Peripheral GFP⁺/CD11b⁺ macrophages were recruited into the brain of GFP⁺ BM-chimeric mice after RSD. GFP⁺ BM-chimeric mice were subjected to six cycles of social defeat (RSD) or left undisturbed as controls (CON). Brains were collected 14 h after RSD and enriched CD11b⁺ cells were assessed with flow cytometry (n = 4–5). A, Representative flow bivariate dot plots of GFP/CD11b labeling of Percoll-isolated microglia/macrophages. B, The percentage of GFP⁺/CD11b⁺ cells in the brain. C, The number of GFP⁺/CD11b⁺ cells that were CD45^lo or CD45^hi. Bars represent the mean ± SEM. Means with asterisk (*) are significantly different from CON (p < 0.05). Another group of mice were perfused and brains were collected for histology (n = 4–6, 2 independent experiments). D, E, Representative images of GFP (green), merged GFP/Iba-1 (red), and merged GFP/Iba-1/Ly6C (blue) immunofluorescence in the HPC of CON and RSD mice. F–H, In separate studies, mice that received intraocular injury [(+) Control], RSD, or busulfan treatment were retro-orbitally injected with Evans blue dye (1% solution in 100 μl). Mice were perfused and brains were collected for histology 2 h after Evans blue dye injection. Representative images of the whole brain (inset) and in the HPC of (+) Control (F), RSD (G), and busulfan-treated (H) mice. Scale bars, 100 μm.