Figure 9.

Expression of CCR2 and CX₃CR1 on peripheral myeloid cells was required for RSD-induced macrophage infiltration into the brain parenchyma. WT recipient mice received either CCR2^HET(+/RFP), CCR2^KO(RFP/RFP), CX₃CR1^HET(+/GFP), or CX₃CR1^KO(GFP/GFP) BM-derived donor cells. BM-chimeric mice were subjected to six cycles of social defeat (RSD) or left undisturbed as controls (CON). The neuroanatomical distribution of GFP⁺ cells was determined 14 h after the final cycle of RSD (n = 3–6, 2 independent experiments). A, Representative merged images of Iba-1 (green)/CCR2 (red)/Ly6C (blue) immunofluorescence in the PFC of CON or RSD mice that received CCR2^HET and CCR2^KO donor BM. B–D, Quantification of the total number of perivascular and parenchymal cells in the PFC (B), AMYG (C), and HPC (D). E, Representative merged images of CX₃CR1 (green)/Iba-1 (red)/Ly6C (blue) immunofluorescence in the AMYG of CON or RSD mice that received CX₃CR1^HET or CX₃CR1^KO donor BM. F–H, Quantification of the total number of perivascular and parenchymal GFP⁺ cells in the PFC (F), AMYG (G), and HPC (H). Bars represent the mean ± SEM. Means with asterisk (*) are significantly different from CON (p < 0.05) and means with number sign (#) tend to be different from CON (p = 0.06).