The effects of melatonin supplementation on neurobehavioral outcomes and clinical severity in rodent models of multiple sclerosis; a systematic review and meta-analysis.

BACKGROUND: Through the antioxidant and anti-inflammation pathways, melatonin is proposed as a safe and effective intervention in neurological diseases. This study aims to evaluate the effects of melatonin supplementation on the neurobehavioral and clinical outcomes in animal models of multiple sclerosis (MS). METHODS: This study was conducted following the PRISMA statement. Animal studies that reported the effects of melatonin in preclinical MS models, including the experimental autoimmune encephalomyelitis (EAE) and cuprizone model for demyelination are included in this study. A systematic search in PubMed, Web of Science, Embase, and Scopus up was conducted in April 2023. The collaborative Approach to Meta-Analysis and Review of Animal Experimental Studies (CAMARADES) critical appraisal tool was used for the quality assessment of the studies and the quantitative synthetizes were conducted using the comprehensive meta-analysis software. RESULTS: Out of 542 studies, finally 21 studies, including 14 studies in the EAE model and 7 studies of the toxic demyelination method with cuprizone were included. The route of administration was intraperitoneal in 18 studies, oral in 2 studies, and subcutaneous in 1 study. The quantitative synthesis of the EAE clinical severity scale was associated with significant differences (standardized mean difference [SDM]: - 2.52; - 3.61 to - 1.42; p value < 0.01). In subgroup analyses, the difference was statistically significant in the mouse subgroup (SMD: - 2.60; - 3.74 to - 1.46; p value < 0.01). DISCUSSION: This study encountered that melatonin may be associated with improved behavioral and cognitive outcomes of preclinical models of MS with acceptable safety profiles. FUNDING: The research was supported by the Student Research Committee, Tabriz University of Medical Sciences (grant number: 71005).

Cu,Zn-Superoxide Dismutase has Minimal Effects Against Cuprizone-Induced Demyelination, Microglial Activation, and Neurogenesis Defects in the C57BL/6 Mouse Hippocampus.

Cuprizone causes consistent demyelination and oligodendrocyte damage in the mouse brain. Cu,Zn-superoxide dismutase 1 (SOD1) has neuroprotective potential against various neurological disorders, such as transient cerebral ischemia and traumatic brain injury. In this study, we investigated whether SOD1 has neuroprotective effects against cuprizone-induced demyelination and adult hippocampal neurogenesis in C57BL/6 mice, using the PEP-1-SOD1 fusion protein to facilitate the delivery of SOD1 protein into hippocampal neurons. Eight weeks feeding of cuprizone-supplemented (0.2%) diets caused a significant decrease in myelin basic protein (MBP) expression in the stratum lacunosum-moleculare of the CA1 region, the polymorphic layer of the dentate gyrus, and the corpus callosum, while ionized calcium-binding adapter molecule 1 (Iba-1)-immunoreactive microglia showed activated and phagocytic phenotypes. In addition, cuprizone treatment reduced proliferating cells and neuroblasts as shown using Ki67 and doublecortin immunostaining. Treatment with PEP-1-SOD1 to normal mice did not show any significant changes in MBP expression and Iba-1-immunoreactive microglia. However, Ki67-positive proliferating cells and doublecortin-immunoreactive neuroblasts were significantly decreased. Simultaneous treatment with PEP-1-SOD1 and cuprizone-supplemented diets did not ameliorate the MBP reduction in these regions, but mitigated the increase of Iba-1 immunoreactivity in the corpus callosum and alleviated the reduction of MBP in corpus callosum and proliferating cells, not neuroblasts, in the dentate gyrus. In conclusion, PEP-1-SOD1 treatment only has partial effects to reduce cuprizone-induced demyelination and microglial activation in the hippocampus and corpus callosum and has minimal effects on proliferating cells in the dentate gyrus.

Ginsenoside Rg1 promotes remyelination and functional recovery in demyelinating disease by enhancing oligodendrocyte precursor cells-mediated myelin repair.

