Fig. 2.

6 days of variable stress impacted female microglia differently than males in the NAc (A) Female mice exposed to 6 days of variable stress had fewer microglia than stressed males as indicated by a significant interaction between sex and stress (p ​< ​0.05). (B) Microglia phenotypes differed between male and female mice when exposed to 6 days of variable stress (p ​< ​0.05). The percentage of primed microglia increased in stressed females compared to their same sex controls, whereas the percentage of surveillant microglia decreased. There was a trend for stressed females to have more primed microglia than stressed males (p =0.07). Male phenotypes did not differ significantly between stressed and unstressed individuals. (C) The ratio of primed to surveillant microglia between males and females changed with stress. The ratio increased in stressed females compared to their same sex controls (p ​< ​0.01) but did not significantly differ in males (p ​= ​0.4). (D) Example of the process to perform skeleton and Sholl analysis. Individual microglia images were cleaned to remove unconnected processes from the image. They were traced and skeletonized to analyze area and branch length. For Sholl analysis, the largest radius was first defined by drawing a straight line from the center of the microglial soma, starting radius was defined at 10 ​μm and radius step size was set at 5 ​μm. (E) Microglia area was reduced with stress in females but not males (p ​< ​0.05). (F) Branch length was reduced in stressed females but not males (p ​< ​0.05). (G) 6 days of variable stress reduced the complexity of microglia in females (p values ​< ​0.05). (H) 6 days of variable stress had no impact on the complexity of male microglia. Figures show mean ​± ​SEM. Cells were counted on 3 sections per animal and averaged for each animal, n= 5 animals per group. ∗Indicates significant interaction, # indicates a main effect of stress and ˆ indicates a main effect of sex.