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Painful neuropathic injuries are accompanied by robust inflammatory and oxidative stress responses that contribute to the development and maintenance of pain. After neural trauma the inflammatory enzyme cyclooxygenase-2 (COX-2) increases concurrent with pain onset. Although pre-treatment with the COX-2 inhibitor, meloxicam, before a painful nerve root compression prevents the development of pain, the pathophysiological mechanisms are unknown. This study evaluated if pre-treatment with meloxicam prior to painful root injury prevents pain by reducing spinal inflammation and peripheral oxidative stress. Glial activation and expression of the inflammatory mediator secreted phospholipase A 2 (sPLA 2 ) in the spinal cord were assessed at day 7 using immunohistochemistry. The extent of oxidative damage was measured using the oxidative stress marker, 8-hydroxyguanosine (8-OHG) and localization of 8-OHG with neurons, microglia and astrocytes in the spinal cord and peripherally in the dorsal root ganglion (DRG) at day 7. In addition to reducing pain, meloxicam reduced both spinal microglial and astrocytic activation at day 7 after nerve root compression. Spinal sPLA 2 was also reduced with meloxicam treatment, with decreased production in neurons, microglia and astrocytes. Oxidative damage following nerve root compression was found predominantly in neurons rather than glial cells. The expression of 8-OHG in DRG neurons at day 7 was reduced with meloxicam. These findings suggest that meloxicam may prevent the onset of pain following nerve root compression by suppressing inflammation and oxidative stress both centrally in the spinal cord and peripherally in the DRG., (Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.)

Objective: To explore the effects of sacral canal injection on nerve root local inflammatory factors in rat model with lumbar disc herniation, in order to identify its mechanism of treatment., Methods: Forty-eight male SD rats were randomly divided into sham operation group(group A), model group (group B), Chinese medicine group(group C) and western medicine group(group D). There were 12 rats in each group. The model of lumbar disc herniation was established using compression and inflammatory stimulation in group B, C, D. All rats were given epidural catheterization and group A and B with physiological saline (1 ml/kg), group C with mixed liquor of 2% lidocaine and compound Danshen injections and physiological saline (2:2: 16) and group D with mixed liquor of 2% lidocaine and triamcinolone acetonide injection and physiological saline (2:2:16), once a week for a total of three treatments. Four rats were killed every 1 week after injection for once, and the inflammatory factors of tumor necrosis factor (TNF-alpha), prostaglandin E2 (PGE2), interleukin-l (IL-1) and interleukin-6 (IL-6) were detected by ELISA method., Results: The levels of TNF-alpha, PGE2, IL-1 and IL-6 in compressed nerve tissues in group B were increased than those of group A (P < 0.01). The levels of PGE2, IL-1 and IL-6 in group C and D were decreased than those of group B, and group D was much less(P<0.05). There was no significant difference in level of TNF-alpha among group B, C, D (P > 0.05)., Conclusion: Compound compression with inflammatory stimulation can lead to massive release of inflammatory mediators, such as TNF-alpha, PGE2, IL-1 and IL-6. Both injection with compound Danshen injections and triamcinolone acetonide injections by sacral canal can reduce the levels of part inflammatory mediators (PGE2, IL-1 and IL-6), and the effect of Glucocorticoid is better than Danshen (P < 0.05).

Guillain-Barré syndrome (GBS) is one of the reasons of acute polyneuropathy causing severe morbidity and mortality. Forty-six patients with GBS were included in our study. Clinical, laboratory, electrophysiological and prognostic features of the patients were evaluated retrospectively. Patients were divided into two groups. Group A consisted of children who attained a full recovery within 2 months from onset of the disease; group B consisted of children who experienced complete or partial recovery beyond 2 months from onset of the disease. Acute inflammatory demyelinating polyradiculoneuropathy was found in 56.5% of patients and axonal form in 43.5% patients. Antecedent events were found in 28 (60.9%) patients. Five patients (10.8%) needed mechanical ventilation and one patient (2.1%) died. Poor outcome was related with clinic stage and electrophysiological subtypes (axonal form). In our study, poor prognostic factors were related with clinic stage and electrophysiological subtypes (axonal form).

Purpose: Nerve root traction injuries induce spinal cord inflammation and lead to neuronal death within days. In the present study, we examined the inflammatory response one week after multiple cervical root transections., Methods: In the transection group, the left cervical roots (C6-8) of rats were cut at the spinal cord junction. In the repair group, transected roots were repaired with nerve grafts and the subsequent application of aFGF and fibrin glue. A sham group had nerve roots exposed without transection. Mechanical allodynia and spinal glial responses were evaluated., Results: Allodynia did not differ between the treatment groups on day 2. Rats with transected spinal nerve roots had significantly more allodynia by 7 days, which was associated with IL-1β expression in dorsal and ventral horn astrocytes, and microglia activation. Repair of nerve roots with autologous intercostal nerve grafts and FGF in fibrin glue attenuated the allodynia, reduced IL-1β expression in astroctyes and reduced microglia activation, along with a significant increase in arginase I expression., Conclusion: This study demonstrated a correlation between an increased number of IL-1β-positive astrocytes and the development of allodynia. Our treatment significantly decreased IL-1β-positive astrocytes, thus preventing the occurrence of neuropathic pain following multiple cervical root injuries.

Background: Inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-alpha) are pleiotropic molecules with widespread action in autoimmune diseases., Objective: This study characterizes the distribution of iNOS and TNF-alpha in the spinal nerve roots, dorsal root ganglia and sciatic nerve of Lewis rats during experimental autoimmune neuritis (EAN)., Methods: Macrophages and neutrophils were identified by immunofluorescence as cellular sources of iNOS and TNF-alpha at various stages of EAN induced by synthetic peptide 26., Results: As the disease progressed, iNOS- and TNF-alpha-bearing cells gradually infiltrated the cauda equina, dorsal root ganglia, Th12-L3 spinal roots, and the sciatic nerve. A severer EAN profile developed when more iNOS- and TNF-alpha-bearing cells were present, and the recovery from EAN was related to the disappearance of these cells and the regeneration of nerve fibers., Conclusions: This is the first report to show iNOS- and TNF-alpha-immunoreactive cells in dorsal root ganglia during EAN, suggesting an underlying pathology for the neuropathic pain behavior in EAN. Our results suggest that the cells bearing iNOS and TNF-alpha in the different parts of the peripheral nervous system are involved in the development of the clinical signs observed at each stage of EAN., (Copyright 2009 S. Karger AG, Basel.)

