Fig. 2
Effects of SiO2-n, SiO2-FITC, and SiO2-p in vivo and distribution of SiO2-FITC in the lung. SiO2-n, SiO2-p, SiO2-FITC NPs were intratracheally instilled into rat lungs (0.36 mg per animal, n = 5 animals per group) and compared to vehicle-treated controls (CTR). a, b Analysis of broncho-alveolar lavage fluid 3 d post instillation: a alveolar macrophages (AM) and polymorphonuclear leukocytes (PMN); b total protein concentration. Columns represent means ± standard deviation; significance was tested by ANOVA and post-hoc Dunnett’s multiple comparison test (***: p ≤ 0.001). c-e Fluorescence micrographs of transversal cryo-sections of the left lung resected 30 min (c), and 3 d (d, e) after intratracheal instillation of SiO2-FITC. Dashed lines mark the outer rim of each section. Large bronchi (br) appear as strongly autofluorescent structures. e Detail of the section shown in (d); nuclei of lung cells were visualized with 4′, 6-diamidin-2-phenylindol (DAPI). Note that the fluorescent signal is confined to phagocytic cells (arrows) which were identified as alveolar macrophages in preceding studies