Multiple sclerosis (MS) is an autoimmune-mediated degenerative disease of the central nervous system (CNS) characterized by immune cell infiltration, demyelination and axonal injury. Oxidative stress-induced inflammatory response, especially the destructive effect of immune cell-derived free radicals on neurons and oligodendrocytes, is crucial in the onset and progression of MS. Therefore, targeting oxidative stress-related processes may be a promising preventive and therapeutic strategy for MS. Animal models, especially rodent models, can be used to explore the in vivo molecular mechanisms of MS considering their similarity to the pathological processes and clinical signs of MS in humans and the significant oxidative damage observed within their CNS. Consequently, these models have been used widely in pre-clinical studies of oxidative stress in MS. To date, many natural products have been shown to exert antioxidant effects to attenuate the CNS damage in animal models of MS. This review summarized several common rodent models of MS and their association with oxidative stress. In addition, this review provides a comprehensive and concise overview of previously reported natural antioxidant products in inhibiting the progression of MS.

Background. Bu Shen Yi Sui capsule (BSYS) is a traditional Chinese medicine prescription that has shown antineuroinflammatory and neuroprotective effects in treating multiple sclerosis (MS) and its animal model of experimental autoimmune encephalomyelitis (EAE). Microglia play an important role in neuroinflammation. The M1 phenotype of microglia is involved in the proinflammatory process of the disease, while the M2 phenotype plays an anti‐inflammatory role. Promoting the polarization of microglia to M2 in MS/EAE is a promising therapeutic strategy. This study is aimed at exploring the effects of BSYS on microglial polarization in mice with EAE. Methods. The EAE model was established by the intraperitoneal injection of pertussis toxin and subcutaneous injection of myelin oligodendrocyte glycoprotein (MOG)_35-55 in C57BL/6J mice. The mice were treated with BSYS (3.02 g/kg), FTY720 (0.3 mg/kg), or distilled water by intragastric administration. H&E and LFB staining, transmission electron microscopy, qRT‐PCR, immunofluorescence, ELISA, fluorescence in situ hybridization, and western blotting were used to detect the histological changes in myelin, microglial M1/M2 polarization markers, and the expression of key genes involved in EAE. Results and Conclusions. BSYS treatment of EAE mice increased the body weight, decreased the clinical score, and reduced demyelination induced by inflammatory infiltration. BSYS also inhibited the mRNA expression of M1 microglial markers while increasing the mRNA level of M2 markers. Additionally, BSYS led to a marked decrease in the ratio of M1 microglia (iNOS⁺/Iba1⁺) and an obvious increase in the number of M2 microglia (Arg1⁺/Iba1⁺). In the EAE mouse model, miR‐124 expression was decreased, and miR‐155 expression was increased, while BSYS treatment significantly reversed this effect and modulated the levels of C/EBP α, PU.1, and SOCS1 (target genes of miR‐124 and miR‐155). Therefore, the neuroprotective effect of BSYS against MS/EAE was related to promoting microglia toward M2 polarization, which may be correlated with changes in miR‐124 and miR‐155 in vivo.

Background/Aims. Multiple sclerosis (MS) is an autoimmune disorder that affects the central nervous system (CNS) primarily hallmarked by neuroinflammation and demyelination. The activation of astrocytes exerts double‐edged sword effects, which perform an integral function in demyelination and remyelination. In this research, we examined the therapeutic effects of the Bu Shen Yi Sui capsule (BSYS), a traditional Chinese medicine prescription, in a cuprizone‐ (CPZ‐) triggered demyelination model of MS (CPZ mice). This research intended to evaluate if BSYS might promote remyelination by shifting A1 astrocytes to A2 astrocytes. Methods. The effects of BSYS on astrocyte polarization and the potential mechanisms were explored in vitro and in vivo utilizing real‐time quantitative reverse transcription PCR, immunofluorescence, and Western blotting. Histopathology, expression of inflammatory cytokines (IL‐10, IL‐1β, and IL‐6), growth factors (TGF‐β, BDNF), and motor coordination were assessed to verify the effects of BSYS (3.02 g/kg/d) on CPZ mice. In vitro, A1 astrocytes were induced by TNF‐α (30 ng/mL), IL‐1α (3 ng/mL), and C1q (400 ng/mL), following which the effect of BSYS‐containing serum (concentration of 15%) on the transformation of A1/A2 reactive astrocytes was also evaluated. Results and Conclusions. BSYS treatment improved motor function in CPZ mice as assessed by rotarod tests. Intragastric administration of BSYS considerably lowered the proportion of A1 astrocytes, but the number of A2 astrocytes, MOG+, PLP+, CNPase+, and MBP+ cells was upregulated. Meanwhile, dysregulation of glutathione peroxidase, malondialdehyde, and superoxide dismutase was reversed in CPZ mice after treatment with BSYS. In addition, the lesion area and expression of proinflammatory cytokines were decreased and neuronal protection factors and anti‐inflammatory cytokines were increased. In vitro, BSYS‐containing serum suppressed the A1 astrocytic markers’ expression and elevated the expression levels of A2 markers in primary astrocytes triggered by C1q, TNF‐α, and IL‐1α. Importantly, the miR‐155/SOCS1 signaling pathway was involved in the modulation of the A1/A2 phenotype shift. Overall, this study demonstrated that BSYS has neuroprotective effects in myelin repair by modulating astrocyte polarization via the miR‐155/SOCS1 pathway.