BACKGROUND: Inefficient differentiation of oligodendrocyte precursor cells (OPCs) is one of the significant pathological obstacles of myelin repair and provides an essential therapeutic target against behavioral dysfunction in various neurodegenerative diseases, especially in secondary progressive multiple sclerosis (SPMS). Ginsenoside Rg1 (Rg1) has traditionally been recognized as a protector of neuronal damages, preventing its degeneration. PURPOSE: We investigated the effects of Rg1 on myelin regeneration-mediated by OPCs and its therapeutic significance in SPMS. METHODS: A cuprizone (CPZ) model was established and then administered with Rg1 specific for evaluations of functional recovery and remyelination. In vitro, the primary mouse OPCs were isolated and cultured for examining their ability of myelin repair. Furthermore, a chronic experimental autoimmune encephalomyelitis (EAE) model was utilized to assess the therapeutic value on SPMS. RESULTS: We found that Rg1 promoted functional recovery of the demyelinated mice, including spatial memory, motor function, and anxiety-like behavior. Histologically, Rg1 enhanced myelin-genesis as proven by myelin staining and microstructures of myelin observed by transmission electron microscope. Furthermore, Rg1 significantly increased Olig2+ oligodendrocyte lineage cells in callosum, implying that the pro-remyelination effect of Rg1 was closely correlated to the enhanced differentiation of OPCs. We further demonstrated that Rg1 increased the survival and proliferation of OPCs as well as induced maturation in oligodendrocytes (OLs). Molecular analysis showed that Rg1 transduced the pro-differentiation signaling programmed by the GSK3ß/ß-Catenin pathway. Notably, relying on its pro-remyelination effects, Rg1 ameliorated severity and histopathology of EAE disease. CONCLUSION: By paving the way for OPCs differentiation, Rg1 could maintain the integrity of myelin and is a promising candidate for functional recovery in demyelinating diseases.

Total astragalosides promote oligodendrocyte precursor cell differentiation and enhance remyelination in cuprizone-induced mice through suppression of Wnt/ß-catenin signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Radix Astragali is a traditional Chinese medicine with various pharmacological effects. Total astragalosides (TA), the main effective ingredients in Radix Astragali, exert properties including anti-oxidative stress, anti-neuroinflammation, and neuroprotection. We previously found that TA alleviated experimental autoimmune encephalomyelitis (EAE) progression, a widely used animal model of multiple sclerosis (MS). As a chronic demyelination disease, MS generally manifests myelin loss and fails to myelin regeneration. Regulation of oligodendrocyte progenitor cells (OPCs) differentiation and remyelination is the fundamental strategy for MS treatment. However, whether TA could directly promote OPCs differentiation and remyelination is still unknown. AIMS OF THE STUDY: This study was aimed to investigate pro-differentiation and myelin regeneration effects of TA on OPCs and Cuprizone (CPZ)-induced demyelination mice, an animal model of MS, and to explore mechanism underlying from regulation of OPCs differentiation and maturation. MATERIALS AND METHODS: Mice were orally given CPZ (400 mg/kg) daily for 4 weeks to induce myelin loss, and then treated with TA (25 and 50 mg/kg) daily for 1 week. Cell proliferation assay, Western blot, RT-PCR, immunocytochemistry and immunohistochemistry were performed to explore the mechanisms. The role of TA in oligodendrocyte differentiation and maturation was evaluated using MO3.13, a human oligodendrocytic hybrid cell line. RESULTS: TA was shown to mitigate behavioral impairment in CPZ-induced mice. It markedly ameliorated myelin loss and enhanced remyelination in the corpus callosum of mice, evidenced by increased expression of myelin basic protein (MBP) and the number of CC1+ newly generated oligodendrocytes (OLs). TA also enhanced the expression of MBP at both mRNA and protein levels in MO3.13 cells. In CPZ-induced mice and MO3.13 cells, TA remarkably promoted the activation of GSK3ß, repressed the phosphorylation of ß-catenin, reduced the expression of transcription factor 4 and inhibitor of DNA binding 2. The agonist of ß-catenin, SKL2001, partially abolished the pro-differentiation effect of TA in MO3.13 cells. CONCLUSIONS: Taken together, we clarified that TA could effectively enhance the differentiation and maturation of OPCs and accelerate remyelination in CPZ-induced mice through inhibition of Wnt/ß-catenin signaling pathway. This study provides new insight into the beneficial effect of TA in the treatment of MS.

The effect of Urtica dioica extract on oxidative stress, heat shock proteins, and brain histopathology in multiple sclerosis model.

