myelin-basic-protein and Nerve-Degeneration

Autoimmunity is usually considered only as a cause of disease; nevertheless, human T-cell repertoires are filled naturally with autoimmune lymphocytes. Here, we review evidence that autoimmune T cells can help heal damaged tissues, indicating that natural autoimmunity could also be a cause of health.

Topics: Animals; Autoantigens; Autoimmunity; Central Nervous System; Chemotaxis, Leukocyte; Contusions; Encephalomyelitis, Autoimmune, Experimental; Humans; Injections, Intraperitoneal; Lymphocyte Activation; Models, Immunological; Myelin Basic Protein; Myelin Sheath; Neovascularization, Physiologic; Nerve Crush; Nerve Degeneration; Optic Nerve Injuries; Regeneration; Spinal Cord Injuries; T-Lymphocyte Subsets; Wound Healing

Topics: Humans; Male; Multiple System Atrophy; Myelin Basic Protein; Myelin Sheath; Nerve Degeneration

Longstanding psychological stress has been associated with increased risk of neurodegenerative disorders, such as dementia and Alzheimer's disease. In a prospective population study of women (n = 81), we tested if midlife stress (mean age 49 years) was associated with late-life biomarkers of neurodegeneration in cerebrospinal fluid (CSF) (mean age 74 years) in linear regression models. It was found that women who report of stress at baseline (n = 20) had higher levels of CSF visinin-like protein-1 (VILIP-1) (age adjusted β = 0.113, p = 0.017) and CSF myelin basic protein (β = 0.060, p = 0.030) compared with women without midlife stress (n = 61). There was also a trend observed for higher CSF neurofilament light (β = 0.133, p = 0.056). In addition, longer periods of stress (i.e., stress at 2-3 midlife examinations) were associated with higher levels of CSF VILIP-1. The results suggest that longstanding stress might be associated with neurodegenerative processes in the brain, as CSF VILIP-1 is an unspecific marker for neuronal injury and CSF myelin basic protein reflects neuroaxonal demyelination.

Topics: Aged; Aging; Alzheimer Disease; Axons; Biomarkers; Brain; Dementia; Demyelinating Diseases; Female; Follow-Up Studies; Humans; Middle Aged; Myelin Basic Protein; Nerve Degeneration; Neurocalcin; Neurodegenerative Diseases; Neurofilament Proteins; Risk; Stress, Psychological; Time Factors

Topics: Animals; Anterior Horn Cells; Disease Models, Animal; Gene Expression Regulation; Male; Monoamine Oxidase Inhibitors; Movement; Myelin Basic Protein; Nerve Degeneration; Nerve Fibers, Myelinated; Nerve Regeneration; Pain Threshold; Phosphopyruvate Hydratase; Rats; Rats, Wistar; Recovery of Function; Sciatic Neuropathy; Selegiline; Spinal Cord; Weight-Bearing

In multiple sclerosis (MS), neurodegeneration is the main reason for chronic disability. Alpha-lipoic acid (LA) is a naturally occurring antioxidant which has recently been demonstrated to reduce the rate of brain atrophy in progressive MS. However, it remains uncertain if it is also beneficial in the early, more inflammatory-driven phases. As clinical studies are costly and time consuming, optic neuritis (ON) is often used for investigating neuroprotective or regenerative therapeutics. We aimed to investigate the prospect for success of a clinical ON trial using an experimental autoimmune encephalomyelitis-optic neuritis (EAE-ON) model with visual system readouts adaptable to a clinical ON trial.. All forms of LA provided equal neuroprotective capacities in vitro. In EAE-ON, prophylactic LA therapy attenuated the clinical EAE score and prevented the thinning of the inner retinal layer while therapeutic treatment was not protective on visual outcomes.. A prophylactic LA treatment is necessary to protect from visual loss and retinal thinning in EAE-ON, suggesting that a clinical ON trial starting therapy after the onset of symptoms may not be successful.

Topics: Animals; CD3 Complex; Disease Models, Animal; Encephalomyelitis, Autoimmune, Experimental; Female; Glutathione; Mice; Mice, Inbred C57BL; Myelin Basic Protein; Nerve Degeneration; Nystagmus, Optokinetic; Protein Carbonylation; Retina; Thioctic Acid; Tomography, Optical Coherence; Vision Disorders; Vitamin B Complex

Spinocerebellar ataxia type 1 (SCA1) is a devastating neurodegenerative disorder in which an abnormally expanded polyglutamine tract is inserted into causative ataxin-1 proteins. We have previously shown that SCA1 knockin (SCA1-KI) mice over 6 months of age exhibit a degeneration of motor neuron axons and their encasing myelin sheaths, as reported in SCA1 patients. We examined whether axon degeneration precedes myelin degeneration or vice versa in SCA1-KI mice and then attempted to mitigate motor neuron degeneration by intrathecally administering mesenchymal stem cells (MSCs). Temporal examination of the diameters of motor neuron axons and their myelin sheaths revealed a decrease in diameter of the axon but not of the myelin sheaths in SCA1-KI mice as early as 1 month of age, which suggests secondary degeneration of the myelin sheaths. We injected MSCs into the intrathecal space of SCA1-KI mice at 1 month of age, which resulted in a significant suppression of degeneration of both motor neuron axons and myelin sheaths, even 6 months after the MSC injection. Thus, MSCs effectively suppressed peripheral nervous system degeneration in SCA1-KI mice. It has not yet been clarified how clinically administered MSCs exhibit significant therapeutic effects in patients with SCA1. The morphological evidence presented in this current mouse study might explain the mechanisms that underlie the therapeutic effects of MSCs that are observed in patients with SCA1.

Topics: Analysis of Variance; Animals; Ataxin-1; Cell- and Tissue-Based Therapy; Disease Models, Animal; Gene Expression Regulation; Green Fluorescent Proteins; Humans; Mesenchymal Stem Cells; Mice; Mice, Inbred C57BL; Mice, Transgenic; Motor Neurons; Myelin Basic Protein; Nerve Degeneration; Spinal Cord; Spinocerebellar Ataxias; Time Factors

Dementia risk in women is higher than in men, but the molecular neuropathology of this gender difference remains poorly defined. In this study, we used unbiased, discovery-driven quantitative proteomics to assess the molecular basis of gender influences on risk of Alzheimer's disease with cerebrovascular disease (AD + CVD).. We detected modulation of several redox proteins in the temporal lobe of AD + CVD subjects, and we observed sex-specific alterations in the white matter (WM) and mitochondria proteomes of female patients. Functional proteomic analysis of AD + CVD brain tissues revealed increased citrullination of arginine and deamidation of glutamine residues of myelin basic protein (MBP) in female which impaired degradation of degenerated MBP and resulted in accumulation of non-functional MBP in WM. Female patients also displayed down-regulation of ATP sub-units and cytochromes, suggesting increased severity of mitochondria impairment in women.. Our study demonstrates that gender-linked modulation of white matter and mitochondria proteomes influences neuropathology of the temporal lobe in AD + CVD.

Topics: Aged; Aged, 80 and over; Alzheimer Disease; Amino Acids; Case-Control Studies; Cerebrovascular Disorders; Demography; Female; Humans; Male; Mitochondria; Myelin Basic Protein; Nerve Degeneration; Proteome; Sex Characteristics; Temporal Lobe; White Matter

Spinocerebellar ataxia type 1 (SCA1) is caused by the ataxin-1 protein (ATXN1) with an abnormally expanded polyglutamine tract and is characterized by progressive neurodegeneration. We previously showed that intrathecal injection of mesenchymal stem cells (MSCs) during the nonsymptomatic stage mitigates the degeneration of the peripheral nervous system (PNS) neurons in SCA1-knock-in (SCA1-KI) mice. We tested in this study whether the therapeutic effects of MSCs in SCA1-KI mice could be reproduced with MSC-releasing factor(s).. To test the effects of MSC-releasing factor(s), we used MSC-conditioned medium (MSC-CM). MSC-CM was intrathecally and/or intravenously injected into young SCA1-KI mice, and the therapeutic effects were assessed in the PNS at later ages using immunostaining, electrophysiology, and behavioral tests.. MSC-CM attenuated the degeneration of axons and myelin of spinal motor neurons. Consequently, the injected SCA1-KI mice exhibited smaller reductions in nerve conduction velocity in spinal motor neurons and reduced motor incoordination than the untreated mice.. These results suggest that factors released from MSC mitigate the morphological and functional abnormalities in the PNS that are observed in SCA1-KI mice in a paracrine manner.

Topics: Age Factors; Animals; Ataxin-1; Axons; Cells, Cultured; Culture Media, Conditioned; Disease Models, Animal; Evoked Potentials, Motor; Humans; Mesenchymal Stem Cells; Mice; Mice, Inbred C57BL; Mice, Transgenic; Motor Activity; Motor Neurons; Myelin Basic Protein; Nerve Degeneration; Reaction Time; Spinocerebellar Ataxias; Tubulin

Secondary degeneration contributes substantially to structural and functional deficits following traumatic injury to the CNS. While it has been proposed that oxidative stress is a feature of secondary degeneration, contributing reactive species and resultant oxidized products have not been clearly identified in vivo. The study is designed to identify contributors to, and consequences of, oxidative stress in a white matter tract vulnerable to secondary degeneration. Partial dorsal transection of the optic nerve (ON) was used to model secondary degeneration in ventral nerve unaffected by the primary injury. Reactive species were assessed using fluorescent labelling and liquid chromatography/tandem mass spectroscopy (LC/MS/MS). Antioxidant enzymes and oxidized products were semi-quantified immunohistochemically. Mitophagy was assessed by electron microscopy. Fluorescent indicators of reactive oxygen and/or nitrogen species increased at 1, 3 and 7days after injury, in ventral ON. LC/MS/MS confirmed increases in reactive species linked to infiltrating microglia/macrophages in dorsal ON. Similarly, immunoreactivity for glutathione peroxidase and haem oxygenase-1 increased in ventral ON at 3 and 7days after injury, respectively. Despite increased antioxidant immunoreactivity, DNA oxidation was evident from 1day, lipid oxidation at 3days, and protein nitration at 7days after injury. Nitrosative and oxidative damage was particularly evident in CC1-positive oligodendrocytes, at times after injury at which structural abnormalities of the Node of Ranvier/paranode complex have been reported. The incidence of mitochondrial autophagic profiles was also significantly increased from 3days. Despite modest increases in antioxidant enzymes, increased reactive species are accompanied by oxidative and nitrosative damage to DNA, lipid and protein, associated with increasing abnormal mitochondria, which together may contribute to the deficits of secondary degeneration.

Topics: Analysis of Variance; Animals; Chromatography, Liquid; Disease Models, Animal; Ectodysplasins; Ethidium; Female; Glutathione Peroxidase; Glutathione Peroxidase GPX1; Guanine; Microscopy, Electron, Transmission; Mitochondria; Myelin Basic Protein; Nerve Degeneration; Optic Nerve Injuries; Oxidative Stress; Rats; Reactive Oxygen Species; Tandem Mass Spectrometry; Time Factors; Tyrosine

In this study, we investigated the effects of a bioactive high-affinity TrkB receptor agonist 7,8- dihydroxyflavone (7,8 DHF) on neonatal brain injury in female and male mice after hypoxia ischemia (HI). HI was induced by exposure of postnatal day 9 (P9) mice to 10% O2 for 50 minutes at 37°C after unilateral ligation of the left common carotid artery. Animals were randomly assigned to HI-vehicle control group [phosphate buffered saline (PBS), intraperitoneally (i.p.)] or HI + 7,8 DHF-treated groups (5 mg/kg in PBS, i.p at 10 min, 24 h, or with subsequent daily injections up to 7 days after HI). The HI-vehicle control mice exhibited neuronal degeneration in the ipsilateral hippocampus and cortex with increased Fluoro-Jade C positive staining and loss of microtubule associated protein 2 expression. In contrast, the 7,8 DHF-treated mice showed less hippocampal neurodegeneration and astrogliosis, with more profound effects in female than in male mice. Moreover, 7,8 DHF-treated mice improved motor learning and spatial learning at P30-60 compared to the HI-vehicle control mice. Diffusion tensor imaging of ex vivo brain tissues at P90 after HI revealed less reduction of fractional anisotropy values in the ipsilateral corpus callosum of 7,8 DHF-treated brains, which was accompanied with better preserved myelin basic protein expression and CA1 hippocampal structure. Taken together, these findings strongly suggest that TrkB agonist 7,8 DHF is protective against HI-mediated hippocampal neuronal death, white matter injury, and improves neurological function, with a more profound response in female than in male mice.

