Synergistic Effect Evaluation and Mechanism Investigation of Vitamin B6 and B12 in Models of Neuroinflammation.

Neurological damage, a debilitating condition closely associated with chronic neuroinflammation, currently lacks disease-modifying treatments, with management limited to symptomatic relief. Vitamins B6 (VB6), B12 (VB12), and proteolipid protein 1 (PLP-1) exhibit multimodal neuroprotective and anti-inflammatory effects; however, their therapeutic potential is limited by low bioavailability and inadequate ability to cross the blood-brain barrier (BBB). To address these limitations, we developed an ursolic acid-based nanoparticle system for the intranasal co-delivery of VB6, VB12, and recombinant PLP-1. The PLP-1 model predicted by AlphaFold3 was used for molecular docking. The docking results confirmed high-affinity binding interactions with VB6 and VB12, elucidating the mechanistic basis of their synergy. In vitro studies using a glucose-deprived PC12 cell injury model identified an optimal synergistic molar ratio of 10:1:2 (VB6: VB12: PLP-1). This combination significantly upregulated neuroprotective markers (PLP-1 and PGC-1α) and downregulated the pro-inflammatory cytokine TNF-α. In a mouse model of neural damage, the nano-encapsulated combination therapy demonstrated improved pharmacokinetics and significantly attenuated neuroinflammation and oxidative stress in brain tissue. This was evidenced by lower TNF-α and IL-1β levels and elevated GSH and SOD concentrations compared to free drug controls. The treatment regimen showed no detectable hepatorenal toxicity. Our findings demonstrate that this nanoformulation represents a safe, effective, and promising disease-modifying strategy to treat vestibular dysfunction by synergistically targeting its underlying neuroimmunological mechanisms.