Cuprizone Administration Research Articles

Endogenous histidine peptides are physiological antioxidants that prevent oligodendrocyte cell death and myelin loss in vivo.

Histidine dipeptides (HDs) are synthesized in brain oligodendrocytes by carnosine synthase (carns1), but their role is unknown. Using metabolomics and in vivo experiments with both constitutive and oligodendrocyte-selective carns1-KO mouse models, we found that HDs are critical for oligodendrocyte survival and protect against oxidative stress. Carns1-KO mouse models had lower numbers of mature oligodendrocytes, increased lipid peroxidation, and behavioral changes. Cuprizone administration, which increases reactive oxygen species in vivo, resulted in higher oligodendrocyte death, demyelination, axonal alterations, and oxidative damage in the corpus callosum of carns1-KO mice. Gliosis and oxidative damage by cuprizone were prevented by pretreatment with the antioxidant N-acetylcysteine. NADPH levels were increased threefold in the brains of carns1-KO mice as an antioxidant response to oxidative stress through acceleration of the pentose phosphate pathway (PPP). This was due to overexpression of glucose-6-phosphate dehydrogenase, the rate-limiting enzyme of the PPP. Likewise, expression of NAD kinase, the biosynthetic enzyme for NADP+, and NAMPT, which replenishes the NAD+ pool, was higher in carns1-KO mice brains than in controls. Our observations suggest that HDs cell-autonomously protect oligodendrocytes from oxidative stress, with implications for demyelinating diseases.

Evidence for TGF-β1/Nrf2 Signaling Crosstalk in a Cuprizone Model of Multiple Sclerosis.

Multiple sclerosis (MS) is a chronic and degenerative disease that impacts central nervous system (CNS) function. One of the major characteristics of the disease is the presence of regions lacking myelin and an oxidative and inflammatory environment. TGF-β1 and Nrf2 proteins play a fundamental role in different oxidative/inflammatory processes linked to neurodegenerative diseases such as MS. The evidence from different experimental settings has demonstrated a TGF-β1-Nrf2 signaling crosstalk under pathological conditions. However, this possibility has not been explored in experimental models of MS. Here, by using the cuprizone-induced demyelination model of MS, we report that the in vivo pharmacological blockage of the TGF-β1 receptor reduced Nrf2, catalase, and TGFβ-1 protein levels in the demyelination phase of cuprizone administration. In addition, ATP production, locomotor function and cognitive performance were diminished by the treatment. Altogether, our results provide evidence for a crosstalk between TGF-β1 and Nrf2 signaling pathways under CNS demyelination, highlighting the importance of the antioxidant cellular response of neurodegenerative diseases such as MS.

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.

5Z-7-Oxozaenol attenuates cuprizone-induced demyelination in mice through microglia polarization regulation.

Demyelination is a key factor in axonal degeneration and neural loss, leading to disability in multiple sclerosis (MS) patients. Transforming growth factor beta activated kinase 1 (TAK1) is a critical molecule involved in immune and inflammatory signaling pathways. Knockout of microglia TAK1 can inhibit autoimmune inflammation of the brain and spinal cord and improve the outcome of MS. However, it is unclear whether inhibiting TAK1 can alleviate demyelination. Eight-week-old male c57bl/6j mice were randomly divided into five groups: (a) the control group, (b) the group treated with cuprizone (CPZ) only, (c) the group treated with 5Z-7-Oxozaenol (OZ) only, and (d) the group treated with both cuprizone and 15 μg/30 μg OZ. Demyelination in the mice of this study was induced by administration of CPZ (ig) at a daily dose of 400mg/kg for consecutive 5weeks. OZ was intraperitoneally administered at mentioned doses twice a week, starting from week 3 after beginning cuprizone treatment. Histology, rotarod test, grasping test, pole test, Western blot, RT-PCR, and ELISA were used to evaluate corpus callosum demyelination, behavioral impairment, oligodendrocyte differentiation, TAK1 signaling pathway expression, microglia, and related cytokines. Our results demonstrated that OZ protected against myelin loss and behavior impairment caused by CPZ. Additionally, OZ rescued the loss of oligodendrocytes in CPZ-induced mice. OZ inhibited the activation of JNK, p65, and p38 pathways, transformed M1 polarized microglia into M2 phenotype, and increased brain-derived neurotrophic factor (BDNF) expression to attenuate demyelination in CPZ-treated mice. Furthermore, OZ reduced the expression of proinflammatory cytokines and increases anti-inflammatory cytokines in CPZ-treated mice. These findings suggest that inhibiting TAK1 may be an effective approach for treating demyelinating diseases.

