Huang H, Wei X, Ye L, Ma M, Ling M, Wu Y. The recycling of AMPA receptors/GABAa receptors is related to neuronal excitation/inhibition imbalance and may be regulated by KIF5A. ANNALS OF TRANSLATIONAL MEDICINE 2022; 10:1103. [PMID: 36388788 PMCID: PMC9652568 DOI: 10.21037/atm-22-4337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 09/30/2022] [Indexed: 09/01/2023]
Abstract
BACKGROUND Excitation/inhibition imbalance (E/I imbalance), which involves an increase of alpha-amino-3-hydroxy-5-methyl-4-isoxazole (AMPA) receptors (AMPARs) and decrease of gamma-aminobutyric acid type A (GABA) type A receptors (GABAaRs) on the neuron surface, has been documented in the pathogenesis of seizures. Notably, it has been established that both the glutamate receptor subunit 2 (GluR2) of AMPARs and beta 2/3 subunits of GABAaRs (Gabrb2+3) participate in the recycling mechanism mediated by the kinesin heavy chain isoform 5A (KIF5A), which determines the number of neuron surface receptors. However, it remains unclear whether receptor recycling is involved in the pathogenesis of seizures. METHODS Twelve adult male Sprague-Dawley rats were randomly allocated to the normal control (Ctl) group (n=6) and the pentylenetetrazol (PTZ)-induced seizure (Sez) group (n=6). The rats in the Ctl group were treated with saline. The rats in the Sez group received an intraperitoneal injection of PTZ at an initial dose of 40 mg/kg. Primary cultured neurons were obtained from newborn rats (24-hour-old). The neurons were exposed to magnesium-free (Mg2+-free) extracellular fluid for 3 hours to establish the seizure model in vitro. We detected the electrophysiology of the seizure model, the expression levels of KIF5A, GluR2, and Gabrb2+3, the recycling ratio of GluR2 and Gabrb2+3, the interaction between KIF5A and GluR2, and the interaction between KIF5A and Gabrb2+3. RESULTS In the Sez group, the expression of GluR2 on the cell surface was increased and the expression of Gabrb2+3 on the cell surface was decreased. The amplitude and frequency of action potentials were significantly increased in the Mg2+-free group. The amplitude and decay time of AMPAR-mediated miniature excitatory postsynaptic currents were increased in the Mg2+-free group. The amplitude and decay time of miniature inhibitory postsynaptic currents were decreased in the Mg2+-free group. The recycling ratio of GluR2 was increased and the recycling ratio of Gabrb2+3 was decreased in the Mg2+-free group. The interaction between KIF5A and GluR2 was increased, and the interaction between KIF5A and Gabrb2+3 was decreased in the seizure model in vivo and in vitro. CONCLUSIONS The recycling of AMPA receptors/GABAa receptors is related to E/I imbalance and may be regulated by KIF5A.
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Affiliation(s)
- Sijun Li
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Hongmi Huang
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Xin Wei
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Lin Ye
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Meigang Ma
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Min Ling
- Department of Biotechnology, Guangxi Medical University, Nanning, China
| | - Yuan Wu
- Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
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Dynamics of neurodegeneration in the hippocampus of Krushinsky-Molodkina rats correlates with the progression of limbic seizures. Epilepsy Behav 2022; 134:108846. [PMID: 35849865 DOI: 10.1016/j.yebeh.2022.108846] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 06/17/2022] [Accepted: 07/04/2022] [Indexed: 11/21/2022]
Abstract
Audiogenic seizures (AGS) (audiogenic kindling) in genetically selected audiogenic rodents are a reliable model of temporal lobe epilepsy (TLE). Temporal lobe epilepsy is accompanied with neurodegeneration in the hippocampus, but how the cells die is not fully understood. We analyzed the dynamics and mechanisms of cell loss in the hippocampus of audiogenic Krushinsky-Molodkina (KM) rats during the development of TLE. Audiogenic kindling of different durations was carried out to reproduce TLE progression in KM rats. Behavioral analysis showed the development of post-tonic clonus, the main indicator of TLE, by the 14th AGS. The severity and duration of post-tonic clonus positively correlated with the increase in the number of AGS. Temporal lobe epilepsy development was accompanied with two peaks of cell loss. The first peak was detected after 7 AGS in the dentate gyrus (DG) granular layer and associated with activation of p53- and mitochondria-dependent apoptosis. After a 7-day rest period, activation of autophagy and restoration of cell number were revealed. The second peak occurred after 14 AGS, affected both granular and hilar mossy cells and persisted further after 21 AGS, but no compensation was observed. Thus, activation of autophagy probably plays a neuroprotective role and supports survival of hippocampal cells at the beginning of epileptogenesis, but exacerbation of limbic seizures during TLE development causes irreversible neurodegeneration.
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Spatio-Temporal Alterations in Synaptic Density During Epileptogenesis in the Rat Brain. Neuroscience 2022; 499:142-151. [PMID: 35878719 DOI: 10.1016/j.neuroscience.2022.07.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 07/07/2022] [Accepted: 07/18/2022] [Indexed: 11/22/2022]
Abstract
Synaptic vesicle glycoprotein 2A (SV2A) is a transmembrane protein that binds levetiracetam and is involved in neurotransmission via an unknown mechanism. SV2A-immunoreactivity is reduced in animal models of epilepsy, and in postmortem hippocampi from patients with temporal lobe epilepsy. It is not known if other regions outside the hippocampus are affected in epilepsy, and whether SV2A is expression permanently reduced or regulated over time. In this study, we induced a generalized status epilepticus (SE) by systemic administration of lithium-pilocarpine to adult female rats. The brains from all animals experiencing SE were collected at different time points after the treatment. The radiotracer, [11C]-UCB-J, binds to SV2A with high affinity, and has been used for in vivo imaging as an a-proxy marker for synaptic density. Here we determined the level of tritiated UCB-J binding by semiquantitative autoradiography in the cerebral cortex, hippocampus, thalamus, and hypothalamus, and in subregions of these. A prominent and highly significant reduction in SV2A binding capacity was observed over the first days after SE in the cerebral cortex and the hippocampus, but not in the thalamus and hypothalamus. The magnitude in reduction was larger and occurred earlier in the hippocampus and the piriform cortex, than in other cortical subregions. Interestingly, in all areas examined, the binding capacity returned to control levels 12 weeks after the SE comparable to the chronic phase. These data show that lithium-pilocarpine-induced epileptogenesis involves both loss and gain of synapses in the in a time-dependent manner.
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