Chronic psychological stress (PS) increases the infiltration of bone marrow-derived microglia into the PVN.

<p>(A, B) After chronic PS-loading for five days, the numbers of GFP-positive cells (green) in the PVN were significantly increased compared with sham-treated mice. Data are expressed as mean ± sem (PS: <i>n</i> = 6−7, sham: <i>n</i> = 5−11). <b><i>#</i></b><i>P</i> < 0.05 with ANOVA followed by Tukey’s multiple comparison. *<i>P</i> < 0.05 with two-tailed Student’s <i>t</i>-test. (C) GFP-positive cells (green) overlapped with Iba-1 (red) in PVN from chronic PS-loaded mice but did not overlap with GFAP (red) in PVN from chronic PS-loaded mice. (D) Photograph of mice received irradiation with head protection and non-irradiated mice. (E, F) After chronic PS-loading for five days, the number of GFP-positive cells (green) in the PVN of mice received the irradiation with head protection was significantly increased compared with sham-treated mice. Data are expressed as mean ± sem. **<i>P</i> < 0.001 for PS (<i>n</i> = 8) to sham (<i>n</i> = 4) with two-tailed Student’s <i>t</i>-test. (G) GFP-positive cells (green) overlapped with Iba-1 (red) in PVN from chronic PS-loaded mice received the irradiation with head protection. PVN shown by dotted line. Scale bars: 50 µm.