Probing Brain Magnetic Susceptibility Alterations in a Mouse Model of Multiple Sclerosis

Multiple sclerosis (MS) is an increasing cause of disability in the United States, characterized by autoimmune demyelinating events in the central nervous system. MS patients can present with a varying range of symptoms and disability due to the chronic inflammatory and relapsing events associated with the disease, such as impaired mobility, slowed cognitive processing, and high probability of disease progression.&#x0D; MS can be morphologically characterized by the damage to the myelin sheath that surrounds axons, oligodendrocytes that produce myelin, and axons that transmit information to different neurons. Due to the complicated mechanism of MS, the advanced MRI methods which can provide both sensitive and specific assessment of MS tissue injury hold the promise to provide critical mechanistic guidance of MS and serve as robust imaging biomarkers for MS. Several animal models have been established to understand the distinct aspects of the disease. Cuprizone, a copper chelator, creates demyelination events comparable to MS, allowing the mouse model to be a representation QSM’s ability to accurately distinguish between and predict acute and chronic demyelination events. Recently, we have demonstrated that the novel quantitative susceptibility mapping (QSM) can identify between the demyelination andremyelination process in the corpus callosum of mice treated with cuprizone. However, how early QSM can detect brain alterations has not been investigated.&#x0D; We acquired high-resolution in vivo whole-brain QSM, T-2 weighted, and magnetization transfer ratio (MTR) images at 0, 2, and 4 weeks after cuprizone administration. The corpus callosum exhibited significant changes in T2-weighted and MTR images at 4 weeks after cuprizone administration. In contrast, QSM decreased significantly in QSM at 2 weeks after cuprizone administration. Since dramatic demyelination only starts after oligodendrocytes depletion (3 weeks after cuprizone treatment), QSM may be able to detect the alteration of oligodendrocytes and serve as a sensitive biomarker even before demyelination occurs.

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

BackgroundMultiple 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. MethodsThirty 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. ResultsResults 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. ConclusionTreadmill training improved myelin sheath structural proteins and axonal injury in cerebellar tissue in a rat model of CPZ-induced toxic demyelination.

Quantitative Analysis of Early White Matter Damage in Cuprizone Mouse Model of Demyelination Using 7.0 T MRI Multiparametric Approach.

Magnetic Resonance Imaging (MRI) is commonly used to follow the progression of neurodegenerative conditions, including multiple sclerosis (MS). MRI is limited by a lack of correlation between imaging results and clinical presentations, referred to as the clinico-radiological paradox. Animal models are commonly used to mimic the progression of human neurodegeneration and as a tool to help resolve the paradox. Most studies focus on later stages of white matter (WM) damage whereas few focus on early stages when oligodendrocyte apoptosis has just begun. The current project focused on these time points, namely weeks 2 and 3 of cuprizone (CPZ) administration, a toxin which induces pathophysiology similar to MS. In vivo T2-weighted (T2W) and Magnetization Transfer Ratio (MTR) maps and ex vivo Diffusion Tensor Imaging (DTI), Magnetization Transfer Imaging (MTI), and relaxometry (T1 and T2) values were obtained at 7 T. Significant changes in T2W signal intensity and non-significant changes in MTR were observed to correspond to early WM damage, whereas significant changes in both corresponded with full demyelination. Some DTI metrics decrease with simultaneous increase in others, indicating acute demyelination. MTI metrics T2A, T2B, f and R were observed to have contradictory changes across CPZ administration. T1 relaxation times were observed to have stronger correlations to disease states during later stages of CPZ treatment, whereas T2 had weak correlations to early WM damage. These results all suggest the need for multiple metrics and further studies at early and late time points of demyelination. Further research is required to continue investigating the interplay between various MR metrics during all weeks of CPZ administration.

