Fig. 5

Exosomes isolated from LPS-treated mice increase astrocyte activation. a Photomicrographs of the hippocampal area from C57BL/6J mice. Mice were either left untreated (Unt) or intravenously injected 1 mg of exosomes (in 200 μl PBS) isolated from the sera of donor mice. Donors were intraperitoneally injected with PBS or treated with one of the three LPS regimens. The recipient mice were euthanized after 24 h. Brain sections were stained with anti-GFAP antibody for astrocytes (green) and with DAPI for nuclei (blue). Scale bar, 50 μm. The white-dotted boxes are zoom-in views of the corresponding photomicrographs, scale bar 10 μm. b Comparison of the relative immunofluorescent intensity of GFAP in the hippocampal area between treatments. n = 3–5 per group. c Quantification of the relative immunofluorescent intensity of Iba1, GFAP, and S100 in the hippocampal area in Saline-Exo- and 5LPS24h-Exo-treated mouse brains. The donor mice received either saline or 5 mg/kg of LPS injection and were kept alive for 24 h before blood collection. The recipient mice were i.v. injected with the purified exosomes and kept alive for 24 h before being sacrificed. n = 3 per group. d Representative photomicrographs of the immunofluorescent staining in the brain sections from Saline-Exo- and 5LPS24h-Exo-treated mice. Anti-Iba1 antibody for microglia, anti-GFAP and anti-S100 antibodies for astrocytes (red), and DAPI for nuclei (blue). Scale bar, 50 μm. The white-dotted boxes are zoom-in views of the corresponding photomicrographs, scale bar 5 μm. Data represent mean ± SEM; *P < 0.05, **P < 0.01, and ***P < 0.001; ^#P < 0.05, ^##P < 0.01, and ^###P < 0.001 as compared to the PBS-Exo-treated group