We evaluated the impact of chronic repeated predation stress (CRPS) on open field behavior and synaptic mitochondrial respiration within the prefrontal cortex (PFC) and hippocampus (HPC). Male and female C57Bl/6NTac mice were subject to CRPS for 15 days during their adolescent (PND36-50) and early adult (PND57-71) stages. All animals were assessed for anxiety-like behavior in the open-field assay in adulthood. Brains were collected (PND106-108) and immediately used to assess synaptic mitochondrial respiration with the SeahorseXFe24 instrument. CRPS induced anxiety-like behavior in female mice in the open field, despite not observing stress effects on mitochondrial respiration within either sex. However, both sexes displayed significant region-specific differences in mitochondrial respiration. PFC mitochondria respiration was higher than synaptic mitochondrial respiration rates in the HPC across multiple mitochondrial dynamics. To further understand regional differences in mitochondrial respiration, we analyzed expression of estrogen receptor beta (ESR2) and uncoupling protein 2 (UCP2) as both are indicated in regulation of mitochondrial dynamics. In the HPC, females expressed higher levels of both genes compared to males. Further, hippocampal ESR2 expression was elevated by CRPS in both sexes, suggesting a potential mechanism by which synaptic mitochondria are protected.
Shaw et al. (Thu,) studied this question.