Fig. 3.

sEVs from hypoxic MSCs increase the tube formation of cerebral microvascular endothelial cells. Relative tube number, evaluated in a Matrigel-based tube formation assay, of hCMEC/D3 cells exposed to different concentrations of A sEVs obtained from MSC culture media that contain platelet lysates (sEV_platelet), B sEVs obtained from MSCs (

source 41.5) cultured under regular ‘normoxic’ conditions (21% O₂; sEV_normoxic) or C sEVs obtained from MSCs (source 41.5) cultured under hypoxic conditions (1% O₂; sEV_hypoxic). D Microvascular tube length density, E microvascular branching point density and F mean branch length between two branching points of hCMEC/D3 cells exposed to control conditions or sEV_platelet, sEV_normoxic (MSC source 41.5) or sEV_hypoxic (MSC source 41.5) at a concentration of 50 µg/mL (n = 3–9 independent experiments). In G, representative microphotographs for hCMEC/D3 cells exposed to control conditions or 50 µg/mL sEVs are shown. Data are mean ± SD values (n = 9 independent experiments [in A–C], 3–9 independent experiments [in D–F]). *p < 0.05, ***p < 0.001 compared with control/^†p < 0.05, ^†††p < 0.001 compared with sEV_platelet/^‡p < 0.05, ^‡‡‡p < 0.001 compared with sEV_normoxic. Scale bars: 500 µm