Schisandra chinensis and Rhodiola rosea exert an anti-stress effect on the HPA axis and reduce hypothalamic c-Fos expression in rats subjected to repeated stress

Abstract

The aim of the present study was to investigate the effects of Schisandra chinensis (S. chinensis) and Rhodiola rosea (R. rosea) on rats subjected to 5 h of stress, induced by water‑floating followed by treadmill exercise. Hypothalamus‑pituitary‑adrenal (HPA) activity and c‑Fos and Fos-related antigen 2 (Fra‑2) mRNA expression levels in the hypothalamus of the rats were evaluated. Rats were distributed into four groups: S. chinensis (n=12), R. rosea (n=10), stress control (n=10) and quiet control (n=8). Following a training period of 6 consecutive days, the S. chinensis, R. rosea and stress control groups underwent a 3‑h water‑floating session in the presence of feline predators immediately followed by 2 h treadmill running to induce psychological and physical stress. Following compound stress induction, the serum levels of corticosterone (CORT), adrenocorticotropic hormone and interleukin‑1β and the mRNA expression levels of hypothalamic corticotropin‑releasing hormone (CRH), neuropeptide‑Y, c‑Fos and Fra‑2 were evaluated using enzyme‑linked immunosorbent assay, radioimmunoassay and quantitative polymerase chain reaction, respectively. The results indicated that S. chinensis and R. rosea markedly decreased the stress‑induced elevation of CRH and peripheral CORT levels. The mRNA expression levels of c‑Fos and Fra‑2 in the hypothalamus were significantly increased after 5 h compound stress, and reduced levels of c‑Fos expression were detected in rats treated with R. rosea. Thus, S. chinensis and R. rosea exert an anti‑stress effect in rats subjected to stress by balancing the HPA axis, and possibly by reducing the expression of c‑Fos in the hypothalamus.