Effect and Mechanism of Chaihu Jia Longgu Muli Tang on Hippocampus of Rats with Chronic Stress Depression Based on BDNF/TrkB/CREB Pathway / 中国实验方剂学杂志

Objective:To explore the effect of Chaihu Jia Longgu Muli Tang on the hippocampus of rats with chronic stress depression based on the brain-derived neurotrophic factor (BDNF)/tyrosine kinase B (TrkB)/cyclic adenosine phosphate response element-binding protein (CREB) pathway. Method:Sixty SD rats were divided into a blank group (<italic>n</italic>=10) and an experimental group (<italic>n</italic>=50) for the induction of the chronic stress depression model. The rats in the experimental group were further divided into the following five groups: a model group， a fluoxetine hydrochloride group (0.003 g·kg^-1), and low-(1.625 g·kg^-1), medium-(3.25 g·kg^-1), and high-dose (6.5 g·kg^-1) Chaihu Jia Longgu Muli Tang groups. The rats were administered correspondingly by gavage once a day for eight weeks. Behavioral tests were performed to evaluate the depression state of the rats before modeling， after modeling， and after drug administration. Hematoxylin-eosin (HE) staining was used to observe the morphological changes in the hippocampus of rats. The immunohistochemical (IHC) staining was used to quantitatively detect BDNF protein expression in the rat hippocampus. The mRNA and protein expression of BDNF， TrkB， and CREB in the rat hippocampus was detected by the real-time fluorescence-based quantitative PCR (Real-time PCR) and Western blot， respectively. Result:Compared with the blank group， the model group showed decreased sucrose preference rate (<italic>P</italic><0.05)， declining horizontal and vertical scores (<italic>P</italic><0.05)， and prolonged immobility time and floating time (<italic>P</italic><0.05). Additionally， HE staining results revealed that hippocampal neuron structure was damaged. IHC staining showed that the mRNA and protein expression of BDNF， TrkB， and CREB was significantly decreased (<italic>P</italic><0.05). Compared with the model group， the fluoxetine hydrochloride group and the Chaihu Jia Longgu Muli Tang groups displayed elevated sucrose preference rate (<italic>P</italic><0.05)， increased horizontal and vertical scores (<italic>P</italic><0.05)， and shortened immobility time and floating time (<italic>P</italic><0.05). Furthermore, the hippocampal neuron structure was significantly repaired. IHC staining showed that the mRNA and protein expression of BDNF， TrkB， and CREB was significantly increased (<italic>P</italic><0.05). Conclusion:Chaihu Jia Longgu Muli Tang can significantly improve the depression-like behaviors of rats after chronic stress stimulation and enhance the regeneration and repair of neurons in the hippocampus. The underlying mechanism may be related to the up-regulation of the BDNF/TrkB/CREB signaling pathway in the hippocampus of rats.

Study on Protection Effect of Mulberry Anthocyanin- 3-glucoside on Epilepsy Model Mice and the Effect of Hippocampal BDNF/TrkB Pathway / 中国药房