Peripheral nervous system involvement is common in Sjögren's syndrome (SS); however, polyradiculopathy has been reported rarely in association with SS, and predominantly chronic forms have been described. We describe a patient with clinical, cerebrospinal fluid, neurophysiological, and neuroradiological evidence of subacute inflammatory polyradiculopathy in whom Sjögren's syndrome was diagnosed after the onset of neurological symptoms. Our case suggests that SS should be included in the differential diagnosis of subacute inflammatory polyradiculopathy.

Experimental autoimmune neuritis (EAN) is a well-known animal model of Guillain-Barré Syndrome. In this study, we studied the spatiotemporal expression of interleukin-16 (IL-16) in the nervous system of EAN rats and pharmacological effects of minocycline on IL-16 expressions in EAN rats. In sciatic nerves and dorsal/ventral roots of EAN rats, IL-16+ cells, identified as macrophages and T cells, were mainly found to concentrate around blood vessels. However, in spinal cords, IL-16+ microglial cells were mainly found in lumbar dorsal horns. Massive IL-16+ cell accumulation in sciatic nerves and spinal roots was temporally correlated with severity of neurological signs of EAN. Furthermore, a strong correlation of IL-16+ cell accumulation with local demyelination in perivascular areas of sciatic nerves, and significant reduction of IL-16+ cell numbers in sciatic nerves and spinal cords by minocycline suggested a pathological contribution of IL-16+ cells in EAN. Taken together, robust IL-16+ cell accumulation in the nervous system and its temporal correlation with severity of neurological signs in EAN might suggest a pathological role of IL-16 in EAN, which makes IL-16 a potential pharmacological target.

Objective: To explore the mechanism of acupuncture for treatment of lumbar nerve root compression injury., Methods: Fifty healthy SD rats were randomly divided into 5 groups, a normal group, a model group treated by saline, a medication group treated with Caerulein, an acupuncture group treated with acupuncture at L5, L6 Jiaji (EX-B 2) and a warm needle group treated with acupuncture and moxibustion at L5, L6 Jiaji (EX-B 2). The lumbar nerve root compress injury model was made by placing microsilica gel tablet. After they were treated for 14 days, the compressed nerve root was taken and the ultra-microstructure changes of the injured nerve root were observed by electron microscope and changes of nitric oxide synthase (NOS) and calcitonin gene-related peptide (CGRP) expressions were investigated by ELISA assay., Results: The changes of ultra-microstructure of the nerve root were the most obvious in the model group and the changes in the medication group, the acupuncture group and the warming needle group reduced in order; the NOS activity and CGRP content in the nerve root tissue of the compressed area in the warm needle group were significantly reduced as compared with the model group (P < 0.05), but with no significant difference as compared with those in the normal group (P > 0.05)., Conclusion: Warm needle treatment can effectively maintain cellular form, and ultra-microstructures of nerve root dorsal root ganglia, and effectively inhibit the release of inflammatory factors NOS and CGRP.

Both chemical irritation and mechanical compression affect radicular pain from disc herniation. However, relative effects of these insults on pain symptoms are unclear. This study investigated chemical and mechanical contributions for painful cervical nerve root injury. Accordingly, the C7 nerve root separately underwent chromic gut exposure, 10gf compression, or their combination. Mechanical allodynia was assessed, and glial reactivity in the C7 spinal cord tissue was assayed at days 1 and 7 by immunohistochemistry using GFAP and OX-42 as markers of astrocytes and microglia, respectively. Both chromic gut irritation and 10gf compression produced ipsilateral increases in allodynia over sham (p<0.048); combining the two insults significantly (p<0.027) increased ipsilateral allodynia compared to either insult alone. Behavioral hypersensitivity was also produced in the contralateral forepaw for all injuries, but only the combined insult was significantly increased over sham (p<0.031). Astrocytic activation was significantly increased over normal (p<0.001) in the ipsilateral dorsal horn at 1 day after either compression or the combined injury. By day 7, GFAP-reactivity was further increased for the combined injury compared to day 1 (p<0.001). In contrast, spinal OX-42 staining was generally variable, with only mild activation at day 1. By day 7 after the combined injury, there were significant (p<0.003) bilateral increases in OX-42 staining over normal. Spinal astrocytic and microglial reactivity follow different patterns after chemical root irritation, compression, and a combined insult. The combination of transient compression and chemical irritation produces sustained bilateral hypersensitivity, sustained ipsilateral spinal astrocytic activation and late onset bilateral spinal microglial activation.

Numerous CNS diseases of primarily non-inflammatory origin, such as idiopathic neurodegenerative diseases, contain elements of inflammation, with T cell infiltration, MHC class II expression and neuron/axon damage. Gene mapping in human clinical materials have in most cases failed to unravel discrete genes, since most genes instrumental in non-Mendelian forms of these complex diseases are likely to modestly affect risk, be evolutionary conserved in the population and vary between individuals. We here describe the exploration of susceptibility to neurodegeneration and inflammatory glial activation in response to mechanical nerve injury using experimental genetic models. The response to ventral root avulsion, which is a simple and reproducible model of nerve injury-induced neurodegeneration and inflammation, was examined in a panel of inbred rat strains. A whole genome scan subsequently performed in a F2(DAxPVG) intercross identified quantitative trait loci (QTLs) regulating different features of the nerve injury response. Fine mapping in an advanced intercross line revealed polymorphisms in the Mhc2ta gene as being responsible for strain differences in MHC class II expression. Furthermore, a polymorphism in the syntenic human gene, MHC2TA, was associated both with lower expression of MHC class II-associated genes and increased susceptibility to inflammatory diseases. These results provide important insights into the genetic regulation of fundamental physiological responses of the nervous system to damage and demonstrate relevance also for human diseases.

RhoA is one of the best-studied members of Rho GTPases. Experimental autoimmune neuritis (EAN), which is characterized by infiltration of T cells and macrophages into the peripheral nervous system, is an autoantigen-specific T-cell-mediated animal model of human Guillain-Barré Syndrome. In this study, RhoA expression has been investigated in the dorsal/ventral roots of EAN rats by immunohistochemistry. A significant accumulation of RhoA+ cells was observed on Day 12, with a maximum around Day 15, correlating to the clinical severity of EAN. In dorsal/ventral roots of EAN, RhoA+ cells were seen in perivascular areas but also in the parenchyma. Furthermore, double-labelling experiments showed that the major cellular sources of RhoA were reactive macrophages and T cells. In conclusion, this is the first demonstration of the presence of RhoA in the dorsal/ventral roots of EAN. The time courses and cellular sources of RhoA together with the functions of RhoA indicate that RhoA may function to facilitate macrophage and T-cell infiltration in EAN and therefore could be a potential therapeutic target.

