myelin-basic-protein and Brain-Ischemia

The initiation of microglial responses to the ischemic injury involves modifications of calcium homeostasis. Changes in [Ca(2+)](i) levels have also been shown to influence the developmental processes that accompany the transition of human oligodendrocyte precursor cells (OPCs) into mature myelinating oligodendrocytes and are required for the initiation of myelination and remyelination processes.We investigated the regional and temporal changes of NCX1 protein in microglial cells of the peri-infarct and core regions after permanent middle cerebral artery occlusion (pMCAO). Interestingly, 3 and 7 days after pMCAO, NCX1 signal strongly increased in the round-shaped microglia invading the infarct core. Cultured microglial cells from the core displayed increased NCX1 expression as compared with contralateral cells and showed enhanced NCX activity in the reverse mode of operation. Similarly, NCX activity and NCX1 protein expression were significantly enhanced in BV2 microglia exposed to oxygen and glucose deprivation, whereas NCX2 and NCX3 were downregulated. Interestingly, in NCX1-silenced cells, [Ca(2+)](i) increase induced by hypoxia was completely prevented. The upregulation of NCX1 expression and activity observed in microglia after pMCAO suggests a relevant role of NCX1 in modulating microglia functions in the postischemic brain.Next, we explored whether calcium signals mediated by NCX1, NCX2, or NCX3 play a role in oligodendrocyte maturation. Functional studies, as well as mRNA and protein expression analyses, revealed that NCX1 and NCX3, but not NCX2, were divergently modulated during OPC differentiation into oligodendrocyte. In fact, while NCX1 was downregulated, NCX3 was strongly upregulated during the oligodendrocyte development. Whereas the knocking down of the NCX3 isoform in OPCs prevented the upregulation of the myelin protein markers CNPase and MBP, its overexpression induced their upregulation. Furthermore, NCX3 knockout mice exhibited not only a reduced size of spinal cord but also a marked hypomyelination, as revealed by the decrease in MBP expression and by the accompanying increase in OPCs number. Our findings indicate that calcium signaling mediated by NCX3 plays a crucial role in oligodendrocyte maturation and myelin formation.

Topics: Animals; Brain Ischemia; Calcium Signaling; Cell Differentiation; Gene Expression Regulation; Humans; Mice; Mice, Knockout; Microglia; Myelin Basic Protein; Myelin Sheath; Neural Stem Cells; Sodium-Calcium Exchanger

A blood test that quantified the extent of brain damage following ischaemic stroke might be a useful surrogate outcome measure in trials of acute stroke treatments. Measures of neuronal and glial damage, such as neuron-specific enolase (NSE), glial fibrillary acidic protein, tau-protein, myelin-basic protein and S100-β are potential candidate biomarkers.. We systematically reviewed the relevant literature to find studies that correlated blood levels of neuronal and glial damage markers with imaging measures of infarct volume.. We identified studies with a comprehensive search of databases and the reference lists of relevant studies. We included studies that: (1) measured the highest level, or area under the curve (AUC) over time of markers of cerebral damage, (2) calculated infarct volume, and (3) correlated the two measures.. Seventeen studies met the criteria for the systematic review. There were sufficient data to provide summary estimates for S100-β and NSE. The peak level and AUC over time of both markers correlated with subacute infarct volume. Measurements of S100-β later than 24 h after stroke were better correlated with subacute infarct size than earlier measurements. However, scan times varied, and none was later than 8 days after stroke.. Peak and AUC levels of NSE and S100-β levels correlated with subacute infarct volume. Correlations of S100-β with infarct volume were stronger when measured after 24 h than closer to admission. Exploratory studies within clinical trials are necessary before blood markers of cerebral tissue damage can be recommended as surrogate endpoints.

Topics: Biomarkers; Brain; Brain Ischemia; Glial Fibrillary Acidic Protein; Humans; Magnetic Resonance Imaging; Myelin Basic Protein; Nerve Growth Factors; Nerve Tissue Proteins; Neuroglia; Neurons; Phosphopyruvate Hydratase; Predictive Value of Tests; Prognosis; S100 Calcium Binding Protein beta Subunit; S100 Proteins; Stroke; tau Proteins; Time Factors; Tomography, X-Ray Computed

Emerging data suggest that biomarkers of brain injury have potential utility as diagnostic, prognostic, and therapeutic adjuncts in the setting of traumatic and ischemic brain injury. Two approaches are being used, namely, assessing markers of structural damage and quantifying mediators of the cellular, biochemical, or molecular cascades in secondary injury or repair. Novel proteomic, multiplex, and lipidomic methods are also being applied.. Biochemical markers of neuronal, glial, and axonal damage such as neuron-specific enolase, S100B, and myelin basic protein, respectively, are readily detectable in biological samples such as serum or cerebrospinal fluid and are being studied in patients with ischemic and traumatic brain injury. In addition, a number of studies have demonstrated that novel tools to assess simultaneously multiple biomarkers can provide unique insight such as details on specific molecular participants in cell death cascades, inflammation, or oxidative stress.. Multifaceted cellular, biochemical, and molecular monitoring of proteins and lipids is logical as an adjunct to guiding therapies and improving outcomes in traumatic and ischemic brain injury and we appear to be on the verge of a breakthrough with the use of these markers as diagnostic, prognostic, and monitoring adjuncts, in neurointensive care.

Topics: Biomarkers; Brain Injuries; Brain Ischemia; Decision Making; Humans; Inflammation; Myelin Basic Protein; Nerve Growth Factors; Oxidative Stress; Phosphopyruvate Hydratase; Prognosis; Proteomics; S100 Calcium Binding Protein beta Subunit; S100 Proteins

Cerebral ischemia usually leads to axonal degeneration and demyelination in the adjacent white matter. Promoting remyelination still remains a challenging issue in the field. Considering that ischemia deprives energy supply to neural cells and high metabolic activities are required by oligodendrocyte progenitor cells (OPCs) for myelin formation, we assessed the effects of transplanting exogenous healthy mitochondria on the degenerating process of oligodendrocytes following focal cerebral ischemia in the present study. Our results showed that exogenous mitochondria could efficiently restore the overall mitochondrial function and be effectively internalized by OPCs in the ischemic cortex. In comparison with control cortex, there were significantly less apoptotic and more proliferative OPCs in mitochondria-treated cortex. More importantly, higher levels of myelin basic protein (MBP) and more morphologically normal myelin-wrapped axons were observed in mitochondria-treated cortex at 21 days postinjury, as revealed by light and electron microscope. Behavior assay showed better locomotion recovery in mitochondria-treated mice. Further analysis showed that olig2 and lipid synthesis signaling were significantly increased in mitochondria-treated cortex. In together, our data illustrated an antidegenerating and myelination-promoting effect of exogenous mitochondria, indicating mitochondria transplantation as a potentially valuable treatment for ischemic stroke.

Topics: Animals; Brain Ischemia; Cell Differentiation; Lipids; Locomotion; Mice; Mitochondria; Myelin Basic Protein; Myelin Sheath; Oligodendroglia; Remyelination

(1) Background: Although myelin disruption is an integral part of ischemic brain injury, it is rarely the subject of research, particularly in animal models. This study assessed for the first time, myelin and oligodendrocyte loss in a three-vessel model of global cerebral ischemia (GCI), which causes hippocampal damage. In addition, we investigated the relationships between demyelination and changes in microglia and astrocytes, as well as oligodendrogenesis in the hippocampus; (2) Methods: Adult male Wistar rats (

Topics: 2',3'-Cyclic Nucleotide 3'-Phosphodiesterase; Animals; Antigens; Antigens, Nuclear; Astrocytes; Biomarkers; Brain Ischemia; Calcium-Binding Proteins; Glial Fibrillary Acidic Protein; Male; Microfilament Proteins; Microglia; Myelin Basic Protein; Myelin Sheath; Nerve Tissue Proteins; Proteoglycans; Rats; Rats, Wistar

Ischemic stroke often causes motor and cognitive deficits. Deregulated glia gap junction communication, which is reflected by increased protein levels of glial fibrillary acidic protein (GFAP) and connexin 43 (Cx43), has been observed in ischemic hippocampus and has been associated with cognitive impairment in animal stroke models. Here, we tested the hypothesis that reactive astrocytes-mediated loss of synaptophysin (SYP) and CREB-regulated transcription coactivator 1 (CRTC1) contribute to dysfunction in glia gap junction communication and memory impairment after ischemic stroke. Male Sprague-Dawley rats were subjected to a 90-min middle cerebral artery occlusion (MCAO) with 7-day reperfusion. Fluorocitrate (1 nmol), the reversible inhibitor of the astrocytic tricarboxylic acid cycle, was injected into the right lateral ventricle of MCAO rats once every 2 days starting immediately before reperfusion. The Morris water maze was used to assess memory in conjunction with western blotting and immunostaining to detect protein expression and distribution in the hippocampus. Our results showed that ischemic stroke caused significant memory impairment accompanied by increased protein levels of GFAP and Cx43 in hippocampal tissue. In addition, the levels of several key memory-related important proteins including SYP, CRTC1, myelin basic protein and high-mobility group-box-1 were significantly reduced in the hippocampal tissue. Of note, inhibition of reactive astrocytes with fluorocitrate was shown to significantly reverse the above noted changes induced by ischemic stroke. Taken together, our findings demonstrate that inhibiting reactive astrocytes with fluorocitrate immediately before reperfusion may protect against ischemic stroke-induced memory impairment through the upregulation of CRTC1 and SYP.

Topics: Animals; Astrocytes; Brain Ischemia; Citrates; Connexin 43; Glial Fibrillary Acidic Protein; Hippocampus; HMGB1 Protein; Learning; Male; Memory Disorders; Motor Activity; Myelin Basic Protein; Rats, Sprague-Dawley; Stroke; Synaptophysin; Transcription Factors; Up-Regulation

Endothelial progenitor cells (EPCs) have been extensively investigated as a therapeutic approach for repairing the vascular system in cerebrovascular diseases. Beyond vascular regeneration per se, EPCs may also release factors that affect the entire neurovascular unit. Here, we aim to study the effects of the EPC secretome on oligovascular remodeling in a mouse model of white matter injury after prolonged cerebral hypoperfusion.. The secretome of mouse EPCs was analyzed with a proteome array. In vitro, the effects of the EPC secretome and its factor angiogenin were assessed on primary oligodendrocyte precursor cells and mature human cerebral microvascular endothelial cells (hCMED/D3). In vivo, mice were subjected to permanent bilateral common carotid artery stenosis, then treated with EPC secretome at 24 hours and at 1 week, and cognitive outcome was evaluated with the Y maze test together with oligodendrocyte precursor cell proliferation/differentiation and vascular density in white matter at 4 weeks.. Multiple growth factors, cytokines, and proteases were identified in the EPC secretome, including angiogenin. In vitro, the EPC secretome significantly enhanced endothelial and oligodendrocyte precursor cell proliferation and potentiated oligodendrocyte precursor cell maturation. Angiogenin was proved to be a key factor since pharmacological blockade of angiogenin signaling negated the positive effects of the EPC secretome. In vivo, treatment with the EPC secretome increased vascular density, myelin, and mature oligodendrocytes in white matter and rescued cognitive function in the mouse hypoperfusion model.. Factors secreted by EPCs may ameliorate white matter damage in the brain by boosting oligovascular remodeling.

