Antiaris africana aqueous extract inhibits chronic demyelination and seizures in mice.

Demyelinating diseases are commonly associated with epileptic seizures and have limited management options. Hence, the need to investigate potential options for management of such seizures. Antiaris Africana extract (AE) was investigated for effect in chronic demyelinating seizures. Cuprizone treatment induced short but frequent spike discharges in mice. Antiaris Africana extract (300 mg/kg) treatment abolished epileptiform discharges. Cuprizone administration caused severe demyelination in the corpus callosum. After the demyelination phase, myelin content decreased to 22.86 ± 1.92 % in the cuprizone-only group. However, there was an increase to 52.14 ± 3.91 % in cuprizone-only group and 62.00 ± 2.78 % in the Antiaris africana extract group respectively, after a 4-week cuprizone cessation period. Treatment with AE and LEV visibly altered myelin growth. Antiaris africana extract treatment produced significant (P < 0.001, F (3, 16) = 698.4) increase in locomotor activity similar to LEV (P < 0.001,F (2, 12) = 678.7) and DZP (P < 0.001, F (2, 12) = 620.4) and improved beam traversal time (18.71 ± 2.244 s; 95 % CI: 13.22-24.20) while causing significantly (P < 0.05, F (2, 15) = 6.667) fewer stepping errors. Antiaris africana extract inhibits seizures induced by chronic demyelination and has beneficial effects on motor coordination.

Synergistic Effect of Coenzyme Q10 and L-Carnitine on Gliosis and Anhedonia, in a Rat Model of Multiple Sclerosis: An Immunohistochemical Study.

Objective: This study provides histological evidence of the combined effects of L-Carnitine, and Coenzyme Q10 on gliosis and anhedonia in a rat model of multiple sclerosis (MS). Methods: Fifty male Sprague Dawley rats were randomly divided into 5 groups of 10 rats each. Group 1 was the control group. The rest of the groups were disease models and were given 0.2% cuprizone w/w to induce MS. After 4 weeks, Group 3 started receiving L-Carnitine, Group 4 was given Coenzyme Q10, and Group 5 received both, while cuprizone poisoning continued. After 12 weeks sucrose preference test and tail suspension test were performed for anhedonia. Rats were euthanized and brains were dissected, and assessed for astrocytes, oligodendrocytes, and microglial count. Results: A significant increase in oligodendrocyte count, while a reduction in astrocyte and microglial count was seen in the synergistic group (p < 0.05). Synergism could not be proved in anhedonia. Conclusion: The combination of Coenzyme Q10 and L-Carnitine has a synergistic effect in controlling gliosis in a rat model of MS, but synergism could not be demonstrated on anhedonia.

High-intensity interval training stimulates remyelination via the Wnt/ß-catenin pathway in cuprizone-induced demyelination mouse model.

OBJECTIVES: This study aims to investigate the role of high-intensity interval training (HIIT) in promoting myelin sheath recovery during the remyelination phase in cuprizone (CPZ)-induced demyelination mice and elucidate the mechanisms involving the Wnt/ß-catenin pathway. METHODS: After 5 weeks of a 0.2% CPZ diet to induce demyelination, a 4-week recovery phase with a normal diet was followed by HIIT intervention. Mice body weight was monitored. Morris water maze (MWM) gauged spatial cognition and memory, while the open field test (OFT) assessed anxiety levels. Luxol fast blue (LFB) staining measured demyelination, and immunofluorescence examined myelin basic protein (MBP) and platelet-derived growth factor receptor-alpha (PDGFR-α). Western blotting analyzed protein expression, including MBP, PDGFR-α, glycogen synthase kinase-3ß (GSK3ß), ß-catenin, and p-ß-catenin. Real-time PCR detected mRNA expression levels of CGT and CST. RESULTS: HIIT promoted remyelination in demyelinating mice, enhancing spatial cognition, memory, and reducing anxiety. LFB staining indicated decreased demyelination in HIIT-treated mice. Immunofluorescence demonstrated increased MBP fluorescence intensity and PDGFR-α+ cell numbers with HIIT. Western blotting revealed HIIT reduced ß-catenin levels while increasing p-ß-catenin and GSK3ß levels. Real-time PCR demonstrated that HIIT promoted the generation of new myelin sheaths. Additionally, the Wnt/ß-catenin pathway agonist, SKL2001, decreased MBP expression but increased PDGFR-α expression. DISCUSSION: HIIT promotes remyelination by inhibiting the Wnt/ß-catenin pathway and is a promising rehabilitation training for demyelinating diseases. It provides a new theoretical basis for clinical rehabilitation and care programs.

