FIGURE 6.

Imperatorin alleviates bleomycin-induced pulmonary fibrosis in mice. (A) Representative images of H&E and Masson’s trichrome staining of lung sections show that imperatorin (2 or 4 mg/kg) ameliorated bleomycin-induced pulmonary fibrosis in a dose-dependent manner. This fibrotic phenomenon was featured in basement membrane thickening, smooth muscle hypertrophy, and subepithelial collagen accumulation in the airway. There was also mild collagen deposition in the interstitium of bleomycin-stimulated mice. Hematoxylin stains the nuclei in blue, and eosin stains the cytoplasm in pink. Trichrome staining demonstrates collagen in blue, cytoplasm in pink, and nuclei in dark brown. The scale bar is 200 μm in the central panel and 400 μm in the right panel. Bleomycin-induced hydroxyproline production (B) was also decreased in a dose-dependent manner by orally administered imperatorin. (C) Expression of GDF15 in BALF was analyzed by GDF15 ELISA. Note that imperatorin enhanced GDF15 production regardless of the presence of bleomycin. Graphs show the mean ± SD of four independent experiments. The p-value was calculated using one-way ANOVA and multiple comparison procedures (Holm–Sidak). ^** p <0.01, ^*** p <0.001 compared to the control group. ^## p <0.01, ^### p <0.001 compared to the bleomycin-treated group.