Effect of regorafenib on PPE-induced expression of inflammatory mediators in lung parenchyme. (A) Experimental scheme. Mice were sensitized by treatment with regorafenib (5 mg/kg) for one day in the only PPE + Reg group. After PPE treatment, regorafenib was administered orally to mice for six days. On the seventh day, lung tissues were removed from mice, prepared in paraffin sections and stained with antibodies for inflammatory mediators. (B) Representative images of stained paraffin sections. Red arrows indicate the macrophages in inserted boxes. Scale bars indicate 50 μm. (C-E) Quantification of Fig. 4B. IL-6 (C), CXCL1/KC (D), and TIMP-1 (E). Error bars indicate the mean ± SEM. N = 5 per group, *P < 0.05, **P < 0.01, t-test.