Specifically, it not only inhibited M1 polarization induced by LPS or LPS combined with IFN-γ in vitro, along with M2 polarization induced by IL-4, but also restrained the expression of CD206, MGL1/2, Arg-1, and Ym1 gene transcription and protein translation in mice with BLM-induced pulmonary fibrosis in vivo (Figures 5, 6, 9A–C). Here, ARG1 is linked to pulmonary fibrosis.