Oligodeoxynucleotide IMT504: Effects on Central Nervous System Repair Following Demyelination.

Multiple sclerosis (MS) is an immune-mediated central nervous system (CNS) disease characterized by demyelination resulting from oligodendrocyte loss and inflammation. Cuprizone (CPZ) administration experimentally replicates MS pattern-III lesions, generating an inflammatory response through microgliosis and astrogliosis. Potentially remyelinating agents include oligodeoxynucleotides (ODN) with a specific immunomodulatory sequence consisting of the active motif PyNTTTTGT. In this work, the remyelinating effects of ODN IMT504 were evaluated through immunohistochemistry and qPCR analyses in a rat CPZ-induced demyelination model. Subcutaneous IMT504 administration exacerbated the pro-inflammatory response to demyelination and accelerated the transition to an anti-inflammatory state. IMT504 reduced microgliosis in general and the number of phagocytic microglia in particular and expanded the population of oligodendroglial progenitor cells (OPCs), later reflected in an increase in mature oligodendrocytes. The intracranial injection of IMT504 and intravenous inoculation of IMT504-treated B lymphocytes rendered comparable results. Altogether, these findings unveil potentially beneficial properties of IMT504 in the regulation of neuroinflammation and oligodendrogenesis, which may aid the development of therapies for demyelinating diseases such as MS.

Automated analysis of gray matter damage in aged mice reveals impaired remyelination in the cuprizone model.

Multiple sclerosis is a chronic autoimmune disease of the central nervous system characterized by myelin loss, axonal damage, and glial scar formation. Still, the underlying processes remain unclear, as numerous pathways and factors have been found to be involved in the development and progression of the disease. Therefore, it is of great importance to find suitable animal models as well as reliable methods for their precise and reproducible analysis. Here, we describe the impact of demyelination on clinically relevant gray matter regions of the hippocampus and cerebral cortex, using the previously established cuprizone model for aged mice. We could show that bioinformatic image analysis methods are not only suitable for quantification of cell populations, but also for the assessment of de- and remyelination processes, as numerous objective parameters can be considered for reproducible measurements. After cuprizone-induced demyelination, subsequent remyelination proceeded slowly and remained incomplete in all gray matter areas studied. There were regional differences in the number of mature oligodendrocytes during remyelination suggesting region-specific differences in the factors accounting for remyelination failure, as, even in the presence of oligodendrocytes, remyelination in the cortex was found to be impaired. Upon cuprizone administration, synaptic density and dendritic volume in the gray matter of aged mice decreased. The intensity of synaptophysin staining gradually restored during the subsequent remyelination phase, however the expression of MAP2 did not fully recover. Microgliosis persisted in the gray matter of aged animals throughout the remyelination period, whereas extensive astrogliosis was of short duration as compared to white matter structures. In conclusion, we demonstrate that the application of the cuprizone model in aged mice mimics the impaired regeneration ability seen in human pathogenesis more accurately than commonly used protocols with young mice and therefore provides an urgently needed animal model for the investigation of remyelination failure and remyelination-enhancing therapies.

Effects of Five Coumarins and Standardized Extracts from Tagetes lucida Cav. on Motor Impairment and Neuroinflammation Induced with Cuprizone.

