ABSTRACT
ETHNOPHARMACOLOGICAL RELEVANCE: Ginsenoside Rg3 has shown multiple pharmacological activities and been considered as one of the most promising approaches for fatigue treatment. However, little is known about the cellular and molecular mechanisms of Rg3 on anti-fatigue and the effect of Rg3 on dopaminergic system has not been reported yet. The major aim of this study is to investigate the effect of Rg3 on TH expression and the related biochemical parameters, such as PKAα, ERK1/2, Akt and α-synuclein in brain of fatigue rats. MATERIALS AND METHODS: Weight-loaded forced swimming was performed to establish an animal model of fatigue. Rg3 (10mg/kg, 50mg/kg and 100mg/kg) was intragastrically administrated before swimming. The effect of Rg3 on the expression and phosphorylation of TH and TH-related proteins in fatigue rats or in SH-SY5Y cells was assessed with western blotting. HPLC was used to examine the level of DA and DOPAC in the fatigue rats tissues. RESULTS: TH and phosphorylated TH were decreased in different brain regions of which ventral midbrain were less affected in weight-loaded forced swimming rats. Pretreatment with Rg3 significantly suppressed fatigue-induced decrease expression of TH and TH phosphorylation. Also treatment with Rg3 reversed the decrease expression of PKAα as well as the phosphorylation of ERK1/2 and Akt which were induced by weight-loaded forced swimming. Moreover, weight-loaded swimming could induce the increase expression of α-synuclein in hippocampus and midbrain, while suppressed α-synuclein expression in striatum and prefrontal cortex. Furthermore, Rg3 could induce the increase of TH expression and phosphorylation which was accompanied with elevated expression and phosphorylation of related kinase proteins in vitro, while the inhibitors of kinase proteins could suppress these effects of Rg3. In addition, HPLC results showed that Rg3 could reverse the weight-loaded swimming-induced increase of DOPAC/DA ratio. CONCLUSION: Our data suggest that fatigue can induce the decrease of DA which might partially result from the change of TH expression and phosphorylation, and Rg3 can reverse these fatigue-induced changes. The underling mechanisms may include the activity changes of PKAα, ERK1/2, Akt and α-synuclein.
Subject(s)
Dopamine/metabolism , Fatigue/metabolism , Ginsenosides/pharmacology , Tyrosine 3-Monooxygenase/metabolism , Animals , Brain/metabolism , Cell Line, Tumor , Cyclic AMP-Dependent Protein Kinases/metabolism , Humans , Male , Mitogen-Activated Protein Kinase 1/metabolism , Mitogen-Activated Protein Kinase 3/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Rats , Rats, Sprague-Dawley , Swimming , alpha-Synuclein/metabolismABSTRACT
OBJECTIVE: To explore whether there are beta-amyloid protein (Abeta) binding elements in heart-beneficial recipe (HBR, a compound traditional Chinese herbal medicine), which can ameliorate the cytotoxicity of Abeta. METHODS: The extract of HBR and Abeta(1-40) were co-precipitated, and the Abeta(1-40) in pellets was detected by immunoblotting. Affi-gel-Abeta(1-40) was constructed, and Affi-gel-Abeta(1-40) affinity elements from the extract of HBR were analyzed by high-performance liquid chromatography (HPLC). The assay of lactic dehydrogenase (LDH) release from the primary cultured rat cortex neurons was used to evaluate the cytotoxicity of Abeta(1-42), and the protection effects of the HBR serum and the Affi-gel-Abeta(1-40) treated HBR serum. RESULTS: Immunoblotting examination showed Abeta(1-40) could be co-precipitated with components of HBR following co-incubation, and the amount of Abeta(1-40) within pellets decreased when the HBR extract was diluted. Abeta(1-40) affinity elements from the extract of HBR, eluted from Affi-gel-Abeta(1-40) by glycine solution (pH=2.5), could be detected by HPLC-fluorescent detector system. The analysis of LDH release showed that exposure of neurons to 5 micromol/L Abeta(1-42) for 48 h caused a significant increase of LDH release in either a serum free or 10% serum contained culture condition (P<0.01). The rat HBR serum was able to suppress Abeta(1-42) induced LDH release (P<0.05), whereas Affi-gel-Abeta(1-40) treated HBR serum still maintained the ability to attenuate Abeta(1-42) induced LDH release although the effect was somewhat decreased compared with Affi-gel treated HBR serum. CONCLUSION: There are Abeta affinity components in HBR, which could not increase the Abeta cytotoxicity, but might be able to inhibit the cytotoxicity of Abeta. The results implied that the exploration of Abeta affinity elements from Chinese medicinal recipe which is effective for Alzheimer disease, might be an important direction in Alzheimer disease therapeutic research area.