Chronic neocortical epileptogenesis in vitro

1994 ◽  
Vol 71 (5) ◽  
pp. 1762-1773 ◽  
Author(s):  
S. N. Hoffman ◽  
P. A. Salin ◽  
D. A. Prince
Keyword(s):  
White Matter ◽  
Current Source ◽  
Nmda Receptor Antagonist ◽  
White Matter Injury ◽  
Posttraumatic Epilepsy ◽  
Layer V ◽  
Vitro Model ◽  
Interictal Discharges ◽  
Interictal Discharge

1. We used an in vitro model to explore critical aspects of chronic epileptogenesis. Partial neocortical isolations having intact blood supply were made in rat and guinea pig from postnatal day 7 to 34 and then examined 1 to 150 days later in standard brain slice preparations. 2. The epileptogenic potential of several different types of lesions was assessed. Slices containing transcortical (i.e., gray matter) lesions, with or without a contiguous white matter injury (i.e., “undercut”), developed chronic epileptogenesis after a latency of approximately 1–2 wk, manifested by evoked and spontaneous “interictal” discharges and evoked “ictal” events. The region of hyperexcitability did not extend beyond approximately 2 mm from the chronic transcortical lesion and was rarely observed in slices having only an apparent white matter injury. 3. Multiple recordings and current source density (CSD) analysis identified layer V as the source of the interictal discharge. 4. Significant differences in CSD profiles of the evoked interictal discharge occurred between chronically epileptogenic slices and control (noninjured) slices bathed in the convulsant, bicuculline methiodide, suggesting that mechanisms other than disinhibition must be involved in posttraumatic epileptogenesis. 5. Interictal events were blocked in most but not all chronically injured slices by application of the N-methyl-D-aspartate (NMDA) receptor antagonist D-2-amino-5-phosphonovalerate (D-AP5), suggesting that non-NMDA receptors were predominantly involved in some preparations. 6. This model of chronic epileptogenesis in vitro will be useful in studies relevant to mechanisms of posttraumatic epilepsy in man.

scholarly journals Axonal degeneration in an in vitro model of ischemic white matter injury

2020 ◽  
Vol 134 ◽  
pp. 104672 ◽  
Author(s):  
Yuexian Cui ◽  
Xuelian Jin ◽  
Dong-Joo Choi ◽  
Jun Young Choi ◽  
Hyung Soon Kim ◽  
...  
Keyword(s):  
White Matter ◽  
In Vitro Model ◽  
Axonal Degeneration ◽  
White Matter Injury ◽  
Vitro Model

scholarly journals Glutamate receptors: the cause or cure in perinatal white matter injury?

2010 ◽  
Vol 6 (4) ◽  
pp. 209-211 ◽  
Author(s):  
R. Douglas Fields
Keyword(s):  
White Matter ◽  
Glutamate Receptors ◽  
Metabotropic Glutamate Receptors ◽  
Experimental Studies ◽  
Perinatal Period ◽  
White Matter Injury ◽  
Glutamate Toxicity ◽  
Diffuse White Matter ◽  
Group I

Glutamate toxicity from hypoxia-ischaemia during the perinatal period causes white matter injury that can result in long-term motor and intellectual disability. Blocking ionotropic glutamate receptors (GluRs) has been shown to inhibit oligodendrocyte injury in vitro, but GluR antagonists have not yet proven helpful in clinical studies. The opposite approach of activating GluRs on developing oligodendrocytes shows promise in experimental studies on rodents as reported by Jartzie et al., in this issue. Group I metabotropic glutamate receptors (mGluRs) are expressed transiently on developing oligodendrocytes in humans during the perinatal period, and the blood–brain-barrier permeable agonist of group I mGluRs, 1-aminocyclopentane-trans-1,3-dicarboxylic acid (ACPD), reduces white matter damage significantly in a rat model of perinatal hypoxia-ischaemia. The results suggest drugs activating this class of GluRs could provide a new therapeutic approach for preventing cerebral palsy and other neurological consequences of diffuse white matter injury in premature infants.