Background: Acute disseminated encephalomyelitis (ADEM) refers to a monophasic acute multifocal inflammatory CNS disease. However, both relapsing and site-restricted variants, possibly associated with peripheral nervous system (PNS) involvement, are also observed, and a systematic classification is lacking., Objective: To describe a cohort of postinfectious ADEM patients, to propose a classification based on clinical and instrumental features, and to identify subgroups of patients with different prognostic factors., Methods: Inpatients of a Neurologic and Infectious Disease Clinic affected by postinfectious CNS syndrome consecutively admitted over 5 years were studied., Results: Of 75 patients enrolled, 60 fulfilled criteria for ADEM after follow-up lasting from 24 months to 7 years. Based on lesion distribution, patients were classified as encephalitis (20%), myelitis (23.3%), encephalomyelitis (13.3%), encephalomyeloradiculoneuritis (26.7%), and myeloradiculoneuritis (16.7%). Thirty patients (50%) had a favorable outcome. Fifteen patients (25%) showed a relapsing course. Poor outcome was related with older age at onset, female gender, elevated CSF proteins, and spinal cord and PNS involvement. All but two patients received high-dose steroids as first-line treatment, with a positive response in 39 (67%). Ten of 19 nonresponders (53%) benefited from high-dose IV immunoglobulin; 9 of 10 had PNS involvement. The data were not controlled., Conclusions: A high prevalence of "atypical variants" was found in this series, with site-restricted damage or additional peripheral nervous system (PNS) involvement. Prognosis and response to steroids were generally good, except for some patient subgroups. In patients with PNS involvement and steroid failure, a favorable effect of IV immunoglobulin was observed.

We investigated the localization of GalNAc-GD1a biochemically in the human and bovine peripheral nervous system (PNS). The high-performance thin-layer chromatography (HPTLC)-overlay method with rabbit IgG polyclonal antibody against GalNAc-GD1a (anti-GalNAc-GD1a antibody) revealed expression of GalNAc-GD1a in the ventral spinal nerve roots (VRs) but not in the dorsal spinal nerve roots (DRs) of both species. The amount of GalNAc-GD1a in the human and bovine VRs was 2.22 +/- 0.35 microg/g wet tissue and 7.71 +/- 0.49 microg/g wet tissue, respectively. These results suggest that IgG anti-GalNAc-GD1a antibody may be involved in disturbance of peripheral motor nerves and in the pathogenesis of pure motor neuropathy.

Molecular mimicry between microbial and self-components is postulated as the mechanism that accounts for the antigen and tissue specificity of immune responses in postinfectious autoimmune diseases. Little direct evidence exists, and research in this area has focused principally on T cell-mediated, antipeptide responses, rather than on humoral responses to carbohydrate structures. Guillain-Barré syndrome, the most frequent cause of acute neuromuscular paralysis, occurs 1-2 wk after various infections, in particular, Campylobacter jejuni enteritis. Carbohydrate mimicry [Galbeta1-3GalNAcbeta1-4(NeuAcalpha2-3)Galbeta1-] between the bacterial lipooligosaccharide and human GM1 ganglioside is seen as having relevance to the pathogenesis of Guillain-Barré syndrome, and conclusive evidence is reported here. On sensitization with C. jejuni lipooligosaccharide, rabbits developed anti-GM1 IgG antibody and flaccid limb weakness. Paralyzed rabbits had pathological changes in their peripheral nerves identical with those present in Guillain-Barré syndrome. Immunization of mice with the lipooligosaccharide generated a mAb that reacted with GM1 and bound to human peripheral nerves. The mAb and anti-GM1 IgG from patients with Guillain-Barré syndrome did not induce paralysis but blocked muscle action potentials in a muscle-spinal cord coculture, indicating that anti-GM1 antibody can cause muscle weakness. These findings show that carbohydrate mimicry is an important cause of autoimmune neuropathy.

Study Design: This study is to investigate the intraradicular inflammation induced by mechanical compression using in vivo model., Objectives: The relationship between the intraradicular edema and nerve fiber degeneration induced by mechanical compression was determined in the nerve root., Summary of Background Data: Recently some studies reported that mechanical compression increased microvascular permeability of the endoneurial capillaries and resulted in an intraradicular inflammation. These changes may be an important factor of the pathogenesis of radiculopathy. However, the natural courses of the intraradicular inflammation after mechanical compression are still poorly understood., Methods: In dogs, laminectomy was performed at L7 and the seventh nerve root was exposed to compression at 7.5 gram force (gf) clipping power. The animals were evaluated at 1 and 3 weeks after clipping. After the appropriate period of nerve root compression, Evans blue albumin (EBA) was injected intravenously. The nerve root sections were divided into two groups. The sections were used to investigate the status of the blood-nerve barrier function under the fluorescence microscope. The other sections were used for light and transmission electron microscopic study., Results: After 1 and 3 weeks, intraradicular edema was observed not only at the site of compression but also in the peripheral zone of a compressed anterior root and in the central zone of a compressed posterior root. The evidence of active Wallerian degeneration was also seen in the area of intraradicular edema. In addition, the nerve roots showing Wallerian degeneration were infiltrated by inflammatory cells, such as macrophages and mast cells., Conclusions: Inflammatory reaction, such as Wallerian degeneration, breakdown of blood-nerve barrier and appearance of macrophage, may be deeply involved in radiculitis arising from mechanical compression, and these factors seem to be important in the manifestation of radiculopathy.

Macrophages in the periaxonal space and surrounding intact myelin sheath are the most prominent pathological feature of acute motor axonal neuropathy (AMAN). We describe this characteristic in nerve roots from paralyzed rabbits immunized with bovine brain ganglioside or GM1. IgG was deposited on nerve root axons. Distal nerve conduction was preserved, and late F wave components were absent during the acute phase. Initial lesions were located mainly on nerve root axons, as in human AMAN. This study thus provides supportive evidence that the rabbits constitute a model of AMAN.

