Therapeutic potential of Polydopamine-Coated selenium nanoparticles in Osteoarthritis treatment

Osteoarthritis (OA) affects millions globally, with its prevalence expected to rise due to an aging population. Selenium nanoparticles (SeNPs) have shown therapeutic potential, and polydopamine (PDA) coatings on nanoparticles offered additional benefits, including enhanced biocompatibility, antioxidant properties, and anti-inflammatory effects. However, while SeNPs and PDA have demonstrated efficacy in several disease models, their role in OA remains underexplored. This study aimed to evaluate the therapeutic effects of PDA-coated SeNPs in the treatment of OA. We developed PDA-coated SeNPs (PDA-SeNP) to improve Reactive Oxygen Species (ROS) control and evaluated their anti-inflammatory and cartilage-regenerative effects in both in vitro and in vivo models of OA. Transmission electron microscopy confirmed that the sizes of PDA-SeNPs was 203 ± 11 nm, with PDA coatings of approximately 12 ± 2 nm on the SeNPs. In vitro, treatment with PDA-SeNPs significantly enhanced the expression of cartilage-regeneration markers while reducing inflammatory marker levels in chondrocytes. For the in vivo analysis, OA was induced by injecting monoiodoacetate into the knee joints of rats. Four weeks after treatment with phosphate-buffered saline (PBS, n = 6), SeNPs (n = 6), or PDA-SeNPs (n = 6), the incapacitance test demonstrated improved weight-bearing capacity in the SeNP and PDA-SeNP groups compared to the PBS control. Gross morphological assessment and histological analysis revealed that PDA-SeNPs mitigated cartilage damage more effectively than SeNPs alone. These findings suggest that PDA-SeNPs promote cartilage repair, enhance extracellular matrix synthesis, and reduce knee pain in OA, establishing them as promising candidates for future OA treatment.