Figure 4

The effect of electronic cigarettes without and with nicotine airway remodeling in allergic airways disease. Mice were challenged with phosphate buffered saline (control) or HDM and exposed to Room Air (RA, blue), 50% propylene glycol/50% vegetable glycerin (PG/VG, vehicle, green), Black Licorice (BL, black), Kola (dark red), Banana Pudding (BP, yellow) or Cinnacide (Cin, red). Mice were exposed to e-cigarette liquid without nicotine (left hand panels, 0 mg/mL) or e-cigarette liquid containing 12 mg/mL nicotine (right hand panels). Airway remodeling was measured as (A) soluble collagen (B) the percentage of Periodic Acid-Schiff (PAS) staining within the airway epithelial layer. Data are presented as mean ± SEM or Box-and-whisker plots of 6–12 mice/group. In mice exposed to nicotine-free e-cigarette, HDM increased soluble collagen and PAS staining (HDM effect p < 0.001 for all). In mice exposed to e-cigarette with nicotine, HDM increased soluble collagen and PAS staining (HDM effect p < 0.001 for all). Comparisons between HDM treated mice exposed to Room Air HDM and exposed to e-cigarettes were made by Dunnett analyses: *p < 0.05.