Pre-treatment with Meloxicam Prevents the Spinal Inflammation and Oxidative Stress in DRG Neurons that Accompany Painful Cervical Radiculopathy.

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 A2 (sPLA2) 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 sPLA2 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.

[Effects of sacral canal injection on nerve root local inflammatory factors in rat model with lumbar disc herniation].

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).

Treatment with nerve grafts and aFGF attenuates allodynia caused by cervical root transection injuries.

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-1ß 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-1ß 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-1ß-positive astrocytes and the development of allodynia. Our treatment significantly decreased IL-1ß-positive astrocytes, thus preventing the occurrence of neuropathic pain following multiple cervical root injuries.

Guillain-Barré syndrome in children.

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).

Distribution of inducible nitric oxide synthase and tumor necrosis factor-alpha in the peripheral nervous system of Lewis rats during ascending paresis and spontaneous recovery from experimental autoimmune neuritis.

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.

Subacute inflammatory polyradiculopathy associated with Sjögren's syndrome.

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.

[Effects of warm needle moxibustion on nerve root local inflammatory factors (NOS and CGRP) in the lumbar nerve root compress model rats].

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.

Expression of interleukin-16 in sciatic nerves, spinal roots and spinal cords of experimental autoimmune neuritis rats.

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.

Chemical and mechanical nerve root insults induce differential behavioral sensitivity and glial activation that are enhanced in combination.

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.

The axon reaction: identifying the genes that make a difference.

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.

Expression of RhoA by inflammatory macrophages and T cells in rat experimental autoimmune neuritis.

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.

Postinfectious inflammatory disorders: subgroups based on prospective follow-up.

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.

GalNAc-GD1a is localized specifically in ventral spinal roots, but not in dorsal spinal roots.

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.

Carbohydrate mimicry between human ganglioside GM1 and Campylobacter jejuni lipooligosaccharide causes Guillain-Barre syndrome.

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.

Pathology of lumbar nerve root compression. Part 1: Intraradicular inflammatory changes induced by mechanical compression.

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.

Acute motor axonal neuropathy rabbit model: immune attack on nerve root axons.

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.

GalNAc-GD1a in human peripheral nerve: target sites of anti-ganglioside antibody.

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.

Effects on axonal conduction of anti-ganglioside sera and sera from patients with Guillain-Barré syndrome.

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.

Efficacy of leukemia inhibitory factor in experimental autoimmune neuritis.

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.