Multiple sclerosis (MS) results from the destruction of myelin and focal inflammation. The study aimed to evaluate the effect of hydroalcoholic extract of Urtica dioica on oxidative stress, heat shock proteins, and brain histopathology in multiple sclerosis model. Sixty male C57BL/6 mice were divided into six groups of 10. Groups included positive control, negative control, and treatment groups with U. dioica extract at a dose of 50, 100, 200, and 400 mg/kg for 21 days (three times a week). The MS model was developed by a diet containing 0.2% cuprizone for 6 weeks. A section of brains was evaluated with Luxol Fast Blue staining and the other part evaluated with heat shock protein (HSP) kits 60 and 70, total antioxidant capacity (TAC), and malondialdehyde (MDA). In sections of corpus callosum, the highest amount of myelin was observed in the negative controls, while the use of cuprizone in the positive controls caused the destruction and reduction of myelin. The use of U. dioica extract in therapeutic groups except at a dose of 50 mg/kg could reduce myelin degradation to some extent and lead to remyelination. However, myelin levels in treatment groups were not significantly different from any of the negative and positive controls. Although HSP60 decreased in the treatment groups, there was no significant difference between the positive and negative controls. Treatment with this extract significantly reduced the amount of HSP70 compared with the positive controls. The decreased TAC and increased MDA in positive controls indicated oxidative stress, respectively. Furthermore, the extract led to an increase and decrease of TAC and MDA in the treatment groups, respectively. However, only the MDA level was significantly different from that of the positive controls. Therefore, the antioxidant effects of U. dioica extract could decrease cuprizone-induced oxidative stress and be effective in improving demyelination.

Suppressive Effect of Fruiting Bodies of Medicinal Mushrooms on Demyelination and Motor Dysfunction in a Cuprizone-Induced Multiple Sclerosis Mouse Model.

Epidemiologic studies have shown a high prevalence of multiple sclerosis (MS) in Europe and North America, and a low prevalence in East Asia. Mushrooms contain various biological response modifiers (BRMs) and are widely used in traditional Chinese medicine in East Asian countries. To investigate whether mushrooms have potential beneficial effects on MS, we administered mushrooms to cuprizone (bis-cyclohexanone-oxalyldihydrazone, CPZ)-induced MS model mice. This model is used to study the processes of demyelination in the CNS. The CPZ-induced demyelination is involved in the apoptotic death of mature oligodendrocytes, neuroinflammation, and motor dysfunction. Mice were fed a powdered diet containing 5% each mushroom and CPZ diet for 5 weeks, which coincides with peak demyelination. We measured the body weight of the mice, evaluated their motor function using a rotarod, and quantified the myelin levels using Black-Gold II staining. Ganoderma lucidum and Hericium erinaceus treatments showed recovery from weight loss. Pleurotus eryngii, G. lucidum, and Flammulina velutipes treatments significantly improved CPZ-induced motor dysfunction. P. eryngii, G. lucidum, F. velutipes, and H. erinaceus treatments effectively suppressed CPZ-induced demyelination. The four medicinal mushrooms may be promising BRMs for prevention and alleviation of the symptoms of MS.

Modulation of pacemaker channel function in a model of thalamocortical hyperexcitability by demyelination and cytokines.

A consensus is yet to be reached regarding the exact prevalence of epileptic seizures or epilepsy in multiple sclerosis (MS). In addition, the underlying pathophysiological basis of the reciprocal interaction among neuroinflammation, demyelination, and epilepsy remains unclear. Therefore, a better understanding of cellular and network mechanisms linking these pathologies is needed. Cuprizone-induced general demyelination in rodents is a valuable model for studying MS pathologies. Here, we studied the relationship among epileptic activity, loss of myelin, and pro-inflammatory cytokines by inducing acute, generalized demyelination in a genetic mouse model of human absence epilepsy, C3H/HeJ mice. Both cellular and network mechanisms were studied using in vivo and in vitro electrophysiological techniques. We found that acute, generalized demyelination in C3H/HeJ mice resulted in a lower number of spike-wave discharges, increased cortical theta oscillations, and reduction of slow rhythmic intrathalamic burst activity. In addition, generalized demyelination resulted in a significant reduction in the amplitude of the hyperpolarization-activated inward current (Ih) in thalamic relay cells, which was accompanied by lower surface expression of hyperpolarization-activated, cyclic nucleotide-gated channels, and the phosphorylated form of TRIP8b (pS237-TRIP8b). We suggest that demyelination-related changes in thalamic Ih may be one of the factors defining the prevalence of seizures in MS.

Paeonol Ameliorates Cuprizone-Induced Hippocampal Demyelination and Cognitive Deficits through Inhibition of Oxidative and Inflammatory Events.