Topics: Aging; Animals; Cerebral Cortex; Corpus Callosum; Female; Flavones; Gliosis; Hippocampus; Hypoxia-Ischemia, Brain; Learning; Male; Mice; Microtubule-Associated Proteins; Myelin Basic Protein; Nerve Degeneration; Nerve Fibers, Myelinated; Neuroimaging; Neuroprotective Agents; Receptor, trkB; Recovery of Function; Sex Characteristics

Trophic support and myelination of axons by Schwann cells in the PNS are essential for normal nerve function. Herein, we show that deletion of the LDL receptor-related protein-1 (LRP1) gene in Schwann cells (scLRP1(-/-)) induces abnormalities in axon myelination and in ensheathment of axons by nonmyelinating Schwann cells in Remak bundles. These anatomical changes in the PNS were associated with mechanical allodynia, even in the absence of nerve injury. In response to crush injury, sciatic nerves in scLRP1(-/-) mice showed accelerated degeneration and Schwann cell death. Remyelinated axons were evident 20 d after crush injury in control mice, yet were largely absent in scLRP1(-/-) mice. In the partial nerve ligation model, scLRP1(-/-) mice demonstrated significantly increased and sustained mechanical allodynia and loss of motor function. Evidence for central sensitization in pain processing included increased p38MAPK activation and activation of microglia in the spinal cord. These studies identify LRP1 as an essential mediator of normal Schwann cell-axonal interactions and as a pivotal regulator of the Schwann cell response to PNS injury in vivo. Mice in which LRP1 is deficient in Schwann cells represent a model for studying how abnormalities in Schwann cell physiology may facilitate and sustain chronic pain.

Topics: Actins; Analysis of Variance; Animals; Axons; CD11b Antigen; Cytoplasm; Disease Models, Animal; Gene Expression Regulation; Hyperalgesia; In Situ Nick-End Labeling; Indoles; Low Density Lipoprotein Receptor-Related Protein-1; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microscopy, Electron, Transmission; Movement Disorders; Myelin Basic Protein; Nerve Degeneration; p38 Mitogen-Activated Protein Kinases; Pain Measurement; Phosphorylation; Posterior Horn Cells; Receptors, LDL; S100 Proteins; Schwann Cells; Sciatica; Sensation Disorders; Spinal Cord; Tumor Suppressor Proteins

Although peroxisome biogenesis and β-oxidation disorders are well known for their neurodevelopmental defects, patients with these disorders are increasingly diagnosed with neurodegenerative pathologies. In order to investigate the cellular mechanisms of neurodegeneration in these patients, we developed a mouse model lacking multifunctional protein 2 (MFP2, also called D-bifunctional protein), a central enzyme of peroxisomal β-oxidation, in all neural cells (Nestin-Mfp2(-/-)) or in oligodendrocytes (Cnp-Mfp2(-/-)) and compared these models with an already established general Mfp2 knockout. Nestin-Mfp2 but not Cnp-Mfp2 knockout mice develop motor disabilities and ataxia, similar to the general mutant. Deterioration of motor performance correlates with the demise of Purkinje cell axons in the cerebellum, which precedes loss of Purkinje cells and cerebellar atrophy. This closely mimics spinocerebellar ataxias of patients affected with mild peroxisome β-oxidation disorders. However, general knockouts have a much shorter life span than Nestin-Mfp2 knockouts which is paralleled by a disparity in activation of the innate immune system. Whereas in general mutants a strong and chronic proinflammatory reaction proceeds throughout the brain, elimination of MFP2 from neural cells results in minor neuroinflammation. Neither the extent of the inflammatory reaction nor the cerebellar degeneration could be correlated with levels of very long chain fatty acids, substrates of peroxisomal β-oxidation. In conclusion, MFP2 has multiple tasks in the adult brain, including the maintenance of Purkinje cells and the prevention of neuroinflammation but this is not mediated by its activity in oligodendrocytes nor by its role in very long chain fatty acid degradation.

Topics: 2',3'-Cyclic Nucleotide 3'-Phosphodiesterase; Age Factors; Animals; Antigens, Differentiation; Brain; Calcium-Binding Proteins; Cytokines; Deficiency Diseases; Encephalitis; Fatty Acids; Gas Chromatography-Mass Spectrometry; Gene Expression Regulation; Locomotion; Mice; Mice, Transgenic; Microfilament Proteins; Myelin Basic Protein; Nerve Degeneration; Nestin; Peroxisomal Multifunctional Protein-2; Purkinje Cells

This study evaluated the function of mouse optic nerves after transient retinal ischemia using in vitro electrophysiologic recordings of compound action potentials (CAPs) correlated with diffusion tensor imaging (DTI) injury markers with confirmation by immunohistochemistry-determined pathology.. Retinal ischemia was induced in 7- to 8-week-old female C57BL/6 mice by elevating intraocular pressure to 110 mm Hg for 60 minutes. At 3 and 7 days after retinal ischemia, optic nerves were removed for CAP measurements. The CAP amplitude was recorded using suction electrodes in isolated control and injured optic nerves followed by ex vivo DTI evaluation. After DTI, optic nerves were embedded in paraffin and cut for immunohistochemical analyses.. Consistent with previous in vivo DTI measurements, a 25% decrease in axial diffusivity with normal radial diffusivity was seen at 3 days after retinal ischemia, suggesting axonal injury without myelin damage. At 7 days, there was no additional change in axial diffusivity compared with that at 3 days, but radial diffusivity significantly increased by 50%, suggestive of significant myelin damage due to sustained axonal injury. The relative anisotropy (RA) progressively decreased after retinal ischemia when compared with that of the controls. The CAP amplitude in injured nerves also progressively decreased after retinal ischemia, which correlated with the reduced RA (r = 0.80).. This study suggests that CAP amplitude reflects both axonal and myelin integrity and RA is an optimal parameter for functional assessment compared with axial or radial diffusivity alone in murine optic nerves after retinal ischemia.

Topics: Action Potentials; Animals; Axons; Diffusion Tensor Imaging; Disease Models, Animal; Electrophysiology; Female; Mice; Mice, Inbred C57BL; Myelin Basic Protein; Myelin Sheath; Nerve Degeneration; Optic Nerve Diseases; Reperfusion Injury; Retinal Diseases; Retinal Ganglion Cells

MicroRNAs have been shown to effectively regulate gene expression at the translational level. Recently, we identified novel microRNAs that were upregulated in a mouse model of spinal cord injury. Among those, we have focused on microRNA 486, which directly represses NeuroD6 expression through a conserved sequence in its untranslated region. We correlated the overexpression of microRNA 486 in motor neurons with a poor outcome due to progressive neurodegeneration and a pathophysiology that is mediated by reactive oxygen species. The expression of microRNA 486 was induced by reactive oxygen species that were produced by inflammatory factors, and reactive oxygen species were accumulated in response to the knockdown of NeuroD6, which enhances the downregulation of glutathione peroxidase 3 and thioredoxin-like 1 after traumatic spinal cord injury. NeuroD6 directly bound to regulatory regions of thioredoxin-like 1 and glutathione peroxidase 3 in motor neurons and activated their expression, which promoted reactive oxygen species scavenging. Moreover, knocking down microRNA 486 induced the expression of NeuroD6, which effectively ameliorated the spinal cord injury and allowed the mice to recover motor function. The infusion of exogenic NeuroD6 in spinal cord injury lesions effectively blocked apoptosis by reactivating thioredoxin-like 1 and glutathione peroxidase 3, which was accompanied by a recovery of motor function. Collectively, these findings have identified a novel microRNA in spinal cord injury lesions called microRNA 486, demonstrating a new role for NeuroD6 in neuroprotection, and suggest a potential therapeutic target for spinal cord injuries.

Topics: Adenosine Triphosphate; Analysis of Variance; Animals; Basic Helix-Loop-Helix Transcription Factors; Caspase 3; Cells, Cultured; Cytokines; Disease Models, Animal; Female; Gene Expression Regulation; Glial Fibrillary Acidic Protein; Mice; Mice, Inbred ICR; MicroRNAs; Motor Activity; Motor Neurons; Myelin Basic Protein; Nerve Degeneration; Neural Stem Cells; Neurofilament Proteins; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Oligodeoxyribonucleotides, Antisense; Peroxidase; Reactive Oxygen Species; Recovery of Function; RNA, Small Interfering; Spinal Cord Injuries; Time Factors

To explore myelin components and mitochondrial changes within the central nervous system in patients with well-characterized mitochondrial disorders due to nuclear DNA or mitochondrial DNA (mtDNA) mutations.. Immunohistochemical analysis, histochemical analysis, mtDNA sequencing, and real-time and long-range polymerase chain reaction were used to determine the pathogenicity of mtDNA deletions.. Department of Clinical Pathology, Columbia University Medical Center, and Newcastle Brain Tissue Resource.. Seventeen patients with mitochondrial disorders and 7 controls were studied from August 1, 2009, to August 1, 2010.. Regions of myelin-associated glycoprotein (MAG) loss.. Myelin-associated glycoprotein loss in Kearns-Sayre syndrome was associated with oligodendrocyte loss and nuclear translocation of apoptosis-inducing factor, whereas inflammation, neuronal loss, and axonal injury were minimal. In a Kearns-Sayre syndrome MAG loss region, high levels of mtDNA deletions together with cytochrome- c oxidase-deficient cells and loss of mitochondrial respiratory chain subunits (more prominent in the white than gray matter and glia than axons) confirmed the pathogenicity of mtDNA deletions.. Primary mitochondrial respiratory chain defects affecting the white matter, and unrelated to inflammation, are associated with MAG loss and central nervous system demyelination.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Antigens, CD; Antigens, Differentiation, Myelomonocytic; Autopsy; Basic Helix-Loop-Helix Transcription Factors; Case-Control Studies; DNA Mutational Analysis; DNA, Mitochondrial; Electron Transport Complex IV; Female; Gene Deletion; Gene Expression Regulation; Humans; Kearns-Sayre Syndrome; Male; Middle Aged; Mitochondria; Myelin Basic Protein; Myelin Sheath; Myelin-Associated Glycoprotein; Nerve Degeneration; Nerve Tissue Proteins; Oligodendrocyte Transcription Factor 2; Retrospective Studies; Succinate Dehydrogenase; Synaptophysin; Young Adult

Electromagnetic fields (EMFs) may affect the endogenous neural stem cells within the brain. The aim of this study was to assess the effects of EMFs on the process of toxin-induced demyelination and subsequent remyelination. Demyelination was induced using local injection of lysophosphatidylcholine within the corpus callosum of adult female Sprague-Dawley rats. EMFs (60 Hz; 0.7 mT) were applied for 2 h twice a day for 7, 14, or 28 days postlesion. BrdU labeling and immunostaining against nestin, myelin basic protein (MBP), and BrdU were used for assessing the amount of neural stem cells within the tissue, remyelination patterns, and tracing of proliferating cells, respectively. EMFs significantly reduced the extent of demyelinated area and increased the level of MBP staining within the lesion area on days 14 and 28 postlesion. EMFs also increased the number of BrdU- and nestin-positive cells within the area between SVZ and lesion as observed on days 7 and 14 postlesion. It seems that EMF potentiates proliferation and migration of neural stem cells and enhances the repair of myelin in the context of demyelinating conditions.

Topics: Animals; Bromodeoxyuridine; Cell Movement; Cell Proliferation; Corpus Callosum; Disease Models, Animal; Electric Stimulation Therapy; Female; Intermediate Filament Proteins; Multiple Sclerosis; Myelin Basic Protein; Myelin Sheath; Nerve Degeneration; Nerve Regeneration; Nerve Tissue Proteins; Nestin; Neural Stem Cells; Rats; Rats, Sprague-Dawley; Stem Cell Niche; Transcranial Magnetic Stimulation

To examine chronic changes occurring at 6 months following partial optic nerve (ON) transection, assessing optic axons, myelin, and visual function.. Dorsal ON axons were transected, leaving ventral optic axons vulnerable to secondary degeneration. At 3 and 6 months following partial transection, toluidine-blue stained sections were used to assess dimensions of the ON injury site. Transmission electron microscopy (TEM) images of ventral ON were used to quantify numbers, diameter, area, and myelin thickness of optic axons. Immunohistochemistry and fluoromyelin staining were used to assess semiquantitatively myelin protein, lipids in ventral ON, and retinal ganglion cells (RGCs) in midventral retina. Visuomotor function was assessed using optokinetic nystagmus.. Following partial ON transection, optic axons and function remained disrupted at 6 months. Although ventral ON swelling observed at 3 months (P ≤ 0.05) receded to normal by 6 months, ultrastructurally, myelinated axons remained swollen (P ≥ 0.05), and myelin thickness increased (P ≤ 0.05) due to loosening of lamellae and an increase in the number of intraperiodic lines. Axons with decompacted myelin persisted and were distinguished as having large axonal calibers and thicker myelin sheaths. Nevertheless, progressive loss of myelin lipid staining with fluoromyelin was seen at 6 months. Despite no further loss of ventral optic axons between 3 and 6 months (P ≥ 0.05), visuomotor function progressively declined at 6 months following partial transection (P ≤ 0.05).. Continued decompaction of myelin, altered myelin structure, and swelling of myelinated axons are persistent features of the chronic phases of secondary degeneration and likely contribute to progressive loss of visual function.