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) with no curative treatment, and the available therapies aim to modify the course of the disease. It has been demonstrated that extracts of Tagetes lucida have immunomodulatory and neuroprotective effects. This work induced motor damage and neuroinflammation in male BALB/c mice by oral administration of cuprizone (CPZ) (40 mg/kg) for five weeks. In addition, the extracts and coumarins of Tagetes lucida (25 mg/kg) were used to control these damage variables; during the experiment, animals were subject to behavioral tests, and at the end of 5 weeks, mice from each group were used to measure the integrity of biological barriers (brain, kidneys, and spleen) through the extravasation test with blue Evans dye. In another group of animals, the ELISA method measured the brain concentrations of IL-1β, IL-4, IL-10, and TNF-α. The results presented here allow us to conclude that the extracts and coumarins IC, HN, PE, DF, and SC of Tagetes lucida exert a neuroprotective effect by controlling the motor damage and neuroinflammation by increasing the expression of IL-4 and IL-10 and decreasing IL-1β and TNF-α; notably, these treatments also protect organs from vascular permeability increase, mainly the BBB, in mice with CPZ-induced experimental encephalomyelitis (VEH * p < 0.05). However, more studies must be carried out to elucidate the molecular mechanisms of the pharmacological effects of this Mexican medicinal plant.

Bifidobacterium breve Probiotic Compared to Lactobacillus casei Causes a Better Reduction in Demyelination and Oxidative Stress in Cuprizone-Induced Demyelination Model of Rat.

Despite the anatomical separation, strong evidence suggested a bidirectional association between gut microbiota and central nervous system. Cross-talk between gut microbiota and brain has an important role in the pathophysiology of neurodegenerative disorders and regenerative processes. However, choosing the appropriate probiotics and combination therapy of probiotics to provide a synergistic effect is very crucial. In the present study, we investigated the effect of Lactobacillus casei (L. casei) and Bifidobacterium breve (B. breve) on alternation performance, oxidant/antioxidant biomarkers, the extent of demyelination, and the expression level of HO-1, Nrf-2, Olig2, MBP, PDGFRα, and BDNF in cuprizone (CPZ)-induced demyelination model of rat corpus callosum. In order to induce this model, rats received oral administration of CPZ 0.6% w/w in corn oil for 28days. Then, L. casei, B. breve, or their combinations were orally administrated for 28days. Y maze test was performed to investigate the alternation performance. Oxidant/antioxidant biomarkers were determined by colorimetric methods. Extent of demyelination was investigated using FluoroMyelin staining. The genes' expression levels of antioxidant and myelin lineage cells were assessed by quantitative real time PCR. The results showed the probiotics supplementation significantly improve the alternation performance and antioxidant capacity in demyelinated corpus callosum. Interestingly, B. breve supplementation alleviated demyelination and oxidative stress levels more than the administration of L. casei alone or the combination of two probiotics. These observations suggest that B. breve could provide a supplementary strategy for the treatment of multiple sclerosis by increasing antioxidant capacity and remyelination.

Reaction of different cell types of the brain on neurotoxin cuprizone and hormone melatonin treatment in young and aging mice.

