Fig. 4

Treatment of human dermal fibroblasts with MSC-sEVs. Representative confocal microscopy images of the internalization of PKH67-labeled MSC-sEVs (green) in human fibroblasts (nuclei blue) after (A) 3 h, (B) 6 h, and (C) 24 h incubation. Fibroblasts incubated with PKH67-labeled PBS without MSC-EVs for (A’) 3 h, (B’) 6 h, and (C’) 24 h do not show any positivity to the probe. Scale bars 20 μm. (D) Proliferation and (E) migration of fibroblasts treated with increasing doses of MSC-sEVs (20, 40, 80, 120 µg) compared to control (ctrl; no EVs). (F) Gene expression of endothelial cell markers (COL1A1, COL3A1, ELN) after 24 h incubation with MSC-sEVs. *p < 0.05, **p < 0.01, ***p < 0.001 compared to control (0 µg)