Topics: Animals; Axons; Chronic Disease; Female; Fluorescent Antibody Technique, Indirect; Microscopy, Electron, Transmission; Myelin Basic Protein; Myelin Sheath; Nerve Degeneration; Nystagmus, Optokinetic; Optic Nerve; Optic Nerve Diseases; Optic Nerve Injuries; Rats; Retinal Ganglion Cells; Tubulin

Information about the effect of tooth movement on the myelinated nerve in the periodontal ligament is limited. In this study, we aimed to investigate what responses of the periodontal myelinated nerve can be evoked during experimental tooth movement.. In experimental-I group, the maxillary left and mandibular right third molars were moved distally. In experimental-II group, the maxillary left third molar but not the right one was moved, and the bilateral mandibular third molars were extracted. The ultrastructures of the myelinated nerve in the periodontal ligament of the bilateral maxillary third molars were observed under a transmission electron microscope. The expression of myelin basic protein was evaluated by immunohistochemistry.. Degenerative ultrastructural changes of the myelinated nerve in the periodontal ligament were noticed mainly in the myelin sheath; these were observed earlier and were recoverable in the experimental-I group. In contrast, the ultrastructural changes of the myelinated nerve occurred mainly in the axons, were observed later, and were unrecoverable in the experimental-II group. A concomitant decrease of myelin basic protein expression was observed in both groups.. Both experimental tooth movement and occlusal changes accompanying it caused changes of the myelinated nerve in the periodontal ligament.

Topics: Animals; Mitochondria; Myelin Basic Protein; Nerve Degeneration; Nerve Fibers, Myelinated; Periodontal Ligament; Rats; Tooth Movement Techniques

Microglial activation in multiple sclerosis has been postulated to contribute to long-term neurodegeneration during disease. Fingolimod has been shown to impact on the relapsing remitting phase of disease by modulating autoreactive T-cell egress from lymph organs. In addition, it is brain penetrant and has been shown to exert multiple effects on nervous system cells.. In this study, the impact of fingolimod and other sphingosine-1-phosphate receptor active molecules following lysophosphotidyl choline-induced demyelination was examined in the rat telencephalon reaggregate, spheroid cell culture system. The lack of immune system components allowed elucidation of the direct effects of fingolimod on CNS cell types in an organotypic situation.. Following demyelination, fingolimod significantly augmented expression of myelin basic protein in the remyelination phase. This increase was not associated with changes in neurofilament levels, indicating de novo myelin protein expression not associated with axonal branching. Myelin wrapping was confirmed morphologically using confocal and electron microscopy. Increased remyelination was associated with down-regulation of microglial ferritin, tumor necrosis factor alpha and interleukin 1 during demyelination when fingolimod was present. In addition, nitric oxide metabolites and apoptotic effectors caspase 3 and caspase 7 were reduced during demyelination in the presence of fingolimod. The sphingosine-1-phosphate receptor 1 and 5 agonist BAF312 also increased myelin basic protein levels, whereas the sphingosine-1-phosphate receptor 1 agonist AUY954 failed to replicate this effect on remyelination.. The results presented indicate that modulation of S1P receptors can ameliorate pathological effectors associated with microglial activation leading to a subsequent increase in protein and morphological markers of remyelination. In addition, sphingosine-1-phosphate receptor 5 is implicated in promoting remyelination in vitro. This knowledge may be of benefit for treatment of chronic microglial inflammation in multiple sclerosis.

Topics: Animals; Biomarkers; Cell Culture Techniques; Cells, Cultured; Demyelinating Diseases; Female; Fingolimod Hydrochloride; Humans; Immunosuppressive Agents; Lysophosphatidylcholines; Microglia; Multiple Sclerosis, Relapsing-Remitting; Myelin Basic Protein; Myelin Sheath; Nerve Degeneration; Pregnancy; Propylene Glycols; Rats; Rats, Sprague-Dawley; Receptors, Lysosphingolipid; Spheroids, Cellular; Sphingosine

Diffusion tensor imaging (DTI) measures the random motion of water molecules reflecting central nervous system tissue integrity and pathology. Glaucoma damages retinal ganglion cells (RGCs) and their axons. The authors hypothesized that DTI-derived axonal and myelin injury biomarkers may be used to detect early axonal damage and may be correlated with RGC loss in the mouse model of optic nerve crush (ONC).. The progression of RGC axon degeneration was quantitatively assessed with DTI in vivo, corroborated with axon/myelin immunohistochemical staining and retrograde fluorogold labeling in mice after ONC.. Decreased axial diffusivity (λ(‖)) and relative anisotropy (RA) of damaged axons were observed from 6 hours to 14 days, reflecting axonal injury. DTI detected axonal injury at 6 hours after ONC when SMI-31 did not detect axonal abnormality. Both decreased λ(‖), and SMI-31 identified axon damage at 3 days after ONC. Decreased λ(‖) correlated with reduced SMI-31-positive axon counts from 3 days after ONC. In contrast, the increased λ(⊥) was seen only in the distal segment of optic nerve whereas decreased myelin basic protein-positive axon counts were seen in all segments 3 days after ONC. The number of retrograde-labeled RGCs did not decline significantly until 7 days after ONC. There was a significant correlation between RGC loss and optic nerve axon damage.. The authors demonstrated that in vivo DTI detected axonal injury earlier than SMI-31. Results suggest that in vivo DTI of optic nerve injury may be used as a noninvasive tool for assessing the pathogenesis of RGC axonal injury.

Topics: Animals; Axons; Biomarkers; Cell Count; Diffusion Tensor Imaging; Disease Models, Animal; Female; Mice; Mice, Inbred C57BL; Myelin Basic Protein; Nerve Crush; Nerve Degeneration; Neurofilament Proteins; Optic Nerve Diseases; Retinal Ganglion Cells; Stilbamidines

In our previous investigations, we demonstrated that CD4(+) antimyelin basic protein (MBP) T cells protect hippocampal neurons against trimethyltin-induced damage. We hypothesized involvement of T cells, interacting with the various glial populations activated during the neurodegeneration process. In this study, we employ immunocytochemical methods to investigate the influence of administration of T cells on the response of microglia and of NG2(+) cells to trimethyltin (TMT)-induced damage. Female Lewis rats were treated with anti-MBP CD4(+) T cells (4 million per animal, i.v) 24 hr after TMT (8 mg/kg, i.p) intoxication. TMT caused degeneration of CA4 hipppocampal neurons and evoked an abundant reaction of microglial and NG2(+) cells in the injured region. The cells changed morphology into the activated state, and the number of OX42(+) and NG2(+) cells increased about 4.5-fold and 3-fold, respectively, relative to controls as assessed on day 21 after TMT treatment. Additionally, the cells of ameboid morphology, which expressed NG2 or microglial antigens, appeared in the zone of neurodegeneration. Furthermore, certain cells of ameboid phenotype shared both antigens. In rats treated with T cells, down-regulation of the activation of both glial classes and reduction of formation of their ameboid forms was observed. The number of the total OX42(+) and NG2(+) cells decreased by 21% and 54%, respectively, and the number of their ameboid forms decreased by 46% and 73%, respectively. Our data suggest that the diminished activation of microglia and NG2(+) cells, particularly the reduced number of their ameboid forms, may contribute to the neuroprotective effect of T cells.

Topics: Animals; Antigens; CD4-Positive T-Lymphocytes; Cell Count; Cytoprotection; Down-Regulation; Female; Fluorescent Antibody Technique; Hippocampus; Microglia; Microscopy, Confocal; Myelin Basic Protein; Nerve Degeneration; Neurons; Neuroprotective Agents; Proteoglycans; Rats; Statistics, Nonparametric; Trimethyltin Compounds

Glutamate excitotoxicity plays a role in white matter injury in many neurological diseases. Oligodendrocytes in particular are highly vulnerable to excitotoxicity, mediated through activation of AMPA/kainate receptors. Myelin may also be injured independently via NMDA (N-methyl-D-aspartic acid) receptors located on peripheral oligodendroglial processes. Central axons are susceptible to glutamate receptor activation in vivo, but it is unclear whether this is mediated directly by activation of receptors expressed on axons, or indirectly through glutamate toxicity of myelin or neighboring glial cells. We examined axonal vulnerability in mice deficient in myelin basic protein (shiverer), also expressing yellow fluorescent protein (YFP) in a subset of axons. YFP fluorescence, EM, and mouse behavior were assessed 24 h after microstereotactical injections of S-AMPA or NMDA into lumbar dorsal columns. S-AMPA injection led to impaired rotarod performance and widespread axonal degeneration and was more pronounced in shiverer mice than controls. In contrast, NMDA injection did not cause axonal injury or behavioral changes in either group. These results indicate that spinal cord axons in vivo are vulnerable to toxicity mediated by AMPA but not NMDA receptors. The presence of compact myelin is not required for excitotoxic axon damage, and its absence may increase vulnerability. Further understanding of AMPA receptor-mediated axonal toxicity may provide new targets for neuroprotective therapy in WM diseases.

Topics: alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; Animals; Biomarkers; Brain; Disease Models, Animal; Excitatory Amino Acid Agonists; Female; Hereditary Central Nervous System Demyelinating Diseases; Luminescent Proteins; Mice; Mice, Inbred C57BL; Mice, Neurologic Mutants; Movement Disorders; Myelin Basic Protein; N-Methylaspartate; Nerve Degeneration; Nerve Fibers, Myelinated; Neurotoxins; Receptors, AMPA

The aim of this study was to characterize myelin loss as one of the features of white matter abnormalities across three common dementing disorders. We evaluated post-mortem brain tissue from frontal and temporal lobes from 20 vascular dementia (VaD), 19 Alzheimer's disease (AD) and 31 dementia with Lewy bodies (DLB) cases and 12 comparable age controls. Images of sections stained with conventional luxol fast blue were analysed to estimate myelin attenuation by optical density. Serial adjacent sections were then immunostained for degraded myelin basic protein (dMBP) and the mean percentage area containing dMBP (%dMBP) was determined as an indicator of myelin degeneration. We further assessed the relationship between dMBP and glutathione S-transferase (a marker of mature oligodendrocytes) immunoreactivities. Pathological diagnosis significantly affected the frontal but not temporal lobe myelin attenuation: myelin density was most reduced in VaD compared to AD and DLB, which still significantly exhibited lower myelin density compared to ageing controls. Consistent with this, the degree of myelin loss was correlated with greater %dMBP, with the highest %dMBP in VaD compared to the other groups. The %dMBP was inversely correlated with the mean size of oligodendrocytes in VaD, whereas it was positively correlated with their density in AD. A two-tier regression model analysis confirmed that the type of disorder (VaD or AD) determines the relationship between %dMBP and the size or density of oligodendrocytes across the cases. Our findings, attested by the use of three markers, suggest that myelin loss may evolve in parallel with shrunken oligodendrocytes in VaD but their increased density in AD, highlighting partially different mechanisms are associated with myelin degeneration, which could originate from hypoxic-ischaemic damage to oligodendrocytes in VaD whereas secondary to axonal degeneration in AD.

Topics: Aged; Aged, 80 and over; Dementia; Female; Frontal Lobe; Glutathione Transferase; Humans; Immunohistochemistry; Male; Middle Aged; Myelin Basic Protein; Myelin Sheath; Nerve Degeneration; Nerve Fibers, Myelinated; Oligodendroglia; Regression Analysis; Temporal Lobe

After peripheral nerve injury, Schwann cells (SCs) vigorously divide to survive and produce a sufficient number of cells to accompany regenerating axons. Matrix metalloproteinases (MMPs) have emerged as modulators of SC signaling and mitosis. Using a 5-bromo-2-deoxyuridine (BrdU) incorporation assay, we previously found that a broad-spectrum MMP inhibitor (MMPi), GM6001 (or ilomastat), enhanced division of cultured primary SCs. Here, we tested the hypothesis that the ability of MMPi to stimulate SC mitosis may advance nerve regeneration in vivo. GM6001 administration immediately after rat sciatic nerve crush and daily thereafter produced increased nerve regeneration as determined by nerve pinch test and growth-associated protein 43 expression. The MMPi promoted endoneurial BrdU incorporation relative to vehicle control. The dividing cells were mainly SCs and were associated with growth-associated protein 43-positive regenerating axons. After MMP inhibition, myelin basic protein mRNA expression (determined by Taqman real-time quantitative polymerase chain reaction) and active mitosis of myelin-forming SCs were reduced, indicating that MMPs may suppress their dedifferentiation preceding mitosis. Intrasciatic injection of mitomycin,the inhibitor of SC mitosis, suppressed nerve regrowth, which was reversed by MMPi, suggesting that its effect on axonal growth promotion depends on its promitogenic action in SCs. These studies establish novel roles for MMPs in peripheral nerve repair via control of SC mitosis, differentiation, and myelin protein mRNA expression.

