Murine Model of Repeated Exposures to Conspecific Trained Aggressors Simulates Features of Post-Traumatic Stress Disorder
ARMY CENTER FOR ENVIRONMENTAL HEALTH RESEARCH FORT DETRICK MD
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We evaluated repeated exposures of mice to a trained aggressor mouse as a model adapted from social stress models of traumatic stress for aspects of post-traumatic stress disorder PTSD. Using a cagewithin- cage resident-intruder protocol, subject C57BL6J mice were exposed to aggressors for 6 h daily for 5 or 10 days. At one to three random times during each 6-h session, subjects were exposed directly to aggressor for 1 min or 10 bites, whichever came first. Behavioral, physiological, and histological changes associated with aggressor-exposure were assessed for up to 6 weeks. During aggressor exposure, subjects displayed less territorial behavior, gained weight, and increased body temperature. One day after the last aggressor exposure, inflammatory cardiac histopathologies were prevalent after 10 days, only mild myocardial degeneration with fibrosis or fibroplasias was evident, while controls showed almost no cardiac abnormalities at any time. After 4 weeks, the medial prefrontal cortex of control mice showed increased dendritic spine density, but aggressor-exposed mice showed no increase.