ObjectiveTo identify differentially expressed proteins in the hippocampus of rats after chronic immobilization stress (CIS) using a proteomics approach, and to study the effect of the Xiao Yao San (XYS) decoction on differentially expressed proteins.

MethodsTwenty-four Sprague Dawley rats were randomly assigned to one of four groups of equal body weight: control (non-stress), 7-day stress, 21-day stress and 21-day stress + XYS treatment groups. Two-dimensional gel electrophoresis (2-DE) was used to detect differences in protein expression in rat hippocampus. One differentially expressed protein was measured and verified by western blotting.

ResultsSeventeen proteins showed differential expression. Among these, eight could be identified: glial fibrillary acidic protein-2 (GFAP-2), tubulin alpha-1c, cytoplasmic muscle actin 2, 14-3-3 protein, β-2a tubulin, phosphatidylethanolamine binding protein, synuclein α syn3, and a low molecular weight (18 kD) protein. Six of these proteins exhibited increased expression, one showed decreased expression, and the other protein, which comprised five subtypes, were either increased or decreased. These proteins are known to be involved in immunity, signal transduction, cell cycle control, apoptosis, regulation of enzyme activity, cytoskeleton structure, and synaptic plasticity. GFAP-2 was further analyzed, and its differential expression confirmed by western blotting.

ConclusionSome proteins are differentially expressed in the hippocampus of rats under chronic stress. The biological functions of these differentially expressed proteins are varied. Finally, the XYS decoction can significantly up- or down-regulate these protein expression levels.