Next, we established an ex vivo model of early-stage IPF by treating precision-cut lung slices (PCLSs) from wild type C57BL/6 mice with fibrotic cocktail (FC) which was composed of TGF-β, tumor necrosis factor-α (TNF-α), platelet-derived growth factor-AB (PDGF-AB), and lysophosphatidic acid (LPA) [21], and examined the potential anti-fibrotic effect of Kl in this model by adding mouse rKL into the medium. Here, KL is linked to idiopathic pulmonary fibrosis.