The brain myelin and neurons destruction in multiple sclerosis may be associated with the production of neuroinflammatory cells (macrophages, astrocytes, T-lymphocytes) of pro-inflammatory cytokines and free radicals. The age-associated changes of the above cells can influence on the response of nervous system cells to toxic damaging and regulatory factors of humoral/endocrine nature, in particular pineal hormone melatonin. The study aim was (1) to evaluate changes of the brain macrophages, astrocytes, T-cells, neural stem cells, neurons, and central nervous system (CNS) functioning in the neurotoxin cuprizone-treated mice of different age; and (2) to assess in such mice the effects of exogenous melatonin and possible courses of its action. A toxic demyelination and neurodegeneration model was induced in 129/Sv mice aged 3-5 and 13-15 months by adding cuprizone neurotoxin to their food for 3 weeks. From the 8th day of the cuprizone treatment, melatonin was injected intraperitoneally at 6 p.m. daily, at a dose of 1 mg/kg. The brain GFPA + -cells were evaluated by immunohistochemical method, the proportion of CD11b+, CD3+CD11b+, CD3+, CD3+CD4+, CD3+CD8+, Nestin+-cells was determined via flow cytometry. Macrophage activity was evaluated by their ability to phagocytose latex beads Morphometric analysis of the brain neurons and the behavioral reactions ("open field" and rotarod tests) were performed. To assess the involvement of the bone marrow and thymus in the action of melatonin, the amount of granulocyte/macrophage colony-forming cells (GM-CFC), and blood monocytes and thymic hormone thymulin were evaluated. The numbers of the GFAP+-, CD3+-, CD3+CD4+, CD3+CD8+, CD11b+, CD3+CD11b+, Nestin+-cells and macrophages phagocytic latex beads and malondialdehyde (MDA) content were increased in the brain of young and aging mice under cuprizone influence. The proportion of undamaged neurons within the brain, motor, affective, and exploratory activities, and muscle tone decreased in mice of both ages. Introducing melatonin to mice of any age reduced the number of GFAP+-, CD3+- cells and their subpopulations, macrophage activation, and MDA content. At the same time, the percentage of brain neurons that were unchanged increased as the number of Nestin+ cells decreased. The behavioral responses were also improved. Besides, the number of bone marrow GM-CFC and the blood level of monocytes and thymulin increased. The effects of both neurotoxin and melatonin on the brain astrocytes, macrophages T-cells, and immune system organs as well as the structure and functioning of neurons were more pronounced in the young mice. We have observed the involvement of the astrocytes, macrophages, T-cells, neural stem cells, and neurons in the brain reaction of mice different age after administration of neurotoxin cuprizone and melatonin. The brain cell composition reaction has the age features. The neuroprotective effects of melatonin in cuprizone-treated mice have been realized through an improvement of the brain cell composition and oxidative stress factors and functioning of bone marrow and thymus.

Brain-specific glycosylation of protein tyrosine phosphatase receptor type Z (PTPRZ) marks a demyelination-associated astrocyte subtype.

Astrocytes are the most abundant glial cell type in the brain, where they participate in various homeostatic functions. Transcriptomically, diverse astrocyte subpopulations play distinct roles during development and disease progression. However, the biochemical identification of astrocyte subtypes, especially by membrane surface protein glycosylation, remains poorly investigated. Protein tyrosine phosphatase receptor type zeta (PTPRZ) is a highly expressed membrane protein in CNS glia cells that can be modified with diverse glycosylation, including the unique HNK-1 capped O-mannosyl (O-Man) core M2 glycan mediated by brain-specific branching enzyme GnT-IX. Although PTPRZ modified with HNK-1 capped O-Man glycans (HNK-1-O-Man+ PTPRZ) is increased in reactive astrocytes of demyelination model mice, whether such astrocytes emerge in a broad range of disease-associated conditions or are limited to conditions associated with demyelination remains unclear. Here, we show that HNK-1-O-Man+ PTPRZ localizes in hypertrophic astrocytes of damaged brain areas in patients with multiple sclerosis. Furthermore, we show that astrocytes expressing HNK-1-O-Man+ PTPRZ are present in two demyelination mouse models (cuprizone-fed mice and a vanishing white matter disease model), while traumatic brain injury does not induce glycosylation. Administration of cuprizone to Aldh1l1-eGFP and Olig2KICreER/+ ;Rosa26eGFP mice revealed that cells expressing HNK-1-O-Man+ PTPRZ are derived from cells in the astrocyte lineage. Notably, GnT-IX but not PTPRZ mRNA was up-regulated in astrocytes isolated from the corpus callosum of cuprizone model mice. These results suggest that the unique PTPRZ glycosylation plays a key role in the patterning of demyelination-associated astrocytes.