Topics: Angiogenesis Inducing Agents; Animals; Brain Ischemia; Carotid Stenosis; Cell Proliferation; Culture Media, Conditioned; Cytokines; Disease Models, Animal; Endothelial Progenitor Cells; Glutathione S-Transferase pi; Humans; In Vitro Techniques; Intercellular Signaling Peptides and Proteins; Mice; Myelin Basic Protein; Oligodendrocyte Precursor Cells; Peptide Hydrolases; Platelet Endothelial Cell Adhesion Molecule-1; Receptor, Platelet-Derived Growth Factor alpha; Ribonuclease, Pancreatic; Vascular Remodeling; White Matter

Chronic cerebral hypoperfusion is a model for white matter lesions (WMLs) and cognitive impairment. In this study, we used the model in testing the protective effect of (-)-(2R)-1-[（4-β-D-glucopyranosyloxy)benzyl]-4-[4-(β-D-glucopyranosyloxy)benzyl]-2-isobutyl malate (militarine) on the white matter damaged. The model was established by bilateral common carotid ligation. Militarine (10 and 20 mg·kg(-1)·d(-1)) or saline was intragastrically administered daily for 30 days following the operation. Militarine (20 mg·kg-1·d-1)-treated rats exhibited significantly shorter escape latency, latency of the first time crossing and more numbers of platform crossings in Morris water maze task. Luxol fast blue (LFB) staining and Western blot analysis indicated that militarine promoted rehabilitation of white matter and increased levels of myelin basic protein (MBP) in the rats. Immunohistochemical staining for 2’,3’-cyclic-nucleotide 3’-phosphodiesterase (CNPase) revealed that militarine (20 mg·kg(-1)·d(-1)) markedly suppressed loss of CNPase-positive oligodendrocytes in the rat model. In conclusion, militarine can improve WMLs and cognitive impairment in the rat chronic hypoperfusion model.

Topics: 2',3'-Cyclic-Nucleotide Phosphodiesterases; Animals; Brain Ischemia; Cognitive Dysfunction; Disease Models, Animal; Maze Learning; Myelin Basic Protein; Rats; Succinates; White Matter

Cerebroprotective activity of phenyl derivatives of GABA (phenibut, 25 mg/kg) and L-glutamic acid (neuroglutam, 26 mg/kg) in rats with cerebral ischemia was studied on the background of intact and altered immunoreactivity. Tested compounds were administered intraperitoneally for 7 days after two phase ligation of common carotid arteries (second artery was ligated 3 days after ligation of the first artery). Immunosuppression caused by cyclosporin (daily dose 5 mg/kg, p.o., for 13 days) worsened brain ischemia outcome, as manifested by increased mortality, more severe neurological marker score, increased levels of brain damage markers (NSE and MBP) in the blood serum, decrease in muscle strength and locomotor activity, and impairment of orientation and research activity as compared to animals with brain ischemia and intact immunity. Activation of immune system was caused by lipopolysaccharide (10 mg/kg, i.p., 7 injections every second day). Upon activation of the immune system, brain ischemia produced lower mortality, while the survived rats exhibited more favorable outcome of ischemia than animals with suppression of immune system: lover neurological marker score, lower blood serum NSE and MBP levels (-35% on average,p < 0.05), and much higher level of performance in motor coordination, muscular strength, and locomotor activity (+90% on average, p < 0.05). The state of immune system significantly influenced the neuroprotective activity of drugs tested. Neuroglutam administration produced positive effect both in animals with intact immunity and on the background of altered immunoreactivity. However, most positive outcome after neuroglutam administration in ischemic rats was observed in animals with suppression of immune system, with significant increase in the cerebral blood flow level (+56%), decrease in NSE and MBP blood serum levels (57 and 76%, respectively) after 7-day treatment as compared to the control group. The therapeutic potential of phenibut was somewhat lower than that of neuroglutam, and it was more pronounced in rats with activated immune system, whereas the drug effectiveness in rats with suppressed immune system was less pronounced.

Topics: Animals; Animals, Outbred Strains; Biomarkers; Brain Ischemia; Carotid Artery, Common; Cerebrovascular Circulation; Cyclosporine; gamma-Aminobutyric Acid; Glutamic Acid; Immunity, Innate; Immunosuppression Therapy; Immunosuppressive Agents; Ligation; Lipopolysaccharides; Locomotion; Male; Muscle Strength; Myelin Basic Protein; Neuroprotective Agents; Orientation, Spatial; Phosphopyruvate Hydratase; Rats; Survival Analysis

We investigated the probability of newly generated neurons that could survive and mature in the ischemic hippocampal CA1 region (CA1) of a gerbil model of transient cerebral ischemia. Neuronal death was shown in the stratum pyramidale (SP) from 4 days post-ischemia, and a significant increase in NeuN-positive ((+) ) neurons was found in the SP at 180 days post-ischemia. 5-Bromo-2-deoxyuridine (BrdU)(+) cells were co-stained with NeuN and glutamic decarboxylase 67 (GAD67). Brain-derived neurotrophic factor (BDNF) immunoreactivity and protein level was shown in nonpyramidal cells from 4 days post-ischemia, and the immunoreactivity was strong at 30 days post-ischemia and not significantly changed until 180 days post-ischemia. Furthermore, TrkB immunoreactivity was co-stained with GAD67 when we examined at 180 days post-ischemia. Myelin basic protein (MBP)(+) nerve fibers were reduced at 4 days post-ischemia and maintained until 60 days post-ischemia, and MBP immunoreactivity and levels were significantly increased at 180 days post-ischemia. In the passive avoidance test, cognitive dysfunction was improved at 180 days post-ischemia. These results suggest that the differentiation of neural progenitor cells into new GABAergic neurons may be promoted via BDNF in the ischemic CA1 and that the neurogenesis may partially mediate the recovery of cognitive impairments via increasing myelinated nerve fibers.

Topics: Animals; Avoidance Learning; Brain Ischemia; Brain-Derived Neurotrophic Factor; Bromodeoxyuridine; CA1 Region, Hippocampal; Calcium-Binding Proteins; Cell Count; Disease Models, Animal; DNA-Binding Proteins; GABAergic Neurons; Gene Expression Regulation; Gerbillinae; Glial Fibrillary Acidic Protein; Glutamate Decarboxylase; Male; Microfilament Proteins; Myelin Basic Protein; Neurogenesis; Phosphopyruvate Hydratase; Reaction Time; Time Factors

Chronic cerebral hypoperfusion can lead to ischemic white matter injury resulting in vascular dementia. To characterize white matter injury in vascular dementia, we investigated disintegration of diverse white matter components using a rat model of chronic cerebral hypoperfusion.. Chronic cerebral hypoperfusion was modeled in Wistar rats by permanent occlusion of the bilateral common carotid arteries. We performed cognitive behavioral tests, including the water maze task, odor discrimination task, and novel object test; histological investigation of neuroinflammation, oligodendrocytes, myelin basic protein, and nodal or paranodal proteins at the nodes of Ranvier; and serial diffusion tensor imaging. Cilostazol was administered to protect against white matter injury.. Diverse cognitive impairments were induced by chronic cerebral hypoperfusion. Disintegration of white matter was characterized by neuroinflammation, loss of oligodendrocytes, attenuation of myelin density, structural derangement at the nodes of Ranvier, and disintegration of white matter tracts. Cilostazol protected against cognitive impairments and white matter disintegration.. White matter injury induced by chronic cerebral hypoperfusion can be characterized by disintegration of diverse white matter components. Cilostazol might be a therapeutic strategy against white matter disintegration in patients with vascular dementia.

Topics: Animals; Behavior, Animal; Brain Ischemia; Carotid Stenosis; Chronic Disease; Cilostazol; Cognition; Dementia, Vascular; Diffusion Tensor Imaging; Disease Models, Animal; Hippocampus; Inflammation; Leukoencephalopathies; Myelin Basic Protein; Neuroprotective Agents; Neuropsychological Tests; Oligodendroglia; Ranvier's Nodes; Rats; Rats, Wistar; Tetrazoles; White Matter

Preclinical Research The aim of the present study was to evaluate the neuroprotective benefits of rhGLP-1 in diabetic rats subjected to acute cerebral ischemia/reperfusion injury induced by middle cerebral artery occlusion/reperfusion (MCAO/R). Streptozotocin (STZ)-induced diabetic rats were pretreated with rhGLP-1 (10, 20, or 40 μg/kg ip, tid) for 14 days. During this time, body weight and fasting blood glucose levels were assessed. Rats were then subjected to MCAO 90 min/R 24 h. At 2 and 24 h of reperfusion, rats were evaluated for neurological deficits and blood samples were collected to analyze markers of brain injury. Rats were then sacrificed to assess the infarction volume. rhGLP-1 pretreatment lowered blood glucose levels, improved neurological scores, attenuated infarct volumes, and reduced the blood levels of S100 calcium-binding protein B (S100B), neuron-specific enolase (NSE), and myelin basic protein (MBP). rhGLP-1 has neuroprotective benefits in diabetic rats with cerebral ischemia/reperfusion injury and could potentially be used as a prophylatic neuroprotectant in diabetic patients at high risk of ischemic stroke. Drug Dev Res 77 : 124-133, 2016.   © 2016 Wiley Periodicals, Inc.