Multiple sclerosis (MS) is a chronic and inflammatory disorder of the central nervous system with autoimmune nature that is typified by varying degrees of demyelination and axonal damage. Paeonol is an active ingredient in some medicinal plants with anti-inflammatory and neuroprotective property. This study was conducted to reveal whether paeonol can alleviate hippocampal demyelination and cognitive deficits in cuprizone-induced murine model of demyelination as a model of MS. C57BL/6 mice received oral cuprizone (400 mg/kg) for 6 weeks, and paeonol was administered p.o. at two doses of 25 or 100 mg/kg, starting from the second week post-cuprizone for 5 weeks. After assessment of learning and memory in different tasks, oxidative stress and inflammation were evaluated besides immunohistochemical assessment of hippocampal myelin basic protein (MBP). Paeonol (100 mg/kg) properly ameliorated cognitive deficits in Y maze, novel object discrimination (NOD) test, and Barnes maze with no significant improvement of performance in passive avoidance task. In addition, paeonol treatment at the higher dose was also associated with partial restoration of hippocampal level of oxidative stress and inflammatory markers including MDA, ROS, GSH, SOD, catalase, NF-kB, and TNF. Besides, paeonol improved MMP as an index of mitochondrial integrity and health and reduced MPO as a factor of neutrophil infiltration. Furthermore, paeonol treatment prevented hippocampal MBP immunoreactivity, indicating its prevention of demyelination. In conclusion, the current study showed the preventive effect of paeonol against cuprizone-induced demyelination and cognitive deficits through reversing most oxidative stress- and inflammation-related parameters in addition to its improvement of mitochondrial health.

Rg1 exerts protective effect in CPZ-induced demyelination mouse model via inhibiting CXCL10-mediated glial response.

Myelin damage and abnormal remyelination processes lead to central nervous system dysfunction. Glial activation-induced microenvironment changes are characteristic features of the diseases with myelin abnormalities. We previously showed that ginsenoside Rg1, a main component of ginseng, ameliorated MPTP-mediated myelin damage in mice, but the underlying mechanisms are unclear. In this study we investigated the effects of Rg1 and mechanisms in cuprizone (CPZ)-induced demyelination mouse model. Mice were treated with CPZ solution (300 mg· kg-1· d-1, ig) for 5 weeks; from week 2, the mice received Rg1 (5, 10, and 20 mg· kg-1· d-1, ig) for 4 weeks. We showed that Rg1 administration dose-dependently alleviated bradykinesia and improved CPZ-disrupted motor coordination ability in CPZ-treated mice. Furthermore, Rg1 administration significantly decreased demyelination and axonal injury in pathological assays. We further revealed that the neuroprotective effects of Rg1 were associated with inhibiting CXCL10-mediated modulation of glial response, which was mediated by NF-κB nuclear translocation and CXCL10 promoter activation. In microglial cell line BV-2, we demonstrated that the effects of Rg1 on pro-inflammatory and migratory phenotypes of microglia were related to CXCL10, while Rg1-induced phagocytosis of microglia was not directly related to CXCL10. In CPZ-induced demyelination mouse model, injection of AAV-CXCL10 shRNA into mouse lateral ventricles 3 weeks prior CPZ treatment occluded the beneficial effects of Rg1 administration in behavioral and pathological assays. In conclusion, CXCL10 mediates the protective role of Rg1 in CPZ-induced demyelination mouse model. This study provides new insight into potential disease-modifying therapies for myelin abnormalities.

A novel probiotic strain exerts therapeutic effects on mouse model of multiple sclerosis by altering the expression of inflammasome and IDO genes and modulation of T helper cytokine profile.

Multiple sclerosis is an inflammatory demyelinating disease that commences to neuronal cell destruction. Recently, a promising evidence of synergic effects of combined supplementation with vitamin D and probiotics in modulating the gut microbiota and metabolome is emerging. Bacillus Coagulans IBRC-M10791 as a novel strain was chosen, prevention and treatment impacts of regular administered were studied in Cuprizone-induced C57bl/6 mouse of demyelination. The mice were divided into six groups and received a daily dose of cuprizone or probiotics. To investigate the effect of probiotic, the IDO-1, CYP27B1, NLRP1, NLRP3, and AIM2 expression were estimated by Real-Time PCR, and IL-4, IL-17, IFN-gamma, and TGF-beta cytokines were measured by ELISA. The results showed that there was significant decrease in IL-17 and IFN-γ and modulatory effects on IL-4 and TGF-ß. On the other hand, we demonstrated that there are significant decrease for expression of IDO-1, CYP27b1, NLRP1, NLRP3 and AIM2 genes in prevention and treatment groups compared to cuprizone group. Also, a significant enhancement in rate of remyelination and alternations proved by LFB staining and Y-Maze test. In conclusion, our study provides insight into how the therapeutic effect of the chosen strain of probiotic was correlated with the modulation of the level of inflammatory and anti-inflammatory cytokines. Further, we demonstrated that the expression of genes related to Tryptophan, Vitamin D and Inflammasome pathways could be affected by B.coagulans. Our study could be beneficial to provide a novel Co-therapeutic strategy for Multiple sclerosis.

