Mechanism of Proanthocyanidins B2 in Alleviating Experimental Autoimmune Encephalomyelitis via Inhibition of Th17 Cells

Objective Proanthocyanidins B2 (PC-B2), a naturally derived antioxidant, exhibits potent anti-inflammatory properties. Multiple sclerosis (MS), an autoimmune demyelinating disease of the central nervous system (CNS), is driven by neuroinflammation. This study aimed to investigate the therapeutic potential and mechanisms of PC-B2 in experimental autoimmune encephalomyelitis (EAE), a murine model of MS.Methods EAE-induced mice received intraperitoneal injections of PC-B2 (50 mg/kg) from day 10 (post-symptom onset) until day 18, followed by sacrifice. Luxol fast blue staining, immunofluorescence, flow cytometry, ELISA, and Western blotting were employed to assess PC-B2’s effects on demyelination, inflammatory responses, and T-cell dynamics in the CNS and peripheral spleen.Results PC-B2 significantly alleviated spinal cord demyelination and reduced the secretion of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-12, and IL-23) in both the CNS and spleen. Furthermore, PC-B2 suppressed Th17 cell polarization and downregulated the expression of interferon regulatory factor 4 (IRF4) in Th17 cells.Conclusion These findings demonstrate that PC-B2 exerts therapeutic effects in EAE by inhibiting IRF4-mediated Th17 polarization, thereby reshaping the inflammatory microenvironment. This highlights PC-B2 as a promising candidate for MS treatment.