scholarly journals Transplanted Oligodendrocyte Progenitor Cells Survive in the Brain of a Rat Neonatal White Matter Injury Model but Less Mature in Comparison with the Normal Brain

2020 ◽  
Vol 29 ◽  
pp. 096368972094609
Author(s):  
Shino Ogawa ◽  
Mutsumi Hagiwara ◽  
Sachiyo Misumi ◽  
Naoki Tajiri ◽  
Takeshi Shimizu ◽  
...  
Keyword(s):  
White Matter ◽  
Replacement Therapy ◽  
Fluorescent Protein ◽  
White Matter Injury ◽  
Normal Brain ◽  
Cell Replacement Therapy ◽  
Cell Replacement ◽  
Vitro Effect ◽  
The Brain

Preterm infants have a high risk of neonatal white matter injury (WMI) caused by hypoxia-ischemia. Cell-based therapies are promising strategies for neonatal WMI by providing trophic substances and replacing lost cells. Using a rat model of neonatal WMI in which oligodendrocyte progenitors (OPCs) are predominantly damaged, we investigated whether insulin-like growth factor 2 (IGF2) has trophic effects on OPCs in vitro and whether OPC transplantation has potential as a cell replacement therapy. Enhanced expression of Igf2 mRNA was first confirmed in the brain of P5 model rats by real-time polymerase chain reaction. Immunostaining for IGF2 and its receptor IGF2 R revealed that both proteins were co-expressed in OLIG2-positive and GFAP-positive cells in the corpus callosum (CC), indicating autocrine and paracrine effects of IGF2. To investigate the in vitro effect of IGF2 on OPCs, IGF2 (100 ng/ml) was added to the differentiation medium containing ciliary neurotrophic factor (10 ng/ml) and triiodothyronine (20 ng/ml), and IGF2 promoted the differentiation of OPCs into mature oligodendrocytes. We next transplanted rat-derived OPCs that express green fluorescent protein into the CC of neonatal WMI model rats without immunosuppression and investigated the survival of grafted cells for 8 weeks. Although many OPCs survived for at least 8 weeks, the number of mature oligodendrocytes was unexpectedly small in the CC of the model compared with that in the sham-operated control. These findings suggest that the mechanism in the brain that inhibits differentiation should be solved in cell replacement therapy for neonatal WMI as same as trophic support from IGF2.

scholarly journals Mechanistic Distinctions between Excitotoxic and Acidotic Hippocampal Damage in an in vitro Model of Ischemia

1990 ◽  
Vol 10 (4) ◽  
pp. 527-535 ◽  
Author(s):  
Geoffrey C. Tombaugh ◽  
Robert M. Sapolsky
Keyword(s):  
Nmda Receptor ◽  
Cell Injury ◽  
Neuronal Damage ◽  
Nmda Receptor Antagonist ◽  
Hippocampal Damage ◽  
Neuron Death ◽  
Vitro Model ◽  
Posthypoxic Period ◽  
Ph Range

Excitotoxicity is believed to underlie the selective loss of vulnerable neurons after transient ischemia, while lactic acidosis seems to be the principal feature and probable cause of tissue infarcts. Primary hippocampal cultures containing both neurons and astrocytes derived from fetal rats were used to examine the relative contributions of and interactions between excitotoxic and acidotic cell injury. Hypoxia-induced damage was energy dependent and involved the N-methyl-D-aspartate (NMDA) receptor. Glucose above 1 m M could completely protect against hypoxia-induced injury in a pH range of 7.4–6.5, while the NMDA receptor antagonist D,L-2-amino-5-phosphonovaleric acid (500 μ M) during the posthypoxic period provided only partial protection in the absence of glucose. Astrocyte cultures were undamaged by ischemic-like treatment in this pH range, suggesting that hypoxia-induced cell death in mixed cultures was restricted to neurons. Lowering the extracellular pH to 7.0 and 6.5 caused no neuronal damage in normoxic controls, but in each case provided significant protection against hypoxic neuronal injury. In contrast, a second type of neurotoxicity was observed after a 6-h exposure to pH 6.0, while exposure to pH 5.5 was required to kill astrocytes. This acidotic damage appeared to be energy independent and did not involve the NMDA receptor. These results suggest that excitotoxic neuron death has an energetic component and that acidosis may produce both protective and damaging effects in the hippocampus during ischemic insults.

