Fig. 4

Chronic stress induced microglia reactivity in the HYPO by decreasing the arborization, the length, and number of processes. Males exhibited a more reactive phenotype at baseline. (A) Representative images of the effect of stress on microglia in the HYPO from NS and UCMS groups. Microglia were immunostained with IBA1 (red), nucleus was stained with DAPI (blue). 400× magnification. Scale bar: 50 μm. Nissl staining obtained from the Allen Mouse Brain Atlas and Allen Reference Atlas—Mouse Brain⁶⁵. (B) Quantitative analysis of total length of processes in microglia from the HYPO. Data analyzed using two-way ANOVA and followed by multiple comparison analysis: a significant interaction between stress and sex (F _{(1, 133)} = 19.03, p < 0.0001) with the main effects of stress (F _{(1, 133)} = 50.53, p < 0.0001) and sex (F _{(1, 133)} = 33.87, p < 0.0001). (C) Quantitative analysis of number of processes in microglia from the HYPO. Data analyzed using two-way ANOVA and followed by multiple comparison analysis: a significant interaction between stress and sex (F _{(1, 143)} = 15.29, p = 0.0001) with main effects of stress (F _{(1, 143)} = 110.5, p < 0.0001) and sex (F _{(1, 143)} = 36.10, p < 0.0001). (D) Sholl analysis was conducted to measure the process arborization. Data analyzed using one-way ANOVA followed by multiple comparison analysis (F _{(3, 200)} = 16.02, p < 0.0001). For each mouse, 6 microglia were randomly selected bilaterally for morphological quantification. Data presented as the mean with SEM. ***p < 0.001, ****p < 0.0001.