Effect of regorafenib on PPE-induced inflammatory cells in BAL fluid. (A) Experimental scheme. Regorafenib (5 mg/kg) was sensitized and administered orally in PPE + Reg group for two days after treatment with PPE via the intranasal route. (B) Representative images of stained BAL cells. Scale bars indicate 100 μm. (C-G) Measurement of cell numbers in BAL cells (N = 3 per group). Total number of cells (C), macrophages (D), neutrophils (E), eosinophils (F), and lymphocytes (G) were counted on five areas of stained slides. Error bars indicate the mean ± SEM. **P < 0.01, ****P < 0.0001, One-way ANOVA.