Background/Aims. Multiple sclerosis (MS) and neuromyelitis optica (NMO) are the most common autoimmune demyelinating diseases of the central nervous system (CNS), with some similar pathological and clinical features. Bu-Shen-Yi-Sui (BSYS) Capsule, a Chinese herbal prescription, has been shown to be a potential therapeutic agent for MS and NMO. However, its antidemyelination mechanism in inflammatory demyelinating diseases of the CNS has not been fully clarified. This study is aimed at exploring the key components and potential mechanism of BSYS in the treatment of CNS demyelinating disease (CNSD) based on network pharmacology. Methods. The potential active ingredients and corresponding potential targets of BSYS Capsule were obtained from the TCMSP, BATMAN-TCM, Swiss Target Prediction platform, and literature research. Disease targets of CNSD were explored through the GeneCards and the DisGeNET databases. The matching targets of BSYS in CNSD were identified from a Venn diagram. The protein-protein interaction (PPI) network was constructed using bioinformatics methods. Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to predict the mechanisms of BSYS. Furthermore, the neuroprotective effects of BSYS were evaluated using a cell model of hydrogen peroxide- (H₂O₂-) induced cell death in OLN-93 cells. Results. A total of 59 potential bioactive components of BSYS Capsule and 227 intersection targets were obtained. Topological analysis showed that AKT had the highest connectivity degrees in the PPI network. Enrichment analysis revealed that the targets of BSYS in the treatment of CNSD were the PI3K-Akt and MAPK signaling pathway, among other pathways. GO analysis results showed that the targets were associated with various biological processes, including apoptosis, reactive oxygen species metabolic process, and response to oxidative stress, among others. The experimental results demonstrated that BSYS drug-containing serum alleviated the H₂O₂-induced increase in LDH, MDA, and ROS levels and reversed the decrease in SOD and mitochondrial membrane potential induced by H₂O₂. BSYS treatment also decreased the number of TUNEL (+) cells, downregulated Bcl-2 expression, and upregulated Bax and c-caspase-3 expression by promoting Akt phosphorylation. Conclusion. BSYS Capsule alleviated H₂O₂-induced OLN-93 cell injury by increasing Akt phosphorylation to suppress oxidative stress and cell apoptosis. Therefore, BSYS can be potentially used for CNSD treatment. However, the results of this study are only derived from in vitro experiments, lacking the validation of in vivo animal models, which is a limitation of our study. We will further verify the underlying mechanisms of BSYS in animal experiments in the future.

Remyelination is a refractory feature of demyelinating diseases such as multiple sclerosis (MS). Studies have shown that promoting oligodendrocyte precursor cell (OPC) differentiation, which cannot be achieved by currently available therapeutic agents, is the key to enhancing remyelination. Bu Shen Yi Sui capsule (BSYSC) is a traditional Chinese herbal medicine over many years of clinical practice. We have found that BSYSC can effectively treat MS. In this study, the effects of BSYSC in promoting OPCs differentiation and remyelination were assessed using an experimental autoimmune encephalomyelitis (EAE) model in vivo and cultured OPCs in vitro. The results showed that BSYSC reduced clinical function scores and increased neuroprotection. The expression of platelet-derived growth factor receptor α (PDGFR-α) was decreased and the level of 2,3-cyclic nucleotide 3-phosphodiesterase (CNPase) was increased in the brains and spinal cords of mice as well as in OPCs after treatment with BSYSC. We further found that BSYSC elevated the expression of miR-219 or miR-338 in the serum exosomes of mice with EAE, thereby suppressing the expression of Sox6, Lingo1, and Hes5, which negatively regulate OPCs differentiation. Therefore, serum exosomes of BSYSC-treated mice (exos-BSYSC) were extracted and administered to OPCs in which miR-219 or miR-338 expression was knocked down by adenovirus, and the results showed that Sox6, Lingo1, and Hes5 expression was downregulated, MBP expression was upregulated, OPCs differentiation was increased, and the ability of OPCs to wrap around neuronal axons was improved. In conclusion, BSYSC may exert clinically relevant effects by regulating microRNA (miR) levels in exosomes and thus promoting the differentiation and maturation of OPCs.