Genetic models of cleavage-reduced and soluble TREM2 reveal distinct effects on myelination and microglia function in the cuprizone model

Triggering receptor expressed on myeloid cells 2 (TREM2) is a cell-surface immunoreceptor expressed on microglia, osteoclasts, dendritic cells and macrophages. Heterozygous loss-of-function mutations in TREM2, including mutations enhancing shedding form the cell surface, have been associated with myelin/neuronal loss and neuroinflammation in neurodegenerative diseases, such as Alzheimer`s disease and Frontotemporal Dementia. Using the cuprizone model, we investigated the involvement of soluble and cleavage-reduced TREM2 on central myelination processes in cleavage-reduced (TREM2-IPD), soluble-only (TREM2-sol), knockout (TREM2-KO) and wild-type (WT) mice. The TREM2-sol mouse is a new model with selective elimination of plasma membrane TREM2 and a reduced expression of soluble TREM2. In the acute cuprizone model demyelination and remyelination events were reflected by a T2-weighted signal intensity change in magnetic resonance imaging (MRI), most prominently in the external capsule (EC). In contrast to WT and TREM2-IPD, TREM2-sol and TREM2-KO showed an additional increase in MRI signal during the recovery phase. Histological analyses of TREM2-IPD animals revealed no recovery of neuroinflammation as well as of the lysosomal marker LAMP-1 and displayed enhanced cytokine/chemokine levels in the brain. TREM2-sol and, to a much lesser extent, TREM2-KO, however, despite presenting reduced levels of some cytokines/chemokines, showed persistent microgliosis and astrocytosis during recovery, with both homeostatic (TMEM119) as well as activated (LAMP-1) microglia markers increased. This was accompanied, specifically in the EC, by no myelin recovery, with appearance of myelin debris and axonal pathology, while oligodendrocytes recovered. In the chronic model consisting of 12-week cuprizone administration followed by 3-week recovery TREM2-IPD displayed sustained microgliosis and enhanced remyelination in the recovery phase. Taken together, our data suggest that sustained microglia activation led to increased remyelination, whereas microglia without plasma membrane TREM2 and only soluble TREM2 had reduced phagocytic activity despite efficient lysosomal function, as observed in bone marrow-derived macrophages, leading to a dysfunctional phenotype with improper myelin debris removal, lack of remyelination and axonal pathology following cuprizone intoxication.

L-Theanine Improves Locomotor Function in a Model of Multiple Sclerosis Mice.

This study designed to investigate the protective effects of L-theanine on experimental Multiple sclerosis in mice. Frothy Male C57BL/6 mice were allocated into 4 experimental groups: control no treatment received a regular chew pellet, and the cuprizone (CPZ) group received a standard chew pellet containing 0.2% (w/w) CPZ. In group 3, mice were fed a regular diet and administered p.o. with L-theanine (50mg/kg). In group 4, mice received a diet containing CPZ and were administered p.o. with L-theanine (50mg/kg). Finally, reflexive motor behavior and serum antioxidant levels were determined. Based on findings, CPZ significantly decreased ambulation score, hind-limb suspension, front limb suspension, and grip strength (P<0.05). The CPZ + L-theanine reduced the adverse effect of the CPZ on ambulation score, hind-limb foot angle, surface righting, and negative geotaxis (P<0.05). The CPZ + L-theanine increased front and hind-limb suspension, grip strength, number of the cross, and duration of a stay on the rotarod compared to the control animal (P<0.05). CPZ administration significantly elevated serum malondialdehyde (MDA) while superoxide dismutase (SOD) and glutathione peroxidase (GPx) and total antioxidant status (TAS) levels decreased compared to control mice (P<0.05). The CPZ + L-theanine leads to the cessation of MDA production while increasing SOD, GPx, and TAS levels (P<0.05). These results suggested L-theanine has a protective effect against CPZ-induced MS in mice.