Citrullinated myelin induces microglial TNFα and inhibits endogenous repair in the cuprizone model of demyelination.

BACKGROUND: Microglia are the primary phagocytes of the central nervous system and are responsible for removing damaged myelin following demyelination. Previous investigations exploring the consequences of myelin phagocytosis on microglial activation overlooked the biochemical modifications present on myelin debris. Such modifications, including citrullination, are increased within the inflammatory environment of multiple sclerosis lesions. METHODS: Mouse cortical myelin isolated by ultracentrifugation was citrullinated ex vivo by incubation with the calcium-dependent peptidyl arginine deiminase PAD2. Demyelination was induced by 6 weeks of cuprizone (0.3%) treatment and spontaneous repair was initiated by reversion to normal chow. Citrullinated or unmodified myelin was injected into the primary motor cortex above the cingulum bundle at the time of reversion to normal chow and the consequent impact on remyelination was assessed by measuring the surface area of myelin basic protein-positive fibers in the cortex 3 weeks later. Microglial responses to myelin were characterized by measuring cytokine release, assessing flow cytometric markers of microglial activation, and RNAseq profiling of transcriptional changes. RESULTS: Citrullinated myelin induced a unique microglial response marked by increased tumor necrosis factor α (TNFα) production both in vitro and in vivo. This response was not induced by unmodified myelin. Injection of citrullinated myelin but not unmodified myelin into the cortex of cuprizone-demyelinated mice significantly inhibited spontaneous remyelination. Antibody-mediated neutralization of TNFα blocked this effect and restored remyelination to normal levels. CONCLUSIONS: These findings highlight the role of post-translation modifications such as citrullination in the determination of microglial activation in response to myelin during demyelination. The inhibition of endogenous repair induced by citrullinated myelin and the reversal of this effect by neutralization of TNFα may have implications for therapeutic approaches to patients with inflammatory demyelinating disorders.

Antagonizing astrocytic platelet activating factor receptor-neuroinflammation for total flavone of epimedium in response to cuprizone demyelination.

Demyelinating diseases of the central nervous system are characterized by recurrent demyelination and progressive neurodegeneration, but there are no clinical drugs targeting myelin regeneration or improving functional disability in the treatment of multiple sclerosis. Total flavone of Epimedium (TFE) is the main active components of Epimedium, which exhibits the beneficial biological activities in the treatment of diseases, but there is no report in the treatment of demyelinating disorder. The purpose of this study was to explore the therapeutic potential and possible mechanism of TFE in the treatment of demyelination. The results showed that TFE efficiently improved the behavioural performance and histological demyelination in cuprizone (CPZ)-induced demyelinating model. In terms of action, TFE increased astrocytes enrichment in corpus callosum, striatum and cortex, and promoted astrocytes to express neurotrophic factors. Furthermore, the expression of platelet-activating factor receptor (PAFR) in astrocytes was induced by CPZ feeding and LPS stimulation, accompanied by the increase of inflammatory cytokines TNF-α,IL-6 and IL-1ß. TFE declined the expression of PAFR, and inhibited inflammatory response. At the same time, TFE also antagonized PAFR activation and inflammatory response triggered by PAF, which further confirmed that TFE, as a new PAFR antagonist, inhibited the astrocyte-derived inflammatory response by antagonizing PAFR-neuroinflammation axis, thus contributing to myelin protection and regeneration.

Effects of Venlafaxine, Risperidone and Febuxostat on Cuprizone-Induced Demyelination, Behavioral Deficits and Oxidative Stress.