Background: The authors previously reported that immunoglobulin G (IgG) antibody to the ganglioside N-acetylgalactosaminyl GD1a (GalNAc-GD1a) is associated with the pure motor variant of Guillain-Barré syndrome (GBS). Elucidation of the localization of GalNAc-GD1a in human peripheral nerve tissue may lead to understanding of the pathogenetic role of anti-GalNAc-GD1a antibody in GBS., Methods: IgG anti-GalNAc-GD1a-monospecific antibody was purified from anti-GalNAc-GD1a antibody-positive rabbit sera through an affinity column. Anti-neurofilament-200 monoclonal and anti-HNK-1 monoclonal antibodies were used as the markers for axon and myelin. Immunohistochemical study using double fluorescence labeling technique was conducted in human ventral roots (VR), dorsal roots (DR), intramuscular nerves, and sural nerves. Human teased ventral fibers also were studied., Results: Anti-GalNAc-GD1a antibody immunostained an inner part of compact myelin and additionally a periaxonal-axolemma-related portion in the VR, small-diameter DR fibers, and IM nerves. In sural nerves, small fibers were selectively stained. In VR, the staining was localized in the paranodal region., Conclusion: Anti-GalNAc-GD1a antibodies in patients' sera may bind to those regions in the VR and IM nerves where GalNAc-GD1a is localized, and may function in the pathogenesis of pure motor type GBS. Further investigation is needed to explain the discrepancy between the immunolocalization of GalNAc-GD1a in sensory nerves and the absence of sensory disturbance in patients with GBS with IgG anti-GalNAc-GD1a antibodies.

The efficacy of plasma exchange as a therapy for Guillain-Barré syndrome (GBS) suggests that humoral factors might contribute to the axonal conduction block responsible for the major symptoms of the disease. To explore this possibility, we have applied sera to rat spinal roots in vitro while monitoring axonal conduction. Neither fresh sera from 12 patients with GBS or Miller-Fisher syndrome (MFS), nor serum from rabbits immunised with Campylobacter jejuni from patients with GBS, MFS or gastroenteritis were effective in causing acute conduction block, despite the presence of antibodies to gangliosides GD3, GM1, GQ1b and GT1a. Potential explanations are advanced.

Leukemia inhibitory factor (LIF) is a pleiotropic cytokine that exerts neurotrophic and myotrophic actions. We have investigated the effect of LIF in experimental autoimmune neuritis (EAN), an animal model of Guillain-Barré syndrome (GBS). Treatment with LIF at the onset of the disease showed a slight, but not significant, improvement in the clinical course but no effect on nerve histology.

At the onset of Guillain-Barré syndrome, disruption of diffusion barriers, such as the blood-nerve barrier, probably increases the exposure of spinal roots and peripheral nerves to macromolecules, some of which might be pathogenic. As a measure of such disruption, we measured the accumulation in the endoneurium of spinal roots and sciatic nerve of systemically administered 125I-labelled immunoglobulin in adoptive transfer experimental autoimmune neuritis (AT-EAN) in the rat. AT-EAN is a model of Guillain-Barré syndrome, induced by injection of activated T lymphocytes sensitized to myelin P2 protein. Immunoglobulin accumulation was expressed as counts/min/mg in fixative-perfused roots as a percentage of that in serum, measured 24 h after intraperitoneal injection of 0.1 micro Ci 125I-labelled immunoglobulin. Immunoglobulin accumulation in the roots of normal rats was 3 +/- 1% (mean +/- SE), but this first increased 3(1/2) days after cell injection, peaked at 22 +/- 2% on day 4(1/2), and declined to normal by day 8. T lymphocytes and polymorphonuclear leucocytes first appeared within the endoneurium at day 3(1/2), and macrophages and a few erythrocytes at day 4. Neurological deficit appeared on day 4 and was maximal on day 6. Demyelination and axonal degeneration began at day 5. The first abnormality detected in AT-EAN was a rapid increase in the passage of immunoglobulin into spinal roots, together with endoneurial infiltration of T lymphocytes and polymorphonuclear leucocytes. Accumulation of immunoglobulin was maximal during the worsening of neurological deficit, and declined rapidly before the onset of neurological recovery.

Chronic pain can occur after peripheral nerve injury, infection, or inflammation. Under such neuropathic pain conditions, sensory processing in the affected body region becomes grossly abnormal. Despite decades of research, currently available drugs largely fail to control such pain. This review explores the possibility that the reason for this failure lies in the fact that such drugs were designed to target neurons rather than immune or glial cells. It describes how immune cells are a natural and inextricable part of skin, peripheral nerves, dorsal root ganglia, and spinal cord. It then examines how immune and glial activation may participate in the etiology and symptomatology of diverse pathological pain states in both humans and laboratory animals. Of the variety of substances released by activated immune and glial cells, proinflammatory cytokines (tumor necrosis factor, interleukin-1, interleukin-6) appear to be of special importance in the creation of peripheral nerve and neuronal hyperexcitability. Although this review focuses on immune modulation of pain, the implications are pervasive. Indeed, all nerves and neurons regardless of modality or function are likely affected by immune and glial activation in the ways described for pain.

Antidisialosyl antibodies have been previously associated to chronic and acute ataxic neuropathies. We studied the presence of these antibodies in nine patients with acute self-limiting ataxic neuropathy (ASLAN) using ELISA and TLC immunodetection. One patient showed serum IgG immunoreactivity against gangliosides GD3 and GQ1b. The patient's IgG was able to bind to the nodes of Ranvier on frozen human dorsal root. Our studies confirmed that antidisialosyl reactivity is associated to ataxic neuropathy and its specific binding to the dorsal root could explain the predominant sensory involvement. Nevertheless, the low incidence of this reactivity indicates that a different pathogenic mechanism should be involved in most ASLAN patients.

To investigate whether antibodies are pathogenic in Guillain-Barré syndrome (GBS), we injected pre-treatment serum from 11 GBS patients intraperitoneally into rats in which the blood-nerve barrier had been opened by induction of mild adoptive transfer experimental autoimmune neuritis. There was no significant clinical, neurophysiological or pathological difference between rats receiving GBS serum compared with those receiving control serum, except that GBS serum caused minor excess weight loss. Murine monoclonal antibody to Campylobacter jejuni and gangliosides also did not exacerbate disease. This experiment failed to show antibody-mediated disease exacerbation and so does not support an antibody-mediated mechanism in GBS.

