ABSTRACT
ObjectiveTo decipher the mechanism of Wenxiao powder in alleviating corticosterone-induced depression-like behaviors in mice. MethodMale ICR mice were randomized into normal， model， paroxetine （20 mg·kg-1）， and low- and high-dose （3.27， 6.54 g·kg-1， respectively） Wenxiao powder groups. The mice in normal and model groups received equal volume of saline. Other groups except the normal group were injected with corticosterone subcutaneously 0.5 h after gavage to induce depression. Mice were tested for depression-like behaviors after drug administration. Enzyme-linked immunosorbent assay （ELISA） was performed to measure the corticosterone content in the serum. Nissl staining was performed to observe the damage of hippocampal neurons. Immunofluorescence staining was employed to observe the expression of double cortin （DCX） in the dentate gyrus （DG） of the hippocampus. Western blot was employed to determine the expression of proteins in the brain-derived neurotrophic factor （BDNF）/tyrosine kinase receptor B （TrkB）/extracellular signal-regulated kinase （ERK）/cAMP-response element-binding protein （CREB） pathway in the hippocampus. ResultCompared with the normal group， the model group showed decreased sucrose preference rate， increased immobility time in the tail suspension test （P<0.01）， and reduced residence time in the central area of the open field and the total movement distance （P<0.05， P<0.01）. In addition， the modeling elevated the corticosterone level in the serum （P<0.01）， decreased the volume and intensified the nuclear staining of hippocampal neurons in the DG area， reduced the expression of DCX in the DG area， and down-regulated the protein levels of BDNF， phosphorylated （p）-TrkB， p-ERK， and p-CREB in the hippocampus （P<0.05， P<0.01）. Compared with the model group， low-dose Wenxiao powder improved the mouse behavivors in the sucrose preference， open field， and tail suspension tests （P<0.05， P<0.01）， and high-dose Wenxiao powder improved the behaviors in the sucrose preference and open field tests （P<0.05， P<0.01）. In addition， Wenxiao powder lowered the serum corticosterone level （P<0.01） and recovered the structure and morphology of neurons with obvious nuclei and presence of Nissl bodies in the DG area of the hippocampus. Moreover， Wenxiao powder at both doses promoted the expression of DCX in the DG area， and high-dose Wenxiao powder up-regulated the protein levels of BDNF， p-TrkB， p-ERK， and p-CREB in the hippocampus （P<0.05， P<0.01）. ConclusionWenxiao powder can alleviate corticosterone-induced depression-like behaviors and promote neurogenesis in mice possibly by activating the BDNF/TrkB/ERK/CREB signaling pathway.
ABSTRACT
Objective:To observe the effect of Sinisan on the brain-derived neurotrophic factor （BDNF）/tyrosine kinase receptor B （TrKB）， 5-hydroxytryptamine （5-HT）/5-HT1A receptor （5-HT1AR）， and hypothalamus-pituitary-adrenal （HPA） axis in depressed rats， and explore the antidepressant mechanism of Sinisan based on BDNF/TrKB， 5-HT/5-HT1AR， and HPA axis. Method:A total of 120 male Wistar rats were randomly divided into a normal group， a model group， a fluoxetine （0.01 g·kg<sup>-1</sup>） group， and low- （1.25 g·kg<sup>-1</sup>）， medium- （2.5 g·kg<sup>-1</sup>）， and high-dose （5 g·kg<sup>-1</sup>） Sinisan groups， with 20 rats in each group. The depression model was induced by isolation combined with chronic unpredictable mild stimulation（CUMS） in rats except for those in the normal group for 21 days. Rats were then treated correspondingly once a day for 21 days by gavage. Those in the normal group and the model group received an equal volume of normal saline. During the intervention， the model rats were stimulated continuously. The depressive state of CUMS model rats was evaluated by sucrose preference test and open field test. Enzyme-linked immunosorbent assay （ELISA） was used to determine the levels of corticotropin-releasing hormone （CRH）， adrenocorticotropic hormone （ACTH）， and corticosterone （CORT） in the plasma and BDNF and 5-HT levels in the hippocampal homogenate. The mRNA expression of hippocampal TrKB， 5-HT1AR， glucocorticoid receptor （GR）， and mineralocorticoid receptor （MR） was detected by real-time fluorescence-based quantitative polymerase chain reaction （Real-time PCR）. The protein expression of hippocampal TrKB， 5-HT1AR， GR， and MR was detected by Western blot. The histomorphological changes of the hippocampus were observed by hematoxylin-eosin （HE） staining. Result:Compared with the normal group， the model group showed decreased sucrose preference rate （<italic>P</italic><0.01）， reduced horizontal and vertical scores in the open field test （<italic>P</italic><0.01）， increased plasma content of CRH， ACTH， and CORT （<italic>P</italic><0.01）， declining content of BDNF and 5-HT in the hippocampus （<italic>P</italic><0.01）， dwindled mRNA and protein expression levels of TrKB， 5-HT1AR， and GR （<italic>P</italic><0.01）， elevated mRNA and protein expression of MR （<italic>P</italic><0.01）， and damaged hippocampal neurons revealed by HE staining. Compared with the model group， the groups with drug intervention showed increased sucrose preference rate （<italic>P</italic><0.01） and horizontal and vertical scores in the open field test （<italic>P</italic><0.05， <italic>P</italic><0.01）， decreased content of plasma CRH， ACTH， and CORT （<italic>P</italic><0.05， <italic>P</italic><0.01）， elevated content of hippocampal BDNF and 5-HT （<italic>P</italic><0.05， <italic>P</italic><0.01）， elevated mRNA and protein expression levels of hippocampal TrKB， 5-HT1AR， and GR （<italic>P</italic><0.05， <italic>P</italic><0.01）， reduced mRNA and protein expression levels of hippocampal MR （<italic>P</italic><0.05， <italic>P</italic><0.01）， and recovered hippocampal neurons as revealed by HE staining. Conclusion:Sinisan can exert a significant antidepressant effect by increasing hippocampal BDNF and 5-HT content， up-regulating TrKB， 5-HT1AR， and GR mRNA and protein expression， down-regulating MR mRNA and protein expression， inhibiting HPA axis hypertrophy， and enhancing the regeneration and repair of hippocampal neurons.
