Fig. 3

iMSC-sEV promote angiogenesis after stroke and increase migration and tube formation in HUVECs after OGD. a–d Angiogenesis was assessed by immunofluorescence staining of CD31/EdU and CD34 at 7 days after MCAO. a Representative images of CD31 (red) and EdU (Green) in the ischemic boundary zone. Arrow indicates CD31⁺EdU⁺proliferated endothelial cells. Scale bar = 100 μm. b Nissl staining (upper left) showing the region of interest (ROI) and quantification analysis of CD31⁺EdU⁺ cells normalized to that in sham group. Red box: ROI of CD31/EdU staining. N = 3–5 per group. c Representative images of CD34 (red) and DAPI (blue) in the peri-infarct area. Scale bar = 100 μm. d Nissl staining (upper left) showing ROI of the staining and quantification analysis of CD34⁺ cells normalized to that in sham group. Red box: ROI of CD34 staining. N = 3–5 per group. e–h HUVECs were challenged with 8 h OGD, followed by iMSC-sEV or vehicle treatment for 24 h. HUVECs cultured under the normoxia condition without treatment were set as control. e Representative images of crystal violet staining in the transwell assay. Scale bar = 25 μm. f Quantification analysis of migration rate normalized to that in control group. N = 3 per group. g Representative images of the tube formation assay. Scale bar = 25 μm. h Quantification analysis of the relative tube length normalized to that in control group. N = 3 per group. Data are presented as mean ± SD. *P < 0.05