Could PTSD Involve Immune Cell Response to Stress?

Posted on February 24, 2014

Image: Fei

Chronic stress that produces inflammation and anxiety in mice appears to prime their immune systems for a prolonged fight, causing the animals to have an excessive reaction to a single acute stressor weeks later, new research suggests.

After the mice recovered from the effects of chronic stress, a single stressful event 24 days later quickly returned them to a chronically stressed state in biological and behavioral terms. Mice that had not experienced the chronic stress were unaffected by the single acute stressor.

The study further showed that immune cells called to action as a result of chronic stress ended up on standby in the animals’ spleens and were launched from that organ to respond to the later stressor.

Mice without spleens did not experience the same reactivation with the second stressor, signifying the spleen’s role as a reservoir for primed immune cells to remain until they’re activated in response to another stressor.

The excessive immune response and anxiety initiated by a brief stressor mimic symptoms of post-traumatic stress disorder.

The Ohio State University scientists are cautious about extending their findings to humans. But they say their decade of work with this model of stress suggests that the immune system has a significant role in affecting behavior. And they are the first to study this re-establishment of anxiety in animals with a later acute stressor.

“No one else has done a study of this length to see what happens to recovered animals if we subject them again to stress,” said Jonathan Godbout, a lead author of the study and associate professor of neuroscience at Ohio State. “That retriggering is a component of post-traumatic stress. The previously stressed mice are living a normal rodent life, and then this acute stress brings everything back. Animals that have never been exposed to stress before were unaffected by that one event – it didn’t change behavioral or physiological properties.”


Category(s):Post Traumatic Stress Disorder (PTSD) / Trauma / Complex PTSD, Stress Management

Source material from The Ohio State University