Topics: Animals; Body Weight; Brain Ischemia; Diabetes Mellitus, Experimental; Disease Models, Animal; Glucagon-Like Peptide 1; Hypoglycemic Agents; Male; Myelin Basic Protein; Neuroprotective Agents; Phosphopyruvate Hydratase; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Reperfusion Injury; S100 Calcium Binding Protein beta Subunit; Streptozocin; Treatment Outcome

The positive correlation between therapeutic exercise and memory recovery in cases of ischemia has been extensively studied; however, long-term exercise begun after ischemic neuronal death as a chronic neurorestorative strategy has not yet been thoroughly examined.. The purpose of this study is to investigate possible mechanisms by which exercise ameliorates ischemia-induced memory impairment in the aged gerbil hippocampus after transient cerebral ischemia.. Treadmill exercise was begun 5 days after ischemia-reperfusion (I-R) and lasted for 1 or 4 weeks. The animals were sacrificed 31 days after the induction of ischemia. Changes in short-term memory, as well as the hippocampal expression of markers of cell proliferation, neuroblast differentiation, neurogenesis, myelin and microvessel repair, and growth factors were examined by immunohistochemistry and/or western blots.. Four weeks of exercise facilitated memory recovery despite neuronal damage in the stratum pyramidale (SP) of the hippocampal CA1 region and in the polymorphic layer (PoL) of the dentate gyrus (DG) after I-R. Long-term exercise enhanced cell proliferation and neuroblast differentiation in a time-dependent manner, and newly generated mature cells were found in the granule cell layer of the DG, but not in the SP of the CA1 region or in the PoL of the DG. In addition, long-term exercise ameliorated ischemia-induced damage of myelin and microvessels, which was correlated with increased BDNF expression in the CA1 region and the DG.. These results suggest that long-term treadmill exercise after I-R can restore memory function through replacement of multiple damaged structures in the ischemic aged hippocampus.

Topics: Animals; Avoidance Learning; Brain Ischemia; Bromodeoxyuridine; Disease Models, Animal; Exercise Test; Exercise Therapy; Gerbillinae; Glucose Transport Proteins, Facilitative; Male; Memory Disorders; Microvessels; Myelin Basic Protein; Myelin Sheath; Nerve Tissue Proteins; Neurogenesis; Stroke; Stroke Rehabilitation; Time Factors

Whether and when auto-reactivity after stroke occurs is still a matter of debate. By using overlapping 15mer peptide pools consisting of myelin basic protein (MBP) and myelin oligodendrocyte glycoprotein (MOG) we show increased frequencies of immunodominant MOG- and MBP T cell responses in acute ischemic stroke which were associated with reduced frequencies of naïve T cells as well as CD8+ TEMRA cells. Auto-reactive CNS antigen-specific T cells responses as well as alterations of T cell subpopulations normalized in long-term follow up after stroke. Our findings suggest that stroke-induced immunodepression might function as an adaptive mechanism in order to inhibit harmful and long-lasting CNS antigen-specific immune responses.

Topics: Adult; Aged; Aged, 80 and over; Autoimmunity; Brain Ischemia; Enzyme-Linked Immunospot Assay; Female; Flow Cytometry; Follow-Up Studies; Humans; Immunologic Memory; Interferon-gamma; Male; Middle Aged; Myelin Basic Protein; Myelin-Oligodendrocyte Glycoprotein; Neuroimmunomodulation; Stroke; T-Lymphocyte Subsets

Stroke is a leading cause of death and neurological disability worldwide and striatal ischemic stroke is frequent in humans due to obstruction of middle cerebral artery. Several pathological events underlie damage progression and a comprehensive description of the pathological features following experimental stroke in both acute and chronic survival times is a necessary step for further functional studies. Here, we explored the patterns of microglial activation, astrocytosis, oligodendrocyte damage, myelin impairment, and Nogo-A immunoreactivity between 3 and 30 postlesion days (PLDs) after experimental striatal stroke in adult rats induced by microinjections of endothelin-1 (ET-1). The focal ischemia induced tissue loss concomitant with intense microglia activation between 3 and 14 PLDs (maximum at 7 PLDs), decreasing afterward. Astrocytosis was maximum around 7 PLDs. Oligodendrocyte damage and Nogo-A upregulation were higher at 3 PLDs. Myelin impairment was maximum between 7 and 14 PLDs. Nogo-A expression was higher in the first week in comparison to control. The results add important histopathological features of ET-1 induced stroke in subacute and chronic survival times. In addition, the establishment of the temporal evolution of these neuropathological events is an important step for future studies seeking suitable neuroprotective drugs targeting neuroinflammation and white matter damage.

Topics: Animals; Astrocytes; Brain; Brain Ischemia; Disease Models, Animal; Endothelin-1; Immunohistochemistry; Male; Microglia; Microscopy; Myelin Basic Protein; Nogo Proteins; Oligodendroglia; Rats; Rats, Wistar; Stroke; Up-Regulation; White Matter

Neonatal white matter injury (NWMI) is the leading cause of cerebral palsy and other neurocognitive deficits in prematurely-born children, and no restorative therapies exist. Our objective was to determine the fate and effect of glial restricted precursor cell (GRP) transplantation in an ischemic mouse model of NWMI.. Neonatal CD-1 mice underwent unilateral carotid artery ligation on postnatal-Day 5 (P5). At P22, intracallosal injections of either enhanced green fluorescent protein (eGFP) + GRPs or saline were performed in control and ligated mice. Neurobehavioral and postmortem studies were performed at 4 and 8 weeks post-transplantation.. GRP survival was comparable at 1 month but significantly lower at 2 months post-transplantation in NWMI mice compared with unligated controls. Surviving cells showed better migration capability in controls; however, the differentiation capacity of transplanted cells was similar in control and NWMI. Saline-treated NWMI mice showed significantly altered response in startle amplitude and prepulse inhibition (PPI) paradigms compared with unligated controls, while these behavioral tests were completely normal in GRP-transplanted animals. Similarly, there was significant increase in hemispheric myelin basic protein density, along with significant decrease in pathologic axonal staining in cell-treated NWMI mice compared with saline-treated NWMI animals.. The reduced long-term survival and migration of transplanted GRPs in an ischemia-induced NWMI model suggests that neonatal ischemia leads to long-lasting detrimental effects on oligodendroglia even months after the initial insult. Despite limited GRP-survival, behavioral, and neuropathological outcomes were improved after GRP-transplantation. Our results suggest that exogenous GRPs improve myelination through trophic effects in addition to differentiation into mature oligodendrocytes.

Topics: Animals; Animals, Newborn; Axons; Brain; Brain Ischemia; Cell Differentiation; Cell Movement; Cell Survival; Disease Models, Animal; Green Fluorescent Proteins; Mice; Mice, Inbred C57BL; Mice, Transgenic; Myelin Basic Protein; Neuroglia; Spinal Cord; Stem Cell Transplantation; Stem Cells; Treatment Outcome; White Matter

Translational research is beginning to reveal the importance of trophic factors as a therapy for cellular brain repair. The purpose of this study was to analyze whether brain-derived neurotrophic factor (BDNF) administration could mediate oligodendrogenesis and remyelination after white matter injury in subcortical stroke.. Ischemia was induced in rats by injection of endothelin-1. At 24 hours, 0.4 μg/kg of BDNF or saline was intravenously administered to the treatment and control groups, respectively. Functional evaluation, MRI, and fiber tract integrity on tractography images were analyzed. Proliferation (KI-67) and white matter repair markers (A2B5, 2',3'-cyclic-nucleotide 3'-phosphodiesterase [CNPase], adenomatous polyposis coli [APC], platelet-derived growth factor receptor alpha [PDGFR-α], oligodendrocyte marker O4 [O4], oligodendrocyte transcription factor [Olig-2], and myelin basic protein [MBP]) were analyzed at 7 and 28 days.. The BDNF-treated animals showed less functional deficit at 28 days after treatment than the controls (P<0.05). Although T2-MRI did not show differences in lesion size at 7 and 28 days between groups, diffusion tensor imaging tractography analysis revealed significantly better tract connectivity at 28 days in the BDNF group than in the controls (P<0.05). Increased proliferation of oligodendrocyte progenitors was observed in treated animals at 7 days (P<0.05). Finally, the levels of white matter repair markers (A2B5, CNPase, and O4 at 7 days; Olig-2 and MBP at 28 days) were higher in the BDNF group than in the controls (P<0.05).. BDNF administration exerted better functional outcome, oligodendrogenesis, remyelination, and fiber connectivity than controls in rats subjected to subcortical damage in ischemic stroke.

Topics: 2',3'-Cyclic-Nucleotide Phosphodiesterases; Adenomatous Polyposis Coli Protein; Animals; Basic Helix-Loop-Helix Transcription Factors; Brain; Brain Ischemia; Brain-Derived Neurotrophic Factor; Cell Differentiation; Diffusion Tensor Imaging; Magnetic Resonance Imaging; Myelin Basic Protein; Myelin Sheath; Oligodendroglia; Rats; Receptor, Platelet-Derived Growth Factor alpha; Stroke; White Matter

Ischemia, white matter injury, and Alzheimer's disease (AD) pathologies often co-exist in aging brain. How one condition predisposes to, interacts with, or perhaps causes the others remains unclear.. To better understand the link between ischemia, white matter injury, and AD, adult rats were administered lipopolysaccharide (LPS) to serve as an inflammatory stimulus, and 24 h later subjected to 20-min focal cerebral ischemia (IS) followed by 30-min hypoxia (H).. Myelin and axonal damage, as well as amyloid-β (Aβ) and amyloid-β protein precursor (AβPP) deposition were examined by Western blot and immunocytochemistry following LPS/IS/H. Findings were compared to the 5XFAD mouse AD brain.. Myelin/axonal injury was observed bilaterally in cortex following LPS/IS/H, along with an increase in IL-1, granzyme B, and LPS. AβPP deposition was present in ischemic striatum in regions of myelin loss. Aβ(1-42) and AβPP were deposited in small foci in ischemic cortex that co-localized with myelin aggregates. In the 5XFAD mouse AD model, cortical amyloid plaques also co-localized with myelin aggregates.. LPS/IS/H produce myelin injury and plaque-like aggregates of myelin. AβPP and Aβ co-localize with these myelin aggregates.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Brain; Brain Ischemia; Disease Models, Animal; Inflammation; Lipopolysaccharides; Male; Mice; Mice, Transgenic; Myelin Basic Protein; Myelin Sheath; Peptide Fragments; Plaque, Amyloid; Rats; Rats, Sprague-Dawley

Fructus mume (F. mume) has been used as a traditional medicine for many years in Asian countries. The present study was designed to determine the effect of a 70% ethanol extract of F. mume on white matter and hippocampal damage induced by chronic cerebral hypoperfusion.. Permanent bilateral common carotid artery occlusion (BCCAo) was performed on male Wistar rats to induce chronic cerebral hypoperfusion. Daily oral administration of F. mume (200 mg/kg) was initiated 21 days after BCCAo and continued for 42 days. The experimental groups in this study were divided into three groups: a sham-operated group, a BCCAo group, and a BCCAo group that was administered with the F. mume extract. The activation of glial cells, including microglia and astrocytes, and the levels of myelin basic protein (MBP), inflammatory mediators, Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and p38 mitogen-activated protein kinase (MAPK) phosphorylation were measured in brains from rats subjected to chronic BCCAo.. Our results revealed that F. mume alleviates the reduction in MBP expression caused by chronic BCCAo in the white matter and the hippocampus and significantly attenuates microglial and astrocytic activation induced by chronic BCCAo in the optic tract of white matter. In addition, F. mume treatment reduced the increased expression of cyclooxygenase-2 (COX-2), interleukin-1β (IL-1β) and interleukin-6 (IL-6), as well as the activation of TLR4/MyD88 and p38 MAPK signaling, in the hippocampus of rats subjected to chronic BCCAo.. Taken together, our findings demonstrate that brain injury induced by chronic BCCAo is ameliorated by the anti-inflammatory effects of F. mume via inhibition of MBP degradation, microglial and astrocytic activation, increased inflammatory mediator expression, and activated intracellular signalings, including TLR4 and p38 MAPK, implying that F. mume is potentially an effective therapeutics for the treatment of vascular dementia.

