Fig. 6

Recruitment of inflammatory cells to the small airways and inflammatory mediators in BAL fluid. Eosinophil (black arrow head, A) infiltrated around small airways increased significantly in rats exposed DEP for 4 weeks and 8 weeks (** p < 0.01, B). For the mast cells (red arrows head, C), exposure of rats to DEP for 8 weeks (* p < 0.05, D), but not for shorter durations, demonstrated a significant increase around the small airways. The infiltrations of Iba-1 immuno-positive macrophages (blue arrow head, E) were significantly increased in small airways following 4-wk (*** p < 0.001) or 8-wk DEP exposure (** p < 0.01), as compared to the filtered air controls, respectively (F). Bar in the images (Panel A, C, E) = 100 μm. ns = not significant. SA = small airways. Cell differentials in BALF showed significant increases of total leukocyte, macrophage as well as neutrophil, but not eosinophils, following 8-week DEP exposure, as compared to filtered air control, respectively (** p < 0.01, ns, not significant, G-J). DEP exposure for 4-wk or 8-wk significantly increased BALF concentrations of TNF-α, IL-6, IL-13 and IL-17 A, respectively (** p < 0.01, ns, not significant, K-N). Data were expressed as mean (95% CI)