Maternal Separation Induces Sex-Specific Differences in Sensitivity to Traumatic Stress
Dayan Knox1, Stephanie A Stout-Oswald2,3, Melissa Tan2,3
1Department of Psychological and Brain Sciences, University of Delaware, Newark, DE, United States.
Frontiers in Behavioral Neuroscience
|December 27, 2021
Summary
Early life stress and sex impact post-traumatic stress disorder (PTSD) susceptibility. Female rats exposed to maternal separation and traumatic stress showed heightened startle responses, unlike males.
Area of Science:
- Neuroscience
- Psychiatry
- Animal Models of Stress
Background:
- Post-traumatic stress disorder (PTSD) is a significant psychiatric condition with considerable economic impact.
- Female sex and early life stress are identified risk factors for PTSD development.
- Existing animal models lack the ability to fully explore the interaction between early life stress, sex, and traumatic stress susceptibility.
Purpose of the Study:
- To investigate the combined effects of early life stress (maternal separation, MS) and adolescent/adult traumatic stress (single prolonged stress, SPS) on stress reactivity in male and female rats.
- To establish a reliable animal model for examining sex differences in susceptibility to traumatic stress following early life adversity.
Main Methods:
- Utilized the maternal separation (MS) model for early life stress and the single prolonged stress (SPS) model for adolescent/adult traumatic stress.
- Assessed startle reactivity, anxiety-like behavior in the open field (OF), and basal corticosterone levels in male and female rats.
- Compared outcomes between rats exposed to MS/SPS, MS/control, control/SPS, and control/control conditions.
Main Results:
- Female rats subjected to both MS and SPS exhibited significantly enhanced startle reactivity compared to MS/control females.
- MS/SPS males did not show enhanced startle reactivity; however, SPS exposure alone in non-separated males increased startle reactivity.
- Female rats displayed higher basal corticosterone levels and increased locomotor activity in the OF than males, irrespective of MS or SPS exposure.
Conclusions:
- The combined MS and SPS models provide a viable platform for studying how early life stress interacts with sex to influence sensitivity to traumatic stress.
- Findings suggest distinct pathways through which early life adversity and sex contribute to the development of stress-related disorders.
- This model can elucidate mechanisms underlying sex differences in PTSD vulnerability.
