MgO@SiO₂ nanocapsules: a controlled magnesium ion release system for targeted inhibition of osteoarthritis...

Osteoarthritis (OA) is a chronic joint disease characterized by degenerative changes in articular cartilage and chronic inflammation. Recent studies suggest that intra-articular (i.a.) injection of magnesium salts holds promise as a therapeutic approach for OA. However, the rapid diffusion of magnesium ions limits their efficacy, resulting in a short duration of action. To overcome this limitation, we developed a nanoparticle delivery system using MgO@SiO₂ core/shell nanoparticles, designed as a depot for the controlled release of magnesium ions. Electron microscopy confirmed the formation of the core/shell structure with silica shells of varying thickness. Release studies demonstrated that the silica coating effectively slows nanoparticle degradation, extending magnesium release to over 72 hours. In a rabbit OA model, i.a. injection of these nanocapsules significantly mitigated the pathological progression of OA within four weeks without inducing systemic toxicity. Immunohistochemical analysis further revealed that MgO@SiO₂ nanocapsules alleviate the inflammatory response in OA cartilage by inhibiting the NF-κB/p65 signaling pathway. In summary, this study confirms the potential of intra-articular magnesium supplementation as a therapeutic option for OA and introduces a novel approach to enhance the delivery and efficacy of magnesium ions in OA treatment, addressing a relatively underexplored area in the field.