Fig. 1
From: Microglia reactivity is brain region and sex specific in the context of chronic stress
Chronic stress induced weight loss and avoidance behaviors in males. Independent of stress, the number of microglia was region specific. (A) Mice were randomly assigned to treatment groups based on sex: no stress (NS; male n = 6, female n = 6), stress (UCMS; male n = 7, female n = 6). Experimental design and timeline for the UCMS paradigm with the LDT performed on day 13. Experimental timeline generated using biorender.com. (B) Schematic illusion of stressors utilized in the UCMS paradigm. Stressors include isolation, light on/off, cage tile at 45°, wet bedding, stroboscope, static noise, food deprivation, restraint, cage shake, cold surface, new partner, and predator odor. Image generated using biorender.com. (C) mice were weighed on day 0, 7, and 14. Percent weight change is reported. A mixed-effect analysis revealed significant interactions of time and stress (F (2, 76) = 8.591, p = 0.0004), sex and stress (F (1, 76) = 18.99, p < 0.0001), sex, stress and time (F (2, 76) = 6.621, p = 0.0022). The mixed-effect analysis also indicated main effects of time (F (2, 76) = 28.38, p < 0.0001) and stress (F (1, 76) = 26.21, p < 0.0001) (D) In the OFT, total distance traveled is reported. Data was analyzed using two-way ANOVA followed by multiple comparison analysis: a significant interaction between stress and sex (F (1, 20) = 5.806, p = 0.0257) with only a main effect of sex (F (1, 20) = 10.61, p = 0.0039). (E) In the LDT, we measured the duration in the light zone. Two-way ANOVA of the total time spent in the light zone revealed a significant interaction between stress and sex (F (1, 20) = 5.080, p = 0.0356), with main effects of stress (F (1, 20) = 13.84, p = 0.0014) and sex (F (1, 20) = 7.845, p = 0.0110). F. The number of microglia was quantified using IBA1-positive cells in the PFC, NAC, HYPO, AMY, CA1, and CA3. Data analyzed using mixed-effect analysis and followed by multiple comparison analysis on the number of microglia: a significant effect of region (F (5, 66) = 4.484, p = 0.0014). Data presented as the mean with SEM. **p < 0.01, ****p < 0.0001.
