RESUMO
Objective::To investigate the possible mechanism of Dabuyuan Jian to promote neurogenesis by studying the effect of Dabuyuan Jian on Wnt/β-catenin signaling pathway in hippocampus of amyloid precursor protein/presenilil(APP/PS1) mice. Method::Totally 30 5-month-old APP/PS1 mice and 10 wild mice were divided into control group, model group, donepezil group (6.5×10-4 g·kg-1·d-1) and Dabuyuan Jian group (13.2 g·kg-1·d-1), and given drugs by gavage for 30 days. The control group and the model group were given an equal volume of saline. The learning and memory of mice were evaluated by water maze. The pathological changes of hippocampal neurons were observed by hematoxylin-eosin (HE) staining. The immunohistochemistry (IHC) was used to detect label positive cells of 5-bromodeoxyuridine (Brdu), adrenocortical hormone (Dcx) and neuronal nuclear antigen (NeuN). Real-time fluorescence quantitative polymerase chain reaction (Real-time PCR) and Western bolt were used to detect the mRNA and protein expression levels of β-catenin and glycogen synthase kinase-3β(GSK-3β) in hippocampus of mice. Result::Compared with the control group, the latency and swimming total distance of the model group were significantly increased (P<0.01), while the number of crossing platforms and the target quadrant time were significantly reduced (P<0.01). Compared with the model group, the platform latency and the total swimming distance of the donepezil group and the Dabuyuan Jian group were decreased (P<0.05, P<0.01), while the number of crossing platforms and the target quadrant time were increased (P<0.05). Compared with the control group, the number of neurons in the hippocampal dentate gyrus (DG) area of the model group was decreased, and necrotic neurons were observed. Compared with the model group, the number of neurons in the hippocampal DG area of the mice in the donepezil group and the Dabuyuan Jian group was increased, while the number of necrotic neurons was decreased. Compared with the control group, the number of positive cells labeled with Brdu, Dcx and NeuN in the hippocampal DG area of the model group was significantly decreased (P<0.01). Compared with the model group, the number of positive cells labeled with Brdu, Dcx and NeuN in the hippocampal DG area of the donepezil group and the Dabuyuan Jian group was increased (P<0.05, P<0.01). Compared with the control group, gene and protein expression levels of β-catenin in the hippocampus of the model group were significantly decreased (P<0.01), whereas gene and protein expression levels of GSK-3β were significantly increased (P<0.01). Compared with the model group, gene and protein expression levels of β-catenin in hippocampus of donepezil group and Dabuyuan Jian group were increased (P<0.05, P<0.01), while gene and protein expression levels of GSK-3β were increased (P<0.05, P<0.01). Conclusion::Dabuyuan Jian could promote hippocampal neurogenesis in APP/PS1 double transgenic mice by regulating Wnt/β-catenin signaling pathway.
RESUMO
Objective:To observe the effect of Dabuyuan Jian on the synaptic plasticity of hippocampus and the brain derived neurotrophic factor （BDNF）/tyrosine kinase receptor （TrkB）/cyclic adenosine phosphate reactive element binding protein （CREB） signaling pathway in amyloid precursor protein/presenilil （APP/PS1） mice， and to explore its possible mechanism for improving synaptic plasticity. Method:Totally 36 APP/PS1 mice were divided into model group， donepezil group（6.5×10-4 g·kg-1·d-1） and Dabuyuan Jian group （13.2 g·kg-1·d-1）， and another wild mice were set as control group. The mice in control group and model group received an equal volume of saline， and the mice in each group received drugs by gavage for 30 days. The learning ability and memory of mice in each group were detected by Morris water maze. The pathological changes of neurons and synapses in the hippocampus of each group were observed by Nissl staining and Golgi staining. The expression levels of postsynaptic density protein 95 （PSD95） and synaptophysin （SYN） in hippocampus of each group were detected by immunofluorescence （IF）. The protein expression levels of BDNF， TrkB， CREB and phosphorylated CREB （p-CREB） in hippocampus were detected by Western blot. Result:As compared with the control group， the platform latency and total swimming distance of the model group were increased in the model group （P<0.01）， with decreased times of crossing the platform and staying time in the target quadrant （P<0.01）， the intracellular Nissl bodies of neurons in hippocampal CA3 area decreased or disappeared in model group， with decreased number of neurons and dendritic branches and decreased density of dendritic spine in hippocampal CA3 area of the mice （P<0.01）， and the protein expression levels of SYN， PSD95， BDNF， TrkB and p-CREB in hippocampus of mice were also decreased in model group （P<0.05， P<0.01）. As compared with the model group， the platform latency and total swimming distance were decreased in the donepezil group and Dabuyuan Jian group （P<0.05， P<0.01）， with increased times of crossing platform and staying time in target quadrant （P<0.05， P<0.01）， the number of Nissl bodies of neurons in hippocampal CA3 area was increased in the donepezil group and Dabuyuan Jian group， with increased number of neurons and dendritic branches and increased density of dendritic spine in hippocampal CA3 area of the mice， and the protein expression levels of SYN， PSD95， BDNF， TrkB and p-CREB in hippocampus of mice were increased in the donepezil group and Dabuyuan Jian group （P<0.05， P<0.01）. Conclusion:Dabuyuan Jian can improve the synaptic plasticity of APP/PS1 double transgenic mice， and its mechanism may be related to its up-regulation of BDNF/TrkB/CREB signal pathway in mouse hippocampus.