Multiple sclerosis (MS) is a demyelinating, autoimmune disease that affects a large number of young adults. Novel therapies for MS are needed considering the efficiency and safety limitations of current treatments. In our study, we investigated the effects of venlafaxine (antidepressant, serotonin-norepinephrine reuptake inhibitor), risperidone (atypical antipsychotic) and febuxostat (gout medication, xanthine oxidase inhibitor) in the cuprizone mouse model of acute demyelination, hypothesizing an antagonistic effect on TRPA1 calcium channels. Cuprizone and drugs were administered to C57BL6/J mice for five weeks and locomotor activity, motor performance and cold sensitivity were assessed. Mice brains were harvested for histological staining and assessment of oxidative stress markers. Febuxostat and metabolites of venlafaxine (desvenlafaxine) and risperidone (paliperidone) were tested for TRPA1 antagonistic activity. Following treatment, venlafaxine and risperidone significantly improved motor performance and sensitivity to a cold stimulus. All administered drugs ameliorated the cuprizone-induced deficit of superoxide dismutase activity. Desvenlafaxine and paliperidone showed no activity on TRPA1, while febuxostat exhibited agonistic activity at high concentrations. Our findings indicated that all three drugs offered some protection against the effects of cuprizone-induced demyelination. The agonistic activity of febuxostat can be of potential use for discovering novel TRPA1 ligands.

Bee Venom-Derived BBB Shuttle and its Correlation with Oligodendrocyte Proliferation Markers in Mice Model of Multiple Sclerosis.

Multiple sclerosis is a chronic demyelinating disease with a functional disturbance in the immune system and axonal damages. It was shown that Apamin as a blood-brain barrier shuttle acts as a Ca2+ activated K+ channels (SK channels) blocker. In this study, the effects of Apamin on oligodendrocyte differentiation markers were evaluated on an induced model of MS. Briefly, C57BL/6 male mice (22 ± 5 g) except the control group were fed with 0.2% (w/w) cuprizone pellets for 6 weeks. After cuprizone withdrawal, mice were divided randomly into six groups. Apamin (100 µg/kg/BW) was administered intraperitoneally as a co-treatment during phase I (demyelination) or post-treatment phase II (remyelination) twice a week. Mice were anesthetized, perfused with phosphate-buffered saline, then fixed brains were coronally sectioned and the changes in oligodendrocytes markers such as Olig2, PDGFR-α, and BrdU incorporation were assessed by immunohistochemistry assay. Apamin administration increased Olig2+ cells in phase I as compared to the control group (p < 0.0001). Also, a decreasing trend in PDGFRa+ cells observed after cuprizone withdrawal (p < 0.001). 5-Bromo-2'-deoxyuridine (BrdU) incorporation test was confirmed stimulation of oligodendrocyte progenitor cell proliferation in phase I in the Apamin exposed group (p < 0.0001), especially at the subventricular zone. This study highlights the potential therapeutic effects of Apamin as a bee venom-derived peptide on oligodendrocyte precursor proliferation and elevation in myelin content in an oxidative induced multiple sclerosis model due to cuprizone exposure.

Remyelination is enhanced by Astragalus polysaccharides through inducing the differentiation of oligodendrocytes from neural stem cells in cuprizone model of demyelination.

Demyelination is the hallmark of multiple sclerosis (MS). Promoting remyelination is an important strategy to treat MS. Our previous study showed that Astragalus polysaccharides (APS), the main bioactive component of Astragalus membranaceus, could prevent demyelination in experimental autoimmune encephalomyelitis mice. To investigate the effects of APS on remyelination and the underlying mechanisms, in this study we set up a cuprizone-induced demyelination model in mice and treated them with APS. It was found that APS relieved the neurobehavioral dysfunctions caused by demyelination, and efficaciously facilitated remyelination in vivo. In order to determine whether the mechanism of enhancing remyelination was associated with the differentiation of neural stem cells (NSCs), biomarkers of NSCs, astrocytes, oligodendrocytes and neurons were measured in the corpus callosum tissues of mice through Real-time PCR, Western blot and immunohistochemistry assays. Data revealed that APS suppressed the stemness of NSCs, reduced the differentiation of NSCs into astrocytes, and promoted the differentiation into oligodendrocytes and neurons. This phenomenon was confirmed in the differentiation model of C17.2 NSCs cultured in vitro. Since Sonic hedgehog signaling pathway has been proven to be crucial to the differentiation of NSCs into oligodendrocytes, we examined expression levels of the key molecules in this pathway in vivo and in vitro, and eventually found APS activated this signaling pathway. Together, our results demonstrated that APS probably activated Sonic hedgehog signaling pathway first, then induced NSCs to differentiate into oligodendrocytes and promoted remyelination, which suggested that APS might be a potential candidate in treating MS.

Neuroprotective Effects of Telmisartan and Nifedipine Against Cuprizone-Induced Demyelination and Behavioral Dysfunction in Mice: Roles of NF-κB and Nrf2.