scholarly journals HDAC inhibition reduces white matter injury after intracerebral hemorrhage

2020 ◽  
pp. 0271678X2094261
Author(s):  
Heng Yang ◽  
Wei Ni ◽  
Pengju Wei ◽  
Sicheng Li ◽  
Xinjie Gao ◽  
...  
Keyword(s):  
White Matter ◽  
Intracerebral Hemorrhage ◽  
Hdac Inhibitor ◽  
Histone Deacetylases ◽  
Macrophage Polarization ◽  
Conditional Knockout ◽  
White Matter Injury ◽  
Hdac Inhibition

Inhibition of histone deacetylases (HDACs) has been shown to reduce inflammation and white matter damage after various forms of brain injury via modulation of microglia/macrophage polarization. Previously we showed that the HDAC inhibitor scriptaid could attenuate white matter injury (WMI) after ICH. To access whether modulation of microglia/macrophage polarization might underlie this protection, we investigated the modulatory role of HDAC2 in microglia/macrophage polarization in response to WMI induced by intracerebral hemorrhage (ICH) and in primary microglia and oligodendrocyte co-cultures. HDAC2 activity was inhibited via conditional knockout of the Hdac2 gene in microglia or via administration of scriptaid. Conditional knockout of the Hdac2 gene in microglia and HDAC inhibition with scriptaid both improved neurological functional recovery and reduced WMI after ICH. Additionally, HDAC inhibition shifted microglia/macrophage polarization toward the M2 phenotype and reduced proinflammatory cytokine secretion after ICH in vivo. In vitro, a transwell co-culture model of microglia and oligodendrocytes also demonstrated that the HDAC inhibitor protected oligodendrocytes by modulating microglia polarization and mitigating neuroinflammation. Moreover, we found that scriptaid decreased the expression of pJAK2 and pSTAT1 in cultured microglia when stimulated with hemoglobin. Thus, HDAC inhibition ameliorated ICH-mediated neuroinflammation and WMI by modulating microglia/macrophage polarization.

scholarly journals Neurosurgery (Neuro Vascular)

2015 ◽  
Vol 42 (S1) ◽  
pp. S48-S48
Author(s):  
CK Lee ◽  
A Alarfaj ◽  
J Ai ◽  
B Alharbi ◽  
P Vasdev ◽  
...  
Keyword(s):  
White Matter ◽  
Brain Slices ◽  
Axonal Damage ◽  
Oxidation Products ◽  
White Matter Injury ◽  
Unmyelinated Axons ◽  
Electrophysiological Recordings ◽  
All Solutions ◽  
Bilirubin Toxicity

Background: Blood breakdown products such as bilirubin and bilirubin oxidation products damage cortex and white matter after intracerebral hemorrhage(ICH). Here, we tested whether albumin can antagonize axonal damage caused by bilirubin. Methods: The effect of albumin on white matter injury was investigated using brain slices in vitro. After CD-1 mice brain slices were cut using a vibratome, they were incubated in one of five solutions: artificial cerebral spinal fluid (ACSF), bilirubin ACSF, bilirubin and albumin ACSF, bilirubin ACSF that had albumin added 1 hour(h) later, and bilirubin and denatured albumin ACSF. All solutions were continuously aerated with 95% O2 and 5% CO2. Subsequently, electrophysiological recordings of axonal response to electrical stimulation were performed 8h after incubation of brain slices. Results: Bilirubin treatment profoundly damaged both myelinated and unmeylinated axons in brain slices, but had a greater effect on myelinated axons. Unmyelinated axons were found to be more susceptible to damage from denatured albumin. Albumin treatment at 0 h and 1 h significantly diminished bilirubin toxicity for both myelinated and unmyelinated axons, with 1 h delayed albumin treatment conferring greater neuroprotection. Conclusions: These results implicate the role of albumin in preventing bilirubin-induced axonal damage following ICH and its potential therapeutic value for hemorrhagic stroke.