OBJECTIVE：To study the protection ef fects of mulberry anthocyanin- 3-glucoside on epilepsy model mice and the effect of hippocampal brain derived neurotrophic factor （BDNF）/tyrosine kinase B （TrkB）pathway. METHODS ：Totally 120 C57BL/6 mice were randomly divided into normal group ，model group ，single medication group （mulberry anthocyanin- 3- glucoside），agonist combination group（mulberry anthocyanin- 3-glucoside+TrkB agonist LM 22B-10），with 30 mice in each group. single medication group and agonist combination group were given mulberry anthocyanin- 3-glucoside 600 μg/kg intragastrically once a day ，for consecutive 6 weeks. The agonist combination group was given LM22B-10（5 mg/kg）via the lateral ventricle once a day at 6th week. Normal group and model group were given constant volume of normal saline intragastrically. After last medication，except for normal group ，other groups were given lithium chloride-pilocarpine to establish epilepsy model. After modeling，10 mice in each group were taken to record the latency ，frequency and duration of spontaneous recurrent epilepsy ， observed for 6 hours a day for 4 weeks；EEG was recorded on the 14th，28th and 36th day after modeling ，and the abnormal frequency of EEG in 1 h was counted . On the 6th day of modeling ，other 10 mice in each group were taken to detect the serum calcium level ，and the remaining 10 mice in each group were taken to detect the expressions of BDNF mRNA and protein in the hippocampus. RESULTS ：Compared with normal group ，latency，frequency and duration of spontaneous recurrent epilepsy and the times of abnormal brain wave on the 14th，28th and 36th day after modeling were increased significantly in model group （P＜ 0.05）. The serum calcium level ， mRNA and proteinexpression of BDNF in hippocampus were increased E-mail：wangfang7699@126.com significantly （P＜0.05）. Compared with model group ，the latency，frequency，duration of spontaneous recurrent epilepsy and the times of abnormal brain wave on the 28th and 36th day after modeling were decreased significantly in single medication group（P＜0.05），while serum calcium level ，mRNA and protein expression of BDNF in hippocampus were decreased significantly （P＜0.05）. Compared with single medication group ，the latency，frequency and duration of spontaneous recurrent epilepsy and the times of abnormal brain wave on the 28th and 36th day after modeling were increased significantly in agonist combination group （P＜0.05），while serum calcium level ，mRNA and protein expressions of BDNF in hippocampus were increased significantly （P＜0.05）. CONCLUSIONS ：Mulberry anthocyanin- 3- glucoside has a good protection effect on epilepsy model mice ，the mechanism of which may be associated with inhibiting the activation of hippocampal BDNF/TrkB pathway.

Construction and identification of a lentiviral vector mediating RNA interference of tyrosine kinase B gene / 中华行为医学与脑科学杂志

Objective To construct a tyrosine kinase B(TrkB) targeted RNA interference (RNAi) lentiviral vector.Methods Four oligonucleotides targeting rat TrkB gene were synthesized and cloned into lentiviral vector pXZRNAi 1.0 to construct recombinant lentiviral vectors pXZRNAi-shTrkB-1,2,3,4.Neural stem cells prepared from rat hippocampus were infected with these high-titer viruses.Real-time PCR was employed to detect the TrkB mRNA expression and western blot was used to assess the gene silencing efficacy of these recombinants.Results Enzyme digestion and DNA sequencing results demonstrated that these shRNAs were correctly inserted into lentiviral vectors and the four recombinants were constructed successfully with the titer of 8.6 × 105cfu/ml.The infection efficiency of the letivirus on neural stem cells reached 80％.Compared with the uninfection group,the expression levels of TrkB mRNA in neural stem cells decreased significantly after transfected with pXZRNAi-shTrkB-3 and 4((66.7 ± 5.5) ％ and(76.8 ± 4.9) ％ respectively,P ＜ 0.05) ; and the protein expression levels were also significantly decreased ((68.5 ± 4.3)％ and (78.2 ± 5.1)％ respectively,P ＜ 0.05).Conclusion The lentiviral vectors for TrkB have been successfully constructed with high yield of lentivirus,which provides versatile method for assessing gene function in neural stem cells.

Isoflurane Induces Transient Anterograde Amnesia through Suppression of Brain-Derived Neurotrophic Factor in Hippocampus

