Fig. 4

Characteristics of DPSCs derived Exosomes. DPSC derived exosomes could inhibit macrophages M1 polarization through MAPK-NFκB P65 signaling pathway in vivo. A Representative images of exosomes are observed under transmission electron microscopy (TEM). Size distribution of extracellular vesicle is measured by nanoparticle tracking analysis (NTA, ZetaView, Particle Metrix Inc., German). Western-blotting analysis of indicated proteins is detected, including CD63, CD9, tubulin, albumin and the MSC marker CD73. B and C Raw264.7 cells were treated with LPS or LPS + EXO for 2, 4, 6 and 24 h. ROS level was detected by using FACS with a flow cytometry. The LPS + Exos group had a lower ROS level than the LPS group. D and E Raw264.7 cells were treated with LPS or LPS + EXO for 24 h. M1 macrophages surface expression (CD86) was detected using using flow cytometry. DPSC-derived exosomes could lower the LPS-induced increase in the M1 polarization rate. F and G The ERK1/2 and p-ERK1/2 protein expression in Raw264.7 cells was either investigated. LPS + Exos group had a lower P-ERK/ERK level than the LPS group. H–J P65 protein expression are determined by immunofluorescences and flow cytometry. DPSC-derived exosomes also inhibited the increase in P65 fluorescence induced by LPS. *p < 0.05, ***p < 0.01