Multiple sclerosis is a chronic inflammatory neurodegenerative disease of the central nervous system which injures the myelin sheath. Telmisartan and nifedipine are antihypertensive drugs that recently showed neuroprotective properties against neurodegenerative diseases. This study evaluated the neuroprotective effect of telmisartan or nifedipine in cuprizone-induced demyelination in mice by examining the underlying mechanisms. C57BL/6 mice received a diet containing 0.7% (w/w) cuprizone for 7 days followed by 3 weeks on a 0.2% cuprizone diet. Telmisartan (5 mg/kg/day, p.o.) or nifedipine (5 mg/kg/day, p.o.) was administered for 3 weeks starting from the second week. Telmisartan or nifedipine improved locomotor activity and enhanced motor coordination as demonstrated by open field, rotarod, and grip strength tests. Furthermore, telmisartan or nifedipine restored myelin basic protein mRNA and protein expression and increased luxol fast blue-staining intensity. Telmisartan or nifedipine attenuated cuprizone-induced oxidative stress and apoptosis by decreasing brain malondialdehyde and caspase-3 along with restoring reduced glutathione and brain-derived neurotrophic factor levels. Telmisartan or nifedipine exerted an anti-inflammatory effect by reducing the expression of nuclear factor kappa B (NF-κB p65) as well as pro-inflammatory cytokines and elevating the expression of IκB-α. In parallel, telmisartan or nifedipine upregulated the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and the levels of heme oxygenase-1 and NADPH quinone oxidoreductase 1 enzymes. In conclusion, the current study provides evidence for the protective effect of telmisartan and nifedipine in cuprizone-induced demyelination and behavioral dysfunction in mice possibly by modulating NF-κB and Nrf2 signaling pathways.

Shi-Zhen-An-Shen Decoction, a Herbal Medicine That Reverses Cuprizone-Induced Demyelination and Behavioral Deficits in Mice Independent of the Neuregulin-1 Pathway.

Shi-Zhen-An-Shen decoction (SZASD), a Chinese herbal medicine that is a liquor extracted from plants by boiling, has been reported to be effective in treating schizophrenia. However, the mechanism is unclear. Abnormal demyelination has been implicated in schizophrenia. The aim of this study was to investigate the effect of SZASD on myelin in demyelinated mice exhibiting schizophrenia-like behaviors. Sixty male C57BL/6 mice were randomly divided into six groups (n = 10 per group): (1) control group, (2) cuprizone (CPZ, a copper chelator that induced demyelination, 0.2% w/w)+saline, (3) CPZ+low-dose SZASD (8.65 g·kg-1·d-1), (4) CPZ+medium-dose SZASD (17.29 g·kg-1·d-1), (5) CPZ+high-dose SZASD (25.94 g·kg-1·d-1), and (6) CPZ+quetiapine (QTP, an atypical antipsychotic that served as a positive treatment control, 10 mg·kg-1·d-1). Mice in groups 2-6 were treated with CPZ added to rodent chow for six weeks to induce demyelination. During the last two weeks, these mice were given an oral gavage of sterile saline, SZASD, or quetiapine. Behavioral tests and brain analyses were conducted after the last treatment. The brain expression of myelin basic protein (MBP) and neuregulin-1 (NRG-1) was assessed using immunohistochemistry and Western blots. CPZ induced significant schizophrenia-like behaviors in the mice, including reduced nest-building activity and sensory gating deficits. Hyperlocomotor activity was accompanied by significant reductions in MBP expression in the corpus callosum, hippocampus, and cerebral cortex. However, both QTP and SZASD significantly reversed the schizophrenia-like behaviors and demyelination in CPZ-fed mice. The QTP and medium-dose SZASD resulted in better therapeutic effects compared to the low and high SZASD doses. Reduced NRG-1 expression was observed in CPZ-fed mice compared with controls, but neither QTP nor SZASD showed significant influence on NRG-1 expression in the hippocampus. Together, SZASD showed a therapeutic effect on demyelinated mice, and the improvement of demyelination might not be through the NRG-1 pathway.

Neurotherapeutic and antioxidant response of D-ribose-L-Cysteine nutritional dietary supplements on Alzheimer-type hippocampal neurodegeneration induced by cuprizone in adult male wistar rat model.

