Mice were exposed to air, PG, and PG with nicotine (PG+Nicotine) for 3 days (2 hrs/day). Mice were sacrificed 2 hrs post-last exposure on day 3. Pro-inflammatory mediators in the BALF were measured by Bio-Plex Pro-mouse cytokine 23-plex assay kit (Bio-Rad). Data are shown as mean ± SEM (n=6/group; equal number of male and female mice were used; *P < 0.05, **P < 0.01, ***P < 0.001, significant compared with air control; #P < 0.05, # #P < 0.01, significant compared with PG exposed group.)