Topics: Animals; Bromodeoxyuridine; Cell Differentiation; Cell Proliferation; Dipeptides; Disease Models, Animal; Female; GAP-43 Protein; Gene Expression Regulation; Matrix Metalloproteinase Inhibitors; Mitosis; Myelin Basic Protein; Nerve Degeneration; Pain Measurement; Protease Inhibitors; Rats; Rats, Sprague-Dawley; RNA, Messenger; Schwann Cells; Sciatic Neuropathy

Deferoxamine (DFO) and erythropoietin (EPO) have each been shown to provide neuroprotection in neonatal rodent models of brain injury. In view of the described anti-oxidative actions of DFO and the anti-apoptotic and anti-inflammatory effects of EPO, we hypothesized that the combination of DFO and EPO would increase neuroprotection after neonatal hypoxic-ischemic brain injury as compared to single DFO or EPO treatment. At postnatal day 7 rats underwent right common carotid artery occlusion followed by a 90-min exposure to 8% oxygen. Rats were treated intraperitoneally with DFO (200mg/kg), recombinant human EPO (1 kU/kg), a combination of DFO-EPO or vehicle at 0, 24 and 48 h after hypoxia-ischemia (HI) and were sacrificed at 72 h. DFO-EPO administration reduced the number of cleaved caspase 3-positive cells in the ipsilateral cerebral cortex. Early neuronal damage was assessed by staining for microtubuli-associated protein (MAP)-2. In our model 63+/-9% loss of ipsilateral MAP-2 was observed after HI, indicating extensive brain injury. DFO, EPO or DFO-EPO treatment did not improve neuronal integrity as defined by MAP-2. Cerebral white matter tracts were stained for myelin basic protein (MBP), a constituent of myelin. Hypoxia-ischemia strongly reduced MBP staining which suggests white matter damage. However, DFO, EPO and DFO-EPO treatment had no effect on the loss of MBP staining. Finally, HI-induced loss of striatal tyrosine hydroxylase staining was not attenuated by DFO, EPO or DFO-EPO. Although DFO-EPO treatment reduced the number of cleaved caspase 3(+) cells, treatment with DFO, EPO, or with the combination of DFO and EPO did not protect against gray or white matter damage in the experimental setting applied.

Topics: Animals; Animals, Newborn; Anti-Inflammatory Agents; Antioxidants; Brain Infarction; Caspase 3; Cerebral Cortex; Cytoprotection; Deferoxamine; Disease Models, Animal; Drug Combinations; Drug Synergism; Erythropoietin; Hypoxia-Ischemia, Brain; Microtubule-Associated Proteins; Myelin Basic Protein; Nerve Degeneration; Nerve Fibers, Myelinated; Neurons; Rats; Rats, Wistar

Multiple system atrophy (MSA) is a progressive neurodegenerative disease characterized by autonomic failure, parkinsonism, cerebellar ataxia, and oligodendrocytic accumulation of alpha-synuclein (alphasyn). Oxidative stress has been linked to neuronal death in MSA and the mitochondrial toxin 3-nitropropionic acid (3NP) is known to enhance the motor deficits and neurodegeneration in transgenic mice models of MSA. However, the effect of 3NP administration on alphasyn itself has not been studied. In this context, we examined the neuropathological effects of 3NP administration in alphasyn transgenic mice expressing human alphasyn (halphasyn) under the control of the myelin basic protein (MBP) promoter and the effect of this administration on posttranslational modifications of alphasyn, on levels of total alphasyn, and on its solubility. We demonstrate that 3NP administration altered levels of nitrated and oxidized alphasyn in the MBP-halphasyn tg while not affecting global levels of phosphorylated or total alphasyn. 3NP administration also exaggerated neurological deficits in the MBP-halphasyn tg mice, resulting in widespread neuronal degeneration and behavioral impairment.

Topics: alpha-Synuclein; Animals; Brain; Convulsants; Disease Models, Animal; Mice; Mice, Transgenic; Mitochondria; Multiple System Atrophy; Myelin Basic Protein; Nerve Degeneration; Nitrates; Nitro Compounds; Oxidative Stress; Promoter Regions, Genetic; Propionates

Acute multiple sclerosis lesions are characterized by accumulation of T cells and macrophages, destruction of myelin and oligodendrocytes, and axonal damage. There is, however, limited information on neuroimmune interactions distal to sites of axonal damage in the T cell-infiltrated central nervous system. We investigated T-cell infiltration, myelin clearance, microglial activation, and phagocytic activity distal to sites of axonal transection through analysis of the perforant pathway deafferented dentate gyrus in SJL mice that had received T cells specific for myelin basic protein (TMBP) or ovalbumin (TOVA). The axonal lesion of TMBP-recipient mice resulted in lesion-specific recruitment of large numbers of T cells in contrast to very limited T-cell infiltration in TOVA-recipient and -naïve perforant pathway-deafferented mice. By double immunofluorescence and confocal microscopy, infiltration with TMBP but not TOVA enhanced the microglial response to axonal transection and microglial phagocytosis of myelin debris associated with the degenerating axons. Because myelin antigen-specific immune responses may provoke protective immunity, increased phagocytosis of myelin debris might enhance regeneration after a neural antigen-specific T cell-mediated immune response in multiple sclerosis.

Topics: Animals; Antigens, CD; Axons; Axotomy; Cell Count; Central Nervous System; Female; Macrophage-1 Antigen; Mice; Microglia; Myelin Basic Protein; Myelin Sheath; Nerve Degeneration; Neurofilament Proteins; Perforant Pathway; Phagocytes; Statistics, Nonparametric; T-Lymphocytes

Sphingolipids containing 2-hydroxylated fatty acids are among the most abundant lipid components of the myelin sheath and therefore are thought to play an important role in formation and function of myelin. To prove this hypothesis, we generated mice lacking a functional fatty acid 2-hydroxylase (FA2H) gene. FA2H-deficient (FA2H(-/-)) mice lacked 2-hydroxylated sphingolipids in the brain and in peripheral nerves. In contrast, nonhydroxylated galactosylceramide was increased in FA2H(-/-) mice. However, oligodendrocyte differentiation examined by in situ hybridization with cRNA probes for proteolipid protein and PDGFalpha receptor and the time course of myelin formation were not altered in FA2H(-/-) mice compared with wild-type littermates. Nerve conduction velocity measurements of sciatic nerves revealed no significant differences between FA2H(-/-) and wild-type mice. Moreover, myelin of FA2H(-/-) mice up to 5 months of age appeared normal at the ultrastructural level, in the CNS and peripheral nervous system. Myelin thickness and g-ratios were normal in FA2H(-/-) mice. Aged (18-month-old) FA2H(-/-) mice, however, exhibited scattered axonal and myelin sheath degeneration in the spinal cord and an even more pronounced loss of stainability of myelin sheaths in sciatic nerves. These results show that structurally and functionally normal myelin can be formed in the absence of 2-hydroxylated sphingolipids but that its long-term maintenance is strikingly impaired. Because axon degeneration appear to start rather early with respect to myelin degenerations, these lipids might be required for glial support of axon function.

Topics: Age Factors; Amidohydrolases; Animals; Animals, Newborn; Axons; Behavior, Animal; beta-Galactosidase; Cell Differentiation; Central Nervous System; Exploratory Behavior; Gene Expression Regulation, Developmental; Lipid Metabolism; Mice; Mice, Inbred C57BL; Mice, Knockout; Microscopy, Electron, Transmission; Myelin Basic Protein; Myelin Sheath; Nerve Degeneration; Neural Conduction; Oligodendroglia; Optic Nerve; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Sphingolipids

Injuries to the cauda equina/conus medullaris portion of the spinal cord can result in motor, sensory, and autonomic dysfunction, and neuropathic pain. In rats, unilateral avulsion of the motor efferents from the lumbosacral spinal cord results in at-level allodynia, along with a corresponding glial and inflammatory response in the dorsal horn of the spinal cord segments immediately rostral to the lesion. Here, we investigated the fate of intramedullary primary sensory projections following a motor efferent lesion. The lumbosacral (L6 and S1) ventral roots were unilaterally avulsed from the rat spinal cord (VRA; n=9). A second experimental group had the avulsed roots acutely reimplanted into the lateral funiculus (Imp; n=5), as this neural repair strategy is neuroprotective, and promotes the functional reinnervation of peripheral targets. A laminectomy-only group served as controls (Lam; n=7). At 8 weeks post-lesion, immunohistochemical examination showed a 42% reduction (P<0.001) in the number of RT97-positive axons in the ascending tracts of the dorsal funiculus of the L4-5 spinal segment in VRA rats. Evidence for degenerating myelin was also present. Reimplantation of the avulsed roots ameliorated axon and myelin degeneration. Axons in the descending dorsal corticospinal tract were unaffected in all groups, suggesting a specificity of this lesion for spinal primary sensory afferents. These results show for the first time that a lesion restricted to motor roots can induce the degeneration of intramedullary sensory afferents. Importantly, reimplantation of the lesioned motor roots ameliorated sensory axon degeneration. These data further support the therapeutic potential for reimplantation of avulsed ventral roots following trauma to the cauda equina/conus medullaris.

Topics: Animals; Calcium-Binding Proteins; Cauda Equina; Disease Models, Animal; Female; Functional Laterality; Glial Fibrillary Acidic Protein; Indoles; Microfilament Proteins; Myelin Basic Protein; Nerve Degeneration; Nerve Regeneration; Neurofilament Proteins; Rats; Rats, Sprague-Dawley; Recovery of Function; Replantation; Spinal Cord Injuries; Spinal Nerve Roots

We have previously reported that in the distal stump of ligated sciatic nerves, there is a change in the distribution of myelin basic protein (MBP) and P0 protein immunoreactivities. These results agreed with the studies of myelin isolated from the distal stump of animals submitted to ligation of the sciatic nerve, showing a gradual increase in a 14 kDa band with an electrophoretic mobility similar to that of an MBP isoform, among other changes. This band, which was resolved into two bands of 14 and 15 kDa using a 16% gel, was found to contain a mixture of MBP fragments and peptides with great homology with alpha- and beta-globins. In agreement with these results, we have demonstrated that the mRNA of alpha-globin is present in the proximal and distal stumps of the ligated nerve. It is also detected at very low levels in Schwann cells isolated from normal nerves. These results could be due to the presence of alpha- and/or beta-globin arising from immature cells of the erythroid series. Also, they could be present in macrophages, which spontaneously migrate to the injured nerve to promote the degradation of myelin proteins. Cells isolated from normal adult rat bone marrow which were injected intraortically were found to migrate to the injured area. These cells could contribute to the remyelination of the damaged area participating in the removal of myelin debris, through their transdifferentiation into Schwann cells or through their fusion with preexisting Schwann cells in the distal stump of the injured sciatic nerve.

Topics: Animals; Blotting, Western; Bone Marrow Cells; Cell Movement; Electrophoresis, Polyacrylamide Gel; Female; Globins; Immunohistochemistry; Male; Myelin Basic Protein; Nerve Degeneration; Nerve Regeneration; Nuclease Protection Assays; Peptides; Peripheral Nerves; Rats; Rats, Wistar; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Schwann Cells; Sciatic Nerve; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Trypsin

The present study investigated cerebrospinal fluid (CSF) biomarkers for estimating degeneration of the central nervous system (CNS) in experimental dogs with GM1 gangliosidosis and preliminarily evaluated the efficacy of long-term glucocorticoid therapy for GM1 gangliosidosis using the biomarkers identified here. GM1 gangliosidosis, a lysosomal storage disease that affects the brain and multiple systemic organs, is due to an autosomal recessively inherited deficiency of acid beta-galactosidase activity. Pathogenesis of GM1 gangliosidosis may include neuronal apoptosis and abnormal axoplasmic transport and inflammatory response, which are perhaps consequent to massive neuronal storage of GM1 ganglioside. In the present study, we assessed some possible CSF biomarkers, such as GM1 ganglioside, aspartate aminotransferase (AST), lactate dehydrogenase (LDH), neuron-specific enolase (NSE) and myelin basic protein (MBP). Periodic studies demonstrated that GM1 ganglioside concentration, activities of AST and LDH, and concentrations of NSE and MBP in CSF were significantly higher in dogs with GM1 gangliosidosis than those in control dogs, and their changes were well related with the months of age and clinical course. In conclusion, GM1 ganglioside, AST, LDH, NSE and MBP could be utilized as CSF biomarkers showing CNS degeneration in dogs with GM1 gangliosidosis to evaluate the efficacy of novel therapies proposed for this disease. In addition, we preliminarily treated an affected dog with long-term oral administration of prednisolone and evaluated the efficacy of this therapeutic trial using CSF biomarkers determined in the present study. However, this treatment did not change either the clinical course or the CSF biomarkers of the affected dog, suggesting that glucocorticoid therapy would not be effective for treating GM1 gangliosidosis.

