Fig. 4
Effect of control EVs and Cur-EVs on IL-1β-induced OA-CH. a, b Cell Titer-Blue assay and Caspase-3/7 assay were used to determine viability and apoptosis of OA-CH after treatment with Cur-mediumultra, free curcumin (10 μM), both EV groups and IL-1β for 24 h; n = 4. c–e Live/dead cells were visualized by fluorescence microscopy after labeling cells with calcein and ethidium homodimers. Living cells were labeled with calcein (green fluorescence) and dead cells were stained with ethidium homodimer (red fluorescence); n = 4, scale bar = 200 μm. f, g A scratch (wound healing) assay was used to evaluate the effect of control EVs and Cur-EVs on migration of IL-1β-induced OA-CH. Images of gaps were taken at 0 h, 24 h, 48 h, and 72 h after treatment of cells with Cur-mediumultra, free curcumin (10 μM), both EV groups, and IL-1β. Wound closure rate was used to calculate the migration ability of each group; n = 3. All values represent mean ± standard deviation. Difference to no treatment controls (OA-CH): *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001, #Difference between groups: #p < 0.05; ##p < 0.01; ###p < 0.001; 1-way ANOVA with Newman-Keuls multiple comparison test