Effect of Jieyuwan on depression-like behaviors and expression of BDNF in hippocampus and prefrontal cortex of WKY rats

AIM:To investigate the mechanism of depression and its development, and to study the expression of brain-derived neurotrophic factor (BDNF) in the hippocampus and prefrontal cortex of Wistar-Kyoto (WKY) rats treated with Jieyuwan. METHODS:Adult male WKY rats were used as an animal model of endogenous depression. Wistar rats of the same strain were selected as control group. WKY rats were randomly divided into model group, citalopram group and Jieyuwan group. After intragastric administration for 21 d, the changes of depression-like behaviors were observed by sucrose preference test and forced swimming test. Immunofluorescence and Western blot were used to detect the expression of BDNF in the hippocampus and prefrontal cortex. RESULTS:WKY rats showed significant depression-like behaviors, and the expression of BDNF was significantly decreased in the hippocampus and prefrontal cortex (P<0.01). The reduction of neuronal axons in hippocampus was also observed. After drug treatment, the depression-like behaviors of WKY rats were significantly attenuated, and the expression of BDNF and the number of axons were increased (P<0.01). CONCLUSION:Jieyuwan effectively attenuates the depression-like behaviors of WKY rats, and BDNF is a key factor in its antidepressant effect. Our findings further confirm the involvement of BDNF in the development of depression.     

Phosphodiesterase 4 inhibitor rolipram prevents chronic alcoholism and withdrawal-induced depression-like behaviors in mice

AIM: To investigate the effect of phosphodiesterase 4 (PDE4) inhibitor rolipram on the levels of cyclic adenosine monophosphate (cAMP), protein kinase A (PKA), cAMP response element-binding protein (CREB), phosphorylated CREB (p-CREB) and brain-derived neurotrophic factor (BDNF) in the hippocampus and the prefrontal cortex (PFC) of alcoholism model mice.METHODS: The mice (n=60) were randomly divided into control group, control+rolipram group, alcoholism model group, and alcohol+rolipram (0.1, 0.5 and 1 mg/kg) groups. The mice were given alcohol preference test on days 6, 13, 20 and 27. After the test, the mice received withdrawal of alcohol for 1 d. On day 28, the mice were given behavior test of depression, and after the test, the mice were sacrificed. The cAMP levels in the hippocampus and PFC were detected by ELISA, and the protein levels of PKA, CREB, p-CREB and BDNF were detected by Western blot.RESULTS: The mice showed an obvious drinking phenomenon (P<0.01), and the immobility time of forced swimming test and tail suspension test was significantly increased (P<0.01), with increasing drinking days and withdrawal times. However, chronic treatment with rolipram for 28 d reversed this phenomenon. Moreover, the cAMP levels in the hippocampus and PFC were significantly decreased after 28 d alcohol treatment (P<0.01), and pretreatment with rolipram (1 mg/kg) obviously reversed this decrease (P<0.01). Parallel to these changes of cAMP, the protein levels of PKA, p-CREB and BDNF were also decreased in the hippocampus and PFC (P<0.01), and 28 d rolipram administration inhibited the decreased cAMP, PKA, p-CREB and BDNF levels in the hippocampus. Moreover, 28 d rolipram administration also reversed decreased cAMP, PKA and p-CREB in the PFC.CONCLUSION: Rolipram treatment protects against alcohol-induced depression-like behaviors, and also reduces alcohol drinking. These effects may be related to PDE4-cAMP-PKA-CREB-BDNF pathway.     

