Fig. 5

ADSC-EVs shifted the M1/M2 polarization of microglia towards M2 phenotype after tMCAO. A PKH-26 labeled ADSC-EVs (Red) were detected around the nucleus (Blue) both in the ipsilateral and contralateral hemisphere of tMCAO mice brain. Scale bar = 15 μm. B Immunofluorescence imaging showed the uptake of ADSC-EVs by microglia in vivo. PKH26 labeled ADSC-EVs (Red) were intravenously injected to the mouse at 24 h after tMCAO. The internalization of ADSC-EVs by Iba1⁺ microglia (Green) was detected 1 h after the administration. Scale bar = 25 μm. The 3D image showed the localization of ADSC-EV in the cytoplasm of microglia. White arrows indicated ADSC-EVs internalized by microglia. C ADSC-EVs administration reduced the ratio of M1 microglia at 7 days and 14 days after tMCAO. White arrows indicated CD16⁺/Iba1⁺ cells. Scale bar = 50 μm. D Zoom in-picture of a single microglia in M1 phenotype. E Quantification graph showed the ratio of CD16⁺/Iba1⁺ cells to total Iba1⁺ cells. F ADSC-EVs administration increased the ratio of M2 microglia at 7 days and 14 days after tMCAO. White arrows indicated Arg-1⁺/Iba1⁺ cells. Scale bar = 50 μm. G Zoom in-picture of a single microglia in M2 phenotype. H Quantification graph showed the ratio of Arg-1⁺/Iba1⁺ cells to total Iba1⁺ cells. n = 4 per group. Data were mean ± SEM, *p < 0.05, **p < 0.01, ***p < 0.001