Figure 4
Phagocytosis in quartz-stimulated cells in the presence of DXS and Cytocalasin B. (A) Confocal microscopy analysis of quartz phagocytosis in RAW 264.7 cells (single stacks acquired with oil objective 63.0 ×, digital zoom 4 ×), red staining marking quartz autofluorescence. I, cells challenged for 1 h with 100 μg/ml quartz particles; II, the same in the presence of 100 μg/ml DXS, and III in the presence of 2 μg/ml Cytocalasin B. The white bar spans 8 μm. (B) Analysis of free intacellular silicates in RAW 264.7 cells challenged with or without (C) 100 μg/ml Q or QA in the presence (Q+D, QA+D and Q+Cyto, QA+Cyto) or absence of 100 μg/ml DXS or 2 μg/ml Cytocalasin B, after 6 h (black bars) or 24 h (white bars). Values are the mean ± SD from 4 experiments. The asterisk indicates a statistically significant difference between Q or QA and C at 6 h (T test, p < 0.0025), while the symbol § indicates a statistically significant difference between Q or QA and C at 24 h (T test, p < 0.0005).