Non‐invasive visual evoked potentials to assess optic nerve involvement in the dark agouti rat model of experimental autoimmune encephalomyelitis induced by myelin oligodendrocyte glycoprotein

Experimental autoimmune encephalomyelitis (EAE) is the primary disease model of multiple sclerosis (MS), one of the most diffused neurological diseases characterized by fatigue, muscle weakness, vision loss, anxiety and depression. EAE can be induced through injection of myelin peptides to susceptible mouse or rat strains. In particular, EAE elicited by the autoimmune reaction against myelin oligodendrocyte glycoprotein (MOG) presents the common features of human MS: inflammation, demyelination and axonal loss. Optic neuritis affects visual pathways in both MS and in several EAE models. Neurophysiological evaluation through visual evoked potential (VEP) recording is useful to check visual pathway dysfunctions and to test the efficacy of innovative treatments against optic neuritis. For this purpose, we investigate the extent of VEP abnormalities in the dark agouti (DA) rat immunized with MOG, which develops a relapsing–remitting disease course. Together with the detection of motor signs, we acquired VEPs during both early and late stages of EAE, taking advantage of a non‐invasive recording procedure that allows long follow‐up studies. The validation of VEP outcomes was determined by comparison with ON histopathology, aimed at revealing inflammation, demyelination and nerve fiber loss. Our results indicate that the first VEP latency delay in MOG‐EAE DA rats appeared before motor deficits and were mainly related to an inflammatory state. Subsequent VEP delays, detected during relapsing EAE phases, were associated with a combination of inflammation, demyelination and axonal loss. Moreover, DA rats with atypical EAE clinical course tested at extremely late time points, manifested abnormal VEPs although motor signs were mild. Overall, our data demonstrated that non‐invasive VEPs are a powerful tool to detect visual involvement at different stages of EAE, prompting their validation as biomarkers to test novel treatments against MS optic neuritis.     

Temporal overexpression of IL‐22 and Reg3γ differentially impacts the severity of experimental autoimmune encephalomyelitis

IL‐22 is an alpha‐helical cytokine which belongs to the IL‐10 family of cytokines. IL‐22 is produced by RORγt+ innate and adaptive lymphocytes, including ILC3, γδ T, iNKT, Th17 and Th22 cells and some granulocytes. IL‐22 receptor is expressed primarily by non‐haematopoietic cells. IL‐22 is critical for barrier immunity at the mucosal surfaces in the steady state and during infection. Although IL‐22 knockout mice were previously shown to develop experimental autoimmune encephalomyelitis (EAE), a murine model of multiple sclerosis (MS), how temporal IL‐22 manipulation in adult mice would affect EAE course has not been studied previously. In this study, we overexpressed IL‐22 via hydrodynamic gene delivery or blocked it via neutralizing antibodies in C57BL/6 mice to explore the therapeutic impact of IL‐22 modulation on the EAE course. IL‐22 overexpression significantly decreased EAE scores and demyelination, and reduced infiltration of IFN‐γ+IL‐17A+Th17 cells into the central nervous system (CNS). The neutralization of IL‐22 did not alter the EAE pathology significantly. We show that IL‐22‐mediated protection is independent of Reg3γ, an epithelial cell‐derived antimicrobial peptide induced by IL‐22. Thus, overexpression of Reg3γ significantly exacerbated EAE scores, demyelination and infiltration of IFN‐γ+IL‐17A+ and IL‐17A+GM‐CSF+Th17 cells to CNS. We also show that Reg3γ may inhibit IL‐2‐mediated STAT5 signalling and impair expansion of Treg cells in vivo and in vitro. Finally, Reg3γ overexpression dramatically impacted intestinal microbiota during EAE. Our results provide novel insight into the role of IL‐22 and IL‐22‐induced antimicrobial peptide Reg3γ in the pathogenesis of CNS inflammation in a murine model of MS.     

