Effects of voluntary, involuntary exercise and sertraline on anxiety, social and cognitive behavior in female rat model of post-traumatic stress disorder

Abstract

Post-traumatic stress disorder (PTSD) is considered as a complex syndrome comprising extremely severe anxiety levels, social-interpersonal dysfunction, and cognitive impairment that may be based on severe traumatic events. Although PTSD is more prevalent in females than in males, most preclinical studies have been carried out in males. The present study investigated the effects of voluntary and involuntary exercise, as well as sertraline on behavioral deficits in a female nonhuman animal model of PTSD using the single-prolonged stress (SPS) paradigm. Female adult rats were exposed to SPS protocol (2-hour restrain, 20-minute forced swimming, 15-minute rest, and 2–3 minute diethyl ether exposure) and were then kept undisturbed. Following a 7-day undisturbed period, animals were subjected to a 10 min restraint (re-stress). SPS rats were treated with voluntary wheel running or moderate treadmill exercise (5 days/week) and/or the administration of sertraline (10 mg/kg/day) for four consecutive weeks. Behavioral assessments were conducted using the Elevated Plus Maze (EPM) test for anxiety, the Three-Chamber Social Test (3-CST) for social interaction, and the Morris Water Maze (MWM) test for spatial memory. Involuntary exercise combined with sertraline significantly increased time spent in the open arms of the EPM test (P < 0.001), and interaction with new rats in 3-CST (P < 0.001) compared to SPS rats. The voluntary exercise plus sertraline group showed a significant increase in entries into the training platform during the probe phase of the MWM test (P < 0.001) compared to SPS rats. Overall, sertraline combined with involuntary exercise was more effective than voluntary exercise plus sertraline in enhancing social interaction and reducing anxiety in the SPS model of PTSD. Conversely, voluntary exercise combined with sertraline provided greater benefits for spatial memory enhancement in female rats.