Topics: Animals; Anti-Inflammatory Agents; Brain; Brain Ischemia; Cytokines; Dementia, Vascular; Down-Regulation; Drugs, Chinese Herbal; Hippocampus; Inflammation; Inflammation Mediators; Male; Myelin Basic Protein; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Phytotherapy; Prunus; Rats, Wistar; Signal Transduction; Toll-Like Receptor 4; White Matter

This study highlights the possible pathological role of MMP-12 in the context of ischemic stroke. Male rats were subjected to a two-hour middle cerebral artery occlusion (MCAO) procedure. MMP-12 shRNA expressing plasmid formulation was administered to these rats twenty-four hours after reperfusion. The results showed a predominant upregulation of MMP-12 (approximately 47, 58, 143, and 265 folds on days 1, 3, 5, 7 post-ischemia, respectively) in MCAO subjected rats. MMP-12 expression was localized to neurons, oligodendrocytes and microglia, but not astrocytes. Transcriptional inactivation of MMP-12 significantly reduced the infarct size. The percent infarct size was reduced from 62.87±4.13 to 34.67±5.39 after MMP-12 knockdown compared to untreated MCAO subjected rats. Expression of myelin basic protein was increased, and activity of MMP-9 was reduced in ischemic rat brains after MMP-12 knockdown. Furthermore, a significant reduction in the extent of apoptosis was noticed after MMP-12 knockdown. TNFα expression in the ipsilateral regions of MCAO-subjected rats was reduced after MMP-12 knockdown in addition to the reduced protein expression of apoptotic molecules that are downstream to TNFα signaling. Specific knockdown of MMP-12 after focal cerebral ischemia offers neuroprotection that could be mediated via reduced MMP-9 activation and myelin degradation as well as inhibition of apoptosis.

Topics: Animals; Apoptosis; Brain Injuries; Brain Ischemia; Cell Line, Tumor; Gene Knockdown Techniques; Gene Silencing; Male; Matrix Metalloproteinase 12; Matrix Metalloproteinase 9; Myelin Basic Protein; Neurons; Plasmids; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction; Reperfusion; RNA, Small Interfering; Substrate Specificity; Transcription, Genetic; Tumor Necrosis Factor-alpha; Up-Regulation

Oligodendrocyte precursor cells (OPCs) in the adult brain contribute to white matter homeostasis. After white matter damage, OPCs compensate for oligodendrocyte loss by differentiating into mature oligodendrocytes. However, the underlying mechanisms remain to be fully defined. Here, we test the hypothesis that, during endogenous recovery from white matter ischemic injury, astrocytes support the maturation of OPCs by secreting brain-derived neurotrophic factor (BDNF). For in vitro experiments, cultured primary OPCs and astrocytes were prepared from postnatal day 2 rat cortex. When OPCs were subjected to chemical hypoxic stress by exposing them to sublethal CoCl2 for 7 d, in vitro OPC differentiation into oligodendrocytes was significantly suppressed. Conditioned medium from astrocytes (astro-medium) restored the process of OPC maturation even under the stressed conditions. When astro-medium was filtered with TrkB-Fc to remove BDNF, the BDNF-deficient astro-medium no longer supported OPC maturation. For in vivo experiments, we analyzed a transgenic mouse line (GFAP(cre)/BDNF(wt/fl)) in which BDNF expression is downregulated specifically in GFAP(+) astrocytes. Both wild-type (GFAP(wt)/BDNF(wt/fl) mice) and transgenic mice were subjected to prolonged cerebral hypoperfusion by bilateral common carotid artery stenosis. As expected, compared with wild-type mice, the transgenic mice exhibited a lower number of newly generated oligodendrocytes and larger white matter damage. Together, these findings demonstrate that, during endogenous recovery from white matter damage, astrocytes may promote oligodendrogenesis by secreting BDNF.. The repair of white matter after brain injury and neurodegeneration remains a tremendous hurdle for a wide spectrum of CNS disorders. One potentially important opportunity may reside in the response of residual oligodendrocyte precursor cells (OPCs). OPCs may serve as a back-up for generating mature oligodendrocytes in damaged white matter. However, the underlying mechanisms are still mostly unknown. Here, we use a combination of cell biology and an animal model to report a new pathway in which astrocyte-derived BDNF supports oligodendrogenesis and regeneration after white matter damage. These findings provide new mechanistic insight into white matter physiology and pathophysiology, which would be broadly and clinically applicable to CNS disease.

Topics: Animals; Antimutagenic Agents; Astrocytes; Brain Ischemia; Brain-Derived Neurotrophic Factor; Cell Differentiation; Cells, Cultured; Chromones; Cobalt; Culture Media, Conditioned; Disease Models, Animal; Enzyme Inhibitors; Gene Expression Regulation; Glial Fibrillary Acidic Protein; Glutathione S-Transferase pi; Hypoxia-Inducible Factor 1, alpha Subunit; Leukoencephalopathies; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Morpholines; Myelin Basic Protein; Myelin Sheath; Phosphopyruvate Hydratase; Stem Cells

Chronic cerebral hypoperfusion, a sustained modest reduction in cerebral blood flow, is associated with damage to myelinated axons and cognitive decline with ageing. Oligodendrocytes (the myelin producing cells) and their precursor cells (OPCs) may be vulnerable to the effects of hypoperfusion and in some forms of injury OPCs have the potential to respond and repair damage by increased proliferation and differentiation. Using a mouse model of cerebral hypoperfusion we have characterised the acute and long term responses of oligodendrocytes and OPCs to hypoperfusion in the corpus callosum. Following 3 days of hypoperfusion, numbers of OPCs and mature oligodendrocytes were significantly decreased compared to controls. However following 1 month of hypoperfusion, the OPC pool was restored and increased numbers of oligodendrocytes were observed. Assessment of proliferation using PCNA showed no significant differences between groups at either time point but showed reduced numbers of proliferating oligodendroglia at 3 days consistent with the loss of OPCs. Cumulative BrdU labelling experiments revealed higher numbers of proliferating cells in hypoperfused animals compared to controls and showed a proportion of these newly generated cells had differentiated into oligodendrocytes in a subset of animals. Expression of GPR17, a receptor important for the regulation of OPC differentiation following injury, was decreased following short term hypoperfusion. Despite changes to oligodendrocyte numbers there were no changes to the myelin sheath as revealed by ultrastructural assessment and fluoromyelin however axon-glial integrity was disrupted after both 3 days and 1 month hypoperfusion. Taken together, our results demonstrate the initial vulnerability of oligodendroglial pools to modest reductions in blood flow and highlight the regenerative capacity of these cells.

Topics: Animals; Antigens; Axons; Blotting, Western; Brain Ischemia; Cell Count; Cell Differentiation; Cell Proliferation; Cerebrovascular Circulation; Chronic Disease; Corpus Callosum; Disease Models, Animal; Immunohistochemistry; Male; Mice; Mice, Inbred C57BL; Microscopy, Confocal; Myelin Basic Protein; Myelin Sheath; Nerve Tissue Proteins; Neural Stem Cells; Neuroglia; Oligodendroglia; Proliferating Cell Nuclear Antigen; Proteoglycans; Receptors, G-Protein-Coupled; Time Factors

To explore the neuroprotective effect and optimize the therapeutic dose and time window of picroside II by orthogonal test and the expression of myelin basic protein (MBP) in cerebral ischemic injury in rats. Bilateral common carotid artery occlusion (BCCAO) was used to establish forebrain ischemia models. The successful rat models were grouped according to orthogonal experimental design and injected picroside II intraperitoneally at different ischemic time with different doses. Myelin sheath fast green staining(FGS) and transmission electron microscopy (TEM) were used to observe nerve fiber myelin; the expression of MBP was tested qualitatively and quantitatively by immunohistochemical assay (IHC) and Western blot (WB); Reverse transcription polymerase chain reaction (RT-PCR) was used to detect the transcription level of MBP mRNA.. The protective effect of picroside II was presented by increasing the expression of MBP and decreasing demyelination after cerebral ischemic injury. The best therapeutic time window and dose was (1) ischemia 2.0 h with picroside II 10 mg/kg body weight according to the results of FGS, IHC and WB; (2) ischemia 1.5 h with picroside II 20 mg/kg according to the analysis of RT-PCR.. Given the principle of the longest time window and the lowest therapeutic dose, the optimized therapeutic dose and time window should be injecting picroside II intraperitoneally with 10-20 mg/kg body weight at ischemia 1.5-2.0 h in cerebral ischemic injury.

Topics: Animals; Brain Ischemia; Cinnamates; Dose-Response Relationship, Drug; Down-Regulation; Gene Expression Regulation; Injections, Intraperitoneal; Iridoid Glucosides; Male; Myelin Basic Protein; Myelin Sheath; Neuroprotective Agents; Rats; Rats, Wistar; Treatment Outcome

White matter ischemia is difficult to quantify histologically. Myelin-associated glycoprotein (MAG) is highly susceptible to ischemia, being expressed only adaxonally, far from the oligodendrocyte cell body. Myelin-basic protein (MBP) and proteolipid protein (PLP) are expressed throughout the myelin sheath. We compared MAG, MBP, and PLP levels in parietal white matter homogenates from 17 vascular dementia (VaD), 49 Alzheimer's disease (AD), and 33 control brains, after assessing the post-mortem stability of these proteins. Small vessel disease (SVD) and cerebral amyloid angiopathy (CAA) severity had been assessed in paraffin sections. The concentration of MAG remained stable post-mortem, declined with increasing SVD, and was significantly lower in VaD than controls. The concentration of MBP fell progressively post-mortem, limiting its diagnostic utility in this context. Proteolipid protein was stable post-mortem and increased significantly with SVD severity. The MAG/PLP ratio declined significantly with SVD and CAA severity. The MAG and PLP levels and MAG/PLP did not differ significantly between AD and control brains. We validated the utility of MAG and MAG/PLP measurements on analysis of 74 frontal white matter samples from an Oxford cohort in which SVD had previously been scored. MAG concentration and the MAG/PLP ratio are useful post-mortem measures of ante-mortem white matter ischemia.