Topics: Animals; Anti-Inflammatory Agents; Aspartate Aminotransferases; Biomarkers; Brain; Cerebrospinal Fluid Proteins; Disease Models, Animal; Dogs; G(M1) Ganglioside; Gangliosidosis, GM1; L-Lactate Dehydrogenase; Myelin Basic Protein; Nerve Degeneration; Phosphopyruvate Hydratase; Predictive Value of Tests; Prednisolone; Treatment Outcome; Up-Regulation

Exposure to environmental toxins increases the risk of neurodegenerative diseases including Parkinson's disease (PD). Rotenone is a neurotoxin that has been used to induce experimental Parkinsonism in rats. We used the rotenone model of experimental Parkinsonism to explore a novel aspect of extra-nigral degeneration, the neurodegeneration of spinal cord (SC), in PD. Rotenone administration to male Lewis rats caused significant neuronal cell death in cervical and lumbar SC as compared with control animals. Dying neurons were motoneurons as identified by double immunofluorescent labeling for terminal deoxynucleotidyl transferase, recombinant-mediated dUTP nick-end labeling-positive (TUNEL(+)) cells and choline acetyltransferase (ChAT)-immunoreactivity. Neuronal death was accompanied by abundant astrogliosis and microgliosis as evidenced from glial fibrillary acidic protein (GFAP)-immunoreactivity and OX-42-immunoreactivity, respectively, implicating an inflammatory component during neurodegeneration in SC. However, the integrity of the white matter in SC was not affected by rotenone administration as evidenced from the non co-localization of any TUNEL(+) cells with GFAP-immunoreactivity and myelin basic protein (MBP)-immunoreactivity, the selective markers for astrocytes and oligodendrocytes, respectively. Increased activities of 76 kD active m-calpain and 17/19 kD active caspase-3 further demonstrated involvement of these enzymes in cell death in SC. The finding of ChAT(+) cell death also suggested degeneration of SC motoneurons in rotenone-induced experimental Parkinsonism. Thus, this is the first report of its kind in which the selective vulnerability of a putative parkinsonian target outside of nigrostriatal system has been tested using an environmental toxin to understand the pathophysiology of PD. Moreover, rotenone-induced degeneration of SC motoneuron in this model of experimental Parkinsonism progressed with upregulation of calpain and caspase-3.

Topics: Animals; Calpain; Caspase 3; CD11b Antigen; Choline O-Acetyltransferase; Enzyme Activation; Glial Fibrillary Acidic Protein; In Situ Nick-End Labeling; Male; Motor Neurons; Myelin Basic Protein; Nerve Degeneration; Phosphopyruvate Hydratase; Rats; Rats, Inbred Lew; Rotenone; Spinal Cord Diseases; Time Factors; Tyrosine 3-Monooxygenase

We investigated the influence of administration of autoimmune T cells on trimethyltin-induced degeneration of hippocampal neurons. Female Lewis rats received 8 mg/kg trimethyltin intraperitoneally alone, or followed 24 h later by a second intravenous injection of anti-myelin basic protein T cells (green fluorescent protein-tagged). Neurodegeneration was assessed by NeuN and Nissl cell counts 21 days after trimethyltin injection. We found that neurodegeneration in the CA4 region of the hippocampus was significantly reduced in the group receiving T cells. T cells also caused an augmentation of trimethyltin-induced hippocampal astrocytic activation and astrocytic TrkA expression, which was particularly intense in the CA4 region. Our study provides the first evidence of neuroprotection evoked by transferred T cells following a neurotoxic brain insult. The data suggest that mediation of the neuroprotective effects of T-cell-released nerve growth factor occurs mainly via hippocampal astroglial TrkA receptors.

Topics: Animals; Cell Count; Female; Glial Fibrillary Acidic Protein; Hippocampus; Myelin Basic Protein; Nerve Degeneration; Neurons; Phosphopyruvate Hydratase; Rats; Rats, Inbred Lew; Receptor, trkA; T-Lymphocytes; Trimethyltin Compounds

We previously demonstrated that IGF-1 blocks glutamate-mediated death of late oligodendrocyte progenitors (OPs) by preventing Bax translocation, mitochondrial cytochrome c release and cleavage of caspases 9 and 3. Here, we demonstrate that IGF-1 prevents caspase 3 activation in late OPs when administered up to 16 h following exposure to glutamate. Moreover, late addition of IGF-1 to OPs previously exposed to toxic levels of glutamate promotes oligodendrocyte maturation as measured by myelin basic protein expression. We also demonstrate that intraventricularly administered IGF-1 retains OPs in the perinatal white matter after hypoxia-ischemia when given after insult. These results suggest that delayed administration of IGF-1 will rescue OPs in the immature white matter and promote myelination following hypoxia-ischemia.

Topics: Animals; Animals, Newborn; Apoptosis; Caspase 3; Cells, Cultured; Cytoprotection; Drug Administration Schedule; Glutamic Acid; Hypoxia-Ischemia, Brain; Insulin-Like Growth Factor I; Myelin Basic Protein; Nerve Degeneration; Nerve Fibers, Myelinated; Nerve Growth Factors; Neurotoxins; Oligodendroglia; Rats; Rats, Sprague-Dawley; Rats, Wistar; Stem Cells; Time Factors; Treatment Outcome

To characterize a model of optic nerve axonal degeneration induced by tumor necrosis factor (TNF)-alpha and to determine the role of nuclear factor (NF)-kappaB p65 in axonal degeneration.. Groups of rats were euthanatized at 1 day, 1 or 2 weeks, or 1 or 2 months after intravitreal injection of TNF-alpha. Morphometric analyses of neurofilament- or Thy-1-positive cells, retinal ganglion cells (flat preparations stained with cresyl violet or retrograde labeling with a neurotracer), the number of axons, immunostaining for myelin basic protein, and TUNEL assays were performed. Levels of NF-kappaB p65 protein in retina and optic nerve were determined by Western blot analysis and immunohistochemistry. The effects of antisense oligodeoxynucleotide (AS ODN) against NF-kappaB p65 and helenalin, an inhibitor of NF-kappaB p65 activation, on TNF-alpha-induced optic nerve degeneration were determined by counting the number of axons.. Intravitreal injections of TNF-alpha induced obvious axonal loss and extensive degeneration of the axons from 2 weeks to 2 months after injection, whereas significant retinal ganglion cell loss was noted only at 2 months after injection. NF-kappaB p65 was increased in the optic nerve but not in the retina and was found to colocalize with ED-1 and Iba1, markers of microglia. Inhibition of NF-kappaB p65 with AS ODN or helenalin significantly ameliorated the effects of TNF-alpha-mediated axonal loss.. TNF-alpha causes axonal degeneration with probable delayed loss of retinal ganglion cell bodies. NF-kappaB p65 may play a pivotal role in axonal degeneration, with the possible involvement of microglial cells.

Topics: Animals; Axons; Blotting, Western; Immunohistochemistry; In Situ Nick-End Labeling; Injections; Male; Myelin Basic Protein; Nerve Degeneration; Oligodeoxyribonucleotides, Antisense; Optic Nerve; Rats; Rats, Inbred Lew; Retina; Sesquiterpenes; Sesquiterpenes, Guaiane; Transcription Factor RelA; Tumor Necrosis Factor-alpha; Vitreous Body

Dithiocarbamates (DTCs), such as disulfiram, have been used in aversion therapy for alcoholism even though an inherent toxicity is induced, which is related mainly to peripheral neuropathy and is associated with behavioural and neurological complications. At anatomical and histopathological levels, DTCs affect structural elements in nervous tissue, such as axonal degeneration and alterations in the cytoskeletal proteins of astrocytes. Therefore, given the axonal effects of DTCs and to gain further insight into axonal growth and axonal pathfinding in the central nervous system (CNS), here we established an in vivo experimental model of mouse development. Daily intraperitoneal injections of N,N-diethyldithiocarbamate (DEDTC), the first metabolite of disulfiram, were given from postnatal day 2 (P2) until P15. From P16 until P30, animals were not treated. Treatment induced considerable physiological alterations, such as growth delay, throughout postnatal development. Moreover, by immunohistochemistry techniques, we observed important alterations in the cytoskeletal glial protein at early stages of postnatal development. At later stages (P15), the immunoreactivity pattern detected by an antibody against axonal neurofilaments (anti-NF-H) showed alteration in the axonal distribution pattern followed by drastic axonal loss at P22, data that were corroborated using an anti-MBP (myelin basic protein) antibody. Using an antibody against the beta amyloid precursor protein (APP), we detected axonal injury. Furthermore, given that we observed axonal re-growth in adulthood in the in vivo model presented, we propose that this model would be a good system in which to identify new strategies for inducing regenerative growth in neural diseases in which axonal regeneration is blocked.

Topics: Aging; Amyloid beta-Protein Precursor; Animals; Animals, Newborn; Antidotes; Axons; Cell Differentiation; Central Nervous System; Cytoskeletal Proteins; Disease Models, Animal; Ditiocarb; Growth Cones; Immunohistochemistry; Mice; Myelin Basic Protein; Nerve Degeneration; Nerve Regeneration; Neurofilament Proteins; Neurotoxins; Wallerian Degeneration

Myelin-forming oligodendrocytes facilitate saltatory nerve conduction and support neuronal functions in the mammalian CNS. Although the processes of oligodendrogliogenesis and differentiation from neural progenitor cells have come to light in recent years, the molecular mechanisms underlying oligodendrocyte myelinogenesis are poorly defined. Herein, we demonstrate the pivotal role of the basic helix-loop-helix transcription factor, Olig1, in oligodendrocyte myelinogenesis in brain development. Mice lacking a functional Olig1 gene develop severe neurological deficits and die in the third postnatal week. In the brains of these mice, expression of myelin-specific genes is abolished, whereas the formation of oligodendrocyte progenitors is not affected. Furthermore, multilamellar wrapping of myelin membranes around axons does not occur, despite recognition and contact of axons by oligodendrocytes, and Olig1-null mice develop widespread progressive axonal degeneration and gliosis. In contrast, myelin sheaths are formed in the spinal cord, although the extent of myelination is severely reduced. At the molecular level, we find that Olig1 regulates transcription of the major myelin-specific genes, Mbp, Plp1, and Mag, and suppresses expression of a major astrocyte-specific gene, Gfap. Together, our data indicate that Olig1 is a central regulator of oligodendrocyte myelinogenesis in brain and that axonal recognition and myelination by oligodendrocytes are separable processes.

Topics: Animals; Axons; Basic Helix-Loop-Helix Transcription Factors; Brain; Cell Differentiation; Cells, Cultured; Chlorocebus aethiops; COS Cells; DNA-Binding Proteins; Genes, Lethal; Glial Fibrillary Acidic Protein; Gliosis; Helix-Loop-Helix Motifs; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Neurologic Mutants; Myelin Basic Protein; Myelin Proteolipid Protein; Myelin Sheath; Myelin-Associated Glycoprotein; Nerve Degeneration; Nerve Tissue Proteins; Oligodendroglia; Phenotype; Spinal Cord; Transcription Factors; Transcription, Genetic; Transfection

Nigrostriatal degeneration, the pathological hallmark of Parkinson's disease (PD), is mirrored by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxication. MPTP-treated animals show the common behavioral, motor, and pathological features of human disease. We demonstrated previously that adoptive transfer of Copaxone (Cop-1) immune cells protected the nigrostriatal dopaminergic pathway in MPTP-intoxicated mice. Herein, we evaluated this protection by quantitative proton magnetic resonance spectroscopic imaging (1H MRSI). 1H MRSI performed in MPTP-treated mice demonstrated that N-acetyl aspartate (NAA) was significantly diminished in the substantia nigra pars compacta (SNpc) and striatum, regions most affected in human disease. When the same regions were coregistered with immunohistochemical stains for tyrosine hydroxylase, numbers of neuronal bodies and termini were similarly diminished. MPTP-intoxicated animals that received Cop-1 immune cells showed NAA levels, in the SNpc and striatum, nearly equivalent to PBS-treated animals. Moreover, adoptive transfer of immune cells from ovalbumin-immunized to MPTP-treated mice failed to alter NAA levels or protect dopaminergic neurons and their projections. These results demonstrate that 1H MRSI can evaluate dopaminergic degeneration and its protection by Cop-1 immunization strategies. Most importantly, the results provide a monitoring system to assess therapeutic outcomes for PD.