Advancing understanding of the role of IL-22 in myelination: insights from the Cuprizone mouse model.

Despite significant advancements in the field, the pathophysiology of multiple sclerosis (MS) remains partially understood, with limited therapeutic options available for this debilitating condition. The precise impact of Interleukin-22 (IL-22) in the context of MS is still incompletely elucidated with some evidence suggesting its protective role. To provide a more comprehensive understanding of the role of IL-22, we investigated its effect on remyelination in a mouse model of demyelination induced by Cuprizone. Mice underwent a 6 week regimen of Cuprizone or vehicle, followed or not by intraperitoneal administration of IL-22. Behavioral assessments including tail suspension and inverted screen tests were conducted, alongside histological, histochemical, and quantitative PCR analyses. In Cuprizone-treated mice, IL-22 significantly improved motor and behavioral performance and robustly promoted remyelination in the corpus callosum. Additionally, IL-22 administration led to a significant elevation in MBP transcription in brain biopsies of treated mice. These findings collectively suggest a crucial role for IL-22 in the pathophysiology of MS, particularly in supporting the process of remyelination. These results offer potential avenues for expanding therapeutic strategies for MS treatment. Ongoing experiments aim to further unravel the underlying mechanisms of IL-22 action.

Nalfurafine promotes myelination in vitro and facilitates recovery from cuprizone + rapamycin-induced demyelination in mice.

The kappa opioid receptor has been identified as a promising therapeutic target for promoting remyelination. In the current study, we evaluated the ability of nalfurafine to promote oligodendrocyte progenitor cell (OPC) differentiation and myelination in vitro, and its efficacy in an extended, cuprizone-induced demyelination model. Primary mouse (C57BL/6J) OPC-containing cultures were treated with nalfurafine (0.6-200 nM), clemastine (0.01-100 µM), T3 (30 ng/mL), or vehicle for 5 days. Using immunocytochemistry and confocal microscopy, we found that nalfurafine treatment increased OPC differentiation, oligodendrocyte (OL) morphological complexity, and myelination of nanofibers in vitro. Adult male mice (C57BL/6J) were given a diet containing 0.2% cuprizone and administered rapamycin (10 mg/kg) once daily for 12 weeks followed by 6 weeks of treatment with nalfurafine (0.01 or 0.1 mg/kg), clemastine (10 mg/kg), or vehicle. We quantified the number of OLs using immunofluorescence, gross myelination using black gold staining, and myelin thickness using electron microscopy. Cuprizone + rapamycin treatment produced extensive demyelination and was accompanied by a loss of mature OLs, which was partially reversed by therapeutic administration of nalfurafine. We also assessed these mice for functional behavioral changes in open-field, horizontal bar, and mouse motor skill sequence tests (complex wheel running). Cuprizone + rapamycin treatment resulted in hyperlocomotion, poorer horizontal bar scores, and less distance traveled on the running wheels. Partial recovery was observed on both the horizontal bar and complex running wheel tests over time, which was facilitated by nalfurafine treatment. Taken together, these data highlight the potential of nalfurafine as a remyelination-promoting therapeutic.

Rapid and prolonged response of oligodendrocyte lineage cells in standard acute cuprizone demyelination model revealed by in situ hybridization.

Dietary administration of a copper chelator, cuprizone (CPZ), has long been reported to induce intense and reproducible demyelination of several brain structures such as the corpus callosum. Despite the widespread use of CPZ as an animal model for demyelinating diseases such as multiple sclerosis (MS), the mechanism by which it induces demyelination and then allows robust remyelination is still unclear. An intensive mapping of the cell dynamics of oligodendrocyte (OL) lineage during the de- and remyelination course would be particularly important for a deeper understanding of this model. Here, using a panel of OL lineage cell markers as in situ hybridization (ISH) probes, including Pdgfra, Plp, Mbp, Mog, Enpp6, combined with immunofluorescence staining of CC1, SOX10, we provide a detailed dynamic profile of OL lineage cells during the entire course of the model from 1, 2, 3.5 days, 1, 2, 3, 4,5 weeks of CPZ treatment, as well as after 1, 2, 3, 4 weeks of recovery from CPZ treatment. The result showed an unexpected early death of mature OLs and response of OL progenitor cells (OPCs) in vivo upon CPZ challenge, and a prolonged upregulation of myelin-forming OLs compared to the intact control even 4 weeks after CPZ withdrawal. These data may serve as a basic reference system for future studies of the effects of any intervention on de- and remyelination using the CPZ model, and imply the need to optimize the timing windows for the introduction of pro-remyelination therapies in demyelinating diseases such as MS.