Sulforaphane, an Nrf-2 Agonist, Modulates Oxidative Stress and Inflammation in a Rat Model of Cuprizone-Induced Cardiotoxicity and Hepatotoxicity

Cuprizone (CPZ) is a neurotoxic agent that is used to induce demyelination and neurotoxicity in rats. This study aimed to investigate the protective potential of sulforaphane (SF), nuclear factor E2 related factor (Nrf-2) activator, against CPZ-induced cardiotoxicity and hepatotoxicity. Male adult Wistar rats (n = 18) were fed with a regular diet or a CPZ-contained diet (0.2%) for four weeks. The rats were divided into three groups (n = 6): negative control rats, CPZ-exposed rats, and CPZ + SF treated rats. SF was intraperitoneally administrated (2 mg/kg/day) for two weeks. The anti-inflammatory and anti-oxidative functions of SF were investigated biochemically, histologically, and immunohistochemically. CPZ increased serum levels of cardiac troponin 1 (CTn1), aspartate amino transaminase (AST), alanine amino transaminase (ALT), and alkaline phosphatase (ALP). In addition, serum levels of inflammatory interferon-gamma (IFN-γ), and pro-inflammatory interleukin 1β (IL-1β) were significantly elevated. Moreover, CPZ administration provoked oxidative stress as manifested by declined serum levels of total antioxidant capacity (TAC), as well as, stimulated lipid peroxidation and decreased catalase activities in both cardiac and hepatic tissues. SF treatment reversed all these biochemical alterations through exerting anti-oxidative and anti-inflammatory activities, and this was supported by histopathological investigations in both cardiac and hepatic tissues. This SF-triggered modulation of oxidative stress and inflammation is strongly associated with Nrf-2 activation, as evidenced by activated immunoexpression in both cardiac and hepatic tissues. This highlights the cardioprotective and hepatoprotective activities of SF via Nrf-2 activation and enhancing catalase function.

Sex Differences in the Behavioural Aspects of the Cuprizone-Induced Demyelination Model in Mice.

Multiple sclerosis is an autoimmune disease characterised by demyelination in the central nervous system. The cuprizone-induced demyelination model is often used in mice to test novel treatments for multiple sclerosis. However, despite significant demyelination, behavioural deficits may be subtle or have mixed results depending on the paradigm used. Furthermore, the sex differences within the model are not well understood. In the current study, we have sought to understand the behavioural deficits associated with the cuprizone-induced demyelination model in both male and female C57BL/6J mice. Using Black gold II stain, we found that cuprizone administration over 6 weeks caused significant demyelination in the corpus callosum that was consistent across both sexes. Cuprizone administration caused increased mechanical sensitivity when measured using an electronic von Frey aesthesiometer, with no sex differences observed. However, cuprizone administration decreased motor coordination, with more severe deficits seen in males in the horizontal bar and passive wire hang tests. In contrast, female mice showed more severe deficits in the motor skill sequence test. Cuprizone administration caused more anxiety-like behaviours in males compared to females in the elevated zero maze. Therefore, this study provides a better understanding of the sex differences involved in the behavioural aspects of cuprizone-induced demyelination, which could allow for a better translation of results from the laboratory to the clinic.

N-acetylcysteine protects against cuprizone-induced demyelination: histological and immunohistochemical study.

Myelination is a sequential process that is tightly controlled by a number of intrinsic and extrinsic factors. Any central nervous system disease in which the neuronal myelin sheath is damaged is referred to as demyelinating disease. The present work was designed to study the histopathological, ultrastructural and immunohistochemical changes in rat brain, mainly corpus callosum (CC), following oral administration of cuprizone (CPZ), and the role of N-acetylcysteine (NAC) in reducing these changes. Demyelination was induced by CPZ administration for short (4 weeks) and long (8 weeks) periods. NAC was given concomitantly and sequentially for similar periods. Spontaneous recovery after cessation of CPZ followed by no medication was also investigated. At the end of each experimental period, both cerebral hemispheres were extracted and prepared for light and electron microscopic examination and immuno-histochemical study. The obtained results showed a direct proportion between the duration of CPZ administration and the severity of demyelination. The co-administration of CPZ and NAC, had a fair protective impact that was stronger than the sequential administration of the two drugs. Incomplete spontaneous remyelination was observed after cessation of CPZ, being more evident in short than in long period group, indicating that when CPZ administration is prolonged, remyelination is delayed. In the light of the above results, it could be concluded that NAC has neuroprotective effects and has the potential to be a novel therapeutic approach for the treatment of demyelinating diseases such as multiple sclerosis; however, treatment should begin as soon as the disease manifests.

