Protective and therapeutic role of Bilobalide in cuprizone-induced demyelination

Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system characterized by recurrent and progressive demyelination, neuroinflammation and oligodendrocyte loss. The cuprizone (CPZ) model is characterized by primary and reversible demyelination, accompanied by oligodendrocyte loss and neuroinflammation. In the current study, we explored the efficiency of Bilobalide in the demyelination and remyelination. The results demonstrate that Bilobalide improved behavioral abnormality and promoted remyelination in the corpus callosum by using Luxol Fast Blue, Black Gold II and myelin basic protein (MBP) staining. We for the first time found that CPZ caused the splenic atrophy and induced the formation of myelin oligodendrocyte glycoprotein (MOG) antibody, which was attenuated by Bilobalide. Thus, Bilobalide decreased the loss of O4+ oligodendrocytes possibly through MOG antibody-dependent cell cytotoxicity. Bilobalide also prevented the infiltration of CD4⁺ T cells, CD68⁺ macrophages and B220⁺ B cells within the brain, and reduced the inflammatory microenvironment mediated with Iba1⁺iNOS⁺ and Iba1⁺NF-kB⁺ microglia after CPZ challenge, accompanied by the inhibition of IL-1β and IL-6 in the brain. These results identify a potent therapeutic efficiency for Bilobalide and highlight clear pleiotropic effects of the compound beyond specific autoantibody and inflammatory microenvironment in CPZ-mediated demyelination.