OBJECTIVE: Transient anterograde amnesia is occasionally observed in a number of conditions, including migraine, focal ischemia, venous flow abnormalities, and after general anesthesia. The inhalation anesthetic, isoflurane, is known to induce transient anterograde amnesia. We examined the involvement of brain-derived neurotrophic factor (BDNF) and its receptor tyrosine kinase B (TrkB) in the underlying mechanisms of the isoflurane-induced transient anterograde amnesia. METHODS: Adult male Sprague-Dawley rats were divided into three groups : the control group, the 10 minutes after recovery from isoflurane anesthesia group, and the 2 hours after recovery from isoflurane anesthesia group (n=8 in each group). The rats in the isoflurane-exposed groups were anesthetized with 1.2% isoflurane in 75% nitrous oxide and 25% oxygen for 2 hours in a Plexiglas anesthetizing chamber. Short-term memory was determined using the step-down avoidance task. BDNF and TrkB expressions in the hippocampus were evaluated by immunofluorescence staining and western blot analysis. RESULTS: Latency in the step-down avoidance task was decreased 10 minutes after recovery from isoflurane anesthesia, whereas it recovered to the control level 2 hours after isoflurane anesthesia. The expressions of BDNF and TrkB in the hippocampus were decreased immediately after isoflurane anesthesia but were increased 2 hours after isoflurane anesthesia. CONCLUSION: In this study, isoflurane anesthesia induced transient anterograde amnesia, and the expressions of BDNF and TrkB in the hippocampus might be involved in the underlying mechanisms of this transient anterograde amnesia.

Effects of electroacupuncture combined with rehabilitation training on expression of brain derived neurotrophic factor and its receptor tyrosine kinase B in rats with hemitransectional spinal cord injury / 中华物理医学与康复杂志

Objective To observe the changes of expressions of brain-derived neurotrophic factor (BDNF)and its receptor tyrosine kinase B(TrkB)and in rats with hemitransectional spinal cord injury(SCI)after electroacupuncture on Du Meridian and rehabilitation training.Methods The animal model of acute hemitransectional lesion at the right half of T11 spinal cord was established in 96 adult female rats,which were then divided randomly into an electroacupuncture group,a rehabilitation training group,an electroacupuncture combined with rehabilitation training group and a control group.All the groups received treatment on the 3rd d after operation.The electroacupuncture group and rehabilitation training group were given electroacupuncture on points of Du Meridian and rehabilitation training,respectively,and the combined group was given Du Meridian electroacupuncture in addition to rehabilitation training.Basso-Beattie-Bresnahan(BBB)scale was used to evaluate motor function every week.Twelve rats of each group were sacrificed 4 and 8 weeks after operation,respectively,and their spinal cord tissues were extracted.The polymerase chain reaction(PCR),reverse transcription-polymerase chain reaction(RT-PCR)and immunohistochemical techniques were used to detect the expressions of BDNF and TrkB.Results BBB grade increased gradually as time went on.There were significant differences between control group and other groups at the same time point(P ＜ 0.05).The scores increased obviously in electroacupuncture combined with rehabilitation training group compared with electroacupuncture group and rehabilitation training group(P ＜ 0.05).The result of immunohistochemical observation and RT-PCR also showed that there were significant differences of expressions of BDNF and TrkB among control group and other groups at the same time(P ＜ 0.05).The effects in electroacupuncture combined with rehabilitation training group were much more obvious than those in electroacupuncture group and rehabilitation training group(P ＜ 0.05),but there was no significant difference between electroacupuncture group and rehabilitation training group (P ＞ 0.05).Conclusions Electroacupuncture on Du Meridian combined with rehabilitation training had synergic effect on rat's SCI,and could obviously improve the restoration of rat's motor function; the mechanism maybe related to the upregulation of expressions of BDNF and TrkB.

The Role of Brain-Derived Neurotrophic Factor in the Onset of Vascular Dementia / 国际脑血管病杂志

Vascular dementia,an acquired,persistent syndrome of intelligent disorder,mainly caused by cerebrovascular disease is one of the main types of senile dementia.Its pathogenesis remains unclear.Brain-derived neurotrophic factor sustains multiple neuronic survival,development, differentiation,and repair following injury.It also induces and maintains the long-term potentiation of hippocampus and cortex,and changes the morphologic plasticity of hippocampal neuron by regulating hippocanoal synaptic transmission and synaptic plasticity.It participates in the processes of hippocampus-dependent learning and memory,and it may play an important role in the onset and development of vascular dementia.