Methylnissolin preserves chondrocyte homeostasis and attenuates experimental osteoarthritis through modulation of the PI3K-AKT-NF-κB signaling axis.

BACKGROUND: Osteoarthritis (OA) involves extracellular matrix (ECM) degradation, inflammation, oxidative stress, mitochondrial dysfunction, and chondrocyte loss. Methylnissolin (MN) is a natural isoflavonoid with anti-inflammatory and antioxidant properties, but its effects in OA remain unclear. PURPOSE: To evaluate the chondroprotective effects of MN in experimental OA and examine the involvement of PI3K-AKT-NF-κB signaling. METHODS: MN was investigated in interleukin-1β (IL-1β)-stimulated primary rat chondrocytes and a rat destabilization of the medial meniscus model. ECM metabolism, inflammation, oxidative stress, mitochondrial function, and apoptosis were assessed using molecular, cellular, and histological methods. Network pharmacology and molecular docking were used to identify candidate targets and pathways, and the PI3K activator 740Y-P was used for pharmacological reversal experiments. RESULTS: MN reduced IL-1β-induced ECM catabolism and inflammatory mediator production, decreased intracellular and mitochondrial reactive oxygen species, preserved mitochondrial membrane potential, and inhibited chondrocyte apoptosis. In vivo, MN alleviated cartilage degeneration and improved histological outcomes. Network analysis identified 39 overlapping MN- and OA-related targets and highlighted ECM remodeling and PI3K-AKT-related processes. MN reduced IL-1β-induced activation of PI3K-AKT-NF-κB signaling, whereas 740Y-P partially reversed several protective effects. CONCLUSION: MN protects against experimental OA by preserving ECM homeostasis and attenuating inflammatory, oxidative, mitochondrial, and apoptotic injury. These effects are associated, at least in part, with reduced PI3K-AKT-NF-κB pathway activation, while the computational findings remain hypothesis-generating.