Influence of chronic corticosterone injection on depression-like behavior and brain glycogen levels in mice

AIM: To study the effect of chronic corticosterone (CORT) injection on the depression-like behaviors and the brain glycogen level in mice. METHODS: Male C57BL/6N mice (n=40) were randomly divided into normal control group and model group. The mice in model group were subcutaneously consecutively injected with CORT for 4 weeks. The mouse model of chronic stress depression was constructed. The forced swim test and open field experiment were conducted to prove chronic stress model. The serum level of CORT in the mice was measured by radioimmunoassay. The protein levels of hippocampal synaptophysin (SYP) and brain-derived neurotrophic factor (BDNF) were detected by Western blot. Hippocampus glycogen, glycogen synthase and glycogen phosphorylase were determined by indirect fluorescence measurement. RESULTS: Compared with normal control group, the immobility time of the forced swim test in model group was significantly lengthened (P<0.01), and the ability of spontaneous activity was reduced (P<0.01), indicating that chronic CORT injection induced depression-like behaviors in mice. The CORT level increased significantly (P<0.01) in model group. CORT injection decreased the protein expression of hippocampal SYP and BDNF (P<0.01), reduced hippocampal glycogen level (P<0.05) and glycogen synthase activity (P<0.05), and increased glycogen phosphorylase activity (P<0.05). CONCLUSION: Chronic CORT injection causes hippocampal neuron damage and induces the depression-like behaviors of mice, which may be associated with decreasing hippocampal glycogen level by CORT.     

Phosphodiesterase 4 inhibitor rolipram prevents depression- and anxiety-like behaviors in rats exposed to chronic restraint stress

AIM: To discuss the impact of phosphodiesterase 4 (PDE4) inhibitor rolipram on chronic restraint stress-induced depression- and anxiety-like behaviors in rats. METHODS: (1)Forty SD rats were randomly divided into 4 weight-matched groups: unstressed animals injected with vehicle of lithium chloride (LiCl) and rolipram, restraint-stressed animals injected daily with vehicle prior to stress, restraint stress plus 100 mg/kg LiCl group and restraint stress plus 1 mg/kg rolipram group. The open field test was conducted 24 h before the first stress and drug administration,and then the rats received drugs daily 1 h prior to restraint stress (6 h/d) for 25 d. Daily body weight recording, forced swimming test, elevated plus-maze and open field test were conducted to determine the changes of depression- and anxiety-like behaviors. The expression of phosphorylated cAMP response element-binding protein (p-CREB), brain-derived Reurotrophic factor (BDNF), p-Ser21-glycogen synthase kinase (GSK) 3α, p-Ser9-GSK3β, p-Tyr279-GSK3α, p-Tyr216-GSK3β, total GSK3α and total GSK3β was measured by Western blotting. (2)Thirty SD rats were randomly divided into 6 groups and the cannula was surgically placed above the CA1 region in the hippocampus. Seven days after the surgery, the restraint stress was conducted for 21 d after microinjection of protein kinase A (PKA) antagonist H89 and intraperitoneal injection of LiCl and rolipram everyday. The expression of PDE4D, PKA, p-CREB and p-Ser9-GSK3β was measured by Western blotting. RESULTS: (1)No difference of the locomotor activity among all groups before stress was observed. After repeated stress, the body weight,and the crossing, rearing and grooming in open field test were lower than those in control group, and LiCl and rolipram reversed these effects significantly. In addition, in comparison with control group, the immobility in forced swimming test was increased, the climbing in forced swimmming test and the open-arm exploration in elevated plus-maze were decreased and the expression of p-CREB, BDNF, p-Ser21-GSK3α and p-Ser9-GSK3β was down-regulated. Stress induced depression- and anxiety-like behaviors, and rolipram reversed these changes. The LiCl showed similar effects as rolipram except for the expression of p-CREB and BDNF. No significant difference of the expression of p-Tyr279-GSK3α, p-Tyr216-GSK3β, total GSK3α and total GSK3β among all groups was found. (2)The expression of PDE4D was increased, the expression of PKA, p-CREB and p-Ser9-GSK3β was decreased in the hippocampus induce by restraint stress. However, the effect of rolipram on the expression of PKA, p-CREB and p-Ser9-GSK3β was blocked by PKA inhibitor H89. CONCLUSION: Rolipram significantly reduces the depression- and anxiety-like behaviors, possibly through CREB/BDNF signaling and inhibitory serine-phosphorylation of GSK3-mediated signaling. Importantly, the CREB/BDNF signaling also plays a key role in the down-regulation of serine-phosphorylation of GSK3.     

