Mouse model of post-traumatic stress disorder negatively impacts cardiac homeostasis

Post-traumatic stress disorder (PTSD) is a disabling psychological disorder characterized by chronic symptoms of intrusiveness, avoidance, and hyperarousal after a traumatic event. Retrospective studies have indicated PTSD increases the risk for cardiovascular disease (CVD) including arrhythmia, hypertension, and myocardial infarction. The goal of this study was to: 1) use a murine model of cued fear conditioning (inescapable foot shock, IFS) to develop a scoring method to distinguish a PTSD-like phenotype, and 2) use this model system to characterize the cardiac phenotype and function in mice with extreme PTSD-like behaviors. We compared 3 groups, controls, non-responders (NR), and PTSD-like mice at 2 time points [4-weeks and 8-weeks post-IFS] to compare left ventricular structure and function. Assessment of cardiac function showed both male and female PTSD-like mice had increased isovolumetric relaxation time at 8-weeks post-IFS, whereas only females demonstrated increases in E/e’, left atrial diameter, and decreased ejection fraction compared to control mice. Female PTSD-like mice also demonstrated increased interstitial fibrosis through picrosirius red staining and increased expression of fibrotic genes including Col3a1 and Lox. Overall, our data indicated that mice displaying behavioral characteristics associated with PTSD present with sex-dependent diastolic dysfunction likely due, at least in part, to an activation of cardiac fibrosis.