Effects of ginsenoside Rb1 on the stress-induced changes of BDNF and HSP70 expression in rat hippocampus.

Ginsenoside Rb1 (GRb1) has been determined to exert diverse neuromodulatory effects including antistress effects in the brain. The hippocampus is a key brain structure for memory, learning, and cognition and is especially vulnerable to neurotoxic effects associated with stress. The aim of this study was to further explore neuroprotective potential of GRb1 on stress-mediated changes in hippocampal gene expression. Recent studies recognize agents that inducing brain-derived neurotrophic factor (BDNF) and heat shock protein (HSP) 70 as important neuroprotective approaches. Thus, we specifically determined the effects of GRb1 on mRNA expression of BDNF and HSP70, in a model of immobilization stress. In agreement with these reports, acute immobilization stress led to a decrease and an increase in the mRNA levels of the BDNF and HSP70, respectively, in the hippocampus. When pretreated orally, GRb1 significantly inhibited the stress-mediated decline of BDNF level whereas it further increased the stress-mediated elevation of HSP70 level. Our results strongly suggest GRb1 effective in controlling stress-related hippocampal dysfunction. Our finding also contributes further understanding of medicinal usefulness of GRb1 targeting hippocampal network alteration which is commonly observed in aging and neurodegenerative disorders.