Figure 1

Inhaled rCNTs induce strong pulmonary eosinophilia in mice after exposure for 4 consecutive days. C57BL/6 mice were exposed to rCNT or tCNT for 4 h/day for 4 consecutive days and the samples were collected 24 h after the last treatment. a,b: BAL cell counts showed the ability of rCNT to cause a decrease in the number of alveolar macrophages (a) and induce recruitment of inflammatory cells, especially eosinophils (b). c-e: H&E-stained lung sections of untreated (c), tCNT-treated (d) and a rCNT-treated (e) mouse exhibiting that eosinophilia was specific to rCNT (e, see inset for eosinophils). f: internalized rCNT fibers in alveolar macrophages were detected in interstitial areas in Picrosirius red-stained lung sections. g: an image of BAL cells showing a foreign-body giant cell containing rCNT, macrophages undergoing “frustrated phagocytosis”, eosinophils and a neutrophil. Columns and error bars in a and b represent mean values ± standard error of mean (SEM; n = 9-20). Images c and d are shown with a 100 μm scale bar, f-g and the inset is shown with a 25 μm scale bar. **P < 0.01; ***P < 0.001. C, untreated control group; HPF, high power field.