Fisetin Mitigates Ferroptosis and Promotes Remyelination in a Cuprizone Model of Multiple Sclerosis

Multiple sclerosis (MS) is a long-lasting autoimmune condition characterized by myelin destruction and neurodegeneration. Research indicates that ferroptosis significantly influences MS pathogenesis, exacerbating neuronal tissue damage. Our study intended to explore the possible neuroprotective role of fisetin (FIS) in cuprizone (CPZ) model of MS and the associated molecular mechanisms. The 9-week experiment comprised a 5-week demyelination period in which C57BL/6 mice were provided with 0.2% w/w CPZ added to rodent chow, followed by a 4-week remyelination period in which mice were fed CPZ-free chow. FIS (80 mg/kg/day) was given by oral gavage to mice daily for 4 weeks starting in the 2nd week of demyelination. For remyelination, FIS was administered daily during the 4 weeks recovery. During demyelination, FIS significantly improved CPZ-induced behavioral and locomotor deficits, as demonstrated by tail suspension test and inverted screen grip strength test. LFB and H & E staining, MBP, GFAP and vimentin immunostaining revealed that FIS treatment significantly improved myelination, alleviated astrogliosis and neuronal injury in CPZ-fed mice throughout both phases. FIS attenuated ferroptosis and neuroinflammation during de- and remyelination as supported by reduced brain iron deposits, IL-1 β, MDA concentrations and restored GPX4. Moreover, FIS significantly downregulated NCOA4 and TfR1 gene expression and TfR1 protein level but upregulated FTH1 gene expression and ferritin protein level. Additionally, FIS upregulated Olig-1 during demyelination, but not remyelination. Fisetin has a potential neuroprotective effect in CPZ model of MS and can be studied as a promising adjuvant therapy to enhance remyelination and mitigate disability in MS patients possibly by modulating ferroptosis pathway.