Inherited demyelinating neuropathies are chronically disabling human disorders caused by various genetic defects, including deletions, single site mutations, and duplications in the respective myelin genes. We have shown in a mouse model of one distinct hereditary demyelinating neuropathy (heterozygous P0-deficiency, P0+-) that an additional null mutation in the recombination activating gene-1 (RAG-1--) leads to a substantially milder disorder, indicating a disease modifying role of T-lymphocytes. In the present study, we addressed the role of lymphocytes in the mouse model by reconstituting bone marrow of P0+-/RAG-1-- mice with bone marrow from immunocompetent wild-type mice. We compared the pathology and nerve conduction in double mutant mice (P0+-/RAG-1-- on a C57BL/6 background) with that in double mutants after receiving a bone marrow transplant. We found that the milder demyelination seen in the lymphocyte-deficient P0+-/RAG-1-- mutants was reverted to the more severe pathology by reestablishing a competent immune system by bone marrow transfer. These data corroborate the concept that the immune system contributes substantially to the pathologic process in this mouse model and may open new avenues to ameliorate human hereditary neuropathies by exploiting immunosuppressive treatments., (Copyright 2001 Academic Press.)

T lymphocytes of the Th1 subset producing the proinflammatory cytokine interferon-gamma (IFN-gamma) have been implicated in the pathogenesis of immune-mediated diseases of the peripheral nervous system (PNS) such as the acute Guillain-Barré syndrome (GBS) and its animal model experimental autoimmune neuritis (EAN). Interleukin-18 (IL-18) is a potent IFN-gamma-inducing cytokine that is synthesized as an inactive precursor molecule and cleaved by caspase-1 into its mature active form. In our present study we analyzed the expression of IL-18 and caspase-1 in the nerve roots of EAN rats using reverse transcriptase-polymerase chain reaction and immunocytochemistry. Using an enzyme-linked immunosorbent assay, we furthermore determined IL-18 protein levels in paired serum and cerebrospinal fluid (CSF) samples from patients with GBS as well as from noninflammatory neurologic disease (NIND) controls. In EAN, IL-18 and caspase-1 mRNA levels in the nerve roots increased during the stage of active disease progression. Immunocytochemically, both perivascular and parenchymal IL-18 protein expression was increased in the roots of EAN rats and mainly associated with ED1+ macrophages stained on serial sections. IL-18 serum levels were significantly higher in GBS patients than in NIND controls (238+/-71 vs. 42+/-7 pg/ml, P<0.001). Our data implicate the Th1-inducing cytokine IL-18 in the pathogenesis of acute immune-mediated PNS demyelination.

Study Design: Possible statistically significant relationships between inflammatory cells and either motor weakness or straight leg raising were determined., Objectives: To look for any clinically relevant links between inflammatory cells in disc herniations and signs of radiculopathy., Summary of Background Data: Many studies have during recent years shown a presence of various types of inflammatory cells in disc herniations, but their clinical relevance has been questioned. To be clinically relevant, a presence of inflammatory cells should show a clear relationship to clinical evidence of nerve root involvement. Macrophages repeatedly demonstrated in a high proportion of disc herniations studied are of particular interest. Their major role may be in disc herniations tissue resorption and not in sciatica., Methods: A total of 96 disc herniations, all transligamentous, were analyzed by immunohistochemistry for presence of macrophages, T or B lymphocytes, and activated T lymphocytes separately. From recorded patient data, motor weakness and straight leg raising data were compared with a presence or absence of abundant (+ = at least 20 cells in a group) inflammatory cells. When not abundant, inflammatory cells were classified as "only few cells" (+) and grouped together with "no cells" (-). Patients with or without motor weakness were compared. Straight leg raising was compared for a positive (at <70 degrees ) or a negative test, and separately using the median as cut-off value. Groups were compared by chi-square analysis with the level of statistical significance set at P<0.05., Results: None of the four inflammatory cell types showed any significant association with motor weakness. Nor was any association observed when comparing positive and negative straight leg raising. With the median (straight leg raising = 47.5 degrees ) as cut-off, only activated T cells showed a weak (chi2 = 4.40, P<0.05) relationship with tighter straight leg raising, but none of the other cell types did. Even when straight leg raising was < 47.5 degrees, three times more disc herniations lacked (n = 34) inflammatory cells than showed (n = 13) inflammation. In a subgroup of only sequestrated discs, the findings were similar. However, in the patients with a bilaterally positive straight leg raising (n = 25), the prevalence of at least one inflammatory cell type was much higher in sequestrated discs (80%) than in extrusions (33%). This may suggest more subtle interrelationships between type of disc herniation, straight leg raising, and inflammatory cells., Conclusions: The results of this study do not support a clinically relevant role for disc herniation inflammatory cells in sciatica. For the cells to be clinically relevant, a strong relationship between a presence of inflammatory cells and either or both of motor weakness and a tight straight leg raising should have been observed. The authors conclude that macrophages, which have been demonstrated in a high proportion of disc herniations in previous studies, are probably more important for disc tissue resorption processes than for producing sciatica. Other types of inflammatory cells are more rarely observed and may have no clinical meaning at all. However, more subtle interrelationships, considering the various types of disc herniations, should be further explored.

Autoimmune responses to the myelin-associated glycoprotein (MAG) are implicated in the immunopathogenesis of both multiple sclerosis (MS) and certain peripheral neuropathies. In this study we demonstrate that T cell responses to defined epitopes of MAG mediate a pathological inflammatory response in the nervous system of the Lewis rat. Peptide-specific T cells were generated against four different MAG epitopes, three of which are common to both L- and S-isoforms of MAG (amino acid (a.a.) sequence: 20-34, 124-137, 354-377) whilst the fourth epitope (a.a. sequence: 570-582) is located in the C-terminal sequence of S-MAG. The adoptive transfer of T cells specific for these epitopes initiated a mild but dose-dependent inflammatory response in the central nervous system (CNS) of naive recipients. Clinical disease was only observed in those animals injected with T cells specific for the a.a. sequence 20-34 (MP1.1), which also initiated an inflammatory response in the peripheral nervous system (PNS). Co-transfer of MP1.1 (a.a. sequence 20-34)-specific T cells with the myelin oligodendrocyte glycoprotein (MOG)-specific monoclonal antibody 8-18C5 enhanced disease severity and induced widespread demyelination in the CNS. In contrast, co-transfer of T cells with the MAG-specific mAb 513 failed to induce demyelination, but had a moderate effect on the local inflammatory response. The ability of MAG to initiate an autoaggressive T cell response in the Lewis rat supports the concept that MAG-specific autoimmune responses may play a role in the pathogenesis of immune mediated diseases of the nervous system in man.