INTRODUCTION: Cuprizone is a neurotoxicant causing neurodegeneration through enzymes inhibition and oxidative stress. D-Ribose-L-Cysteine (DRLC) is a powerful antioxidant with neuroprotective properties. This study explored the antioxidant response of DRLC against cuprizone-induced behavioral alterations, biochemical imbalance and hippocampal neuronal damage in adult wistar rats. MATERIALS AND METHODS: Thirty two (32) adult male wistar rats (150-200g) were divided into four groups (n = 8). Group A received normal saline only as placebo; Group B received 0.5% cuprizone diet only; Group C received a combination of 0.5% cuprizone diet and 100 mg/kg bw of DRLC and Group D received 100 mg/kg bw of DRLC only. The administration was done through oral gavage once daily for 45 days. After the last treatment, neurobehavioral tests (Morris Water Maze and Y maze) was conducted; animals sacrificed and brain harvested for histological analysis and biochemical estimations of levels of antioxidants, oxidative stress markers, neurotransmitters and enzyme activitties. RESULTS: The results showed significant memory decline, hippocampal alterations, decrease levels of antioxidant markers, enzyme and neurotransmitters activities with concomitant increase in norepinephrine and oxidative stress markers in cuprizone induced rats relative to normal but was attenuated with DRLC administration. CONCLUSION: Cuprizone causes cognitive impairment and neurodegeneration through oxidative stress; however, administration of DRLC ameliorated neuropathological alteration induced by cuprizone.

Dendrosomal nanocurcumin promotes remyelination through induction of oligodendrogenesis in experimental demyelination animal model.

Multiple sclerosis (MS) is an autoimmune disease, associated with central nervous system (CNS) inflammation, demyelination, and axonal loss. Myelin, a multilayer membranous that covers nerve fibers, is essential for rapid impulse conduction. Oligodendrocytes that are generated either from CNS-resident oligodendrocyte progenitor cells (OPCs) or subventricular zone-derived neural stem cells (NSCs) are the myelinating cells of the CNS. The adult CNS maintains a certain endogenous potential to repair myelin damage. However, this process often fails as MS progresses. The origin of this failure is not fully understood, but it is likely to relate to progenitors/stem cells' arrestment in a quiescent state, incapable of generating new oligodendrocyte. Current treatments for MS are immunomodulatory or immunosuppressive medications, with little to no effect on myelin restoration. Recent studies have provided proof-of-principle that CNS remyelination can be promoted either via enhancing endogenous remyelination or by transplanting myelinating cells. Curcumin, a natural polyphenolic compound, has been shown to have therapeutic properties in several neurodegenerative diseases. Here, we investigated the effect of a curcumin nanoformulation, dendrosomal nanoparticles (DNC) on oligodendrogenesis and remyelination, both in vitro and in animal model of demyelination. We indicated that DNC enhanced oligodendrogenesis from NSCs and OPCs, in vitro in dose dependent manner. DNC also induced in vivo remyelination via promotion of oligodendrogenesis. Furthermore, DNC enhanced remyelination capacity of transplanted NSCs through promoting their survival and oligodendrogenesis capacity. Our findings suggest that DNC has significant beneficial effects in demyelinating conditions, either as mono-therapy or as being paired with transplantation approaches.

Melatonin improves memory defects in a mouse model of multiple sclerosis by up-regulating cAMP-response element-binding protein and synapse-associated proteins in the prefrontal cortex.

Multiple sclerosis is a progressive autoimmune disorder of the myelin sheath and is the most common inflammatory disease of young adults. Up to 65% of multiple sclerosis patients have cognitive impairments such as memory loss and difficulty in understanding and maintaining attention and concentration. Many pharmacological interventions have been used to reverse motor impairments in multiple sclerosis patients; however, none of these drugs improve cognitive function. Melatonin can diffuse through the blood-brain barrier and has well-known antioxidant and anti-inflammatory properties with almost no side effects; it is, therefore, a promising neuroprotective supplement for many neurological diseases, such as multiple sclerosis, Alzheimer's disease, Parkinson's disease, ischemic stroke, and fibromyalgia. However, only some researches have assessed the effect of melatonin on cognitive dysfunction in multiple sclerosis. Here, we evaluated the effects of melatonin supplementation on memory defects induced by cuprizone in a mouse model of multiple sclerosis. Cuprizone (400 mg/kg) and melatonin (80 mg/kg) were administered to SWR/J mice daily for 5 weeks. Open field, tail-flick, and novel object recognition behavioral tests were performed. Also, expression of cAMP-response element-binding protein, synaptophysin, and postsynaptic density protein 95 were measured in the prefrontal cortex. Melatonin significantly improved the memory defects induced by cuprizone toxicity by up-regulating cAMP-response element-binding protein and by increasing expression of the synapse-associated synaptophysin and postsynaptic density protein 95 genes in the prefrontal cortex. These results indicate that melatonin may provide protective effects against memory impairments associated with multiple sclerosis.