Topics: Adoptive Transfer; Animals; Aspartic Acid; Cell Count; Chromatography, High Pressure Liquid; Corpus Striatum; Dopamine; Glatiramer Acetate; Immunization; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Male; Mice; Microglia; MPTP Poisoning; Myelin Basic Protein; Nerve Degeneration; Nerve Tissue Proteins; Ovalbumin; Parkinsonian Disorders; Peptides; Substantia Nigra; T-Lymphocyte Subsets; Tyrosine 3-Monooxygenase

The cellular prion protein PrP(C) confers susceptibility to transmissible spongiform encephalopathies, yet its normal function is unknown. Although PrP(C)-deficient mice develop and live normally, expression of amino proximally truncated PrP(C) (DeltaPrP) or of its structural homolog Doppel (Dpl) causes cerebellar degeneration that is prevented by coexpression of full-length PrP(C). We now report that mice expressing DeltaPrP or Dpl suffer from widespread leukoencephalopathy. Oligodendrocyte-specific expression of full-length PrP(C) under control of the myelin basic protein (MBP) promoter repressed leukoencephalopathy and vastly extended survival but did not prevent cerebellar granule cell (CGC) degeneration. Conversely, neuron-specific PrP(C) expression under control of the neuron-specific enolase (NSE) promoter antagonized CGC degeneration but not leukoencephalopathy. PrP(C) was found in purified myelin and in cultured oligodendrocytes of both wild-type and MBP-PrP transgenic mice but not in NSE-PrP mice. These results identify white-matter damage as an extraneuronal PrP-associated pathology and suggest a previously unrecognized role of PrP(C) in myelin maintenance.

Topics: Age Factors; Animals; Blotting, Western; Central Nervous System Diseases; Glial Fibrillary Acidic Protein; GPI-Linked Proteins; In Situ Nick-End Labeling; Mice; Mice, Transgenic; Microscopy, Electron, Transmission; Mutation; Myelin Basic Protein; Nerve Degeneration; Neurons; Oligodendroglia; Phosphopyruvate Hydratase; Prions; Protein Conformation; Protein Processing, Post-Translational; PrPC Proteins

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

Periventricular leukomalacia (PVL), the dominant form of brain injury in premature infants, is characterized by diffuse white matter injury and is associated with cerebral palsy (CP). Maternal and placental infections are major causes of prematurity and identifiable etiology of PVL and CP. Here we have evaluated the therapeutic efficacy of N-acetylcysteine (NAC), a potent antioxidant and precursor of glutathione, to attenuate lipopolysaccharide (LPS)-induced white matter injury and hypomyelination in the developing rat brain, an animal model of PVL. Intraperitoneal pretreatment of pregnant female rats with NAC (50 mg/kg), 2 hr prior to administration of LPS at embryonic day 18 (E18), attenuated the LPS-induced expression of inflammatory cytokines such as tumor necrosis factor-alpha, interleukin-1beta, and inducible nitric oxide synthase in fetal rat brains. There were significantly reduced numbers of TUNEL(+) nuclei coimmunostained for platelet-derived growth factor-alphaR(+) [a surface marker for oligodendrocyte progenitor cells (OPCs)] at E20 in the subventricular zone of fetal rat brain in the NAC + LPS group compared with the untreated LPS group. Interestingly, immunostaining for O4 and O1 as markers for late OPCs and immature oligodendrocytes demonstrated fewer O4(+) and O1(+) cells in the LPS group compared with the NAC + LPS and control groups. Consistent with O4(+)/O1(+) cell counts, the expression of myelin proteins such as myelin basic protein, proteolipid protein, and 2'3'-cyclic nucleotide phosphodiesterase, including transcription factors such as MyT1 and Gtx, was less in the LPS group at late postnatal days, indicating severe hypomyelination in the developing rat brain when compared with NAC + LPS and control groups. Collectively, these data support the hypothesis that NAC may provide neuroprotection and attenuate the degeneration of OPCs against LPS evoked inflammatory response and white matter injury in developing rat brain. Moreover, these data suggest the possible use of NAC as a treatment for pregnant women with maternal or placental infection as a means of minimizing the risk of PVL and CP.

Topics: 2',3'-Cyclic-Nucleotide Phosphodiesterases; Acetylcysteine; Age Factors; Analysis of Variance; Animals; Animals, Newborn; Antigens; CD11b Antigen; Cell Count; Cell Death; Cytokines; Demyelinating Diseases; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Interactions; Embryo, Mammalian; Female; Humans; Immunohistochemistry; In Situ Nick-End Labeling; Infant, Newborn; Leukomalacia, Periventricular; Lipopolysaccharides; Male; Myelin Basic Protein; Nerve Degeneration; Neuroprotective Agents; O Antigens; Oligodendroglia; Pregnancy; Proteoglycans; Rats; Rats, Sprague-Dawley; Receptor, Platelet-Derived Growth Factor alpha; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Stem Cells; Survival Rate; Time Factors; Transcription Factors

Multiple sclerosis is increasingly recognized as a neurodegenerative disease which is triggered by inflammation in the central nervous system (CNS). Demyelination-associated axonal or neuronal damage is a primary cause of disability and has thus far not been successfully targeted by available drug therapies. The neuroprotective properties of both endogenous and administered cannabinoids have been shown in in vivo and in vitro models of CNS damage following excitotoxic, oxidative, traumatic and ischaemic insults, with a predominantly apoptotic effector mechanism. In this study a foetal mouse telencephalon aggregate cell culture system was developed to compare tissue from cannabinoid receptor 1 knockout mice with wildtype counterparts. Aggregate formation and neurofilament/myelin basic protein accumulation were dependent on the age of foetal dissection and species used. Following treatment with interferon-gamma, levels of myelin basic protein, neurofilament, neuronal dephosphorylation and caspase 3 activation were assessed in telencephalon tissue in vitro. Cytokine treatment resulted in significant loss of the neuronal marker neurofilament-H in cannabinoid receptor 1 knockout cultures but not in wildtypes, indicating that presence of the cannabinoid receptor 1 gene can be neuroprotective. Caspase 3 activation was higher in cultures from knockout animals, indicating an apoptotic mechanism of cell death. Dephosphorylated neurofilament levels were significantly elevated in knockout mice, lending support to the premise that neurofilament dephosphorylation is a marker for neuronal damage. Taken together, these results indicate that neuroprotection could be elicited through the cannabinoid receptor 1, and point towards a potential therapeutic role for cannabinoid compounds in demyelinating conditions such as multiple sclerosis.

Topics: Animals; Apoptosis; Brain; Cannabinoids; Caspase 3; Caspases; Cell Aggregation; Cells, Cultured; Interferon-gamma; Mice; Mice, Knockout; Models, Biological; Myelin Basic Protein; Nerve Degeneration; Neurofilament Proteins; Neuroprotective Agents; Organ Culture Techniques; Phosphorylation; Receptor, Cannabinoid, CB1

Both axon and myelin degeneration have significant impact on the long-term disability of patients with white matter disorder. However, the clinical manifestations of the neurological dysfunction caused by white matter disorders are not sufficient to determine the origin of neurological deficits. A noninvasive biological marker capable of detecting and differentiating axon and myelin degeneration would be a significant addition to currently available tools. Directional diffusivities derived from diffusion tensor imaging (DTI) have been previously proposed by this group as potential biological markers to detect and differentiate axon and myelin degeneration. To further test the hypothesis that axial (lambdaparallel) and radial (lambdaperpendicular) diffusivities reflect axon and myelin pathologies, respectively, the optic nerve was examined serially using DTI in a mouse model of retinal ischemia. A significant decrease of lambdaparallel, the putative DTI axonal marker, was observed 3 days after ischemia without concurrently detectable changes in lambdaperpendicular, the putative myelin marker. This result is consistent with histological findings of significant axonal degeneration with no detectable demyelination at 3 days after ischemia. The elevation of lambdaperpendicular observed 5 days after ischemia is consistent with histological findings of myelin degeneration at this time. These results support the hypothesis that lambdaparallel and lambdaperpendicular hold promise as specific markers of axonal and myelin injury, respectively, and, further, that the coexistence of axonal and myelin degeneration does not confound this utility.

Topics: Animals; Axons; Diffusion Magnetic Resonance Imaging; Immunohistochemistry; Ischemia; Mice; Models, Neurological; Myelin Basic Protein; Myelin Sheath; Nerve Degeneration; Neurofilament Proteins; Optic Nerve; Retinal Degeneration; Retinal Vessels; Wallerian Degeneration

A1 adenosine receptors (A1ARs) are widely expressed in the brain during development. To examine whether A1AR activation can alter postnatal brain formation, neonatal rats from postnatal days 3 to 14 were treated with the A1AR agonist N6-cyclopentyladenosine (CPA) in the presence or absence of the peripheral A1AR antagonist 8-(p-sulfophenyl)-theophylline (8SPT). CPA or CPA + 8SPT treatment resulted in reductions in white matter volume, ventriculomegaly, and neuronal loss. Quantitative electron microscopy revealed reductions in total axon volume following A1AR agonist treatment. We also observed reduced expression of myelin basic protein in treated animals. Showing that functional A1ARs were present over the ranges of ages studies, high levels of specific [3H]CCPA binding were observed at PD 4, 7 and 14, and receptor-G protein coupling was present at each age. These observations show that activation of A1ARs with doses of CPA that mimic the effects of high adenosine levels results in damage to the developing brain.

Topics: Adenosine; Animals; Animals, Newborn; Body Weight; Cell Count; Cerebral Cortex; Cerebral Ventricles; Drug Combinations; Drug Interactions; GTP-Binding Proteins; Guanosine 5'-O-(3-Thiotriphosphate); Hippocampus; Microscopy, Electron; Myelin Basic Protein; Nerve Degeneration; Nerve Fibers, Myelinated; Neuroglia; Neurons; Presynaptic Terminals; Purinergic P1 Receptor Agonists; Purinergic P1 Receptor Antagonists; Rats; Rats, Sprague-Dawley; Receptors, Purinergic P1; Telencephalon; Theophylline

Voltage-gated sodium channels contribute to the development of axonal degeneration in white matter, and sodium channel blocking drugs are known to have a protective effect on acutely injured white matter axons. To determine whether phenytoin has a protective effect on axons in a neuroinflammatory model, we studied the effect of phenytoin on axonal degeneration in the optic nerve in MOG-induced experimental allergic encephalomyelitis (EAE). We report that, whereas approximately 50% of optic nerve axons are lost at 27-28 days in untreated EAE, only approximately 12% of the axons are lost if mice with MOG-induced EAE are treated with phenytoin. These results demonstrate that it is possible to achieve substantial protection of white matter axons in EAE, a model neuroinflammatory/demyelination disease, with a sodium channel blocking agent.

Topics: Animals; Axons; Cell Death; Disease Models, Animal; Encephalomyelitis, Autoimmune, Experimental; Immunohistochemistry; Mice; Mice, Inbred C57BL; Myelin Basic Protein; Nerve Degeneration; Nerve Fibers, Myelinated; Neurofilament Proteins; Neuroprotective Agents; Optic Nerve; Phenytoin; Sodium Channel Blockers; Sodium Channels; Treatment Outcome

This study analyzes how the antigen specificity, the subtype, and the activation state of T cells modulate their recently discovered neuroprotective potential. We assessed the prevention from neuronal damage in organotypic entorhinal-hippocampal slice cultures after co-culture with Th1 and Th2 cells either specific for myelin basic protein (MBP) or ovalbumin (OVA). We found that MBP-specific Th2 cells were the most effective in preventing central nervous system (CNS) tissue from secondary injury. This neuroprotective T cell effect appears to be mediated by soluble factors. After stimulation with phorbol myristate acetate and ionomycin, all T cells were most effective in preventing neuronal death. Our data show that the T cell subtype and activation state are important features in determining the neuroprotective potential of these cells.