新生儿高胆红素血症闪光视觉诱发电位的检测

应用视觉诱发电位仪对２５例高胆红素血症（简称高胆）新生儿进行了闪光视觉诱发电位（ｒｉｓｕａｌ ｅｖｏｋｅｄ ｐｏｔｅｎｔｉａｌｓ ｔｏ ｆｌａｓｈ,Ｆ－ＶＥＰ）的检测,同时测定了２０例正常新生儿作为对照。结果表明：１．高胆新生儿Ｆ－ＶＥＰ主波潜伏期延长,与正常新生儿比较有显著性差异;２．高胆新生儿胆红素浓度越高,Ｆ－ＦＶＥＰ潜伏越长。提示高胆对视觉神经通道有毒性作用,胆红素浓度越高,毒性损害越大,     

Dual effect of IL‐7/IL‐7R signalling on the osteoimmunological system: a potential therapeutic target for rheumatoid arthritis

The IL‐7/IL‐7R pathway plays a vital role in the immune system, especially in the inflammatory response. Monocytes/macrophages (osteoclast precursors) have been recently recognized as important participants in the osteoclastogenesis of rheumatoid arthritis (RA) patients. Here, we aimed to investigate the therapeutic potential of IL‐7/IL‐7R pathway in RA and to determine whether it could restrain osteoclastogenic functions and therefore ameliorate RA. Firstly, collagen‐induced arthritis (CIA) mice were administered with IL‐7Rα‐target antibodies to assess their therapeutic effect on arthritis. We found that blockade of the IL‐7/IL‐7R pathway protected CIA mice from bone destruction in addition to inducing inflammatory remission, by altering the RANKL/RANK/OPG ratio and consequently decreasing osteoclast formation. To explore the effect and mechanism of this pathway, bone marrow cells were induced to osteoclasts and treated with IL‐7, a STAT5 inhibitor or supernatants from T cells. The results showed that the IL‐7/IL‐7R pathway played a direct inhibitory role in osteoclast differentiation via STAT5 signalling pathway in a RANKL‐induced manner. We applied flow cytometry to analyse the effect of IL‐7 on T‐cell RANKL expression and found that IL‐7/IL‐7R pathway had an indirect role in the osteoclast differentiation process by enhancing the RANKL expression on T cells. In conclusion, the IL‐7/IL‐7R pathway exhibited a dual effect on osteoclastogenesis of CIA mice by interacting with osteoimmunology processes and could be a novel therapeutic target for autoimmune diseases such as RA.     

Oligodendrocyte‐specific deletion of FGFR2 ameliorates MOG35‐55‐induced EAE through ERK and Akt signalling

Fibroblast growth factors (FGFs) and their receptors (FGFRs) are involved in demyelinating pathologies including multiple sclerosis (MS). In our recent study, oligodendrocyte‐specific deletion of FGFR1 resulted in a milder disease course, less inflammation, reduced myelin and axon damage in EAE. The objective of this study was to elucidate the role of oligodendroglial FGFR2 in MOG_35‐55‐induced EAE. Oligodendrocyte‐specific knockout of FGFR2 (Fgfr2^{ind −/−}) was achieved by application of tamoxifen; EAE was induced using the MOG_35‐55 peptide. EAE symptoms were monitored over 62 days. Spinal cord tissue was analysed by histology, immunohistochemistry and western blot. Fgfr2^{ind −/−} mice revealed a milder disease course, less myelin damage and enhanced axonal density. The number of oligodendrocytes was not affected in demyelinated areas. However, protein expression of FGFR2, FGF2 and FGF9 was downregulated in Fgfr2^{ind −/−} mice. FGF/FGFR dependent signalling proteins were differentially regulated; pAkt was upregulated and pERK was downregulated in Fgfr2^{ind −/−} mice. The number of CD3(+) T cells, Mac3(+) cells and B220(+) B cells was less in demyelinated lesions of Fgfr2^{ind −/−} mice. Furthermore, expression of IL‐1β, TNF‐α and CD200 was less in Fgfr2^{ind −/−} mice than controls. Fgfr2^{ind −/−} mice showed an upregulation of PLP and downregulation of the remyelination inhibitors SEMA3A and TGF‐β expression. These data suggest that cell‐specific deletion of FGFR2 in oligodendrocytes has anti‐inflammatory and neuroprotective effects accompanied by changes in FGF/FGFR dependent signalling, inflammatory cytokines and expression of remyelination inhibitors. Thus, FGFRs in oligodendrocytes may represent potential targets for the treatment of inflammatory and demyelinating diseases including MS.     