A patient with anti-Hu antibodies, small-cell lung carcinoma, and autopsy-proven subacute sensory neuropathy had early slowing of motor and sensory conduction velocities. In the peripheral nerves, chronic demyelinating and remyelinating lesions with axonal degeneration were associated with an inflammatory reaction consisting of CD8+ T cells and CD68+ macrophages. On immunohistochemical testing, the patient's serum did not react with normal nerve, suggesting that the Hu proteins were not the target of the inflammatory reaction in the nerve.

A series of monoclonal IgM anti-GM1 ganglioside antibodies has been cloned from peripheral blood lymphocytes of patients with multifocal motor neuropathy and Guillain-Barré syndrome. In solid-phase immunoassay, the antibodies react with GMI, and also in differing degrees to the structurally related glycolipids asialo-GM1 (GA1) and GD1b. Here we describe the binding patterns of six human anti-GM I antibodies to epitopes within the human nervous system. Antibodies were observed to bind to motor neurons and spinal grey matter, dorsal and ventral spinal roots, dorsal root ganglion neurons, nodes of Ranvier, neuromuscular junctions and skeletal muscle. The distribution of immunoreactive epitopes, which included sensory structures, extended beyond those sites conventionally regarded as pathologically affected in anti-GM1 antibody-associated motor nerve syndromes. This undermines a model of disease pathogenesis based solely on antigen distribution. Factors other than the presence or absence of antigen, such as the local ganglioside topography, antibody penetration into, and pathophysiological vulnerability of a particular site may also influence the clinicopathological outcome of anti-GM1 antibody-mediated autoimmune attack.

To further investigate the role of complement activation in Experimental Allergic Neuritis (EAN), the effect of systemic complement blockade by soluble CR1 (sCR1) was compared to complement depletion by Cobra Venom Factor (CVF) in EAN rats immunized with bovine peripheral nerve myelin. EAN rats treated with CVF (n = 10) had significantly reduced clinical scores compared to rats treated with sCR1 (n = 9) or saline (n = 10) (score: sCR1 0.66 +/- 0.7; CVF 0; saline 0.6 +/- 0.8; mean +/- SD). CVF treatment more effectively decreased inflammation and demyelination compared to sCR1 treatment which had only a partial effect (inflammation: sCR1 1.8 +/- 1.4; CVF 0.3 +/- 0.7; saline 1.9 +/- 1.2; demyelination; sCR1 1.3 +/- 1; CVF 0.1 +/- 0.6; saline 1.7 +/- 1.2). In lumbosacral nerve roots significantly less infiltrating ED1 positive macrophages and CD11bc (expressing complement receptor 3 or CR3) positive inflammatory cells were present in CVF treated EAN rats while there was a limited decrease in inflammation in the sCR1 treated animals compared to the saline treated rats (ED1: sCR1 1.4 +/- 1.2; CVF 0.5 +/- 0.6; saline 1.7 +/- 1.2; CD11bc: sCR1 1.9 +/- 1.2; CVF 0.9 +/- 1; saline 2.1 +/- 1.2). Our findings suggest that complement depletion by CVF is more effective than complement blockade by sCR1 in reducing the severity of inflammatory peripheral nerve demyelination.

Human immunoglobulin is an effective treatment for Guillain-Barré syndrome, although the mechanism of action is not understood. We have investigated the effect of human immunoglobulin in an animal model of Guillain-Barré syndrome, namely experimental autoimmune neuritis (EAN), induced in Lewis rats by immunization with bovine spinal root myelin. Human immunoglobulin administered intraperitoneally at the time of onset of disease accelerated the rate of recovery from EAN. This improvement was associated with a reduction in the titre of anti-rat myelin antibodies and may be due to earlier remyelination of demyelinated nerve fibres. This model may facilitate further investigation of the mechanism of therapeutic action of immunoglobulin in inflammatory neuropathy.

The localization, mode of action, and roles of complement in the Guillain-Barre syndrome have been controversial. We used high-resolution immunocytochemistry to localize complement activation products in early stages of the acute inflammatory demyelinating polyneuropathy (AIDP) pattern of Guillain-Barre syndrome. Three AIDP subjects who were autopsied had had symptoms for 3 to 9 days at the time of death. Immunocytochemistry was performed on etched, epoxy resin-embedded sections, and the next thin section was compared by electron microscopy (thick/thin sections). Many fibers had a rim of the complement activation marker C3d and the terminal complement complex neoantigen C5b-9 along the outer surface of the Schwann cells. Ultrastructural analysis of these C3d-positive fibers showed mild vesicular changes of the outermost myelin lamellae. Vesicular degeneration was seen before the invasion of macrophages into the myelin, and was the predominant change in the subject with symptoms for 3 days. C3d staining was not found on myelin membranes. The results suggest that at least some forms of AIDP are complement mediated. We speculate that complement is activated by antibody bound to epitopes on the outer surface of the Schwann cell and that the resulting complement activation initiates the vesiculation of myelin.

Study Design: Human arachnoid cells were examined immunohistochemically for expression of HLA-DR or Fc receptors., Objective: To assess the ability of arachnoid cells to express HLA-DR and act as antigen presenting cells., Summary of Background Data: An intradural inflammatory reaction surrounds the cervical nerve roots and radicular vessels in patients with spondylotic cervical myeloradiculopathy. Active arachnoid proliferation and fibrosis in this reaction suggest these cells are actively involved in this inflammatory process. An inflammatory response is initiated by an antigen presenting cell. Evidence suggests that arachnoid cells may be antigen presenting cells, like macrophages, because they can phagocytize foreign tissue and have immunoglobulin G and complement receptors., Methods: Spinal arachnoid obtained from patients undergoing spinal surgery for intramedullary processes was grown in culture. The arachnoid cells were characterized and examined immunohistochemically for the expression of HLA-DR and Fc receptors., Results: HLA-DR was expressed in vivo and in vitro by arachnoid cells. The macrophage Fc receptor was not expressed in vivo nor in vitro by arachnoid cells., Conclusion: Finding in vivo and in vitro HLA-DR expression on arachnoid cells adds further support to the concept that arachnoid cells have the potential to serve as antigen presenting cells. The absence of Fc receptors, although necessary for macrophages, does not negate antigen presenting function because other types of cells-e.g., endothelium-can present antigen without displaying Fc receptors. These experiments provide new evidence that arachnoid cells may initiate or sustain the intradural inflammatory reaction found in cervical myeloradiculopathy.