Effect of transplantation of hMSCs modified by BDNF and GDNF gene on injured brain in rat MCAO model

AIM：To study the therapeutic effect of human mesenchymal stem cells (hMSCs) modified by brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) gene transfer with liposome on middle cerebral artery occlusion (MCAO) model rats. METHODS：The nonviral expression vector was constructed and transfected into the hMSCs by liposomal method. The rat brain injury model was established by the method of MCAO. The gene-modified hMSCs, control hMSCs or PBS was transplanted into the rats 24 h after MCAO by femoral venous injection. The neurological function score, the change of the body weight and the behavior test were used to evaluate the damage of the brain in the rats. The degree of the damage and the migration of the cells 15 d after transplantation were analyzed by observing the histological changes of the brain tissues. RESULTS：The expression levels of BDNF and GDNF in gene-modified hMSCs were much higher than those in control hMSCs. The transplantation of BDNF and GDNF gene-modified hMSCs promoted the functional recovery and reduced the infarct size in the rats after MCAO. A few exogenesis cells only survived in the infarct area of the brain in the MCAO rats, and the cells showed no differentiation. CONCLUSION：Transplantation of BDNF and GDNF gene-modified hMSCs by nonviral expression vector is effective in treating cerebral ischemia. The effect may result from the action of the cytokines secreted by these cells, reducing the injuries induced by the brain ischemia and accelerating the nerve repair following the injury.     

Erythropoietin attenuates cerebral ischemia-induced cognitive dysfunction through stimulation of hippocampal CREB phosphorylation in C57BL/6 mice

AIM: To investigate the neuroprotective effect of erythropoietin (EPO) on cognitive dysfunction and neuronal injury in hippocampal CA1 region induced by cerebral ischemia in mice. METHODS: Male C57BL/6 green fluorescent protein-transgenic mice were randomly divided into 3 groups: sham operation group (sham), ischemia/reperfusion group (I/R) and EPO-treated group. Transient cerebral global ischemia was induced by bilateral common carotid artery occlusion (2-VO). The step-down test was used to measure the capacity of learning and memory of the animals in each group. Nissl staining was applied to examine the neuronal number in hippocampal CA1 region. The expression of phosphorylated cAMP response element-binding protein (pCREB) was determined by Western blotting. Alterations of dendritic morphology in hippocampal CA1 region were evaluated using laser scanning confocal microscopy and Neurolucida software. RESULTS: Transient cerebral ischemia caused deficits of spatial learning and memory, and delayed neuronal death and loss of dendritic spines in hippocampal CA1 region were also obvious. The EPO treatment significantly improved the cognitive function in cerebral ischemic mice, and the protein expression of pCREB was obviously increased. At the same time, neuronal death and loss of dendritic spines were reduced in hippocampal CA1 region. CONCLUSION: Erythropoietin increases the protein expression of pCREB, and reduces neuronal death and loss of dendritic spines. These processes may be responsible for erythropoietin-mediated neuroprotective effects and the improvement of cognitive function in cerebral ischemic mice.     

Effects of three Chinese formulas on BDNF,TrkB in rat contex and hippocampus with chronic immobilization stress