Topics: Animals; Animals, Newborn; Brain; Brain Injuries; Cell Survival; Chemotaxis, Leukocyte; Contact Inhibition; Cytokines; Epitopes; Mice; Mice, Inbred BALB C; Myelin Basic Protein; Nerve Degeneration; Neurons; Ovalbumin; Tetradecanoylphorbol Acetate; Th1 Cells; Th2 Cells

Proteases are involved in a variety of processes including demyelination after injury to the central nervous system. Neuropsin is a serine protease, which is constitutively expressed in the neurons of the limbic system. In the present study, intrahippocampal kainate injection and enucleation were performed on adult mice. Neuropsin mRNA and protein expression was detected by in situ hybridization and immunohistochemistry. Double in situ hybridization confirmed that the mRNA expression was induced in oligodendrocytes. One day after kainate injection to the hippocampus, neuropsin mRNA was expressed, peaking 4-8 days postoperatively and disappearing at 14 days. Immunohistochemistry and immunoelectron microscopy revealed that neuropsin was expressed in the cell body of oligodendrocytes and myelin. To see if neuropsin degrades myelin protein, purified myelin was incubated with recombinant neuropsin. A decrease in the intensity of the bands of myelin basic protein was observed. These results indicate that neuropsin is involved in demyelination.

Topics: Animals; Axons; Brain Injuries; Excitatory Amino Acid Agonists; Eye Enucleation; Hippocampus; Immunohistochemistry; Kainic Acid; Kallikreins; Mice; Myelin Basic Protein; Nerve Degeneration; Oligodendroglia; Optic Nerve; Pyramidal Cells; RNA, Messenger; Serine Endopeptidases

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

Autoimmune T cells against central nervous system myelin associated peptide reduce the spread of damage and promote recovery in injured rat spinal cord, findings that might lead to neuroprotective cell therapy without risk of autoimmune disease.

Topics: Animals; Autoimmunity; Central Nervous System; Magnetic Resonance Imaging; Myelin Basic Protein; Nerve Degeneration; Rats; Spinal Cord Injuries; T-Lymphocytes

Tumor necrosis factor alpha (TNFalpha) appears to take part in the pathogenesis of multiple sclerosis and to contribute to the degeneration of oligodendrocytes as well as neurons. TNFalpha is produced by microglia and astrocytes, which also produce hormones and cytokines that influence its biological activity. Thus, in mixed cultures the effects of exogenous TNFalpha might be modified by products of astrocytes and microglia. The effects of TNFalpha in oligodendrocyte-enriched cultures are reported below. We prepared the cultures by shaking oligodendrocytes off primary mixed glial-cell cultures from brains of 2-day-old rats at 7 days in vitro and plating them (0 days post-shake, DPS). Platelet-derived growth factor and fibroblast growth factor were included in the media at 1-5 DPS in order to encourage proliferation. At 2 DPS media were added with no TNFalpha (controls) or 1000, 2000 or 5000 U/ml of TNFalpha, and at 5 DPS media were replaced with fresh serum-free media. Cultures were fixed with 4% paraformaldehyde at 5, 7, 9 and 12 DPS and immunostained. Oligodendrocyte progenitors were not reduced in numbers immediately after the incubation with TNFalpha (i. e. at 5 DPS). However, after an additional 4 days in culture fewer progenitors remained in the cultures that had been treated with TNFalpha than in the untreated cultures. In the absence of the growth factors there were fewer progenitors, but their numbers also were reduced by TNFalpha. Maturation to the myelin basic protein (MBP)-positive stage was inhibited by about 36% at 9 DPS by 1000-2000 U/ml of TNFalpha, while numbers of O4+/MBP- precursors were unaffected. It is interesting that the steady-state number of O4-positive precursors was unchanged by TNFalpha at 9 DPS, when there were reductions in the numbers of A2B5-positive progenitors and MBP-positive mature oligodendrocytes. That observation suggests that the rates of proliferation, death and maturation are controlled by multiple factors, with a particularly vulnerable time at the maturation to the MBP-positive stage. At 5000 U/ml TNFalpha the specific effect on maturation was overtaken cytotoxicity. These data and a summary of the literature suggest that inhibition of MBP expression is sensitive to lower TNFalpha concentrations and incubation times than is cell survival. Specific effects on numbers of MBP-positive cells, morphology and MBP expression occur at 1000-2000 U/ml for 48-72 h or at up to 10000 U/ml for

Topics: Animals; Astrocytes; Cell Differentiation; Cells, Cultured; In Vitro Techniques; Microglia; Myelin Basic Protein; Nerve Degeneration; Oligodendroglia; Rats; Stem Cells; Tumor Necrosis Factor-alpha

Glial reactivity is implicated in CNS repair and regenerative responses. Microglia, the cells responding earliest to axonal injury, produce tumor necrosis factor-alpha (TNFalpha), a cytokine with both cytopathic and neuroprotective effects. We have studied activation of hippocampal microglia to produce TNFalpha in response to transection of perforant path axons in SJL/J mice. TNFalpha mRNA was produced in a transient manner, peaking at 2 d and falling again by 5 d after lesioning. This was unlike other markers of glial reactivity, such as Mac-1 upregulation, which were sustained over longer time periods. Message for the immune cytokine interferon-gamma (IFNgamma) was undetectable, and glial reactivity to axonal lesions occurred as normal in IFNgamma-deficient mice. Microglial responses to lesion-induced neuronal injury were markedly enhanced in myelin basic protein promoter-driven transgenic mice, in which IFNgamma was endogenously produced in hippocampus. The kinetics of TNFalpha downregulation 5 d after lesion was not affected by transgenic IFNgamma, indicating that IFNgamma acts as an amplifier and not an inducer of response. These results are discussed in the context of a regenerative role for TNFalpha in the CNS, which is innately regulated and potentiated by IFNgamma.

Topics: Animals; Antineoplastic Agents; Axons; Denervation; Gene Expression; Hippocampus; In Situ Hybridization; Interferon-gamma; Macrophage-1 Antigen; Mice; Mice, Transgenic; Microglia; Myelin Basic Protein; Nerve Degeneration; Oligodendroglia; Perforant Pathway; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tumor Necrosis Factor-alpha

Autoimmunity to antigens of the central nervous system is usually considered detrimental. T cells specific to a central nervous system self antigen, such as myelin basic protein, can indeed induce experimental autoimmune encephalomyelitis, but such T cells may nevertheless appear in the blood of healthy individuals. We show here that autoimmune T cells specific to myelin basic protein can protect injured central nervous system neurons from secondary degeneration. After a partial crush injury of the optic nerve, rats injected with activated anti-myelin basic protein T cells retained approximately 300% more retinal ganglion cells with functionally intact axons than did rats injected with activated T cells specific for other antigens. Electrophysiological analysis confirmed this finding and suggested that the neuroprotection could result from a transient reduction in energy requirements owing to a transient reduction in nerve activity. These findings indicate that T-cell autoimmunity in the central nervous system, under certain circumstances, can exert a beneficial effect by protecting injured neurons from the spread of damage.

Topics: Amino Acid Sequence; Animals; Autoimmunity; Axotomy; Central Nervous System; Female; Molecular Sequence Data; Myelin Basic Protein; Nerve Degeneration; Neurons; Optic Nerve; Optic Nerve Injuries; Rats; Rats, Inbred Lew; T-Lymphocytes

Transection of the entorhino-dentate perforant path is a well known model for lesion-induced axonal sprouting and glial reactions in the rat. In this study, we have characterized the microglial reaction in the dentate molecular layer of the SJL/J and C57Bl/6 mouse. The morphological transformation of the microglial cells and their densitometrically measured Mac-1 immunoreactivity were correlated with the density of silver-impregnated axonal and terminal degeneration and the myelination of the degenerating medial and lateral perforant pathways. Anterograde axonal and terminal degeneration leads to: (i) altered myelin basic protein immunoreactivity with the appearance of discrete myelin deposits preferentially in the denervated medial and significantly less so in the lateral perforant path zone from day 2 after lesioning; (ii) an increase in number and Mac-1 immunoreactivity of morphologically-changed microglial cells in the denervated perforant path zones with more pronounced morphological transformation of microglia in the medial than in the lateral perforant path zones at day 2 but not day 5 after lesioning; and (iii) a linear correlation between the density of microglial Mac-1 reactivity and axonal degeneration in the medial but not in the lateral perforant path zone at two days postlesion, and a linear correlation in both zones at five days postlesion. We propose that the differentiated microglial response is due to the different densities of axonal and terminal degeneration, as observed in the individual cases. The finding of a potentiated or accelerated microglial activation in the medial as compared to the lateral perforant path zone suggests different kinetics of microglial activation in areas with degenerating myelinated and unmyelinated fibers.

Topics: Animals; Axons; Coloring Agents; Densitometry; Dentate Gyrus; Immunohistochemistry; Mice; Mice, Inbred C57BL; Mice, Inbred Strains; Microglia; Myelin Basic Protein; Myelin Sheath; Nerve Degeneration; Oligodendroglia; Perforant Pathway; Presynaptic Terminals; Silver Staining; Tolonium Chloride

A rabbit antiserum (anti-EP), induced against a synthetic peptide corresponding to residues 68 to 86 of guinea pig myelin basic protein, powerfully immunostained abnormal-appearing oligodendrocytic processes and cell bodies in demyelinating areas associated with multiple system atrophy (MSA). However, as we reported previously, the antiserum, which is highly specific for the sequence QDENPVV corresponding to human myelin basic protein residues 82 to 88, failed to recognize any structures in normal human brain. QD-9, a mouse monoclonal antibody raised against human myelin basic protein residues 69 to 88, which also recognizes specifically the epitope QDENPVV, gave the same results as did anti-EP. The unusual epitope recognized by anti-EP/QD-9 antibodies appears to be accessible in areas of myelin degeneration, and the antibodies have been shown to detect such areas in multiple sclerosis and infarcted brains. These antibodies detect myelin degeneration more widely than previous conventional methods. The present study emphasizes the importance of myelin degeneration in the pathogenesis of multiple system atrophy.

Topics: Aged; Aged, 80 and over; Animals; Antibodies, Monoclonal; Blotting, Western; Cerebellum; Demyelinating Diseases; Epitopes; Female; Guinea Pigs; Humans; Image Processing, Computer-Assisted; Immunoenzyme Techniques; Inclusion Bodies; Male; Mice; Mice, Inbred BALB C; Middle Aged; Multiple System Atrophy; Myelin Basic Protein; Myelin Sheath; Nerve Degeneration; Oligodendroglia; Peptide Fragments; Rabbits; Tumor Cells, Cultured

Myelin is necessary for the conduction of high frequency and high velocity nerve impulses in the central nervous system of mammals, and severe neurological disturbances develop as a result of myelin loss. In this report, we have characterized changes in the brain proteomic profile of transgenic mice that develop a c-myc-induced degenerative disorder of myelin. Marked differences were seen in the accumulation of cytoskeletal proteins associated with the pathological condition fibrous gliosis in the optic nerves of affected animals, including upregulation of glial fibrillary acid protein and vimentin. In addition, the expression of several major myelin proteins, including five isoforms of myelin basic protein, four isoforms of cyclic nucleotide 3'-phosphodiesterase, and myelin-associated glycoprotein, was markedly reduced in the brains of c-myc transgenic mice as revealed by immunocytochemistry and by two-dimensional immunoblots. A number of novel proteomic disease marker candidates were revealed, which displayed pronounced changes in their expression profile. Sequence determination of these proteins and molecular cloning of their mRNAs will provide an opportunity to further evaluate their roles in the disease process.

Topics: 3',5'-Cyclic-AMP Phosphodiesterases; Animals; Central Nervous System; Gene Expression; Humans; Mice; Mice, Transgenic; Myelin Basic Protein; Myelin Sheath; Nerve Degeneration; Oligodendroglia; Proteins; Proto-Oncogene Proteins c-myc

In order to achieve a better understanding of the pathophysiology of ischemic white matter lesions, oligodendrocytic degeneration and subsequent proliferation were examined in the mouse model of middle cerebral artery occlusion. In situ hybridization histochemistry for proteolipid protein messenger RNA was employed as a sensitive and specific marker of oligodendrocytes, and immunohistochemistry for myelin basic protein was used as a compact myelin marker. Immunohistochemistry for microtubule-associated protein 2 and albumin was employed to monitor neuronal degeneration and the breakdown of the blood brain barrier, respectively. In the ischemic core of the caudoputamen, the immunoreactivity for microtubule-associated protein 2 disappeared and massive albumin extravasation occurred several hours after vessel occlusion, while proteolipid protein messenger RNA signals remained relatively strong at this time. The messenger RNA signals began to attenuate 12 h after ischemia and were hardly detectable 24 h after ischemia in the whole ischemic lesion. In situ end-labeling of fragmented DNA showed some cells with proteolipid protein messenger RNAs to have DNA fragmentation at this period. In contrast to proteolipid protein messenger RNA signals, the immunoreactivity for myelin basic protein was detected as long as five days after ischemia. An apparent increase in the cells possessing strong proteolipid protein messenger RNA signals was found five days after ischemia, mainly in the corpus callosum and the cortex bordering the infarcted areas. A double simultaneous procedure with in situ hybridization for proteolipid protein messenger RNA and immunohistochemistry for glial fibrillary acid protein or lectin histochemistry for macrophages/microglia showed proliferating oligodendrocytes to be co-localized with reactive astrocytes and macrophages/microglia. These findings show that oligodendrocytic damage occurred following ischemic neuronal damage and the breakdown of the blood brain barrier, but preceded the breakdown of myelin proteins in the ischemic lesion, that an apoptosis-like process was involved in ischemic oligodendrocytic death, and that surviving oligodendrocytes responded and proliferated in the outer border of the infarcted area.