Black Seed Oil-Based Curcumin Nanoformulations Ameliorated Cuprizone-Induced Demyelination in the Mouse Hippocampus.

Multiple sclerosis (MS) is a neurodegenerative disease characterized by the demyelination of nerves, axonal damage, and neuroinflammation. Cognition impairment, pain, and loss of mobility are some of the usual complications of MS. It has been postulated that the overproduction of proinflammatory cytokines and reactive oxygen species (ROS) are the main factors that contribute to MS pathology. Among various animal models, the cuprizone model is the most widely used model for investigating MS-related pathology. We assessed the effects of cuprizone along with the protective effects of some black seed oil-based nanoformulations of curcumin with and without piperine, in mice hippocampus in terms of the changes in antioxidant enzymes, transcription factors, and cytokines during demyelination and remyelination processes. The results of behavioral studies point toward impairment in working memory following the feeding of cuprizone for 5 weeks. However, in treatment groups, mice seemed to prevent the toxic effects of cuprizone. Nanoformulations used in this study were found to be highly effective in lowering the amount of ROS as indicated by the levels of antioxidant enzymes like catalase, superoxide dismutase, glutathione, and glutathione peroxidase. Moreover, nanoformulations CCF and CCPF were observed resisting the toxic effects of cuprizone. We observed greater expression of NFκB-p65 in the CPZ group than in the control group. CCF nanoformulation had a better inhibitory effect on NFκB-p65 than other formulations. Histological examination of the hippocampus was also conducted. Nanoformulations used here were found effective in reversing MS-related pathophysiology and hence have the potential to be applied as adjuvant therapy for MS treatment.

The effects of venlafaxine on depressive-like behaviors and gut microbiome in cuprizone-treated mice.

Background: Cuprizone (CPZ)-treated mice show significant demyelination, altered gut microbiome, and depressive-like behaviors. However, the effects of venlafaxine (Ven) on the gut microbiome and depressive-like behavior of CPZ-treated mice are largely unclear. Methods: Male C57BL/6J mice were fed a chow containing 0.2% cuprizone (w/w) for 5 weeks to induce a model of demyelination. Meanwhile, the gut microbiota and depressive-like behaviors were assessed after the mice were fed with Ven (20 mg/kg/day) or equal volumes of distilled water for 2 weeks by oral gavage from the third week onward during CPZ treatment. Results: CPZ treatment decreased the sucrose preference rate in the sucrose preference test and increased the immobility time in the tail-suspension test, and it also induced an abnormality in ß-diversity and changes in microbial composition. Ven alleviated the depressive-like behavior and regulated the composition of the gut microbiota, such as the increase of Lactobacillus and Bifidobacterium in CPZ-treated mice. Conclusion: The anti-depressant effects of Ven might be related to the regulation of gut microbiota in the CPZ-treated mice.

N-butyl-ß-carboline-3-carboxylate (ß-CCB) systemic administration promotes remyelination in the cuprizone demyelinating model in mice.

Demyelination is generated in several nervous system illnesses. Developing strategies for effective clinical treatments requires the discovery of promyelinating drugs. Increased GABAergic signaling through γ-aminobutyric acid type A receptor (GABAAR) activation in oligodendrocytes has been proposed as a promyelinating condition. GABAAR expressed in oligodendroglia is strongly potentiated by n-butyl-ß-carboline-3-carboxylate (ß-CCB) compared to that in neurons. Here, mice were subjected to 0.3% cuprizone (CPZ) added in the food to induce central nervous system demyelination, a well-known model for multiple sclerosis. Then ß-CCB (1 mg/Kg) was systemically administered to analyze the remyelination status in white and gray matter areas. Myelin content was evaluated using Black-Gold II (BGII) staining, immunofluorescence (IF), and magnetic resonance imaging (MRI). Evidence indicates that ß-CCB treatment of CPZ-demyelinated animals promoted remyelination in several white matter structures, such as the fimbria, corpus callosum, internal capsule, and cerebellar peduncles. Moreover, using IF, it was observed that CPZ intake induced an increase in NG2+ and a decrease in CC1+ cell populations, alterations that were importantly retrieved by ß-CCB treatment. Thus, the promyelinating character of ß-CCB was confirmed in a generalized demyelination model, strengthening the idea that it has clinical potential as a therapeutic drug.