AIM: To investigate the changes of brain-derived neruotrophic factor (BDNF), tyrosine kinase B (TrkB) in rat cortex and hippocampus with chronic immobilization stress and the influence of three Chinese formulas (Xiaoyaosan, Sijunzitang, Jinkuishenqiwan) on them. METHODS: Chronic immobilization stress method (180 min daily, repeated 7 days or 21 days) was taken, and the changes of BDNF, TrkB in rat forehead cortex and hippocampus CA1 were measured by immunohistochemistry integrated image analysis. RESULTS: The contents of BDNF in rat forehead cortex and hippocampus CA1 were obviously lower in the model group of 7 days and 21 days than those in the normal control group (P<0.05, P<0.01), especially the lowest in the model group of 21 days. The contents of TrkB in rat forehead cortex and hippocampus CA1 were higher in the model group of 7 days and 21 days than those in the normal control group (P<0.05, P<0.01). All three Chinese formulas increased the intergral absorbance of BDNF in rat cortex and particle number of BDNF in rat hippocampus CA1. The particle number of TrkB in rat hippocampus CA1 and cortex, and intergral absorbance of TrkB in rat hippocampus CA1 were reduced by Xiaoyaosan. The intergral absorbance of TrkB in rat forehead cortex was reduced by Sijunzitang and Jinkuishenqiwan. The particle number of TrkB in rat forehead cortex was decreased by Jinkuishenqiwan. Compared with the influence of BDNF in response to three Chinese formulas, effect of Xiaoyaosan was more remarkable.CONCLUSION: Decreased BDNF in rat forehead cortex and hippocampus CA1 may participate in changes of chronic immobilization stress, and it can be reversed by the Chinese herbs of soothing liver, strengthening spleen, nourishing kidney, but the effect of Xiaoyaosan is better than that of Sijunzitang and Jinkuishenqiwan.     

Effect of concentrated decoction of Chinese herbal compound Buyanghuanwutang on cAMP-PKA-CREB signaling pathway in hippocampus of rats with vascular dementia

AIM: To evaluate the role of concentrated decoction of Chinese herbal compound Buyanghuanwutang (BYHWT) in cyclic adenosine monophosphate(cAMP)-protein kinase A(PKA)-cAMP response element-binding protein(CREB) signaling pathway in hippocampus of rats with vascular dementia (VD). METHODS: The rats were randomly divided into sham operation group (sham-operated rats treated with normal saline), VD model group (VD rats treated with normal saline), BYHWT treatment group (VD rats treated with BYHWT) and nimodipment treating group (VD rats treated with nimodipine). The rat model of VD was build by the method of four-vessel occlusion. The rats in all 4 groups were administered with the corresponding reagents for successive 30 days. The content of cAMP was measured by radioimmunoassay. The expression of PKA catalytic subunit (PKAc) was observed by Western blotting. The changes of DNA-binding activity of CREB in rat hippocampus were detected by electrophoretic mobility shift assay. RESULTS: The content of cAMP, the expression of PKAc and the DNA-bingding activity of CREB in the hippocampus of VD rats were lower than those in the hippocampus of sham-operated rats (P<0.01). The above indexes in both nimodipine treatment group and BYHWT treatment group were definitely higher than those in VD model group (P<0.01). CONCLUSION: BYHWT increases the content of cAMP, the expression of PKAc and the DNA-binding activity of CREB in VD rat hippocampus, thus strengthening the cAMP-PKA-CREB signaling pathway.     

Effect of BDNF expression in cerebral cortex and hippocampus on ability of learning and memory in APP/PS1 transgenic mice

AIM: To investigate the expression changes of brain-derived neurotrophic factor (BDNF) in the cerebral cortex and hippocampus and their effects on the ability of learning and memory in the wild-type (WT) mice and APP/PS1 transgenic mice. METHODS: WT mice and APP/PS1 transgenic mice were selected as study subjects. Aβ plaques, apoptosis rate and BDNF expression in the cerebral cortex and hippocampus of WT mice and APP/PS1 transgenic mice were detected by the methods of Congo red staining, TUNEL, immunofluorescence and Western blot. The abilities of learning and memory were determined by Morris water maze test. RESULTS: The Aβ plaques appeared in the cerebral cortex and hippocampus of APP/PS1 transgenic mice, and the number of Aβ plaques in 12-month-old mice was larger than that in 6-month-old mice (P<0.05). The number of apoptotic neurons in the cerebral cortex and hippocampus of 12-month-old APP/PS1 transgenic mice was larger than that of WT mice (P<0.01). The expression level of BDNF in the cerebral cortex and hippocampus of WT mice was higher than that of APP/PS1 transgenic mice (P<0.01). The Morris water maze test showed that the escape latency in APP/PS1 transgenic mice was longer than that in WT mice, and the times across the platform quadrant in 60 s was less than that in WT mice (P<0.01). The swim-tracking path of APP/PS1 transgenic mice was disordered and irregular. CONCLUSION: The expression of BDNF in the cerebral cortex and hippocampus of APP/PS1 transgenic mice was lower than that of WT mice, accompanied by increased neuronal apoptosis and decreased spatial learning and memory ability. The decrease in learning and memory ability may be related to decreased BDNF expression in the cerebral cortex and hippocampus of APP/PS1 transgenic mice, leading to increased neuronal apoptosis, which may be one of the pathological mechanisms of Alzheimer disease.     

