Hyaluronic Acid Modified Curcumin-Loaded Chitosan Nanoparticles Inhibit Chondrocyte Apoptosis to Attenuate Osteoarthritis via Upregulation of Activator Protein 1 and RUNX Family Transcription Factor 2

Hyaluronic acid (HA) and curcumin (CUR) have been previously utilized for osteoarthritis (OA) treatment. CUR-loaded chitosan nanoparticles (CUR@CS NPs) and HA CUR@CS NPs were synthesized in our research to ascertain the synergistic impacts of HA and CUR-loaded NPs on OA treatment. CUR@CS NPs and HA CUR@CS NPs were synthesized with evaluation of their particle size, potential, PDI, encapsulation efficiency, drug loading and surface coating as well as HA binding rate. The in vitro CUR release curve and stability of HA-CUR@CS NPs were measured. Chondrocytes were isolated from the cartilages of OA patients, followed by cell uptake assay. The chondrocyte viability and apoptosis were determined. Subsequently, the knee OA model was established, followed by H&E, Safranin O/Fast green staining and micro-CT. HA CUR@CS NPs improved CUR stability and bioavailability. CUR@CS NPs and HA-CUR@CS NPs were successfully characterized and could further be internalized by chondrocytes. CUR@CS NPs promoted tBHP-induced chondrocyte viability and inhibited chondrocyte apoptosis. HA-CUR@CS NPs upregulated the AP-1 and RUNX2 transcription levels to activate Hedgehog pathway, which subsequently blocked the Notch pathway. Mechanically, HA-CUR@CS NPs sustained release and long-lasting effect and long-term retention in the joint cavity and downregulated the expression of several pro-inflammatory cytokines in vivo. HA-CUR@CS NPs exhibited superior effects in the preceding experiments than CUR@CS NPs. Altogether, HA-CUR@CS NPs may restrict inflammation and chondrocyte apoptosis in OA through upregulation of AP-1 and RUNX2.