NGF‐Dependent Activation of TrkA Pathway: A Mechanism for the Neuroprotective Effect of Troxerutin in D‐Galactose‐Treated Mice

D‐galactose‐(D‐gal)‐treated mouse, with cognitive impairment, has been used for neurotoxicity investigation and anti‐neurotoxicity pharmacology research. In this study, we investigated the mechanism underlying the neuroprotective effect of troxerutin. The results showed that troxerutin improved behavioral performance in D‐gal‐treated mice by elevating Cu, Zn‐superoxide dismutases (Cu, Zn‐SOD) activity and decreasing reactive oxygen species levels. Furthermore, our results showed that troxerutin significantly promoted nerve growth factor (NGF) mRNA expression which resulted in TrkA activation. On one hand, NGF/TrkA induced activation of Akt and ERK1/2, which led to neuronal survival; on the other hand, NGF/TrkA mediated CaMKII and CREB phosphorylation and increased PSD95 expression, which improved cognitive performance. However, the neuroprotective effect of troxerutin was blocked by treatment with K252a, an antagonist for TrkA. No neurotoxicity was observed in mice treated with K252a or troxerutin alone. In conclusion, administration of troxerutin to D‐gal‐injected mice attenuated cognitive impairment and brain oxidative stress through the activation of NGF/TrkA signaling pathway.     

The effects of electroconvulsive shock on retinal activity.

Two experiments are reported examining the effects of electroconvulsive shock (ECS) on the electroretinogram (ERG) and the retinal oscillatory potentials (OPs) in the albino rat. Immediately after the induction of generalised seizure activity, both the ERG and the OPs were always preserved basically intact, despite minor alterations to their waveforms. In Experiment 1, it was found that small changes in amplitude of the ERG were recorded following ECS, but these were most likely artifactual. The only other notable finding was a temporary decrease in latency of the b-wave of the ERG. In Experiment 2, a slight overall attenuation in the amplitude of the OPs was observed. This was associated with a paradoxical decrease in the latencies of all three OP subcomponents similar to that found for the ERG b-wave. It is concluded that ECS does not interfere to any marked extent with either the transduction of the visual signal or its processing within the various retinal layers. This implies that the blockade of the afferent volley that occurs following ECS must be confined to the optic pathway or to the occipital cortex itself.     

Effect of geranylgeranylacetone on optic neuritis in experimental autoimmune encephalomyelitis

Optic neuritis is an acute inflammatory demyelinating syndrome of the central nervous system (CNS) that often occurs in multiple sclerosis (MS). Since it can cause irreversible visual loss, especially in the optic-spinal form of MS or neuromyelitis optica (NMO), the present study was conducted to assess the effects of geranylgeranylacetone (GGA) on optic neuritis in the experimental autoimmune encephalomyelitis (EAE) mouse model of MS. Myelin oligodendrocyte glycoprotein-induced EAE mice received oral administration of GGA at 500 mg/kg or vehicle once daily for 22 days. The effects of GGA on the severity of optic neuritis were examined by morphological analysis on day 22. Visual functions were measured by the multifocal electroretinograms (mfERG). In addition, the effects of GGA on severity of myelitis were monitored both on clinical signs and morphological aspects. The visual function, as assessed by the second-kernel of mfERG, was significantly improved in GGA-treated mice compared with vehicle-treated mice. GGA treatment decreased the number of degenerating axons in the optic nerve and prevented cell loss in the retinal ganglion cell layer. However, the severity of demyelination in the spinal cord remained unaffected with the treatment of GGA. These results suggest that oral GGA administration has beneficial effect on the treatment for optic neuritis in the EAE mouse model of MS.     

Electroretinography in dogs using a fiber electrode prototype

We compared two electroretinography (ERG) electrodes in dogs using ERG standards of the International Society for Clinical Electrophysiology of Vision (ISCEV). Ten healthy Yorkshire terrier dogs (mean age, 2.80 ± 1.42 years; 6 females) weighing 5.20 ± 1.56 kg were evaluated using an ERG system for veterinary use. Dark- and light-adapted ERG responses were recorded using an ERG-Jet electrode and a fiber electrode prototype. The examinations were performed during 2 visits, 3 weeks apart. Both electrodes (ERG-Jet or fiber prototype) were used on each animal and the first eye to be recorded (OD × OS) was selected randomly. Three weeks later the examination was repeated on the same animal switching the type of electrode to be used that day and the first eye to be examined. The magnitude and waveform quality obtained with the two electrode types were similar for all ERG responses. ERG amplitudes and implicit times obtained from dogs using the fiber electrode prototype were comparable to those obtained with the ERG-Jet electrode for rod, maximal rod-cone summed, cone, and 30-Hz flicker responses. The fiber electrode prototype is a low-cost device, available as an alternative instrument for clinical veterinary ERG recording for retinal function assessment.     

