Animal models for posttraumatic stress disorder: An overview of what is used in research

Abstract

Posttraumatic stress disorder (PTSD) is a common anxiety disorder characterised by its persistence of symptoms after a traumatic experience. Although some patients can be cured, many do not benefit enough from the psychological therapies or medication strategies used. Many researchers use animal models to learn more about the disorder and several models are available. The most-used physical stressor models are single-prolonged stress, restraint stress, foot shock, stress-enhanced fear learning, and underwater trauma. Common social stressors are housing instability, social instability, earlylife stress, and social defeat. Psychological models are not as diverse and rely on controlled exposure to the test animal's natural predator. While validation of these models has been resolved with replicated symptoms using analogous stressors, translating new findings to human patients remains essential for their impact on the field. Choosing a model to experiment with can be challenging; this overview of what is possible with individual models may aid in making a decision. Core tip: There are currently several widely accepted animal models being used in fundamental posttraumatic stress disorder (PTSD) research, and many publications using them have made valuable contributions to the collective knowledge on the subject. Still, the difference between models indicates that their suitability depends on the situation; each model has shown different amounts of success in replicating individual criteria or aspects of PTSD. Accordingly, the selection of the most suitable model for each experiment is important for optimally reliable results. This review offers relevant information to aid in that decision.Borghans B, Homberg JR. Animal models for posttraumatic REVIEW 387December 22, 2015|Volume 5|Issue 4|

Selective dopamine D3 receptor antagonism significantly attenuates stress‐induced immobility in a rat model of post‐traumatic stress disorder

“…The increased freeze time is believed to result from enhanced contextual and cued fear conditioning and impaired fear extinction and retention of extinction memories (Knox et al, ; Schoner et al, ; Yamamoto et al, ), which also occur in patients with PTSD (Bowers & Ressler, ). Our results are consistent with previous reports indicating that in the SPS model, animals have an increase in freezing time and display behaviors indicative of anxiety and stress (Borghans & Homberg, ; Yamamoto et al, ). Furthermore, our results indicate that our modifications of the SPS procedure replacing exposure to ether by foot shock stress produced a robust and significant conditioned fear response.…”

“…Our results are consistent with previous reports indicating that in the SPS model, animals have an increase in freezing time and display behaviors indicative of anxiety and stress (Borghans & Homberg, 2015;Yamamoto et al, 2009). Furthermore, our results indicate that our modifications of the SPS procedure replacing exposure to ether by foot shock stress produced a robust and significant conditioned fear response.…”

Adolescent Social Isolation as a Model of Heightened Vulnerability to Comorbid Alcoholism and Anxiety Disorders

“…Subjects can also be exposed repeatedly to the CS in the absence of the UCS to extinguish the associated between these stimuli (Milad and Quirk, 2012). Fear learning paradigms are highly translational assays that are used in humans and research animals (Borghans and Homberg, 2015; VanElzakker et al, 2014). In fact, patients with trauma and stressor-related disorders often exhibit perturbations in fear learning, particularly deficits in extinction (Milad and Quirk, 2012; VanElzakker et al, 2014).…”

Prediction of individual differences in fear response by novelty seeking, and disruption of contextual fear memory reconsolidation by ketamine

“…From both a diagnostic and therapeutic perspective, the presence of such inter-individual variations strengthens the importance of identifying the factors that influence an individual’s resilience or vulnerability to the development of PTSD symptoms following exposure to trauma. In accordance with the preponderance of individual variability in the PTSD pathology (Kessler et al, 1995), heterogeneity in animal response represents a key criterion for the development of clinically-relevant animal models (Borghans and Homberg, 2015; Matar et al, 2013; Siegmund and Wotjak, 2006; Whitaker et al, 2014; Yehuda and Antelman, 1993). However, while the mechanisms underlying variations in response to a trauma are somewhat understood, little is known about the factors able to predict an individual’s vulnerability prior to the traumatic event.…”