Long-term demyelination and aging-associated changes in mice corpus callosum; evidence for the role of accelerated aging in remyelination failure in a mouse model of multiple sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory and demyelinating disorder affecting the central nervous system. Evidence suggests that age-related neurodegeneration contributes to disability progression during the chronic stages of MS. Aging is characterized by decreased regeneration potential and impaired myelin repair in the brain. It is hypothesized that accelerated cellular aging contributes to the functional decline associated with neurodegenerative diseases. We assessed the impact of aging on myelin content in the corpus callosum (CC) and compared aging with the long-term demyelination (LTD) consequents induced by 12 weeks of feeding with a cuprizone (CPZ) diet. Initially, evaluating myelin content in 2-, 6-, and 18-month-old mice revealed a reduction in myelin content, particularly at 18 months. Myelin thickness was decreased and the g-ratio increased in aged mice. Although a lower myelin content and higher g-ratio were observed in LTD model mice, compared to the normally aged mice, both aging and LTD exhibited relatively similar myelin ultrastructure. Our findings provide evidence that LTD exhibits the hallmarks of aging such as elevated expression of senescence-associated genes, mitochondrial dysfunction, and high level of oxidative stress as observed following normal aging. We also investigated the senescence-associated ß-galactosidase activity in O4+ late oligodendrocyte progenitor cells (OPCs). The senescent O4+/ß-galactosidase+ cells were elevated in the CPZ diet. Our data showed that the myelin degeneration in CC occurs throughout the lifespan, and LTD induced by CPZ accelerates the aging process which may explain the impairment of myelin repair in patients with progressive MS.

The comparative effects of bone marrow mesenchymal stem cells and supernatant transplantation on demyelination and inflammation in cuprizone model.

BACKGROUND: Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system (CNS) with inflammation and immune dysfunction. OBJECTIVES: We compared the remyelination and immunomodulation properties of mesenchymal stem cells (MSCs) with their conditioned medium (CM) in the cuprizone model. METHODS: Twenty-four C57BL/ 6 mice were divided into four groups. After cuprizone demyelination, MSCs and their CM were injected into the right lateral ventricle of mice. The expression level of IL-1ß, TNF-α, and BDNF genes was evaluated using the qRT-PCR. APC antibody was used to assess the oligodendrocyte population using the immunofluorescent method. The remyelination and axonal repair were studied by specific staining of the LFB and electron microscopy techniques. RESULTS: Transplantation of MSCs and CM increased the expression of the BDNF gene and decreased the expression of IL-1ß and TNF-α genes compared to the cuprizone group, and these effects in the cell group were more than CM. Furthermore, cell transplantation resulted in a significant improvement in myelination and axonal repair, which was measured by luxol fast blue and transmission electron microscope images. The cell group had a higher number of oligodendrocytes than other groups. CONCLUSIONS: According to the findings, injecting MSCs intraventricularly versus cell-conditioned medium can be a more effective approach to improving chronic demyelination in degenerative diseases like MS.

3D inversion recovery ultrashort echo time MRI can detect demyelination in cuprizone-treated mice.

Purpose: To test the ability of inversion-recovery ultrashort echo time (IR-UTE) MRI to directly detect demyelination in mice using a standard cuprizone mouse model. Methods: Non-aqueous myelin protons have ultrashort T2s and are "invisible" with conventional MRI sequences but can be detected with UTE sequences. The IR-UTE sequence uses an adiabatic inversion-recovery preparation to suppress the long T2 water signal so that the remaining signal is from the ultrashort T2 myelin component. In this study, eight 8-week-old C57BL/6 mice were fed cuprizone (n = 4) or control chow (n = 4) for 5 weeks and then imaged by 3D IR-UTE MRI. The differences in IR-UTE signal were compared in the major white matter tracts in the brain and correlated with the Luxol Fast Blue histochemical marker of myelin. Results: IR-UTE signal decreased in cuprizone-treated mice in white matter known to be sensitive to demyelination in this model, such as the corpus callosum, but not in white matter known to be resistant to demyelination, such as the internal capsule. These findings correlated with histochemical staining of myelin content. Conclusions: 3D IR-UTE MRI was sensitive to cuprizone-induced demyelination in the mouse brain, and is a promising noninvasive method for measuring brain myelin content.