Topics: Aged; Aged, 80 and over; Alzheimer Disease; Biopsy; Brain Ischemia; Cohort Studies; Dementia, Vascular; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique, Direct; Humans; Middle Aged; Myelin Basic Protein; Myelin Proteolipid Protein; Myelin-Associated Glycoprotein; Parietal Lobe; Postmortem Changes; Protein Stability; Severity of Illness Index

In stroke, a common cause of neurological disability in adults is that the myelin sheaths are lost through the injury or death of mature oligodendrocytes, and the failure of remyelination may be often due to insufficient proliferation and differentiation of oligodendroglial progenitors. In the current study, we used middle cerebral artery occlusion (MCAO) to induced transient focal cerebral ischemia, and found that WIN55, 212-2 augmented actively proliferating oligodendrocytes measured by CC1 immunoreactive cells within the peri-infarct areas. To establish whether these effects were associated with changes in myelin formation, we analyzed the expression of myelin basic protein (MBP) and myelin ultrastructure. We found that WIN55, 212-2 showed more extensive remyelination than vehicle at 14 days post injection (dpi). The extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) signaling pathway may be involved in OPCs differentiation. To determine the regulatory effect of WIN55, 212-2 post-treatment on phospho-ERK 1/2 (p-ERK 1/2) after ischemia/reperfusion, Western blot analysis was performed. We found that WIN55, 212-2 regulated the phosphorylation level of the ERK 1/2 to promote OPCs survival and differentiation. Notably, cannabinoid receptor 1 is coupled to the activation of the ERK cascade. Following rimonabant combined treatment, the effect of WIN55, 212-2 on regulating the phosphorylation level of the ERK 1/2 was reversed, and the effect of accelerated myelin formation was partially inhibited. Together, we first found that WIN55, 212-2 promoted OPCs differentiation and remyelination through regulation of the level of the p-ERK 1/2 via cannabinoid receptor 1.

Topics: Animals; Antimetabolites; Benzoxazines; Blotting, Western; Brain Ischemia; Bromodeoxyuridine; Cannabinoid Receptor Antagonists; Cell Differentiation; Cell Survival; Demyelinating Diseases; Immunohistochemistry; Indicators and Reagents; Male; MAP Kinase Signaling System; Microscopy, Electron; Morpholines; Myelin Basic Protein; Myelin Sheath; Naphthalenes; Oligodendroglia; Phosphorylation; Piperidines; Pyrazoles; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Rimonabant; Stroke

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) inhibitors administered prior to or immediately after experimental stroke confer acute neuroprotection. However, it remains unclear if delayed treatment with a PTEN inhibitor improves long-term functional recovery after stroke. We addressed the issue in this study. Adult male mice were subjected to 1h of middle cerebral artery occlusion (MCAO) followed by treatment with a well-established PTEN inhibitor BPV or saline daily for 14 days, starting at 24h after MCAO. Functional recovery was assessed with behavioral tests and acute infarct volumes were analyzed histologically. Delayed BPV treatment did not reduce infarction during the acute phase, but significantly improved long-term functional recovery after MCAO. Since PTEN is a critical intrinsic inhibitory factor in axonal regeneration, we further examined BPV effects on axonal densities following MCAO using bielschowsky silver staining and immunohistochemistry with antibodies against myelin basic protein. Delayed BPV treatment significantly increased axon densities in the ischemic brain at 14 days after MCAO. Moreover, PTEN expression persistently remained high in the ischemic brain over 14 days after MCAO, and BPV treatment increased post-ischemic activation of Akt and mTOR in the ischemic brain. Akt and mTOR activation are the well-established cascades downstream to PTEN inhibition and have been shown to contribute to post-injury axonal regrowth in response to PTEN inhibition. Consistently, in an in vitro neuronal ischemia model, BPV enhanced axonal outgrowth of primary cortical neurons after oxygen-glucose deprivation and the enhancing effects were abolished by Akt/mTOR inhibition. In conclusion, delayed BPV treatment improved functional recovery from experimental stroke possibly via enhancing axonal growth and Akt/mTOR activation contributed to BPV-enhanced post-stroke axon growth.

Topics: Animals; Axons; Behavior, Animal; Brain; Brain Ischemia; Disease Models, Animal; Enzyme Inhibitors; Male; Mice; Myelin Basic Protein; Neurons; Phosphorylation; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Recovery of Function; Stroke; TOR Serine-Threonine Kinases; Vanadium Compounds

Myelin sheath, either in white matter or in other regions of brain, is vulnerable to ischemia. The specific events involved in the progression of ischemia in white matter have not yet been elucidated. The aim of this study was to determine histopathological alterations in cerebral white matter and levels of myelin basic protein (MBP) in ischemia-injured brain tissue during the acute and subacute phases of central nervous injury following whole-brain ischemia. The whole cerebral ischemia model (four-vessel occlusion (4-VO)) was established in adult Sprague-Dawley rats and MBP gene expression and protein levels in the brain tissue were measured using reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA) at 2 days, 4 days, 7 days, 14 days, and 28 days following ischemia. Demyelination was determined by Luxol fast blue myelin staining, routine histopathological staining, and electron microscopy in injured brain tissue. Results showed that edema, vascular dilation, focal necrosis, demyelination, adjacent reactive gliosis and inflammation occurred 7 days after ischemia in HE staining and recovered to control levels at 28 days. The absence of Luxol fast blue staining and vacuolation was clearly visible at 7 days, 14 days, and 28 days. Semiquantitative analysis showed that the transparency of myelin had decreased significantly by 7 days, 14 days, and 28 days. Demyelination and ultrastructual changes were detected 7 days after ischemia. The relative levels of MBP mRNA decreased 2 days after ischemia and this trend continued throughout the remaining four points in time. The MBP levels measured using ELISA also decreased significantly at 2 days and 4 days, but they recovered by 7 days and returned to control levels by 14 days. These results suggest that the impact of ischemia on cerebral white matter is time-sensitive and that different effects may follow different courses over time.

Topics: Animals; Brain Ischemia; Corpus Callosum; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Microscopy, Electron, Transmission; Myelin Basic Protein; Myelin Sheath; Rats; Rats, Sprague-Dawley; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

Topics: Animals; Animals, Newborn; Brain; Brain Ischemia; Female; Fetal Diseases; Myelin Basic Protein; Oligodendroglia; Pregnancy; Prenatal Exposure Delayed Effects; Rats; Rats, Wistar

A study was undertaken to investigate the effect of neonatal hypoxic-ischemic (HI) brain damage and mesenchymal stem cell (MSC) treatment on the structure and contralesional connectivity of motor function-related cerebral areas.. Brain remodeling after HI±MSC treatment in neonatal mice was analyzed using diffusion tensor magnetic resonance imaging, immunohistochemistry, anterograde tracing with biotinylated dextran amine (BDA), and retrograde tracing with fluorescent pseudorabies virus (PRV).. MSC treatment after HI reduced contralesional rewiring taking place after HI. Following MSC treatment, fractional anisotropy values, which were increased in both ipsi- and contralesional cortices and decreased in the corpus callosum (CC) after HI, were normalized to the level observed in sham-operated mice. These results were corroborated by myelin basic protein intensity and staining pattern in these areas. Anterograde tracing of ipsilesional motor neurons showed that after MSC treatment, fewer BDA-positive fibers crossed the CC and extended into the contralesional motor cortex compared to HI mice. This remodeling was functional, because retrograde labeling showed increased connectivity between impaired (left) forepaw and the contralesional (left) motor cortex after HI, whereas MSC treatment reduced this connection and increased the connection between the impaired (left) forepaw and the ipsilesional (right) motor cortex. Finally, the extent of contralesional rewiring measured with BDA and PRV tracing was related to sensorimotor dysfunction.. This is the first study to describe MSC treatment after neonatal HI markedly reducing contralesional axonal remodeling induced by HI brain injury.

Topics: Age Factors; Animals; Animals, Newborn; Anisotropy; Antigens, Neoplasm; Axons; Biotin; Brain Ischemia; Cerebral Cortex; Dextrans; Diffusion Tensor Imaging; Disease Models, Animal; DNA-Binding Proteins; Functional Laterality; Green Fluorescent Proteins; Luminescent Proteins; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice; Mice, Inbred C57BL; Mice, Transgenic; Myelin Basic Protein; Neural Pathways; Nuclear Proteins; Psychomotor Performance; Recovery of Function; Red Fluorescent Protein; Time Factors; Ubiquitin-Protein Ligases

White matter impairment is a feature of vascular depression. The anti-psychotic quetiapine has been shown to enhance the therapeutic effects of anti-depressants on vascular depression, but the mechanism remains unknown. In this study, we found that 2 weeks of treatment with quetiapine prior to bilateral carotid artery occlusion and reperfusion, in an animal model of vascular depression, resulted in reduced myelin breakdown and oligodendrocyte loss compared to placebo-treated mice on post-operative day (POD) 7. For late stage of recovery (POD40), quetiapine treatment resulted in enhanced oligodendrocyte maturation relative to placebo. The results suggest that quetiapine is a potential intervention for oligodendrocyte damage and this may contribute to its anti-depressant effects through white matter protection in vascular depression.

Topics: Analysis of Variance; Animals; Antigens; Antipsychotic Agents; Brain Ischemia; Bromodeoxyuridine; Carotid Artery Diseases; Cell Differentiation; Dibenzothiazepines; Disease Models, Animal; Gene Expression Regulation; Glial Fibrillary Acidic Protein; Hippocampus; Male; Mice; Myelin Basic Protein; Myelin Sheath; Oligodendroglia; Proteoglycans; Quetiapine Fumarate; Time Factors

Periventricular leukomalacia, PVL, is the leading cause of cerebral palsy in prematurely born infants, and therefore more effective interventions are required. The objective of this study was to develop an ischemic injury model of PVL in mice and to determine the feasibility of in vivo magnetization transfer (MT) magnetic resonance imaging (MRI) as a potential monitoring tool for the evaluation of disease severity and experimental therapeutics. Neonatal CD-1 mice underwent unilateral carotid artery ligation on postnatal day 5 (P5); at P60, in vivo T2-weighted (T2w) and MT-MRI were performed and correlated with postmortem histopathology. In vivo T2w MRI showed thinning of the right corpus callosum, but no significant changes in hippocampal and hemispheric volumes. Magnetization transfer MRI revealed significant white matter abnormalities in the bilateral corpus callosum and internal capsule. These quantitative MT-MRI changes correlated highly with postmortem findings of reduced myelin basic protein in bilateral white matter tracts. Ventriculomegaly and persistent astrogliosis were observed on the ligated side, along with evidence of axonopathy and fewer oligodendrocytes in the corpus callosum. We present an ischemia-induced mouse model of PVL, which has pathologic abnormalities resembling autopsy reports in infants with PVL. We further validate in vivo MRI techniques as quantitative monitoring tools that highly correlate with postmortem histopathology.

