Fig. 3

MSC-EVs improve the cell viability of Dox group. a The morphology of three groups (Blank, Dox, EV). Scale bars, 100 μm. b The apoptotic cells reflected by bright blue nuclei stained by Hoechst 33342. Scale bars, 50 μm. c Flow analysis of apoptotic cells in Dox and EV groups. The percent of apoptotic cells was detected by labeled Annexin V-FITC/PI. Annexin V⁻/PI⁻ represents living cells, Annexin V⁺/PI⁻ represents early apoptotic cells, Annexin V⁻/PI⁺ represents late apoptotic cells, and Annexin V⁺/PI⁺ represents dead cells. d mRNA expression of caspase 9, caspase 3, and bax. Relative gene expression was normalized to β-actin, and the data were analyzed via the 2^−ΔΔCt method. n = 3, ^*P < 0.05 versus Blank groups; ^#P < 0.05 versus Dox groups. e Representative immunofluorescence images of cleaved-caspase 3 (green) in hUC-MSCs treated with Dox and EV. Nuclei were counterstained with DAPI (blue). Scale bars, 20 μm. f Quantification of fluorescence intensity of cleaved-caspase 3 in hUC-MSCs with different treatment. n = 3, ^*P < 0.05 versus Blank groups; ^#P < 0.05 versus Dox groups. g The expression of caspase 3 and cleaved-caspase 3 detected by western blotting. All experiments were performed in three independent experiments and are shown as the mean ± SEM