The therapeutic effect of GAS6 in remyelination is dependent upon Tyro3.

Multiple sclerosis is an autoimmune disease of the central nervous system (CNS) characterized by demyelination, axonal damage and, for the majority of people, a decline in neurological function in the long-term. Remyelination could assist in the protection of axons and their functional recovery, but such therapies are not, as yet, available. The TAM (Tyro3, Axl, and MERTK) receptor ligand GAS6 potentiates myelination in vitro and promotes recovery in pre-clinical models of MS. However, it has remained unclear which TAM receptor is responsible for transducing this effect and whether post-translational modification of GAS6 is required. In this study, we show that the promotion of myelination requires post-translational modification of the GLA domain of GAS6 via vitamin K-dependent γ-carboxylation. We also confirmed that the intracerebroventricular provision of GAS6 for 2 weeks to demyelinated wild-type (WT) mice challenged with cuprizone increased the density of myelinated axons in the corpus callosum by over 2-fold compared with vehicle control. Conversely, the provision of GAS6 to Tyro3 KO mice did not significantly improve the density of myelinated axons. The improvement in remyelination following the provision of GAS6 to WT mice was also accompanied by an increased density of CC1+ve mature oligodendrocytes compared with vehicle control, whereas this improvement was not observed in the absence of Tyro3. This effect occurs independent of any influence on microglial activation. This work therefore establishes that the remyelinative activity of GAS6 is dependent on Tyro3 and includes potentiation of oligodendrocyte numbers.

Magnetic resonance metrics for identification of cuprizone-induced demyelination in the mouse model of neurodegeneration: a review.

Neurodegenerative disorders, including Multiple Sclerosis (MS), are heterogenous disorders which affect the myelin sheath of the central nervous system (CNS). Magnetic Resonance Imaging (MRI) provides a non-invasive method for studying, diagnosing, and monitoring disease progression. As an emerging research area, many studies have attempted to connect MR metrics to underlying pathophysiological presentations of heterogenous neurodegeneration. Most commonly, small animal models are used, including Experimental Autoimmune Encephalomyelitis (EAE), Theiler's Murine Encephalomyelitis (TMEV), and toxin models including cuprizone (CPZ), lysolecithin, and ethidium bromide (EtBr). A contrast and comparison of these models is presented, with focus on the cuprizone model, followed by a review of literature studying neurodegeneration using MRI and the cuprizone model. Conventional MRI methods including T1 Weighted (T1W) and T2 Weighted (T2W) Imaging are mentioned. Quantitative MRI methods which are sensitive to diffusion, magnetization transfer, susceptibility, relaxation, and chemical composition are discussed in relation to studying the CPZ model. Overall, additional studies are needed to improve both the sensitivity and specificity of MRI metrics for underlying pathophysiology of neurodegeneration and the relationships in attempts to clear the clinico-radiological paradox. We therefore propose a multiparametric approach for the investigation of MR metrics for underlying pathophysiology.

Chronic demyelination interferes with normal spermatogenesis in cuprizone-intoxicant C57/BL 6 mice: An experimental study.

Background: Due to myelin and axonal insults in multiple sclerosis individuals, motor coordination problems and endocrine imbalance may develop. Objective: This study aims to evaluate the role of chronic demyelination on the hypothalamic-pituitary-gonadal axis in the mouse model of multiple sclerosis. Materials and Methods: 20 adult C57/BL6 male mice were divided into 2 groups (n = 10/each) as follows: the control group (CONT) received a regular diet for 17 wk; and the experimental group (cuprizone [CPZ]) was fed with 0.2% CPZ for 12 wk and, then CPZ was withdrawn for 5 wk. Serum testosterone, histopathology of the brain and testis, and sperm analysis were evaluated. Results: The hypothalamic myelin content was significantly decreased in the arcuate nucleus following the 12 wk of CPZ consumption compared to the CONT group, and the statistical difference remained until 17 wk. Testosterone levels declined significantly in the CPZ group compared to the CONT group in the 12 th and 17 th wk. A significant decrease was observed in the height of the seminiferous epithelium and the interstitial tissue area, and the number of seminiferous epithelial cells in the CPZ group compared to the CONT group in the 12 th and 17 th wk. The sperm count, motility, and viability in the CPZ group significantly decreased compared to the CONT group in the 12 th and 17 th wk of the study. Conclusion: Chronic demyelination induced by CPZ intoxication, maybe through damage to the hypothalamus arcuate nucleus, leads to the hypothalamic-pituitary-gonadal axis disturbance and damage to the testis and spermatogenesis subsequently.

