Original Article

Exp Neurobiol 2018; 27(3): 200-209

Published online June 30, 2018

© The Korean Society for Brain and Neural Sciences

Radix Polygalae Extract Attenuates PTSD-like Symptoms in a Mouse Model of Single Prolonged Stress and Conditioned Fear Possibly by Reversing BAG1

Ju-Yeon Shin, Jung-Won Shin, Sang-Kyu Ha, Yoorim Kim, Kelley M. Swanberg, Suck Lee, Tae-Woo Kim and Sungho Maeng*

Graduate School of East-West Medical Science, Kyung Hee University, Yongin 17104, Korea

Correspondence to: *To whom correspondence should be addressed.
TEL: 82-31-201-2916, FAX: 82-31-204-8119
These authors contributed equally

Received: April 12, 2018; Revised: May 4, 2018; Accepted: May 7, 2018

Radix Polygalae (RP) has been used to relieve psychological stress in traditional oriental medicine. Recently, cell protective, antiamnestic and antidepressant-like effects were disclosed but the possible application of RP to post-traumatic stress disorder, in which exaggerated fear memory persists, has not yet been explored. For this purpose, the effects of RP on fear behavior was examined in a mouse model of single prolonged stress and conditioned fear (SPS-CF), previously shown to mimic key symptoms of post-traumatic stress disorder. Male mice received daily oral dose of RP extract or vehicle during the SPS-CF procedure. Then fear-related memory (cohort 1, n=25), non-fear-related memory (cohort 2, n=38) and concentration-dependent effects of RP on fear memory (cohort 3, n=41) were measured in 3 separate cohort of animals. Also working memory and anxiety-like behaviors were measured in cohort 1. RP-treated SPS-CF mice exhibited attenuated contextual but not cued freezing and no impairments in the working memory and spatial reference memory performances relative to vehicle-treated SPS-CF controls. RP-treated SPS-CF and naive mice also demonstrated no difference in anxiety-like behavior levels relative to vehicle-treated SPS-CF and naive controls, respectively. In the hippocampus of SPS-CF mice, expression of BAG1, which regulates the activity of GR, was decreased, whereas RP increased expression of BAG1 in naïve and SPS-CF mice. These results suggest that RP exerts some symptomatic relief in a mouse with exaggerated fear response. RP and its molecular components may thus constitute valuable research targets in the development of novel therapeutics for stress-related psychological disorders.

Graphical Abstract

Keywords: Yuan zhi, fear, PTSD, traumatic stress disorders, anxiety