Fig. 3.

CT-sEVs reduced cutaneous wound healing in mice. Representative images (A) and closure rate (B) of wounds treated with PBS, RT-sEVs and CT-sEVs were observed at days 3, 6, 9 and 12 post-wounding. n = 6 per group. (C) Representative images of H&E-stained wound sections at day 12 post-wounding. The double-headed black arrows indicate the edges of the scars. Ep: epithelium. Scale bar: 500 μm. (D) Quantification of the scar widths, n = 4 per group. (E) Quantification of the rate of re-epithelialization, n = 4 per group. (F) Gross view of wounds treated with PBS, RT-sEVs and CT-sEVs at day 12 post-wounding from the undersurface. Newly formed blood vessels were detected in the wound sites. Scale bar: 2 mm. (G) CD31 immunofluorescence staining of wound sections treated with PBS, RT-sEVs and CT-sEVs at day 12 post-wounding. Scale bar: 100 μm. (H) Quantitative analysis of the density of blood vessels in (G), n = 4 per group. (I) Ki67 immunofluorescence staining of wound sections treated with PBS, RT-sEVs and CT-sEVs at day 12 post-wounding. Scale bar: 100 μm. (J) Quantitative analysis of the density of blood vessels in (I), n = 4 per group. One-way ANOVA combined with Bonferroni post hoc test. *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001. (*) Significant difference CT-sEVs group vs. RT-sEVs group, (#) Significant difference RT-sEVs group vs. PBS (control) group