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Evidence-Based Complementary and Alternative Medicine
Volume 2011, Article ID 367619, 7 pages
http://dx.doi.org/10.1093/ecam/nep218
Original Article

Total Flavonoids Extracted from Xiaobuxin-Tang on the Hyperactivity of Hypothalamic-Pituitary-Adrenal Axis in Chronically Stressed Rats

1Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China
2College of pharmacy, Dalian Medical University, Dalian 116044, China
3Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100094, China

Received 15 April 2009; Accepted 25 November 2009

Copyright © 2011 Lei An et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Our previous studies have demonstrated that the total flavonoids (XBXT-2) isolated from the extract of Xiaobuxin-Tang (XBXT), a traditional Chinese herbal decoction, ameliorated behavioral alterations and hippocampal dysfunctions in chronically stressed rats. Studies over the last decades have suggested that the hyperactivity of hypothalamic-pituitary-adrenal (HPA) axis is one of the most consistent findings in stress-related depression. Herein, we used the same chronic mild stress model of rats as before to further investigate the effect of XBXT-2 on the hyperactivity of HPA axis, including the stress hormones levels and glucocorticoid receptors (GRs) expression. Our ELISA results showed that chronic administration of XBXT-2 (25, 50 mg kg−1, p.o., 28 days, the effective doses for behavioral responses) significantly decreased serum corticosterone level and its upstream stress hormone adrenocorticotropic hormone (ACTH) level in chronically stressed rats. Furthermore, western blotting result demonstrated XBXT-2 treatment ameliorated stress-induced decrease of GRs expression in hippocampus, an important target involved in the hyperactivity of HPA axis. These results were similar to that of classic antidepressant imipramine treatment (10 mg kg−1, p.o.). In conclusion, the modulation of HPA axis produced by XBXT-2, including the inhibition of stress hormones levels and up-regulation of hippocampal GRs expression, may be an important mechanism underlying its antidepressant-like effect in chronically stressed rats.