Aged Tmem106b knockout mice display gait deficits in coincidence with Purkinje cell loss and only limited signs of non‐motor dysfunction

Genetic variants in TMEM106B are a major risk factor for several neurodegenerative diseases including frontotemporal degeneration, limbic‐predominant age‐related TDP‐43 encephalopathy, Parkinson''s disease, late‐onset‐Alzheimer''s disease and constitute a genetic determinant of differential aging. TMEM106B encodes an integral lysosomal membrane protein but its precise physiological function in the central nervous system remains enigmatic. Presently, we aimed to increase understanding of TMEM106B contribution to general brain function and aging. We analyzed an aged cohort of Tmem106b knockout‐, heterozygote and wild‐type mice in a behavioral test battery including assessments of motor function as well as, social, emotional and cognitive function. Aged Tmem106b knockout (KO) mice displayed diverse behavioral deficits including motor impairment, gait defects and reduced startle reactivity. In contrast, no prominent deficits were observed in social, emotional or cognitive behaviors. Histologically, we observed late‐onset loss of Purkinje cells followed by reactive gliosis in the cerebellum, which likely contributed to progressive decline in motor function and gait defects in particular. Reactive gliosis was not restricted to the cerebellum but observed in different areas of the brain including the brain stem and parts of the cerebral cortex. Surviving Purkinje cells showed vacuolated lysosomes in the axon initial segment, implicating TMEM106B‐dependent lysosomal trafficking defects as the underlying cause of axonal and more general neuronal dysfunction contributing to behavioral impairments. Our experiments help to elucidate how TMEM106B affects spatial neuronal homeostasis and exemplifies a critical role of TMEM106B in neuronal cells for survival.     

The role of thromboxane prostanoid receptor signaling in gastric ulcer healing

The process of gastric ulcer healing includes cell migration, proliferation, angiogenesis and re‐epithelialization. Platelets contain angiogenesis stimulating factors that induce angiogenesis. Thromboxane A₂ (TXA₂) not only induces platelet activity but also angiogenesis. This study investigated the role of TXA₂ in gastric ulcer healing using TXA₂ receptor knockout (TPKO) mice. Gastric ulcer healing was suppressed by treatment with the TXA₂ synthase inhibitor OKY‐046 and the TXA₂ receptor antagonist S‐1452 compared with vehicle‐treated mice. TPKO showed delayed gastric ulcer healing compared with wild‐type mice (WT). The number of microvessels and CD31 expression were lower in TPKO than in WT mice, and TPKO suppressed the expression of transforming growth factor beta (TGF‐β) and vascular endothelial growth factor A (VEGF‐A) in areas around gastric ulcers. Immunofluorescence assays showed that TGF‐β and VEGF‐A co‐localized with platelets. Gastric ulcer healing was significantly reduced in WT mice transplanted with TPKO compared with WT bone marrow. These results suggested that TP signalling on platelets facilitates gastric ulcer healing through TGF‐β and VEGF‐A.     

Lack of adiponectin leads to increased lymphocyte activation and increased disease severity in a mouse model of multiple sclerosis

Multiple sclerosis (MS) is a presumed autoimmune disease directed against central nervous system (CNS) myelin, in which diet and obesity are implicated as risk factors. Immune responses can be influenced by molecules produced by fat cells, called adipokines. Adiponectin is an adipokine with anti‐inflammatory effects. We tested the hypothesis that adiponectin has a protective role in the EAE model for MS, that can be induced by immunization with myelin antigens or transfer of myelin‐specific T lymphocytes. Adiponectin deficient (ADPKO) mice developed worse EAE with greater CNS inflammation, demyelination, and axon injury. Lymphocytes from myelin‐immunized ADPKO mice proliferated more, produced higher amounts of IFN‐γ, IL‐17, TNF‐α, IL‐6, and transferred more severe EAE than wild type (WT) lymphocytes. At EAE peak, the spleen and CNS of ADPKO had fewer regulatory T (Treg) cells than WT mice and during EAE recovery, Foxp3, IL‐10 and TGF‐β expression levels in the CNS were reduced in ADPKO compared with WT mice. Treatment with globular adiponectin in vivo ameliorated EAE, and was associated with an increase in Treg cells. These data indicate that adiponectin is an important regulator of T‐cell functions during EAE, suggesting a new avenue of investigation for MS treatment.     