Efficacy of different intensity of aquatic exercise in enhancing remyelination and neuronal plasticity using cuprizone model in male Wistar rats.

Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system (CNS). Most exercise studies concentrate on the impact of exercise on cardiovascular system; this study aims to present the effects of exercise of varying intensity on the nervous system. Most recently in MS, positive outcomes were obtained with resistance and high-intensity exercises. This study also analyzes the effects of a prior conditioning program before the induction of demyelination and subsequent neuroprotective effects of such program. To study and determine the neuroprotective and remyelinating effects of different intensity of aquatic exercise and a preconditioning exercise program on demyelination induced by oral administration of cuprizone (Cup). Six groups of animals, each containing 6 rats, were used in the study. The groups were as follows: group I - control group; group II - Cup group; group III - treated with methylprednisolone (MP); group IV - treated with low-intensity exercise (LIE), free swimming for 40 min and high-intensity exercise (HIE); group V - treated with a resistance of 9% body weight and free swimming for 40 min; group VI - treated with preconditioning exercise (free swimming for 40 min for 3 weeks) before Cup administration followed by the same exercise protocol as for group V. All data were analyzed using one-way analysis of variance (ANOVA) with Tukey's test, by means of SigmaPlot v. 14.5 software. Similarly to the MP group, group VI showed a positive outcome. A value of p < 0.001 was considered statistically significant. Also, group VI showed improved areas of remyelination in histopathology, an increased expression of myelin basic protein (MBP), reduced expression of glial fibrillary acidic protein (GFAP) in corpus callosum, and improved gene expression of brain-derived neurotrophic factor (BDNF) in the hippocampus region. General fitness achieved through a preconditioning program combined with HIE showed neuroprotective effects, as evidenced by increased areas of remyelination and improved neuronal plasticity, observed mostly in group VI (conditioning+HIE).

Зміни ендокринної функції тимуса, макрофагів і Т-лімфоцитів головного мозку в мишей різного віку після введення нейротоксину купризону і цитокіну

Актуальність. Відома участь макрофагів і Т­лімфоцитів в ушкодженні нервових клітин головного мозку. Гормон тимуса тимулін виявляє імуномодулюючі й антизапальні властивості. Вікові зміни активності макрофагів, Т­лімфоцитів головного мозку та тимуса можуть впливати на їх відповідь на дію токсичних та регуляторних факторів. Мета — дослідження змін рівня в крові тимуліну та кількості макрофагів і Т­лімфоцитів у головному мозку молодих і старіючих мишей, яким вводили нейротоксин купризон і рекомбінантний лейкемія­інгібіторний фактор людини (rhLIF). Матеріали та методи. Миші лінії 129/Sv отримували з їжею щоденно купризон упродовж 3 тижнів. З 8­ї доби купризонової дієти щоденно вводили rhLIF у дозі 50 мг/кг. Результати. Підвищення рівня в крові тимуліну через 7 діб прийому купризону інтенсивніше в молодих мишей, ніж у старіючих. Через 3 тижні купризонової дієти рівень гормона зменшувався тільки в молодих мишей. Кількість макрофагів у головному мозку молодих мишей збільшувалась вже через 7 діб прийому купризону, а у старіючих — тільки через 3 тижні. У мишей обох вікових груп із купризоновою дієтою (особливо в молодих) збільшувалась кількість Т­клітин у головному мозку. Ін’єкції rhLIF підвищували рівень у крові тимуліну і зменшували кількість Т­клітин у головному мозку молодих мишей, тоді як у старіючих мишей спостерігалось зменшення кількості макрофагів у головному мозку. Висновки. Дія як купризону, так і rhLIF на ендокринну функцію тимуса та кількість макрофагів і Т­лімфоцитів у головному мозку мишей залежить від віку.