Salmon Nasal Cartilage-Derived Proteoglycans Alleviate Cartilage Degeneration in Osteoarthritis by Modulating Inflammation and Apoptosis

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by progressive cartilage damage, inflammatory responses, and apoptosis of chondrocytes. In this study, we investigated the therapeutic potential properties of proteoglycans (PG) extracted from salmon nasal cartilage in both <i>in vitro</i> (HTB-94 human chondrocytic cells) and <i>in vivo</i> (monosodium iodoacetate-induced OA rat model) approaches. Rats were treated with PG, and key parameters related to cartilage integrity, inflammation, and apoptosis were evaluated. Our results showed that PG treatment significantly improved cartilage structure and decreased inflammation, as evidenced by decreased levels of PGE₂ and nitric oxide, as well as reduced expression of pro-inflammatory cytokines, including tumor necrosis factor-alpha, interleukin-1<i>β</i>, and interleukin-6. PG also downregulated matrix metalloproteinases while increasing tissue inhibitors of metalloproteinases, preserving cartilage integrity. Additionally, apoptotic signaling pathways including JNK/c-Fos/c-Jun and FADD/capase-8/caspase-3 were attenuated, and the Bax/Bcl-2 ratio was favorably modulated by PG. These findings suggest that PG can protect articular cartilage by mitigating inflammation, preserving cartilage degradation, and preventing chondrocyte apoptosis. This study supports the potential therapeutic role of PG as a promising treatment option for OA, providing both anti-inflammatory and chondroprotective effects.