ABSTRACT
Objective:To observe the effects of recipes for tonifying kidney and replenishing Qi, Zuoguiwan (ZG) and Yiqi Congming Tang(YQ) on memory capacity, expressions of learning and memory-related genes expression, and explore the changes in relevant epigenetic modification enzymes. Method:SD male rats with natural aging (24 months old) were used as animal models and randomly divided into aged control group, aged ZG group(12.12 g·kg-1), aged YQ group(10.18 g·kg-1), aged compound group(11.15 g·kg-1) and aged antagonist RU38486 group(5×10-3g·kg-1). Another 5 months old male SD rats were included as the young control group. Morris water maze method was used to observe the spatial learning and memory ability of the rats. The co-localizations of histone deacetylase 2 (HDAC2) and methyl CpG binding protein 2 (MeCP2) in hippocampus of rats in each group were observed by laser confocal microscope. The changes in expressions of glucocorticoid receptor (GR), synapsin1(Syn-1), HDAC2, and histone acetyltransferase 1(HAT1) proteins in hippocampus of each group were detected by Western blot, and mRNA expression of HDAC2 was detected by Real-time fluorescence quantitative polymerase Chain reaction (Real-time PCR). At the same time, the effects of ZG, YQ and compound decoction in alleviating the above-mentioned abnormal changes were observed. Result:Compared with the young control group(control group), the latency of the aged control group was significantly prolonged (PPPPPPPConclusion:ZG group, YQ group, and compound group can improve the spatial learning and memory abilities of aged rats by increasing the expression of learning-memory-associated protein GR and epigenetic modification enzyme HAT1, and reducing the expression of HDAC2 and the co-localization of HDAC2 protein and MeCP2 in the nucleus.
ABSTRACT
<p><b>OBJECTIVE</b>To determine the effects of 5-hydroxymethyl furfural (5-HMF), an extract of Rehmannia glutinosa Libosch, on several down-regulated signaling molecules involved in learning and memory in hippocampal neurons.</p><p><b>METHODS</b>After cultured for 7 days, primary hippocampal neurons were divided into 5 groups: normal, corticosterone model, RU38486, 5-HMF, and donepezil group. Neuron survival rates were calculated 24 h later using SYTO13-PI double-fluorescence staining and an 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. β-galactosidase activity was also assayed. Protein expressed by the glucocorticoid receptor (GCR), brainderived neurotrophic factor (BDNF), and N-methyl-D-aspartate receptor 2B (NR2B), as well as phosphorylationcyclic adenosine monophosphate (cAMP) response element binding protein (p-CREB), phosphorylation-extracellular signal-regulated kinase (p-ERK), and phosphorylation-synapsin (p-synapsin) were quantified with Western blot.</p><p><b>RESULTS</b>Hippocampal neuron survival rates and the above-mentioned proteins were dramatically decreased (P<0.05), β-galactosidase activity was significantly increased in the model group. but the effect was reversed by 5-HMF, RU38486, and to a lesser extent by donepezil (P<0.05).</p><p><b>CONCLUSION</b>5-HMF extracts from the Chinese herb Rehmannia glutinosa Libosch could protect hippocampal neurons from glucocorticoid injury and from down-regulated signaling molecules in the GCR-BDNF-NR2B-p-ERK-p-CREB-p-synapsin signal transduction pathway.</p>