Topics: Animals; Brain Ischemia; Cerebral Palsy; Corpus Callosum; Disease Models, Animal; Humans; Infant, Newborn; Infant, Premature; Leukomalacia, Periventricular; Magnetic Resonance Imaging; Mice; Myelin Basic Protein; Radiography; Time Factors

Although the white matter lesions, so called leuko-araiosis, often seen in elderly people have been gaining attention due to their association with cognitive dysfunction (CD) and high risk of incident stroke, the pathological significance of these lesions still remains controversial. Therefore, in the present study, we investigated the alterations in oligodendrocytes (OLG), including oligodendrocytes progenitor cells (OPCs), myelin, and CD following chronic cerebral ischemia in rats. SD rats were subjected to bilateral common carotid artery occlusion. Immunohistochemical staining was performed at 2, 4, 6, 8, and 12weeks after the induction of ischemia with anti-NG2 (OPCs), anti-GST-π (OLG), and anti-MBP antibodies in paramedian corpus callosum (CC). CD was assessed by the Morris water maze test. There was a significant decrease in the number of GST-π positive cells at 2weeks after the start of ischemia compared with that seen in the sham group. There was a significant increase of the number of NG2 positive cells at 4weeks in the ischemia group compared with the sham group. In the ischemic group, the amount of MBP was observed to have decreased significantly at each time point compared with the sham group. CD was observed in the ischemic group than that in the sham group at all time points. Our results indicate that remyelination is strongly correlated with the recovery of cognitive dysfunction following chronic cerebral ischemia.

Topics: Analysis of Variance; Animals; Antigens; Brain Ischemia; Bromodeoxyuridine; Cell Count; Chronic Disease; Cognition Disorders; Corpus Callosum; Disease Models, Animal; Gene Expression Regulation; Maze Learning; Myelin Basic Protein; Myelin Sheath; Oligodendroglia; Proteoglycans; Rats; Rats, Sprague-Dawley; Receptor, Platelet-Derived Growth Factor alpha; Time Factors

Ischemic injury to the central nervous system causes cellular activation and disintegration, leading to release of cell-type-specific proteins into the cerebrospinal fluid (CSF). We investigated CSF concentrations of myelin basic protein (MBP), glial fibrillary astrocytic protein (GFAP), the calcium-binding protein S100B, and neuron-specific enolase (NSE) in acute ischemic stroke patients and their relation to initial stroke severity, stroke location, and long-term stroke outcome.. CSF concentrations of MBP, GFAP, S100B, and NSE were assessed in 89 stroke patients on admission (mean 8.7 h after stroke onset) and in 35 controls. We evaluated the relation between CSF concentrations and (a) stroke severity (NIH Stroke Scale [NIHSS] score on admission, infarct volume), (b) stroke location, and (c) stroke outcome (modified Rankin Scale [mRS] score at month 3).. MBP concentration was significantly higher in subcortical than in cortical infarcts (median MBP, 1.18 vs 0.66 microg/L, P < 0.001). GFAP and S100B concentrations correlated with the NIHSS score on admission (GFAP, R = 0.35, P = 0.001; S100B, R = 0.29, P = 0.006), infarct volume (GFAP, R = 0.34, P = 0.001; S100B, R = 0.28, P = 0.008), and mRS score at month 3 (R = 0.42, P < 0.001 and R = 0.28, P = 0.007). Concentrations of NSE did not correlate with stroke characteristics.. MBP, GFAP, S100B, and NSE display relevant differences in cellular and subcellular origins, which are reflected in their relation to stroke characteristics. MBP is a marker for infarct location. GFAP and S100B correlate with stroke severity and outcome.

Topics: Aged; Aged, 80 and over; Biomarkers; Brain Ischemia; Female; Glial Fibrillary Acidic Protein; Humans; Male; Middle Aged; Myelin Basic Protein; Nerve Growth Factors; Phosphopyruvate Hydratase; S100 Calcium Binding Protein beta Subunit; S100 Proteins; Stroke

We describe a protocol for establishing mouse models of periventricular leukomalacia (PVL). PVL is the predominant form of brain injury in premature infants and the most common antecedent of cerebral palsy. PVL is characterized by periventricular white matter damage with prominent oligodendroglial injury. Hypoxia/ischemia with or without systemic infection/inflammation are the primary causes of PVL. We use P6 mice to create models of neonatal brain injury by the induction of hypoxia/ischemia with or without systemic infection/inflammation with unilateral carotid ligation followed by exposure to hypoxia with or without injection of the endotoxin lipopolysaccharide (LPS). Immunohistochemistry of myelin basic protein (MBP) or O1 and electron microscopic examination show prominent myelin loss in cerebral white matter with additional damage to the hippocampus and thalamus. Establishment of mouse models of PVL will greatly facilitate the study of disease pathogenesis using available transgenic mouse strains, conduction of drug trials in a relatively high throughput manner to identify candidate therapeutic agents, and testing of stem cell transplantation using immunodeficiency mouse strains.

Topics: Animals; Brain Ischemia; Disease Models, Animal; Humans; Hypoxia-Ischemia, Brain; Infant, Newborn; Leukomalacia, Periventricular; Mice; Mice, Transgenic; Myelin Basic Protein

Damage to oligodendrocytes caused by glutamate release contributes to mental or physical handicap in periventricular leukomalacia, spinal cord injury, multiple sclerosis, and stroke, and has been attributed to activation of AMPA/kainate receptors. However, glutamate also activates unusual NMDA receptors in oligodendrocytes, which can generate an ion influx even at the resting potential in a physiological [Mg2+]. Here, we show that the clinically licensed NMDA receptor antagonist memantine blocks oligodendrocyte NMDA receptors at concentrations achieved therapeutically. Simulated ischaemia released glutamate which activated NMDA receptors, as well as AMPA/kainate receptors, on mature and precursor oligodendrocytes. Although blocking AMPA/kainate receptors alone during ischaemia had no effect, combining memantine with an AMPA/kainate receptor blocker, or applying the NMDA blocker MK-801 alone, improved recovery of the action potential in myelinated axons after the ischaemia. These data suggest NMDA receptor blockers as a potentially useful treatment for some white matter diseases and define conditions under which these blockers may be useful therapeutically. Our results highlight the importance of developing new antagonists selective for oligodendrocyte NMDA receptors based on their difference in subunit structure from most neuronal NMDA receptors.

Topics: Action Potentials; Animals; Animals, Newborn; Brain Ischemia; Central Nervous System; Dizocilpine Maleate; Dose-Response Relationship, Drug; Drug Interactions; Excitatory Amino Acid Agonists; Excitatory Amino Acid Antagonists; In Vitro Techniques; Memantine; Myelin Basic Protein; N-Methylaspartate; Oligodendroglia; Patch-Clamp Techniques; Protein Binding; Rats; Receptors, N-Methyl-D-Aspartate

Following acute and chronic neurodegenerative disorders, a cascade of pathological events including inflammatory response, excitotoxicity and oxidative stress induces secondary tissue loss in both gray and white matter. Axonal damage and demyelination are important components of the white matter demise during these diseases. In spite of this, a few studies have addressed the patterns of inflammatory response, axonal damage and demyelination following focal ischemic damage to the central nervous system (CNS). In the present study, we describe the patterns of inflammatory response, axonal damage and myelin impairment following microinjections of 10 pmol of endothelin-1 into the rat striatum. Animals were perfused at 1 day, 3 days and 7 days after injection. 20 mum sections were stained by hematoxylin and immunolabeled for neutrophils (anti-MBS-1), activated macrophages/microglia (anti-ED1), damaged axons (anti-betaAPP) and myelin (anti-MBP). The evolution of acute inflammation was quantitatively assessed by cell counts in different survival times. There was recruitment of both neutrophils and macrophages to the damaged striatal parenchyma with maximum recruitment at 1 day and 7 days, respectively. Progressive myelin impairment in the striatal white matter tracts has been observed mainly at later survival times. beta-APP+ endbulbs were not present in all evaluated time points. These results suggest that progress myelin impairment in the absence of damage to axonal cylinder is a feature of white matter pathology following endothelin-1-induced focal striatal ischemia.

Topics: Amyloid beta-Peptides; Animals; Axons; Biomarkers; Brain Ischemia; Cerebral Arteries; Chemotaxis, Leukocyte; Corpus Striatum; Demyelinating Diseases; Disease Progression; Encephalitis; Endothelin-1; Male; Microcirculation; Microglia; Microinjections; Myelin Basic Protein; Nerve Fibers, Myelinated; Neutrophils; Rats; Rats, Wistar

Inflammatory response, axonal damage and demyelination are important components of the pathophysiology of acute neurodegenerative diseases. We have investigated the outcome of these pathological events following an excitotoxic or an ischemic damage to the spinal nucleus of adult rats at 1 and 7 days postinjury. Microinjections of 80 nmol of NMDA or 40 pmol of endothelin-1 into the rat spinal nucleus induced differential histopathological events. NMDA injection induced intense tissue loss in the gray matter (GM) without significant tissue loss in the white matter (WM). There was a mild inflammatory response, with recruitment of a few neutrophils and macrophages. Axonal damage was present in the GM following NMDA injection, with negligible axonal damage in the WM. Myelin impairment was apparent at 7 days. Microinjections of endothelin-1 into the same region induced lesser tissue loss than NMDA injections, concomitant with an intense inflammatory response characterized by recruitment of macrophages, but not of neutrophils. There were more axonal damage and early myelin impairment after endothelin-1 injection. These results were confirmed by quantitative analysis. Microcysts were present in the WM of the trigeminothalamic tract at 7 days following injection of endothelin-1. These results show that an ischemic damage to the spinal nucleus affects both GM and WM with more bystander inflammation, axonal damage and myelin impairment, while excitotoxic damage induces effects more restricted to the GM. These pathological events may occur following acute damage to the human brain stem and can be an important contributing factor to the underlying functional deficits.