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Objective::To investigate the neuroprotective effect and mechanism by Wutoutang (WTT) in the spinal nerve ligation (SNL) mice by neurotrophic factor (BDNF)/tyrosine kinase receptor B (TrkB) signaling BDNF/tyrosine kinase receptor B (TrkB). Method::The 40 mice were randomly divided into Sham group, SNL group, WTT group(126 mg·kg-1), ANA-12+ WTT group.The L5 spinal nerve ligation model mice were established in mice, After that, WTT was administrated from the first day to the 10th day, then the consecutive 7-day hippocampal injection of ANA-12(0.05 nmol·L-1)were lasted for 7 days.The levels of brain-derived BDNF, cAMP-response element binding protein(CREB), and protein kinase B(Akt)and the change of hippocampal glutamatergic and GABAergic neurons in mice were detected by tissue immunofluorescence.E14 pregnant ICR mice were sacrificed and the hippocampus were dissected which were divided into control group, glycine group, tumo necrosis factor(TNF)-α(5 mg·L-1)+ glycine group, TNF-α+ WTT(5 mg·L-1)+ glycine group, TNF-α+ WTT+ glycine+ BDNF-siRNA group, TNF-α+ WTT+ glycine+ Akt-siRNA group, TNF-α+ WTT+ glycine+ CREB-siRNA group, the primary and secondary dendrrictes, in which the arrowheads indicate the expression od postsynapti desity protein 95(PSD95) in the shafts and arrows were tested by cellular immunofluorescence.The neurons were divided into control group, glycine group, ANA-12 group(0.5 mmol·L-1), ANA-12+ glycine group, ANA-12+ WTT group, ANA-12+ WTT+ glycine group, the morphology of hippocampal neurons were tested by cellular immunofluorescence. Result::Compared with Sham group, BDNF, Akt and CREB positive cell of SNL group decreased significantly(P<0.01), the hippocampal glutamatergic and GABAergic neurons out of balance(P<0.01). Compared with SNL group, the BDNF, Akt and CREB positive cell of WTT group increased significantly(P<0.01), Glutamine-aminobutyric acid neurons regein balance(P<0.01). Compared with WTT group, BDNF and CREB positive cell of ANA-12+ WTT group decreased significantly(P<0.05), Glutamine-aminobutyric acid neurons was disorderedd(P<0.05). Comparaed with control group, the level of PSD95 of glycine group were increase significantly(P<0.01). The number of dendritic spine density apically and basally of glycine group were increase significantly(P<0.01), but the primary and secondary dendrites of ANA-12 group, ANA-12+ glycine group, ANA-12+ WTT group, ANA-12+ WTT+ glycine group were not change.Comparaed with glycine group, the level of PSD95 of TNF-α+ glycine group were decreased significantly(P<0.01). Comparaed with TNF-α+ glycine group, the level of PSD95 of TNF-α+ WTT+ glycine group were increase significantly(P<0.01). Comparaed with TNF-α+ WTT+ glycine group, the level of PSD95 of TNF-α+ WTT+ glycine+ BDNF-siRNA group, TNF-α+ WTT+ glycine+ Akt-siRNA group, TNF-α+ WTT+ glycine+ CREB-siRNA group were decreased significantly(P<0.01). Conclusion::In vivo and in vitro studies have shown that the WTT mediated remission of the primary hippocampal glutamatergic neurons were dependent on the BDNF/TrkB pathway.
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Objective::To study the anti-depressive effect of Qing' ewan in treating chronic unpredictable mild stress (CUMS) in rats, and the regulatory effect on estrogen receptor and estrogen receptor-related signaling pathways, in order to explore its anti-depressive mechanism. Method::The CUMS model was established. The experiment was divided into normal control group, model group, escitalopram oxalate group (positive control) and Qing' ewan groups (1.71, 5.13, 15.39 g·kg-1). After 4 weeks of modeling, rats were treated with corresponding drugs for 2 weeks. Behavioral evaluation [sucrose preference test (SPT), forced swimming test (FST), open field test (OFT)] was conducted to assess if the CUMS model was successful. Western blot was used to analyze the protein expression levels of estrogen receptor α (ERα), estrogen receptor β (ERβ), brain-derived neurotrophic factor (BDNF) and tyrosine kinase receptor B (TrkB). Result::Compared with the normal group, the sucrose consumption rate and the score of OFT in the model group decreased(P<0.05, P<0.01), the immobility time of FST prolonged significantly(P<0.01), and the protein expression levels of ERα, ERβ, BDNF and TrkB decreased(P<0.05, P<0.01). Compared with the model group, the behavioral performance of the treated group was improved, the sucrose consumption rate and the score of OFT increased(P<0.05, P<0.01), and the immobility time decreased(P<0.05). The protein expressions of ERα, ERβ, BDNF and TrkB in the treated group were significantly up-regulated(P<0.05, P<0.01), especially the middle-dose Qing' ewan group (5.13 g·kg-1). Conclusion::Qing' ewan can improve depression-like behavior in CUMS rats. Its mechanism may be related to the neuroprotective effect by up-regulating the expressions of ERα and ERβ and activating estrogen receptor-mediated ERβ/BDNF/TrkB pathways.