The cell bodies and proximal dendrites of postsynaptic dorsal column neurons were examined for synaptic boutons which displayed immunoreactivity for the principal excitatory and inhibitory neurotransmitters, glutamate and GABA. The neurons were labelled by retrograde transport of horseradish peroxidase and GABA or glutamate-containing boutons were revealed by performing postembedding immunogold reactions on electron microscope sections. Five neurons were examined and all of them were postsynaptic to boutons which contained either GABA or glutamate. Quantitative analysis of two of the cells revealed that more than 90% of the synaptic profiles associated with them displayed immunogold reactions for these transmitters. Analysis of series of alternate sections, which were reacted for either GABA or glutamate, showed that there was no overlap in the populations of immunoreactive boutons. Furthermore, GABA and glutamate immunoreactions were associated with boutons which had different morphological characteristics. In addition, some large glutamate-enriched boutons were postsynaptic to small boutons which displayed immunogold reactions for GABA. This study demonstrates morphological bases for direct excitation, postsynaptic inhibition and presynaptic inhibition of postsynaptic dorsal column cells.

Biochemical, immune and morphological changes in peripheral nervous system at different stages of experimental allergic polyradiculoneuritis were studied in 102 rabbits as indicated by total lipids, cholesterol, phospholipids and their fractions, diene conjugates of spinal ganglions, cervical, thoracic and lumbosacral roots, trigeminal ganglions and nerve trunks of extremities. It was found out, that derangement of lipid metabolism in spinal ganglions and nerve roots is the primary phase in the development of the disease. Those could be seen as early as the experiment day 6. From the 8th day after the injection of antigen (myelin in complete Freund adjuvant) impairment of protective function of blood-nerve barrier took place in the form of increased vascular permeability of spinal ganglions, roots and trigeminal ganglions. Fixed antibodies, located on myelin sheath predominantly of intraganglion fibres of lumbar, cervical and thoracic segments, trigeminal ganglions, appeared after these changes. Demyelination and inflammatory infiltration began in the end of the incubation against initial clinical signs of polyneuritis in rabbits and reached its maximum at the peak of the disease.

Background: Experimental autoimmune neuritis (EAN) is an animal model of Guillain-Barré syndrome. The mechanisms underlying cellular trafficking and homing of autoreactive immune cells to the peripheral nervous system during EAN and Guillain-Barré syndrome are unknown. We investigated the role of the adhesion molecule lymphocyte function-associated antigen-1 in the pathogenesis of EAN., Experimental Design: EAN was induced in Lewis rats either by immunization with bovine spinal root myelin or by adoptive transfer of P2-specific T cells. Animals were treated intraperitoneally with a monoclonal antibody to lymphocyte function-associated antigen-1 (WT-1) or phosphate-buffered saline and scored for clinical signs. Histology was performed on sciatic nerve and cauda equina and assessed for infiltration and demyelination. Severity of EAN and the corresponding histologic alterations were compared in the different treatment groups. The in vitro effect of WT-1 on T cell proliferation was evaluated., Results: Treatment with WT-1 prevented or efficiently suppressed myelin-induced EAN. In contrast, sham treatment of animals failed to alter the clinical course of EAN. Histologic examination of the peripheral nervous system showed a marked reduction of inflammatory infiltration and perivascular demyelination in animals treated with WT-1. Adoptive transfer EAN was not affected by the administration of WT-1. The differential action in the two models suggests that WT-1 appears to act primarily on the induction phase of the immune response but has no significant impact on the effector phase. In vitro studies with WT-1 revealed that the antibody inhibits the concanavalin A-dependent proliferation of neuritogenic P2-specific T cells., Conclusions: Our data indicate that lymphocyte function-associated antigen-1 is critically involved in the pathogenesis of EAN. Further analysis of this model may provide insight into the process of immune cell recruitment from the circulation into the peripheral nervous system in immune-mediated neuropathies.

The spinal pia mater receives a rich innervation of small sensory axons via the ventral roots. Other sensory axons enter the ventral roots but end blindly or turn abruptly in hairpin loop-like formations and continue in a distal direction. In the present study, the content of substance P (SP)-, calcitonin gene-related peptide (CGRP)-, growth-associated protein (GAP-43)-, and low-affinity neurotrophin receptor protein (p75NGFr)-like immunoreactivity (-LI) associated with these different types of sensory axons was assessed with light and electron microscopic immunohistochemical techniques. In addition, the binding of antibodies against synthetic peptides representing unique sequences of residues in the products of the trk and trkB protooncogenes was analyzed. These genes encode membrane spanning proteins, which have been shown to constitute specific high affinity binding sites for several members of the nerve growth factor family of neurotrophic factors. The results of the present study imply that the ventral root afferents comprise several different types of sensory axons, which all contain SP-, CGRP-, GAP-43-, and p75NGFr-like immunoreactivities. In addition, at least some of the presumed sensory fiber bundles in ventral roots and the pia mater were immunoreactive for the trkB gene product. Moreover, leptomeningeal cells and nonneuronal cells of the ventral roots were shown to bind antibodies to both the trk and trkB gene products. The ventral root afferents seem to share their immunohistochemical pattern with pain-transducing axons at some other locations, such as the tooth pulp. The contents of SP- and CGRP-LI in sensory axons that reach the central nervous system (CNS) through the ventral root indicate that ventral root afferents may be involved in sensory mechanisms, such as the ventral root pain reaction, as well as in the control of the pial blood vessels. The demonstration of GAP-43 and neurotrophin receptor-immunoreactivities associated with unmyelinated fibers in ventral roots and the pia mater is discussed in relation to previous reports on postnatal plasticity in these axonal populations.

