Il 13

In the in vitro macrophage polarization experiment, BMDMs were cultured in 12‐well plates and induced into an inflammatory state. Then, they were randomly divided into four groups and treated with 10 µL PBS, L‐arginine, FTY720, and PL720, respectively for 24 h. Immunofluorescence staining was carried out using mouse anti‐iNOS antibody (eBioscience) and rabbit anti‐CD206 antibody (Abcam), followed by incubation with corresponding secondary antibodies (Beyotime, China). For flow cytometry analysis, PE‐Cy7‐anti‐ CD86 (eBioscience, USA) and APC‐anti‐CD206 (eBioscience, USA) were used for labeling. The levels of inflammatory factors, including IL‐1β (Mlbio, China), IL‐13 (Multi sciences, China), TNF‐α (Multi sciences, China), and TGF‐β (Multi sciences, China) were determined using ELISA kits following the manufacturer's instructions. The pro‐regenerative M2 phenotype was achieved by treating BMDMs with interleukin‐4 (IL‐4, PeproTech, USA) at a concentration of 20 ng mL⁻¹ for 24 h. Finally, WB analysis was preformed.

Mice serum preparation: orbital blood was collected and centrifuged at a speed of 3000 r min ⁻¹ for 15 min. The upper serum was taken out of a centrifuge tube and stored at – 70 ℃. Contents of IFN-γ (Lot No.228070832, Multi Science), TGF-β (Lot No.228170744, Multi Science), IL-4 (Lot No.220471131, Multi Science), IL-13 (Lot No.221371135, Multi Science), IL-6 (Lot No.220671132, Multi Science), IL-10 (Lot No.221070945, Multi Science), TNF- α (Lot No.218280443, Multi Science) in serum of mice were detected by sandwich ELISA assay according to the Kit instructions.