Fig. 3

W-Exo-L@GelMA exhibits a strong chondrocyte-targeting effect and a pronounced action on promoting anabolism and suppressing catabolism and inflammation without causing the inhibition of chondrocyte viability. A Cell viability assessed by CCK8 assay. No obvious cytotoxicity on chondrocytes was observed when treated with W-Exo-L@GelMA loaded with 0.5, 1.0, 2.5, and 5.0 µM LRRK2-IN-1 for 48 h. Data represent mean ± SD; N = 6/group; one-way ANOVA; ns, not significant. B Immunofluorescence of Dil-labeled exosomes. The uptake of exosomes was observed in the chondrocytes when treated with Exo-L, Exo-L@GelMA or W-Exo-L@GelMA for 48 h. Dil was used for labeling exosomes (red), DAPI to label nuclei (blue), and Phalloidin to label the cytoskeleton (green). Scar bar: 200 μm. C Western blot analyses of the protein levels of anabolic, catabolic, and inflammatory factors in the IL-1β-induced chondrocytes treated with W-Exo-L@GelMA loaded with 0.5, 1.0, 2.5, and 5.0 µM LRRK2-IN-1 for 48 h. W-Exo-L@GelMA promoted COL2 and SOX9 and inhibited iNOS, COX2, MMP3, and MMP13 protein levels in a dose-dependent manner. D Quantitative analysis of the western blot results. Data represent mean ± SD; N = 3/group; *P < 0.05; **P < 0.01 by one-way ANOVA