Association between bone marrow-derived microglia and β-amyloid plaques in the brains of APP/PS1 mice. (a), (b) Immunohistochemical identification of bone marrow-derived microglia and β-amyloid (Aβ) plaques. Bone marrow-derived cells are the cells expressing green fluorescent protein (GFP) (green). Microglia are identified with an anti-Iba1 antibody (red). Yellow cells are the bone marrow-derived microglia that are co-labeled with GFP and Iba1. β-amyloid deposition is determined with an anti-β-amyloid antibody (clone 4G8) (blue). The white arrows indicate β-amyloid deposits surrounded by bone marrow-derived microglial cells (yellow). (c) High-magnification confocal images of the image indicated with dashed lines in (b). (d) Quantification of the bone marrow-derived microglia associated with β-amyloid plaques in the brain. Data presented as mean ± standard error. *P < 0.05. Scale bar: (b) 100 μm (for both images in (a) and (b)); (c) 25 μm. G-CSF, granulocyte colony-stimulating factor; SCF, stem cell factor.