Neuroprotective effects of rutin against cuprizone-induced multiple sclerosis in mice.

Multiple sclerosis (MS) is a chronic inflammatory neurodegenerative disease of the central nervous system that injures the myelin sheath, provoking progressive axonal degeneration and functional impairments. No efficient therapy is available at present to combat such insults, and hence, novel safe and effective alternatives for MS therapy are extremely required. Rutin (RUT) is a flavonoid that exhibits antioxidant, anti-inflammatory, and neuroprotective effects in several brain injuries. The present study evaluated the potential beneficial effects of two doses of RUT in a model of pattern-III lesion of MS, in comparison to the conventional standard drug; dimethyl fumarate (DMF). Demyelination was induced in in male adult C57BL/6 mice by dietary 0.2% (w/w) cuprizone (CPZ) feeding for 6 consecutive weeks. Treated groups received either oral RUT (50 or 100 mg/kg) or DMF (15 mg/kg), along with CPZ feeding, for 6 consecutive weeks. Mice were then tested for behavioral changes, followed by biochemical analyses and histological examinations of the corpus callosum (CC). Results revealed that CPZ caused motor dysfunction, demyelination, and glial activation in demyelinated lesions, as well as significant oxidative stress, and proinflammatory cytokine elevation. Six weeks of RUT treatment significantly improved locomotor activity and motor coordination. Moreover, RUT considerably improved remyelination in the CC of CPZ + RUT-treated mice, as revealed by luxol fast blue staining and transmission electron microscopy. Rutin also significantly attenuated CPZ-induced oxidative stress and inflammation in the CC of tested animals. The effect of RUT100 was obviously more marked than either that of DMF, regarding most of the tested parameters, or even its smaller tested dose. In silico docking revealed that RUT binds tightly within NF-κB at the binding site of the protein-DNA complex, with a good negative score of -6.79 kcal/mol. Also, RUT-Kelch-like ECH-associated protein 1 (Keap1) model clarifies the possible inhibition of Keap1-Nrf2 protein-protein interaction. Findings of the current study provide evidence for the protective effect of RUT in CPZ-induced demyelination and behavioral dysfunction in mice, possibly by modulating NF-κB and Nrf2 signaling pathways. The present study may be one of the first to indicate a pro-remyelinating effect for RUT, which might represent a potential additive benefit in treating MS.

How to Use the Cuprizone Model to Study De- and Remyelination.

Multiple sclerosis (MS) is an autoimmune and inflammatory disorder affecting the central nervous system whose cause is still largely unknown. Oligodendrocyte degeneration results in demyelination of axons, which can eventually be repaired by a mechanism called remyelination. Prevention of demyelination and the pharmacological support of remyelination are two promising strategies to ameliorate disease progression in MS patients. The cuprizone model is commonly employed to investigate oligodendrocyte degeneration mechanisms or to explore remyelination pathways. During the last decades, several different protocols have been applied, and all have their pros and cons. This article intends to offer guidance for conducting pre-clinical trials using the cuprizone model in mice, focusing on discovering new treatment approaches to prevent oligodendrocyte degeneration or enhance remyelination.

Microglial Neuroinflammation-Independent Reversal of Demyelination of Corpus Callosum by Arsenic in a Cuprizone-Induced Demyelinating Mouse Model.