Upregulation of Immunoglobulin‐related Genes in Cortical Sections from Multiple Sclerosis Patients

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system (CNS). Microarray‐based global gene expression profiling is a promising method, used to study potential genes involved in the pathogenesis of the disease. In the present study, we have examined global gene expression in normal‐appearing gray matter and gray matter lesions from the cortex of MS patients, and compared them with cortical gray matter samples from controls. We observed a massive upregulation of immunoglobulin (Ig)‐related genes in cortical sections of MS patients. Using immunohistochemistry, the activation of Ig genes seems to occur within plasma cells in the meninges. As synthesis of oligoclonal IgGs has been hypothesized to be caused by the activation of Epstein–Barr virus (EBV)‐infected B‐cells, we screened the brain samples for the presence of EBV by real‐time quantitative polymerase chain reaction (qPCR) and immunohistochemistry, but no evidence of active or latent EBV infection was detected. This study demonstrates that genes involved in the synthesis of Igs are upregulated in MS patients and that this activation is caused by a small number of meningeal plasma cells that are not infected by EBV. The findings indicate that the Ig‐producing B‐cells found in the cerebrospinal fluid (CSF) of MS patients could have meningeal origin.     

General Aspects and Neuropathology of X‐Linked Adrenoleukodystrophy

X‐adrenoleukodystrophy (X‐ALD) is a metabolic, peroxisomal disease affecting the nervous system, adrenal cortex and testis resulting from inactivating mutations in ABCD1 gene which encodes a peroxisomal membrane half‐adenosine triphosphate (ATP)‐binding cassette transporter, ABCD1 (or ALDP), whose defect is associated with impaired peroxisomal β‐oxidation and accumulation of saturated very long‐chain fatty acids (VLCFA) in tissues and body fluids. Several phenotypes are recognized in male patients including cerebral ALD in childhood, adolescence or adulthood, adrenomyeloneuropathy (AMN), Addison''s disease and, eventually, gonadal insufficiency. Female carriers might present with mild to severe myeloneuropathy that resembles AMN. There is a lack of phenotype–genotype correlations, as the same ABCD1 gene mutation may be associated with different phenotypes in the same family, suggesting that genetic, epigenetic, environmental and stochastic factors are probably contributory to the development and course of the disease. Degenerative changes, like those seen in pure AMN without cerebral demyelination, are characterized by loss of axons and secondary myelin in the long tracts of the spinal cord, possibly related to the impaired lipid metabolism of VLCFAs and the associated alterations (ie, oxidative damage). Similar lesions are encountered following inactivation of ABCD1 in mice (ABCD1 ^‐). A different and more aggressive phenotype is secondary to cerebral demyelination, very often accompanied by inflammatory changes in the white matter of the brain and associated with activation of T lymphocytes, CD1 presentation and increased levels of cytokines, γ‐interferon, interleukin (IL)‐1α, IL‐2 and IL‐6, Granulocyte macrophage colony‐stimulating factor (GM‐CSF), tumor necrosis factor‐α, chemokines and chemokine receptors.     

Physiological roles of axonal ankyrins in survival of premyelinated axons and localization of voltage-gated sodium channels

440 kD ankyrin-B and 480/270 kD ankyrin-G are membrane skeletal proteins with closely related biochemical properties yet distinctive physiological roles in axons. These proteins associate with spectrin-actin networks and also bind to integral membrane proteins including the L1 CAM family of cell adhesion molecules and voltage-gated sodium channels. 440 kD ankyrin-B is expressed with L1 in premyelinated axon tracts, and is essential for survival of these axons, at least in the case of the optic nerve. 440 ankyrin-B may collaborate with L1 in transcellular structures that mediate axon fasciculation and mechanically stabilize axon bundles, although these proteins may also be involved in axon pathfinding. Ankyrin-B (–/–) mice exhibit loss of L1 from premyelinated axon tracts and a similar, although much more severe, phenotype to L1 (–/–) mice and humans with L1 mutations. Ankyrin-B and L1 thus are candidates to collaborate in the same structural pathway and defects in this pathway can lead to nervous system malformations and mental retardation. 480/270 kD ankyrin-G are highly concentrated along with the L1CAM family members neurofascin and NrCAM at nodes of Ranvier and axon initial segments. Voltage-gated sodium channels bind directly to ankyrins, and are likely to associate in a ternary complex containing neurofascin/NrCAM, and ankyrin-G. Mice with ankyrin-G expression abolished in the cerebellum exhibit loss of ability of Purkinje neurons to fire action potentials, as well as loss of restriction of neurofascin/NrCAM to axon initial segments. Ankyrin-G thus is a key component in assembly of functional components of the axon initial segment and possibly the node of Ranvier.     