scholarly journals Inhibition of Mitochondrial ROS by MitoQ Alleviates White Matter Injury and Improves Outcomes after Intracerebral Haemorrhage in Mice

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Weixiang Chen ◽  
Chao Guo ◽  
Zhengcai Jia ◽  
Jie Wang ◽  
Min Xia ◽  
...  
Keyword(s):  
White Matter ◽  
Intracerebral Haemorrhage ◽  
Motor Evoked Potential ◽  
White Matter Injury ◽  
Antioxidant Treatment ◽  
Evidence Based Treatment ◽  
Mitochondrial Ros ◽  
Ros Scavenger ◽  
Oligodendrocyte Precursor

White matter injury (WMI) is an important cause of high disability after intracerebral haemorrhage (ICH). It is widely accepted that reactive oxygen species (ROS) contributes to WMI, but there is still no evidence-based treatment. Here, mitoquinone (MitoQ), a newly developed selective mitochondrial ROS scavenger, was used to test its neuroprotective potential. The data showed that MitoQ attenuated motor function deficits and motor-evoked potential (MEP) latency prolongation. Further research found that MitoQ blunted the loss of oligodendrocytes and oligodendrocyte precursor cells, therefore reduced demyelination and axon swelling after ICH. In the in vitro experiments, MitoQ, but not the nonselective antioxidant, almost completely attenuated the iron-induced membrane potential decrease and cell death. Mechanistically, MitoQ blocked the ATP deletion and mitochondrial ROS overproduction. The present study demonstrates that the selective mitochondrial ROS scavenger MitoQ may improve the efficacy of antioxidant treatment of ICH by white matter injury alleviation.

scholarly journals Ceria Nanoparticles Ameliorate White Matter Injury After Intracerebral Hemorrhage: Microglia-astrocyte Involvement in Remyelination

2020 ◽  
Author(s):  
Jingwei Zheng ◽  
Jia‘nan Lu ◽  
Shuhao Mei ◽  
Haijian Wu ◽  
Zeyu Sun ◽  
...  
Keyword(s):  
White Matter ◽  
Intracerebral Hemorrhage ◽  
Molecular Mechanisms ◽  
White Matter Injury ◽  
Ceria Nanoparticles ◽  
Ros Scavenging ◽  
Transmission Electron Microscopy Analysis ◽  
Positive Effects ◽  
Myelin Debris

