Images of electron microscopy and immunohistochemistry of cells in the lung tissue and bronchoalveolar lavage fluid. Transmission electron microscope images of macrophages in (A) lung tissue and (B) bronchoalveolar lavage fluid (BALF) of mouse of the 14-day high-silica water group (Experiment 5) are shown. The cells contained particle-like substances. Immunohistochemical F4/80 images of the lung tissue of (C) the ultrapure water group (control) and (D) the high-silica water group (14-day exposure, Experiment 5) are also shown. Arrows indicate F4/80 positive cells (macrophages). Mean number of F4/80-positive cells (±SD) is shown in (E). There was no significant difference in the number of F4/80-positive cells in the lung between the ultrapure water and the high-silica water groups. (F) Ratio of mononuclear cells in BALF from Experiment 5 (14-day inhalation; n = 4/group). Scale bars represent (A, B) 1 μm and (C, D) 20 μm. Abbreviation: Ly, lysosome; Mt, mitochondria; N, nucleus; V, cytoplasmic vesicle.