Figure 3

HPC affects peripheral blood leukocyte populations. (A) Whole blood staining identified baseline difference for TCRb⁺ T lymphocytes and CD11b⁺ monocytes in naïve (i.e., not exposed to hypoxia) CCL2 knockout (KO) mice versus naïve wild-type (WT) CX₃CR1^GFP/+ mice. HPC reduced Gr-1⁺ granulocytes, T lymphocytes, and monocytes, while increasing CD19+ B lymphocytes, to a similar extent in both strains. Data are shown as the mean percent of CD45⁺ cells in the peripheral blood. (B) Representative staining for the chemokine receptor CCR2 on circulating monocytes showed significant strain differences at naïve levels that were equalized at 12 h after HPC. Whole blood was stained and expression of CCR2 by CD45⁺CD11b⁺ monocytes was determined by comparison with monocytes stained with an isotype-matched control antibody. (C, D, E) Representative cortical sections from animals in the above experiment display a similar distribution pattern and morphology of resident CX₃CR1-expressing monocytes/microglia at 12 h after HPC when seen at (D) 20 × and (E) 40 × magnification within the area denoted by the white rectangle. (F) CCL2 staining in adjacent sections, denoted by the white squares in cortical and subcortical areas. *p < 0.05, **p < 0.0001 vs. control.