Anxiety in rats exposed to vital stress in association with delayed trauma reminder

BACKGROUND: Modeling intrusive memories of psychologically traumatic event in post-traumatic stress disorder and assessing the development of mental disorders in the long-term period is relevant in order to understand the mechanisms of vital stress caused. Pathological anxiety may reflect the experienced feeling of fear and helplessness and intrusive traumatic memories in post-traumatic stress disorder.

AIM: The purpose of the study was to assess the level of anxiety and exploratory activity of male rats in the Elevated Plus Maze test after experiencing vital stress in association with twice repeated trauma reminders in a delayed period.

MATERIALS AND METHODS: The study was performed on mature male Wistar rats weighing 300–350 g (n = 34). Mental trauma was modeled by the circumstances of experiencing the situation of partner’s death from the action of a predator and the threat to their own life when placing rats in a terrarium with a tiger python. In rats, the behavior in the Elevated Plus Maze test was analyzed two months after an exposure to stress.

RESULTS: In the delayed period after vital stress, the Elevated Plus Maze test showed an increase in anxiety and a decrease in exploratory activity of male rats. When placed twice in a traumatic environment, male rats with previously received psychogenic trauma maintained an increased level of anxiety and suppression of exploratory activity in the long-term period.

CONCLUSIONS: Two months after vital stress, male rats show increased anxiety and reduced exploratory activity. The traumatic event reminder leads to worsening of behavioral disorders caused by psychogenic trauma, indicating a stable, long-lasting development of post-traumatic stress disorder.