Characterization of genipin-crosslinked gelatin/PVA hydrogels and the chondroprotective influence of hydroxytyrosol: an In vitro study

Osteoarthritis (OA) presents a significant therapeutic challenge, necessitating innovative biomaterial strategies to reduce chronic inflammation and promote cartilage regeneration. This study developed a hybrid gelatine (GE)/polyvinyl alcohol (PVA) hydrogel crosslinked with genipin (GNP) to effectively deliver Hydroxytyrosol (HT). A 6% GE was incorporated with 3% and 5% PVA concentrations, followed by 0.1% (w/v) GNP. The physicochemical and biocompatibility properties were further evaluated. Physicochemical analysis identified the GPVA5%-GNP formulation as optimal, featuring an interconnected porous structure, optimal swelling ratio (640.43 ± 22.28%), improved hydrophilicity (44.50 ± 1.81°), controlled biodegradation, and enhanced compressive strength (96.88 ± 0.72%). Chemical tests confirmed thermal and structural stability, while biocompatibility assays showed over 95% cell viability. The therapeutic potential was evaluated using an IL-1β-induced inflammatory model in human chondrocytes. MTT assays revealed that HT at 12.5, 25, and 50 μM restored metabolic activity in a dose-dependent manner over 14 days, outperforming the 9 μM Glucosamine Sulphate positive control. The 50 μM HT dose yielded the best metabolic recovery, supported by Live/Dead imaging that showed increased viable cell density from Day 1 to Day 7. Overall, the GPVA5%-GNP hydrogel loaded with 50 μM HT offers a robust protective environment that reduces catabolic stress and promotes cell proliferation, making it a promising localized therapy for cartilage regeneration in OA.