Prednisone alleviates demyelination through regulation of the NLRP3 inflammasome in a C57BL/6 mouse model of cuprizone-induced demyelination

Abstract

Myelin abnormalities, oligodendrocyte damage, and concomitant glia activation are common in demyelinating diseases of the central nervous system (CNS). Increasing evidence has demonstrated that the inflammatory response triggers demyelination and gliosis in demyelinating disorders. Numerous clinical interventions, including those used to treat multiple sclerosis (MS), have confirmed prednisone (PDN) as a powerful anti-inflammatory drug that reduces the inflammatory response and promotes tissue repair in multiple inflammation sites. However, the underlying mechanism of PDN in ameliorating myelin damage is not well understood. In our study, a cuprizone (CPZ)-induced demyelinated mouse model was used to explore the mechanism of the protection provided by PDN. Open-field tests showed that CPZ-treated mice exhibited significantly increased anxiety and decreased exploration. However, PDN improved emotional behavior, as evidenced by an increase in the total distance traveled, and central distance traveled as well as the mean amount of time spent in the central area. CPZ-induced demyelination was observed to be alleviated in PDN-treated mice based on luxol fast blue (LFB) staining and myelin basic protein (MBP) expression analyses. In addition, PDN reduced astrocyte and microglia activation in the corpus callosum. Furthermore, we demonstrated that PDN inhibited the Nod-like receptor pyrin domain containing 3 (NLRP3) inflammasome signaling pathway and related inflammatory cytokines and chemokines, including TNF-α, CCL8, CXCL10 and CXCL16. PDN also reduced the serum corticosterone levels in the CPZ-treated mice. Taken together, these results suggest that inhibition of the NLRP3 signaling pathway may be a novel mechanism by which PDN exerts its protective actions in demyelinating diseases.

Keywords: Chemokine; Demyelination; Inflammation; NLRP3; Prednisone.