68. Reduction of hair glucocorticoid levels in an animal model of post-traumatic stress disorder (PTSD)

TLDR: These findings replicate evidence of reduced hair cortisol in people with PTSD, which may be a more reliable measure of baseline GCs than is found in serum in rats and traumatized people.

Abstract: PTSD results from exposure to a horrific, life-threatening experience. We have developed an animal model of PTSD which involves intense fear-provoking experiences (predator exposure) occurring in conjunction with social instability. Rats exposed to this psychosocial stress (PSS) regimen exhibit changes in physiology and behavior that are comparable to symptoms of people with PTSD (Stress, 11:259–281, 2008). One clinical anomaly, the subject of much debate, is whether basal glucocorticoid (GC) levels are abnormally low in PTSD. There is inconsistent evidence of lower basal GC levels in PTSD, as well as in our animal model of PTSD (Zoladz and Diamond, Neurosci. & Biobehav. Rev., 2013; PNE, 2012). In the current work we addressed this by measuring corticosterone levels in serum, and in a novel approach, fur cortisol of rats exposed to PSS. Adult male rats were immobilized and exposed to a cat twice during a 31 day period of unstable housing followed by fur and basal blood sampling. Rats administered PSS exhibited reduced cortisol levels in fur (1.84 ± 0.22 vs. 3.08 ± 0.45 ng/dl; p p  = 0.9). These findings replicate evidence of reduced hair cortisol in people with PTSD (Biol Psychiatry 72: 65–69, 2012), which may be a more reliable measure of baseline GCs than is found in serum in rats and traumatized people.