Intra-articular injection of anti-inflammatory peptide-loaded glycol chitosan/fucoidan nanogels to inhibit inflammation and attenuate osteoarthritis progression.

Glycol chitosan/fucoidan nanogels loaded with anti-inflammatory peptide KAFAK (GC/Fu@KAFAK NGs) were fabricated based on the electrostatic interaction and genipin cross-linking methods. The prepared NGs had an average size of 286.3 ± 5.0 nm and positive surface charge of 14.0 ± 0.2 mV. The anti-inflammatory and chondro-protective effects of GC/Fu@KAFAK NGs were evaluated on interlecukin-1β (IL-1β)-stimulated rat chondrocytes. We found that GC/Fu@KAFAK NGs not only inhibited the expression of inflammatory factors interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), but also enhanced the expression of chondrogenic markers type II collagen, aggrecan, and Sox9. More importantly, in rat osteoarthritis (OA) model, the intra-articular (IA) injection of GC/Fu@KAFAK NGs reduced glycosaminoglycan loss and diminished inflammatory cytokine release. In addition, GC/Fu@KAFAK NGs showed good biocompatibility both in vitro and in vivo. In conclusion, IA inject-able GC/Fu@KAFAK NGs might have great potential in OA treatment.