Demyelination is the loss of myelin in CNS, resulting in damaged myelin sheath. Oxidative stress and neuroinflammation play a key role in inducing demyelinating diseases like MS; hence, controlling oxidative stress and neuroinflammation is important. Cuprizone (CPZ), a copper chelator, generates oxidative stress and neuroinflammation, thereby inducing demyelination. Therefore, the CPZ-induced demyelinating mouse model (CPZ model) is widely used in research. The present study was intended to unravel a mechanism of inhibition of demyelination by arsenic in a CPZ model, which is otherwise known for its toxicity. We investigated an alternative mechanism of inhibition of demyelination by arsenic through the reversal of SOD1 activity employing in silico analysis, analytical chemistry techniques, and in vitro and in vivo experiments. In vivo experiments showed protection of body weight, survivability, and myelination of the corpus callosum in CPZ and arsenic-co-exposed animals, where neuroinflammation was apparently not involved. In vitro experiments revealed that arsenic-mediated reversal of impaired SOD1 activity leads to reduced cellular ROS levels and better viability of primary oligodendrocytes. Reversal of SOD1 activity was also observed in the corpus callosum tissue isolated from experimental animals. In silico and analytical chemistry studies revealed that similar to copper, arsenic can potentially bind to CPZ and thereby make the copper freely available for SOD1 activity. Suitable neurobehavior tests further validated the protective effect of arsenic. Taken together, the present study revealed that arsenic protects oligodendrocytes and demyelination of corpus callosum by reversing CPZ-induced impaired SOD1 activity.

The sphingosine-1-phosphate receptor 1 modulator ponesimod repairs cuprizone-induced demyelination and induces oligodendrocyte differentiation.

Sphingosine-1-phosphate receptor (S1PR) modulators are clinically used to treat relapse-remitting multiple sclerosis (MS) and the early phase of progressive MS when inflammation still prevails. In the periphery, S1PR modulators prevent lymphocyte egress from lymph nodes, hence hampering neuroinflammation. Recent findings suggest a role for S1PR modulation in remyelination. As the Giα-coupled S1P1 subtype is the most prominently expressed S1PR in oligodendrocyte precursor cells (OPCs), selective modulation (functional antagonism) of S1P1 may have direct effects on OPC functionality. We hypothesized that functional antagonism of S1P1 by ponesimod induces remyelination by boosting OPC differentiation. In the cuprizone mouse model of demyelination, we found ponesimod to decrease the latency time of visual evoked potentials compared to vehicle conditions, which is indicative of functional remyelination. In addition, the Y maze spontaneous alternations test revealed that ponesimod reversed cuprizone-induced working memory deficits. Myelin basic protein (MBP) immunohistochemistry and transmission electron microscopy of the corpus callosum revealed an increase in myelination upon ponesimod treatment. Moreover, treatment with ponesimod alone or in combination with A971432, an S1P5 monoselective modulator, significantly increased primary mouse OPC differentiation based on O4 immunocytochemistry. In conclusion, S1P1 functional antagonism by ponesimod increases remyelination in the cuprizone model of demyelination and significantly increases OPC differentiation in vitro.

Effects of treadmill training on myelin proteomic markers and cerebellum morphology in a rat model of cuprizone-induced toxic demyelination.

BACKGROUND: Multiple sclerosis (MS) is the most common demyelinating disease of the central nervous system (CNS). If demyelination is persistent, it will result in irreversible axonal injury and loss. The purpose of the current study was to investigate the effects of treadmill training on myelin proteomic markers and cerebellum morphology in a rat model of cuprizone-induced toxic demyelination. METHODS: Thirty male rats were randomly assigned to five groups (n = 6 per group), consisting of a healthy control group (Control), a cuprizone (CPZ) group, and three exercise training groups: exercise training before and during the CPZ administration (EX-CPZ-EX), exercise training before the CPZ administration (EX-CPZ), and exercise training during the CPZ administration (CPZ-EX). A rat model of CPZ-induced toxic demyelination consisted of feeding the rats cuprizone pellets (0.2%) for 6 weeks. All exercise groups performed a treadmill training protocol 5 days/week for 6 weeks. Levels of Myelin proteolipid protein (PLP), Myelin oligodendrocyte glycoprotein (MOG), axonal injury in the cerebellar tissue, and volume, weight, and length of the cerebellum were determined. RESULTS: Results indicated a significant decrease in PLP and MOG in the CPZ groups compared to the Control group (****p < 0.0001). There was a significant increase in PLP and MOG and a significant decrease in axonal injury in the EX-CPZ-EX group as compared to other CPZ groups (****p < 0.0001), and CPZ-MS and CPZ-EX were not significantly different from one another. However, there were no significant differences between the groups for the volume, weight, or length of the cerebellum. CONCLUSION: Treadmill training improved myelin sheath structural proteins and axonal injury in cerebellar tissue in a rat model of CPZ-induced toxic demyelination.