Microglia‐Derived Macrophage Colony Stimulating Factor Promotes Generation of Proinflammatory Cytokines by Astrocytes in the Periventricular White Matter in the Hypoxic Neonatal Brain

Inflammation in the periventricular white matter (PWM) of hypoxic neonatal brain causes myelination disturbances. In this connection, macrophage colony‐stimulating factor (M‐CSF) has been reported to regulate release of proinflammatory cytokines that may be linked to PWM damage. We sought to determine if M‐CSF derived from amoeboid microglial cells (AMC) would promote proinflammatory cytokine production by astrocytes in the PWM following hypoxic exposure, and, if so, whether it is associated with axon degeneration and myelination disturbances. In 1‐day hypoxic rats, expression of M‐CSF was upregulated in AMC. This was coupled with increased expression of CSF‐1 receptor, tumor necrosis factor‐α (TNF‐α) and interleukin‐1β (IL‐1β) in astrocytes, and TNF‐receptor 1 and IL‐receptor 1 on the axons. Neurofilament‐200 immunopositive axons and myelin basic protein immunopositive processes appeared to undergo disruption in 14‐days hypoxic rats. By electron microscopy, some axons showed degenerative changes affecting the microtubules and myelin sheath. Primary cultured microglial cells subjected to hypoxia showed enhanced release of M‐CSF. Remarkably, primary cultured astrocytes treated with conditioned‐medium derived from hypoxic microglia or M‐CSF exhibited increased production of TNF‐α and IL‐1β. Our results suggest that AMC‐derived M‐CSF promotes astrocytes to generate proinflammatory cytokines, which may be involved in axonal damage following a hypoxic insult.     

多发性硬化患者的视觉、听觉和体感诱发电位的诊断价值

目的:探讨视觉诱发电位(VEP)、听觉诱发电位(BAEP)、体感诱发电位(SEP)对多发性硬化(MS)的诊断价值。方法:对22例临床诊断为MS的患者进行VEP、BAEP、SEP检测,并与正常对照组进行比较分析。结果:22例MS患者中VEP异常15例(68.2%),BAEP异常9例(40.9%),SEP异常12例(54.5%),异常中VEP有53.3%、BAEP有44.4%、SEP有58.3%的患者,临床有相应症状。结论:VEP、BAEP、SEP的检测有助于MS诊断以及亚临床病灶的发现。     

An animal model of cortical and callosal pathology in multiple sclerosis

The pathological and radiological hallmarks of multiple sclerosis (MS) include multiple demyelinated lesions disseminated throughout the white matter of the central nervous system (CNS). More recently, the cerebral cortex has been shown to be affected in MS, but the elucidation of events causing cortical demyelination has been hampered by the lack of animal models reflecting such human cortical pathology. In this report, we have described the presence of cortical gray matter and callosal white matter demyelinating lesions in the chronic experimental autoimmune encephalomyelitis (EAE) mouse model of MS. Similar to the pathological lesions of MS patients, EAE lesions have been classified as type I-leukocortical, type II-intracortical and type III-subpial. All of these lesions had varying degrees of demyelination, inflammatory cells and reactive astrocytes. Similar to MS, cortical layers during EAE showed demyelination, microglia activation, synaptic protein alterations and apoptotic cells. In addition, the callosal white matter during EAE had many inflammatory demyelinating lesions and axon degeneration. Functional electrophysiological conduction analysis showed deficits in both myelinated and unmyelinated callosal axons during early and late EAE. The chronic EAE mouse model has features that mimic cortical and callosal pathology of MS, and can be potentially used to screen agents to prevent these features of disease.