Topics: Amyloid beta-Protein Precursor; Analysis of Variance; Animals; Axons; Brain Ischemia; Cell Count; Demyelinating Diseases; Ectodysplasins; Endothelin-1; Inflammation; Male; Myelin Basic Protein; N-Methylaspartate; Neurotoxins; Rats; Rats, Wistar; Time Factors; Trigeminal Nucleus, Spinal

Biochemical markers of acute neuronal injury may aid in the diagnosis and management of acute ischemic stroke. Serum samples from the National Institute for Neurological Disorders and Stroke (NINDS) recombinant tissue plasminogen activator Stroke Study were analyzed for the presence of 4 biochemical markers of neuronal, glial, and endothelial cell injury. These biochemical markers, myelin basic protein (MBP), neuron-specific enolase (NSE), S100beta, and soluble thrombomodulin, were studied for an association with initial stroke severity, infarct volume, and functional outcome.. In the original NINDS study, serum samples were drawn from all patients on presentation to the Emergency Department and at approximately 2 and 24 hours after initiation of study therapy. In this analysis, stored serum samples were available for 359 patients; 107 patients had samples for all 3 time points. Serum marker concentrations were measured by ELISA techniques. We examined the relation between serum concentrations of each marker and the degree of baseline neurological deficit, functional outcome, and infarct size on computed tomography at 24 hours and the effect of fibrinolytic therapy.. Higher 24-hour peak concentrations of MBP, NSE, and S100beta were associated with higher National Institutes of Health Stroke Scale baseline scores (r=0.186, P<0.0001; r=0.117, P=0.032; and r=0.263, P<0.0001, respectively). Higher peak concentrations of MBP and S100beta (r=0.209, P<0.0001; r=0.239, P<0.0001) were associated with larger computed tomography lesion volumes. Patients with favorable outcomes had smaller changes in MBP and S100beta (P<0.05) concentrations in the first 24 hours. Soluble thrombomodulin was not associated with any severity or outcome measure.. This study corroborates previous work demonstrating correlations of MBP, NSE, and S100beta with clinical and radiographic features in acute stroke. Despite significantly better outcomes in the tissue plasminogen activator-treated group, we found no difference in the early release of the 4 biomarkers between treatment groups. Further study will define the role of biomarkers in acute stroke management and prognostication.

Topics: Acute Disease; Adult; Aged; Biomarkers; Brain Damage, Chronic; Brain Infarction; Brain Ischemia; Double-Blind Method; Endothelial Cells; Female; Fibrinolytic Agents; Humans; Male; Middle Aged; Myelin Basic Protein; Nerve Growth Factors; Neuroglia; Neurons; Phosphopyruvate Hydratase; Randomized Controlled Trials as Topic; Recombinant Proteins; S100 Calcium Binding Protein beta Subunit; S100 Proteins; Thrombomodulin; Time Factors; Tissue Plasminogen Activator; Tomography, X-Ray Computed; Treatment Outcome

We investigated the effects of IL-6 and a chimeric derivative of IL-6 and soluble IL-6 receptor (IL6RIL6 chimera) on excitotoxic injury in rat organotypic hippocampal slices. Brief application of N-methyl-d-aspartate (NMDA) induced astrocyte reactivity, neuron cell death, and oligodendrocyte degeneration, the latter caused by secondary activation of AMPA/kainate receptors. Both these cytokines rescued neurons and oligodendrocytes, albeit the chimeric compound was much more potent and efficient than IL-6. No change was produced on reactive astrocytosis. The cytokines preserved myelin basic protein (MBP) production in slices exposed to excitotoxic insult, and when applied singularly for a week, they also enhanced both MBP and proteolipid protein expression. These effects occurred through activating the signal transducer gp130 and were associated with stimulation of transcription factors STAT1 and STAT3. Our results suggest that IL-6 and IL6RIL6 may prove to be valuable in treating neurodegenerative and demyelinating diseases.

Topics: Active Transport, Cell Nucleus; Animals; Antigens, CD; Astrocytes; Brain Ischemia; Cytokine Receptor gp130; DNA-Binding Proteins; Gliosis; Hippocampus; In Vitro Techniques; Interleukin-6; Membrane Glycoproteins; Myelin Basic Protein; Myelin Proteolipid Protein; N-Methylaspartate; Nerve Degeneration; Neurons; Neuroprotective Agents; Neurotoxins; Oligodendroglia; Phosphorylation; Rats; Receptors, Interleukin-6; Recombinant Fusion Proteins; RNA, Messenger; STAT1 Transcription Factor; STAT3 Transcription Factor; Trans-Activators

Breakdown of the blood-brain barrier during stroke allows central nervous system antigens to leak into the systemic circulation and allows circulating leukocytes access to the brain. Encounter of central nervous system antigens by the peripheral immune system can be capitalized on to modulate the postischemic inflammatory response and potentially improve outcome from stroke.. Male Lewis rats were tolerized to myelin basic protein (MBP) or ovalbumin (OVA) and subjected to 3 hours of middle cerebral artery occlusion (MCAO) or used as splenocyte donors for immunologically naive animals undergoing MCAO. Infarct size was determined at 24 hours by 2,3,5-triphenyltetrazolium chloride staining. In separate studies, mononuclear cells were removed from the brains of animals after MCAO for enzyme-linked immunospot (ELISPOT) assay and flow cytometry.. Median infarct volume in animals tolerized to MBP and those receiving splenocytes from MBP-tolerized donors was less than in animals tolerized to OVA and those receiving splenocytes from OVA-tolerized donors (87.7+/-54.9 versus 148+/-61.6 mm3 [P=0.01] and 89.2+/-77.5 versus 153+/-77.1 mm3 [P=0.05], respectively). There was an increase in the number of transforming growth factor-beta1-secreting mononuclear cells in MBP-tolerized animals undergoing sham surgery (P=0.001) as well as in ischemic animals 48 hours (P=0.02) and 336 hours (P=0.04) after stroke. A distinct subset of gammadelta T cells was present in the brains of MBP-tolerized but not control animals after stroke.. Immunologic tolerance and its neuroprotective effects can be transferred to naive animals and appear to be related to antigen-specific induction of transforming growth factor-beta1.

Topics: Administration, Intranasal; Adoptive Transfer; Animals; Brain Ischemia; Cell Count; Cerebral Infarction; Cytoprotection; Disease Progression; Immune Tolerance; Inflammation; Lymphocytes; Male; Myelin Basic Protein; Nasal Mucosa; Rats; Rats, Inbred Lew; Spleen

Cerebral white matter (WM) lesions are observed frequently in human ischemic cerebrovascular disease and have been thought to contribute to cognitive impairment. This type of lesion can be experimentally induced in rat brains under chronic cerebral hypoperfusion by the permanent occlusion of both common carotid arteries. However, it remains uncertain whether chronic ischemia can damage both the gray and white matter, and whether it can induce demyelination with or without axonal damage. Therefore, we examined axonal damage using immunohistochemistry for the amyloid beta/A4 precursor protein (APP), chromogranin A (CgA) and demyelination using immunohistochemistry for the encephalitogenic peptide (EP) in this model. Severe WM lesions such as vacuolation and the loss of nerve fibers appeared in the optic nerve and optic tract after 3 days of ligation, and less intense changes were observed in the corpus callosum, internal capsule, and fiber bundles of the caudoputamen after 7 days with Klüver-Barrera and Bielschowsky staining. These WM lesions persisted even after 30 days. The APP, CgA, and EP-immunopositive fibers increased in number from 1 to 30 days after the ligation in the following WM regions: the optic nerve, optic tract, corpus callosum, internal capsule, and fiber bundles of the caudoputamen. In contrast, only a few APP, CgA, or EP-immunopositive fibers were detected in the gray matter regions, including the cerebral cortex and hippocampus. These results indicate that the WM is more susceptible to chronic cerebral hypoperfusion than the gray matter, with an involvement of both axonal and myelin components. Furthermore, immunohistochemistry for APP, CgA, and EP is far superior to routine histological staining in sensitivity and may become a useful tool to investigate WM lesions caused by various pathoetiologies.

Topics: Amyloid beta-Protein Precursor; Animals; Axons; Brain Ischemia; Cerebral Infarction; Chromogranin A; Chromogranins; Chronic Disease; Demyelinating Diseases; Immunohistochemistry; Male; Myelin Basic Protein; Nerve Fibers, Myelinated; Peptide Fragments; Prosencephalon; Rats; Rats, Wistar; Wallerian Degeneration

The effects of cerebral ischemia on white matter changes in ovine fetuses were examined after exposure to bilateral carotid artery occlusion. Fetal sheep were exposed to 30 min of ischemia followed by 48 (I/R-48, n = 8) or 72 (I/R-72, n = 10) h of reperfusion or control sham treatment (control, n = 4). Serial coronal sections stained with Luxol fast blue/hematoxylin and eosin were scored for white matter, cerebral cortical, and hippocampal lesions. All areas received graded pathologic scores of 0 to 5, reflecting the degree of injury where 0 = 0%, 1 = 1% to 25%, 2 = 26% to 50%, 3 = 51% to 75%, 4 = 76% to 95%, and 5 = 96% to 100% of the area damaged. Dual-label immunofluorescence using antibodies against glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP) were used to characterize white matter lesions. Basic fibroblast growth factor (FGF-2) was measured in the frontal cortex by ELISA. Results of the pathologic scores showed that the white matter of the I/R-72 (2.74 +/- 0.53, mean +/- SEM) was more (p < 0.05) damaged when compared with the control (0.80 +/- 0.33) group. Cortical lesions were greater (p < 0.05) in the I/R-48 (2.12 +/- 0.35) than the control (0.93 +/- 0.09) group. White matter lesions were characterized by reactive GFAP-positive astrocytes and a loss of MBP in oligodendrocytes. The ratio of MBP to GFAP decreased (p < 0.05) as a function of ischemia, indicative of a proportionally greater loss of MBP than GFAP. FGF-2 concentrations were higher (p < 0.05) in the I/R-72 than the control group and there was a direct correlation between the pathologic scores (PS) and FGF-2 concentrations (FGF-2 = e((1.6 PS-0.90)) + 743, n = 17, r = 0.73, p < 0.001). We conclude that carotid artery occlusion results in quantifiable white matter lesions that are associated with a loss of MBP from myelin, and that FGF-2, a purported mediator of recovery from brain injury in adult subjects, increases in concentration in proportion to the severity of brain damage in the fetus.