Topics: Animals; Astrocytes; Blood-Brain Barrier; Brain; Cell Division; Glial Fibrillary Acidic Protein; Immunoenzyme Techniques; Immunohistochemistry; In Situ Hybridization; Ischemic Attack, Transient; Macrophages; Male; Mice; Mice, Inbred C57BL; Microglia; Microtubule-Associated Proteins; Myelin Basic Protein; Myelin Proteolipid Protein; Nerve Degeneration; Nerve Tissue Proteins; Oligodendroglia; Reference Values; Reperfusion; RNA, Messenger; Serum Albumin

A rabbit antiserum (anti-EP), induced against a synthetic peptide corresponding to residues 68 to 86 of guinea pig myelin basic protein, powerfully immunostained abnormal-appearing oligodendrocytic processes and cell bodies in demyelinating areas associated with multiple sclerosis plaques. However, it failed to recognize any structures in normal human, rat, or guinea pig brain. The antiserum recognized the synthetic peptide QDENPVV, which corresponds to human myelin basic protein residues 82 to 88. Immunoabsorption with this peptide eliminated immunohistochemical staining. By contrast, several commercial antibodies recognizing nearby sequences of human myelin basic protein intensely stained all myelinated structures in both normal and multiple sclerosis tissue. The unusual epitope recognized by anti-EP appears to be accessible only in areas of myelin degeneration. If insults occur that repeatedly expose a region of MBP normally sheltered from immunosurveillance, a self-sustaining immune reaction might result.

Topics: Adult; Aged; Amino Acid Sequence; Animals; Autoantigens; Brain Chemistry; Epitopes; Female; Guinea Pigs; Humans; Immune Sera; Immunohistochemistry; Male; Middle Aged; Molecular Sequence Data; Myelin Basic Protein; Myelin Sheath; Nerve Degeneration; Rats

Macrophage recruitment into the distal nerve stump of the cut or crushed sciatic or saphenous nerves of C57BL/6J mice was reduced by prior whole body irradiation. This procedure was successful in keeping the numbers of cells stained with the mouse macrophage-specific antibody F4/80 to the levels found in unsectioned nerves. Quantitative image analysis of immunostained sections showed that the rate of loss of myelin basic protein was identical in nerves from irradiated and unirradiated mice up to 5 days but thereafter was slower in macrophage-deprived nerves. Similar analysis of semithin sections stained with toluidine blue detected more undegenerated myelin in the nerves from irradiated mice 10 days after operation. Quantitative counts made from electron micrographs of the sectioned nerves at 7 days also showed slightly less extensive myelin breakdown in the nerves from irradiated mice. Complete removal of myelin from some Schwann cells can occur without macrophages, but macrophages accelerate the removal of myelin in the later stages of Wallerian degeneration. It is concluded that there are two phases to the breakdown of myelin in peripheral nerves undergoing Wallerian degeneration: an initial stage entirely dependent on the activity of Schwann cells and a later stage dependent on both Schwann cells and the presence of macrophages.

Topics: Animals; Macrophages; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Microscopy, Electron; Myelin Basic Protein; Myelin Sheath; Nerve Degeneration; Peripheral Nerves

Experimental allergic neuritis (EAN) was induced in normal and irradiated Lewis rats by passively transferring T cells sensitized to SP-26, a peptide fragment of P2 myelin protein. The recipients became sick 4-8 days post transfer and the degree of disability correlated directly with the dose of T cells. Smaller doses caused demyelination of nerve roots and sciatic nerves and larger doses produced more severe demyelination and significant axonal degeneration. Irradiated recipients developed similar clinical EAN and showed macrophage-mediated demyelination despite severe suppression of the host inflammatory response.

Topics: Animals; Axons; Edema; Female; Immunization; Immunotherapy, Adoptive; Inflammation; Myelin Basic Protein; Myelin P2 Protein; Myelin Sheath; Nerve Degeneration; Neuritis, Autoimmune, Experimental; Peptide Fragments; Rats; Rats, Inbred Lew; Sciatic Nerve; Spinal Nerve Roots; T-Lymphocytes; Time Factors; Whole-Body Irradiation

There is suggestive but inconclusive evidence for a contribution of T cells and antimyelin antibodies to the pathogenesis of the Guillain-Barré polyneuropathy. We have studied the potential synergism of cellular and humoral immunity in the adoptive transfer model of EAN. EAN was induced in Lewis rats by injecting varying doses of P2 peptide (SP26)-sensitized T lymphocytes. Disease severity was dose-dependent. The addition of intravenous GC-AB to a subclinical dose of SP26-sensitized T cells resulted in overt clinical disease and markedly enhanced demyelination. Intravenous injection of antibody alone had no effect. We conclude that activated neuritogenic T cells, while entering into peripheral nerves, alter the blood-nerve barrier, which gives circulating demyelinating antibodies access to the endoneurium. The observations support the concept of a synergistic role of T-cell autoimmunity and humoral responses in the inflammatory demyelination of Lewis rat EAN.

Topics: Animals; Antibodies; Axons; Demyelinating Diseases; Edema; Female; Galactosylceramides; Ganglia, Spinal; Immunization, Passive; Lymphocyte Activation; Macrophages; Male; Motor Neurons; Myelin Basic Protein; Myelin P2 Protein; Nerve Degeneration; Neurilemma; Neuritis, Autoimmune, Experimental; Neurons, Afferent; Rabbits; Rats; Rats, Inbred Lew; Sciatic Nerve; Spinal Cord; Spinal Nerve Roots; T-Lymphocytes

We report here for the first time the occurrence of apoptosis of cells in the spinal cord in experimental allergic encephalomyelitis (EAE), an autoimmune, T-cell-mediated demyelinating disease. Four different forms of EAE were studied in the Lewis rat: (i) acute EAE induced by inoculation with whole spinal cord and adjuvants; (ii) acute EAE induced by inoculation with myelin basic protein (MBP) and adjuvants; (iii) acute EAE induced by the passive transfer of MBP-sensitized spleen cells; (iv) chronic relapsing EAE induced by inoculation with whole spinal cord and adjuvants followed by treatment with low-dose cyclosporin A. Cells undergoing apoptosis were recognized at light and electron microscopy by the presence of either crescentic masses of condensed chromatin lying against the nuclear envelope or rounded masses of uniformly dense chromatin. They were found in both the white and grey matter of the spinal cord in all 4 forms of this disease. Although it was not possible to identify definitively the types of cells undergoing apoptosis, the size and location of some of the affected cells suggested that they were oligodendrocytes. As there is now a large body of evidence that T-cell-induced target cell death takes the form of apoptosis, it is attractive to hypothesize that oligodendrocyte apoptosis is occurring in EAE as a result of oligodendrocyte-directed T-cell cytotoxicity. However, other apoptotic cells were located within the myelin sheath, meninges and perivascular spaces and were clearly not oligodendrocytes but were most likely blood-derived mononuclear cells. The sparsity of their cytoplasm and the absence of phagocytosed material suggested that they were mainly lymphocytes rather than macrophages. Apoptosis has been shown to be involved in deleting autoreactive T-cells during the normal development of tolerance. Thus apoptotic deletion of myelin/oligodendrocyte-specific lymphocytes in the central nervous system in EAE might explain both the subsidence of inflammation and the acquisition of tolerance in this autoimmune disease.

Topics: Animals; Cyclosporine; Demyelinating Diseases; Encephalomyelitis, Autoimmune, Experimental; Ganglia, Spinal; Immunization, Passive; Inflammation; Meninges; Microscopy, Electron; Myelin Basic Protein; Nerve Degeneration; Rats; Rats, Inbred Strains; Spinal Cord; Spleen

Three aspects of the pathophysiology of experimental autoimmune encephalomyelitis (EAE) are discussed: firstly, the possible electrophysiological effects in the CNS of myelin basic protein, which is released during demyelination; secondly, the partial degeneration of monoaminergic and glutamatergic neurons which occurs during an attack of EAE in addition to demyelination; thirdly, the importance of ischemic events, accompanied by free radical release, in EAE. Especially the third aspect could have therapeutic implications. Treatment with radical scavengers, N-methyl-D-aspartate receptor blockers, or calcium blockers (as suggested for ischemia) might prove effective for EAE. Our present aim is to investigate whether these results are also relevant for MS, for which EAE is an animal model.

Topics: Animals; Autoimmune Diseases; Brain; Encephalomyelitis, Autoimmune, Experimental; Free Radicals; Ischemia; Myelin Basic Protein; Nerve Degeneration; Neurotransmitter Agents; Rats; Synaptic Transmission

Both immunohistochemical and biochemical evidence is presented to show for the first time that carbonic anhydrase II (CA II) activity falls in the brain of mice in cuprizone (bis(cyclohexanone)oxalyldihydrazone) induced demyelination well before demyelination develops. This fall began during the first week, whereas the first signs of myelin degeneration induced by cuprizone did not appear until 3 weeks and demyelination in the superior cerebellar peduncle in the mouse took 6-8 weeks to develop. The findings suggest that oligodendrocyte CA II activity is essential either for the survival of oligodendrocytes or for the maintenance of central myelin.

Topics: Animals; Brain; Carbonic Anhydrases; Cuprizone; Demyelinating Diseases; Glial Fibrillary Acidic Protein; Male; Mice; Myelin Basic Protein; Myelin Sheath; Nerve Degeneration; Neuroglia; Oligodendroglia; Time Factors

After transection of the mouse sciatic nerve, the sequence of events occurring in the distal degenerating segment was followed by the biochemical changes related to the cytoskeletal components and to the myelin protein markers. The components of the intermediate filaments and of the microtubules undergo early changes. Within 3 days, the neurofilament triplet and the peripherin disappear whereas many peptides bearing the antigenic determinant common to all classes of intermediate filaments accumulate. Several of them persist after 1 month. The tubulin pattern changes from a high level of microheterogeneity--reflecting mostly the axonal contribution--to a lower level displayed by the predominant Schwann cells. A decrease in the amount of the myelin markers is also observed. However, a month after transection, immunoreactive basic protein is still present in the degenerated segment homogenate.

Topics: Animals; Cytoskeleton; Electrophoresis, Polyacrylamide Gel; Intermediate Filament Proteins; Isoelectric Point; Membrane Glycoproteins; Mice; Mice, Inbred CBA; Molecular Weight; Myelin Basic Protein; Myelin Proteins; Nerve Degeneration; Nerve Tissue Proteins; Neurofilament Proteins; Peripherins; Sciatic Nerve; Tubulin; Vimentin; Wallerian Degeneration

Changes of myelin proteins in mouse sciatic nerves were studied comparing nerves degenerating in situ with nerves enclosed in millipore diffusion chambers which eliminate invasion of non-resident cells. Nerves kept in chambers showed nearly complete preservation of myelin sheaths with a very slow degradation of myelin proteins. Nerves degenerating in situ showed rapid myelin phagocytosis by macrophages with almost complete disappearance of myelin proteins after 28 days. These data elucidate the role of macrophages for removal of myelin proteins.

Topics: Animals; In Vitro Techniques; Male; Mice; Mice, Inbred C57BL; Monocytes; Myelin Basic Protein; Myelin Sheath; Nerve Degeneration; Phagocytosis; Schwann Cells; Sciatic Nerve; Time Factors; Wallerian Degeneration

Topics: Adult; Brain Diseases; Child; Diagnosis, Differential; Electrophoresis; Erythrocytes; False Negative Reactions; False Positive Reactions; Humans; Immunization; Lymphocytes; Macrophages; Myelin Basic Protein; Neoplasms; Nerve Degeneration

Topics: Animals; Antigens; Electrophoresis, Polyacrylamide Gel; Encephalomyelitis, Autoimmune, Experimental; Glycoproteins; Myelin Basic Protein; Myelin Proteins; Nerve Degeneration; Peripheral Nerves; Rabbits; Radioimmunoassay; Sciatic Nerve; Wallerian Degeneration