Fig. 3.

MWCNT High-COOH nanoparticles induce increases in epidermal thickness and PMN recruitment in skin. Mice were sensitized with 30 μl 0.05% DNFB in a 4:1 acetone/olive oil vehicle on the abdomen on day 0. On day 5 the mice were collared to prevent grooming and challenged with 50 μl of either vehicle (a), 5 μg MWCNT (b), 0.2% DNFB (c), or 0.2% DNFB with 5 μg MWCNT (d) on a 5 cm² area of dorsal skin for 24 h. Skin was fixed in 10% formalin, paraffin embedded, and stained with hematoxylin and eosin to assess the skin histology. Representative images of H&E stained samples are included, and the black arrows indicate the epidermis in each image. Higher magnification images of representative polymorphonuclear cells (PMN) are included, and white arrows indicate the PMN cells. The epidermal skin thickness (e) and total number of PMN cells (f) are quantified. The graphs represent the mean (+/− SEM), N = 6. Significance is defined at a p-value < 0.05. * indicates significance compared to control, # indicate significance within groups