Fig. 3

PLGA-Exos enhanced the osteogenic differentiation in vitro. (A) Representative immunofluorescence images showing the internalization of DII-labeled Exos (red) by BMSCs and the cell nuclei of BMSCs were stained with DAPI (blue). Scale bar: 20 μm. (B) ALP activity assays of BMSCs after 3 days and (C) 7 days of osteogenic induction. Scale bar, and 400 μm. (D, E) Quantitative analyses of ALP and Ca^{2 +} levels in medium from BMSCs receiving Exos treatments. (F-I) ARS staining and Sirius red staining of BMSCs after 14 days of osteogenic induction and determination of the absorbance of the eluate after ARS staining and Sirius red staining. Scale bar, 200 μm (F) and 400 μm (H). (n = 3 per group, ANOVA, *P < 0.05, ** P < 0.01, *** P < 0.001)