Abstract Background: Intracerebral hemorrhage (ICH) can induce excess accumulation of reactive oxygen species (ROS) and subsequently cause severe white matter injury. The process of oligodendrocyte progenitor cell (OPC) differentiation is orchestrated by microglia and astrocytes, and ROS also drives the activation of microglia and astrocytes. In light of the potent ROS scavenging capacity of ceria nanoparticles (CeNP), we aimed to investigate whether treatment with CeNP ameliorates white matter injury by modulating ROS-induced microglial polarization and astrocyte alteration. Methods: ICH was induced in vivo by collagenase VII injection in mice. Mice were administered with PLX3397 for depleting microglia. Primary microglia and astrocytes were used for in vitro experiments. Transmission electron microscopy analysis and immunostaining were performed to verify the positive effects of CeNP in remyelination and OPC differentiation. Flow cytometry, real-time polymerase chain reaction, immunofluorescence and western blotting were used to detect microglia polarization, astrocytes alteration and the underlying molecular mechanisms.Results: CeNP treatment strongly inhibited ROS-induced NF-κB p65 translocation in both microglia and astrocytes, and significantly decreased the expression of M1 microglia and A1 astrocyte. Furthermore, we found that CeNP treatment promoted remyelination and OPC differentiation at 7 days and 21 days post ICH, and such effects were alleviated after microglial depletion. Interestingly, we also found that the number of mature oligodendrocytes was moderately enhanced in ICH + CeNP + PLX3397 treated mice compared to the ICH + Vehicle + PLX3397 group. Therefore, astrocytes might participate in the pathophysiological process. The subsequent phagocytosis assay indicated that A1 astrocyte highly expressed C3, which could bind with microglia C3aR and hinder microglial engulfment of myelin debris. This result further replenished the feedback mechanism from astrocytes to microglia. Conclusion: The present study reveals a new mechanism in white matter injury after ICH: ICH induces M1 microglia and A1 astrocyte through ROS-induced NF-κB p65 translocation that hinders OPC maturation. Subsequently, A1 astrocytes inhibit microglial phagocytosis of myelin debris via an astrocytic C3-microglial C3aR axis. Polyethylene glycol-CeNP treatment inhibits this pathological process and ultimately promotes remyelination. Such findings enlighten us that astrocytes and microglia should be regarded as a functional unit in future works.

Abstract WP148: The Effect of Mitochondrial Migration From Astrocyte to Glial Cells Under Prolonged Cerebral Hypoperfusion

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Nobukazu Miyamoto ◽  
Shunsuke Magami ◽  
Yuji Ueno ◽  
Kenichiro Hira ◽  
Kazuo Yamashiro ◽  
...  
Keyword(s):  
Cell Culture ◽  
White Matter ◽  
Cerebral Metabolism ◽  
Cerebrovascular Disorders ◽  
White Matter Injury ◽  
Cerebral Hypoperfusion ◽  
The Central Nervous System ◽  
Common Carotid Arteries

Introduction: Astrocytes play broad roles in the Central nervous system, and are involved in the regulation of cerebral metabolism and blood flow. Normal astrocytes (A2) protect against oxidative stress and excitotoxicity, but unhealthy astrocytes (A1) may release deleterious factors. Oligodendrocytes (OLGs) differentiate from oligodendrocyte-precursor-cells (OPCs) for myelination in white matter, but OPC were vulnerable for ischemia. Therefore, differentiation is impaired when white matter injury occurs in a chronic cerebral hypoperfusion model. Thus, we examined the effects of the interaction between astrocyte and oligodendrocyte lineage cells on myelination focused on mitochondrial migration. Method: A microcoil was applied to the bilateral common carotid arteries in male C57BL/6 mice as an in vivo cerebral chronic hypoperfusion model (BCAS model). A nonlethal concentration of CoCl 2 was added to the primary cell culture from the postnatal rat cortex and incubated in vitro. Results: White matter injury progressed in the BCAS model as myelin decreased. The numbers of OPCs and astrocytes increased after the operation, whereas that of OLGs decreased at day 28. Increased astrocytes were mainly A1 type, and A2 type were decreased. OPC differentiation was disrupted under the stressed conditions in the cell culture, but improved after administration of astrocyte-conditioned medium (ACM), but injured ACM couldn’t improve maturation. Incubate with CoCl 2 change astrocyte A2 to A1, and mitochondrial migration also reduced. Trkβ agonist could change astrocyte A1 to A2 even in hyperperfused condition, and also help OPC maturation via mitochondrial migration and drug effect in vivo and in vitro. Conclusions: The reduction in incrementing A1 astrocytes protect white matter injury. and Trkβ agonist may play an important role in the impairment under chronic ischemic conditions. Mitochondrial migration could be a broad therapeutic strategy for cerebrovascular disorders.

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