In animal experiments, nerve transection is followed by expression of nerve growth factor receptors (NGFR) on Schwann cells of both motor and sensory nerve fibres distally to the site of the lesion. To determine whether denervated Schwann cells in amyotrophic lateral sclerosis (ALS) similarly express NGFR, a study was made of post-mortem material of peripheral nerves and ventral roots from ALS cases and age-matched controls, using immunolabelling methods. Dorsal roots and spinal cords were also examined for the presence of NGFR. In all the ALS cases and controls, NGFR immunostaining was seen in the outer layer of vessel walls, perineurial sheaths, connective tissue surrounding fascicles in nerve roots and in the substantia gelatinosa of the spinal cord. In ALS, NGFR staining was also present in the Schwann cells of degenerated nerve fibres in mixed peripheral nerves, in ventral roots and, to a lesser extent, in dorsal roots. NGFR immunoreactivity was also seen in elongated cells extending from the perifascicular connective tissue into the nerve fascicles. It is concluded that denervated Schwann cells in ALS express NGFR and that NGFR immunostaining on Schwann cells may be used as an indicator of axonal degeneration. The NGFR labelling in the dorsal roots supports the notion that ALS is not a pure motor syndrome.

Intrathecal injection of interferon-gamma induced a significant increase of the number of class I and class II major histocompatibility complex (MHC)-expressing cells within the rat nervous system. A progressive appearance of MHC-antigen-positive cells was found by light- and electron microscopic immune histology. The first level comprised cells that constitutively expressed MHC antigens in normal animals (meningeal and endoneural monocytes, some perivascular dendritic cells, and few parenchymal microglia cells, especially in the lumbar spinal cord and in the cerebellar white matter). The second level represented cells readily expressing MHC antigens after stimulation with interferon-gamma (all perivascular, dendritic cells, and microglia). The third level included ependymal cells, astrocytes, and Schwann cells. After stimulation with interferon-gamma, these neuroectodermal cells expressed MHC antigens inconsistently, usually in a low density and patchy distribution. The progressive appearance of MHC antigens may be reflected by the variances of lesional patterns found in experimental allergic encephalomyelitis of different histologic severity.

We examined the evolution of demyelination in spinal roots of Lewis rats immunized with whole nerve and complete Freund's adjuvant. Roots were morphologically normal until 11 days after immunization, when we found endoneurial edema and myelin vesiculation in the absence of mononuclear cell contacts. Macrophage-associated myelin stripping was not detected until day 12. Macrophage infiltrations were extensive by day 14, but lymphocytes were sparse. These observations indicate that in experimental allergic neuritis, myelin injury may occur before macrophage-mediated demyelination, and provide support for an early role of serum factors in the development of this disorder.

Circulating immune complexes were assayed in the sera of animals with experimental allergic neuritis (EAN), and immunofluorescent staining and immunohistological examination were performed to clarify the role of immune complexes in the pathogenesis of EAN. The level of immune complexes in the sera of animals with clinical signs of EAN was from 1:32 to 1:64. Control animals showed a titer of immune complexes from 1:2 to 1:4. Animals with EAN showed deposition of immune complexes, which were detected by FITC-conjugated anti-rat IgG or C3-complement, in the vessels of the peripheral nerve. These findings suggest that immune complexes may contribute to the immunopathogenesis of EAN.

Strain differences among rats to the induction and severity of experimental allergic neuritis (EAN) in response to whole PNS myelin were observed. Lewis rats were highly susceptible and developed severe EAN without central nervous system lesions (EAE), while Brown Norway rats were most resistant. Wistar, Sprague-Dawley, and Buffalo rats were susceptible but developed less severe disease than Lewis rats. Only Lewis rats consistantly developed EAN in response to isolated P2 protein. The severity of EAN was enhanced by treatment of the P2 with mercaptoethanol prior to injection. None of the strains developed EAN in response to galactocerebroside and none developed the lesions of EAE in response to any of the bovine myelin antigens tested. Myelin protein profiles from these rat strains were similar which suggests that factors other than target tissue differences, such as genetically determined immune responses to bovine myelin antigens, must be involved in these differing responses.

A monoclonal antibody, termed anti-NSP-5 (anti-Neural cell Surface Protein-5) was obtained from an hybridoma generated by fusing rat myeloma cells with splenocytes of a rat immunized with membranes from the cerebella of weaver mutant mice. This antibody reacted with the surface membrane of a subset of neurones in cultures from cerebella and dorsal root ganglia. In both culture systems, only tetanus toxin-positive cells were stained by the antibody. In sections of adult cerebellum a punctate pattern of staining was seen in the molecular layer, the Purkinje cell layer and the upper part of the granule cell layer. The white matter was strongly positive whereas granule cell and Purkinje cell bodies were clearly negative. In sections from adult dorsal root ganglia anti-NSP-5 labeled most sensory neurones including their axones in the dorsal roots. The expression of the antigen was developmentally regulated. It could not be detected in cerebellar cultures prepared from animals younger than 7 days, in good agreement with the data obtained on tissue sections. Similarly, the antigen could not be detected by immunoblotting in neonatal spinal cord, but a NSP-5-reactive band was present at postnatal day 7. The antibody bound a polypeptide of around MW 180 000 in extracts prepared from adult mouse spinal cord or cerebellum. When purified by immunoaffinity chromatography the antigen co-eluted with numerous strongly associated polypeptides. Upon subcellular fractionation most of it remained associated with a Triton-X100 insoluble fraction thus co-distributing with the cytoskeleton.

Attempts have been made to transfer experimental allergic neuritis (EAN) both by the intraneural and the intravenous injection of cells derived from Lewis rats with the disease into naive recipients of the same strain. Lymph node cells obtained 12 and 15 days after inoculation with bovine dorsal root in Freund's complete adjuvant were injected intraneurally. A small number of demyelinated axons were observed, but clinical weakness was not evident. Lymph node cells, lymph node cells cultured with concanavalin A, or cultured spleen cells from animals with EAN were transferred intravenously to normal rats. Uncultured lymph node cells were transferred to X-irradiated animals. There were no clinical or histological differences between these recipients and controls receiving cells from rats inoculated with Freund's adjuvant alone. The findings are discussed in relation to previous reports of attempts to transmit EAN by cell transfer.

Lewis rats immunized with myelin and complete Freund's adjuvant were treated with cobra venom factor (CVF) which depletes the C3 component of complement. CVF given at day 9 delayed the onset of experimental allergic neuritis (EAN) by 2-3 days and when given at days 9 and 12 delayed the onset of EAN by 4-5 days. Lumbar nerve roots of CVF-treated rats had significantly less demyelination than those from control EAN rats.