Topics: Animals; Astrocytes; Brain Ischemia; Carbon Dioxide; Cerebral Cortex; Coloring Agents; Eosine Yellowish-(YS); Female; Fetus; Fibroblast Growth Factor 2; Glial Fibrillary Acidic Protein; Hematoxylin; Hippocampus; Indoles; Myelin Basic Protein; Nerve Fibers; Oligodendroglia; Oxygen; Pregnancy; Sheep

Chronic ischemic brain injuries were studied in 7- and 14-day-old rat pups, which were subjected to bilateral carotid artery occlusion (BCAO) on postnatal day 1. BCAO preferentially injured white matter in the corpus callosum, subcortex and internal capsule areas while largely spared cortical neurons. White matter rarefaction in the corpus callosum was observed in 12 out of the 17 BCAO rat brains and significantly enlarged lateral ventricles were found in five out of seven P14 BCAO rat brains. These white matter changes were similar to injuries found in newborn infants with periventricular leukomalacia (PVL). White matter injuries in the 7-day-old BCAO rat brain were accompanied with increased activation of microglia/macrophages, as indicated by ED1 and OX42 positive immunostaining. Immature oligodendrocytes in the 7-day-old BCAO rat brain, as indicated by O4+/O1+ staining, were much fewer than in the sham-operated rat brain. Immunostaining for myelin basic protein (MBP) at the fimbria hippocampus and the internal capsule areas in the 7-day-old BACO rat brain was also much less than in the control rat brain. Consistent with the immunostaining data, MBP mRNA expression in the 7-day-old, but not in the 14-day-old, BCAO rat brain was significantly less than in the control rat brain. The overall results suggest that pre-oligodendrocytes and immature oligodendrocytes might be major targets for chronic ischemic insults and activated microglia/macrophages are possibly involved in the process of white matter injury.

Topics: Animals; Animals, Newborn; Biomarkers; Brain; Brain Ischemia; Chronic Disease; Immunohistochemistry; Macrophages; Microglia; Myelin Basic Protein; Oligodendroglia; Rats; Rats, Sprague-Dawley; RNA, Messenger; Staining and Labeling

Although oligodendrocytes are vulnerable to focal cerebral ischemia, remyelination of denuded or regenerating axons in the peri-infarct area has been observed in the central nervous system. We studied the expression of myelin basic protein (MBP), a major component of central nervous system myelin, in peri-infarct areas in adult rat brain after transient middle cerebral artery occlusion (MCAO) and correlated it to the expression of the growth-associated protein-43 (GAP-43), a marker for axonal regeneration and sprouting, using non-radioactive in situ hybridization techniques. Within the infarct, MBP messenger RNA (mRNA) had disappeared by 24 h, whereas myelin protein, identified by MBP and myelin oligodendrocyte glycoprotein (MOG) immunohistochemistry, appeared structurally intact until day 3. Peri-infarct oligodendrocytes increased their expression of MBP mRNA from 24 h to maximal levels at day 7, corresponding to the appearance of process-bearing MBP and occasional MOG-immunoreactive oligodendrocytes in parallel sections. Quantitative analysis revealed significant increases in the density of oligodendrocytes (up to 7.6-fold) and in the level of MBP mRNA expressed by individual cells. Parallel sections showed that increased expression of GAP-43 mRNA in neurons was concomitant to MBP mRNA upregulation in oligodendrocytes. While the mechanisms regulating oligodendrocyte survival and myelination signals are not clear at this point, axonal sprouting could putatively serve as a stimulus for the upregulation of oligodendrocyte cell numbers, differentiation state, and/or active myelination in the peri-infarct areas.

Topics: Animals; Brain; Brain Ischemia; Cerebral Infarction; GAP-43 Protein; Gene Expression Regulation; Immunohistochemistry; In Situ Hybridization; Male; Myelin Basic Protein; Myelin Sheath; Nerve Degeneration; Rats; Rats, Inbred SHR; RNA, Messenger; Transcription, Genetic; Up-Regulation

The ability of putative neuroprotective compounds to protect against white matter injury remains poorly investigated due to the lack of suitable methods for assessing white matter injury. This study was therefore designed to investigate the utility of Tau 1 (oligodendrocytes/axons), myelin basic protein (MBP; myelin) and amyloid precursor protein (APP; axons) immunohistochemistry in assessing white matter injury at various times following middle cerebral artery occlusion (MCAO) in the rat. Focal cerebral, ischaemia was induced in halothane-anaesthetised rats using an intraluminal thread model. At 24 h, 1 and 2 weeks following MCAO, white matter injury was assessed using Tau 1, APP, MBP and Luxol-fast blue staining and neuronal injury with cresyl fast violet (CFV). In histologically normal tissue MBP immunoreactivity was detected in myelinated fibre tracts, while Tau 1 and APP were axonally located. At 24 h following permanent MCAO, MBP, and Tau 1 staining remained relatively unchanged within the myelin and axonal compartments of the ischaemic region. In contrast, increased Tau 1 staining was apparent in oligodendrocytes within ischaemic tissue, while APP accumulated in axons surrounding the lesion. At 1 and 2 weeks following transient MCAO, Tau 1 and APP staining was markedly decreased within ischaemic tissue. Marked reduction in MBP levels within ischaemic tissue were not detected until 2 weeks following MCAO. The area of axonal injury as assessed by reduced Tau 1 or APP staining correlated with the area of neuronal damage as assessed by CFV staining. This study shows that MBP, Tau 1 and APP immunohistochemistry can be utilised to assess myelin and axonal integrity following sustained ischaemia using standard image analysis techniques.

Topics: Amyloid beta-Protein Precursor; Animals; Biomarkers; Brain Ischemia; Cell Death; Cerebral Cortex; Cerebral Infarction; Immunohistochemistry; Male; Myelin Basic Protein; Nerve Degeneration; Nerve Fibers, Myelinated; Rats; Rats, Sprague-Dawley; tau Proteins

An animal model of chronic cerebral hypoperfusion was developed with coiled clips applied to both carotid arteries of adult Mongolian gerbils for between 1 week and 2 months. In the brain of this animal model, rarefaction of white matter with dilatation of the ventricles was frequently observed. To better understand the mechanism of white matter alteration under cerebral hypoperfusion, the chronological sequence of molecular changes in the cerebral white matter of the animal model was determined.. Specially designed coiled clips were placed around both carotid arteries of Mongolian gerbils to create stenosis without occlusion. Changes in levels of myelin basic protein (MBP) as a marker of myelin, neurofilament H (NFH) as a marker of axonal proteins, and glial fibrillary acidic protein (GFAP) in astroglia after 2 months of cerebral hypoperfusion were analyzed with Western blotting and enzyme-linked immunosorbent assay.. Western blotting of the white matter after 2 months of hypoperfusion showed that the levels of MBP and NFH decreased, whereas that of GFAP increased. The time course of MBP and NFH changes determined with enzyme-linked immunosorbent assay revealed that the change of MBP preceded that of NFH.. In the present study it was shown that the damage to myelin precedes that to the axon in the white matter in a chronic cerebral hypoperfusion animal model, suggesting that the change in myelin is the primary pathological event in the cerebral white matter under chronic hypoperfusion. The present study may help in understanding the mechanisms of white matter pathology in leukoaraiosis.

Topics: Animals; Blotting, Western; Brain; Brain Chemistry; Brain Ischemia; Chronic Disease; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Gerbillinae; Glial Fibrillary Acidic Protein; Myelin Basic Protein; Neurofilament Proteins; Time Factors

We questioned whether neuron-specific enolase (NSE) and myelin basic protein (MBP) concentrations in cerebrospinal fluid (CSF) in the first 72 hours of life are correlated with the neurologic condition of asphyxiated full-term infants in the neonatal period and at 1 year of age.. Sixty-nine asphyxiated infants were studied with serial neurologic examination, cranial ultrasonography, and neurologic follow-up. CSF samples were obtained by lumbar puncture at 12 and 72 hours of life. NSE was measured by enzyme immunoassay, and MBP was measured by radioimmunoassay.. Twenty infants had no neonatal encephalopathy and 49 exhibited different stages of encephalopathy. NSE and MBP concentrations in CSF at 12 and 72 hours of life were related to the degree of neonatal encephalopathy. Neither NSE nor MBP levels were correlated with any perinatal factors. Infants with documented brain injury had the highest concentrations of both NSE and MBP. The concentrations of these two biochemical markers at both 12 and 72 hours correlated with adverse outcome (death or cerebral palsy at 1 year). Based on a receiver operating characteristics curve analysis for any given specificity, NSE at 12 hours was a more accurate marker than MBP at either 12 or 72 hours for distinguishing infants with motor impairment at age 1 year from infants with normal outcome at the same age.. Our findings suggest that NSE and MBP are reliable biochemical markers for early estimates of hypoxic-ischemic brain damage in asphyctic full-term newborns, NSE being superior to MBP.

Topics: Asphyxia Neonatorum; Biomarkers; Brain Damage, Chronic; Brain Ischemia; Gestational Age; Humans; Hypoxia, Brain; Infant, Newborn; Myelin Basic Protein; Neurologic Examination; Neuroradiography; Paraplegia; Phosphopyruvate Hydratase; Prospective Studies; Quadriplegia

Tritiated thymidine autoradiography was used to measure cellular proliferation after ischemic injury in gerbil brain. Gerbils were subjected to bilateral occlusion of the common carotid arteries which resulted in areas of necrosis, or infarcts, in the posterior thalamus or midbrain. From 12 h to 10 days following the ischemia, gerbils were injected with 3H thymidine, sacrificed 4 h later, and the brains sectioned. In order to identify astrocytes and monocytes/macrophages, immunocytochemistry was performed prior to autoradiography, using antisera against glial fibrillary acidic protein and endothelial-monocyte reticuloendothelial antigen, respectively. Immunocytochemistry was also used to visualize microvessel laminin, myelin, and leakage of serum albumin. Lastly, a histochemical procedure for acid phosphatase activity was employed to verify cellular phagocytic activity in the wound. A reproducible sequence of reactions took place during the first 10 days after ischemia. Early changes included leakage of albumin and myelin breakdown, followed by arrival of monocytes at 2 days and their differentiation into macrophages by 5 days. These cells exhibited intense proliferation from 2 to 6 days post-ischemia. Microvessel endothelial cells were maximally labeled at 4 days post-ischemia. Hypertrophied astrocytes were apparent at 2 days and proliferated from 3 to 7 days post-ischemia, and by 10 days the wound was replaced by a "glial scar".

Topics: Albumins; Animals; Astrocytes; Autoradiography; Brain Ischemia; Cell Division; Female; Gerbillinae; Glial Fibrillary Acidic Protein; Histocytochemistry; Immunoenzyme Techniques; Leukocytes; Macrophages; Male; Microcirculation; Myelin Basic Protein; Thymidine; Time Factors