Figure 3: Phagocytosis of iron particles by adherent cells derived from mouse bone marrow cells. Human neuroblastoma SH-SY5Y cells (A; negative control), primary cultured rat microglia (A; positive control), and adherent cells derived from mouse bone marrow cells cultured in the presence (C) or absence (B) of human M-CSF were treated with iron particles. The iron particles phagocytosed by cells were stained blue color. Scale bars = 200 μm. The number of total adherent cells (D) and phagocytic cells (E) originated from mouse bone marrow cells was counted, and the ratio of phagocytic cells to total adherent cells was calculated (F). ***p < 0.001 vs. cells cultured in the absence of M-CSF at each time points. A significant difference of the main effect of treatment × culture day interaction at P < 0.0001, P < 0.0001, P = 0.1276 vs. groups cultured in the absence of M-CSF in D, E, and F, respectively. N; number of samples.