Fig. 4
UCMSCs-exo/eNOS enhance the resistance of vascular endothelial cells to oxidative stress and cellular damage brought about by hydrogen peroxide. H2O2: stimulation with 200 μM hydrogen peroxide. UCMSCs-exo: stimulation with 200 μM hydrogen peroxide after 24 h incubation in complete medium supplemented with 20 μg of UCMSCs-exo. UCMSCs-exo/ eNOS: received 200 μM hydrogen peroxide after 24 h of incubation in complete medium supplemented with 20 μg of UCMSCs-exo/eNOS. a Live cells are labeled by Calcein (green fluorescence) and dead cells are labeled by PI (red fluorescence). Examples of the activity profile of HUVECs after stimulation with H2O2, UCMSCs-exo or UCMSCs-exo/eNOS. b Representative plot of mitochondrial membrane potential shown by JC-1 staining of HUVECs cultured with H2O2, UCMSCs-exo or UCMSCs-exo/eNOS. Scale bar: 30 μm. c Histogram showing the ratio of PI/Calcein fluorescence (red/green) in each group of HUVECs (n = 3, two-tailed Student’s t-test). d Histograms showing the ratio of JC-1 polymer/JC-1 monomer (red/green) in each group of HUVECs (n = 4, two-tailed Student’s t-test). e Representative images showing 2,7-Dichlorodi -hydrofluorescein diacetate (DCF, green) staining for the detection of ROS production in each group of HUVECs. Scale bar: 50 μm. f Representative images showing TUNEL staining of apoptotic HUVECs after H2O2, UCMSCs-exo, or UCMSCs-exo/eNOS treatment. g Quantitative analysis of ROS generation (n = 3, two-tailed Student’s t-test). (h) Quantitative analysis of TUNEL-positive cells (n = 5, two-tailed Student’s t-test). (i) (j) Expression of inflammatory factors (IL6, IL8, and TNF-α) in HUVECs and fibroblasts after H2O2, UCMSCs-exo, or UCMSCs-exo/eNOS treatment (n = 6, two-tailed Student’s t-test). k, l Expression of angiogenic and antioxidant-related genes (n = 6, two-tailed Student’s t-test). m Expression of genes associated with fibroblast proliferation (n = 6, two-tailed Student’s t-test). Data represent means ± SD. *p < 0.05, **p < 0.01, ***p < 0.001 vs. H2O2 group; #p < 0.05, ##p < 0.01, ###p < 0.001 vs. UCMSCs-exo group