Dapi fluorescent stain

Paeoniflorin (PF, >95 % purity), DAPI fluorescent stain, and conA type IV were obtained from Sigma (St Louis, MO, USA). The SABC kit for immunohistochemical analysis was obtained from Boster (Wuhan, China). The IL1β ELISA kit was from R&D system (Minneapolis, MN, USA). The antibodies used for the immunohistochemical and western blot analyses were rabbit polyclonal IL1β (sc-7884), goat polyclonal monocyte chemotactic protein 1 (MCP1) (sc-1785), rabbit polyclonal F4/80 (sc-25830), mouse monoclonal CXCR3 (sc-137140) and rabbit polyclonal CXCL11 (sc-28874) purchased from Santa Cruz Biotechnology (La Jolla, CA, USA). Mouse monoclonal CD68 (MCA31R) was obtained from Serotec (Oxfordshire, OX51GE, UK). Secondary fluorescence-labelling goat anti-mouse Cy3 and goat anti-rabbit FITC second antibodies were obtained from Jackson (West Grove, PA, USA).

The exosomes were labelled using green fluorescent membrane dye PKH67 (PKH67GL; Sigma‐Aldrich, St. Louis, MO, USA), according to the protocol. Cells were cultured in Medium 254 containing exosomal solution labelled PKH67 or negative control solution for 24 hours at 37°C in six‐well plates. Then, the slides were washed for three times with PBS, fixed with 4% formaldehyde for 20 minutes and washed for three times again with PBS. Afterwards, the cell nuclei were stained using DAPI fluorescent stain (D9542, Sigma‐Aldrich). The images were acquired using the ImageXpress Micro^® Confocal High‐Content Imaging System (Molecular Devices).