| abstract |
Anxiety and depression are two of the leading mental health issues world-wide, affecting
people of all ages. Stress and biological sex are believed to play a role in the development of
both disorders. Specifically, stress is associated with elevated levels of cortisol, a biomarker of
anxiety and depression. Additionally, women are significantly more likely to be diagnosed with
anxiety and depression than men. Chronic variable stress (CVS) is a commonly used model in
rodents to explore how repeated exposure to various microstressors can lead to long-term
behavioral changes. The aim of this present study was to test the hypothesis that female
Long-Evans are at a higher risk than males for developing anxiety and depression related
behaviors after early life exposure to CVS.
Stressors used were: immobilization, predator odor, cage tilt, strobe lights, ultrasonic
deterrent, and cold room. As an additional stressor, rats were housed overnight in isolation cages
twice a week. Behavioral tests used were: open field test (OFT), elevated zero maze (EZM),
sucrose preference test (SPT), forced swim test (FST), and cocaine-induced locomotor activity
(CLA). Body weights were recorded weekly. At the conclusion of the experiment, animals were
sacrificed, and organs were weighed. For weekly body weights, as a percentage of baseline
weight, males weighed more than females for weeks 2-10. Additionally, control animals weighed
more than CVS animals for weeks 2-4. During the OFT, males spent more time in the outer zone
than females; however, females spent more time in the middle and center zones. Females also
traveled a greater distance than males in all three zones. During the FST, females had a greater
latency to immobility on day one than males. During the CLA, females had greater locomotor
activity than males.
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