Effects of CCK-8 and its receptor antagonists on expression of CREB and pCREB in prefrontal cortex and hippocampus of morphine withdrawal rats

AIM：To observe the effects of cholecystokinin octapeptide (CCK-8) and its receptor antagonists on cAMP response element binding protein (CREB) and phosphorylated CREB (pCREB） expression in frontal cortex and hippocampus of morphine withdrawal rats, which aim to explore the post-receptor mechanism through which CCK-8 regulates morphine withdrawal. METHODS：After the morphine dependence and naloxone-precipitated withdrawal animal models were established, the effects of CCK-8, L-364718 (CCK1 receptor antagonist) and LY-288513 (CCK2 receptor antagonist) pretreatment on CREB and pCREB expression in frontal cortex and hippocampus were observed by Western blotting and immunohistochemistry. RESULTS：In rat frontal cortex neuron, CREB was expressed in both cytoplasm and nucleus, but pCREB was only highly expressed in the nucleus. In the pyramidal cell layer of hippocampal CA1 region, CREB showed high expression in the cytoplasm and low expression in the nucleus, while pCREB was only expressed in the nu-cleus. No obvious change of CREB was observed after either chronic morphine treatment or naloxone withdrawal. The pCREB expression was increased after chronic morphine treatment and further increased after naloxone withdrawal. Compared with the withdrawal group, chronic pretreatment with CCK-8, L-364718 and LY-288513 had no effect on CREB expression in the frontal cortex, but obviously decreased the pCREB expression. In the hippocampus, pretreatment with L-364718 and LY-288513 decreased CREB and pCREB expression, but only the pCREB expression was decreased after CCK-8 treatment. CONCLUSION：CCK-8 and CCK receptor antagonists may alleviate morphine withdrawal symptoms by regulating CREB, with specificity in different brain regions.     

Akt and ERK1/2 are involved in brain derived neurotrophic factor-induced angiogenesis of endothelial cells

AIM: To investigate the role of PI3K/Akt and MEK1/ERK pathway in the brain derived neurotrophic factor(BDNF)-induced angiogenesis in vitro and to explore the further molecular mechanisms. METHODS: The phosphorylations of Akt and ERK1/2 were detected in human umbilical vein endothelial cells(HUVECs) by Western blotting. The angiogenic activity in vitro was evaluated by transwell migration assay and tubule formation assay. Cell proliferation was determined by crystal violet staining. Cell apoptosis was analysed by FITC-Annexin-V/PI double staining and flow cytometry. RESULTS: BDNF activated the PI3K/Akt and MEK1/ERK pathway in a time-dependent manner. Ly294002 and PD98059 blocked the activation of Akt and ERK1/2 in response to BDNF. BDNF at concentration of 100 μg/L significantly increased HUVECs tube formation, migration and proliferation in vitro to a degree similar to those induced by 25 μg/L VEGF. Furthermore, tube formation and migration of HUVECs toward BDNF were significantly inhibited by treatment with 20 μmol/L Ly294002 and 20 μmol/L PD98059. BDNF-induced survival was only blocked by Ly294002 and BDNF-induced proliferation was only inhibited by PD98059. CONCLUSION: BDNF promotes angiogenesis of HUVECs in vitro. The ERK and Akt are two crucial events in BDNF-mediated signal transduction leading to HUVECs angiogenesis by different mechanisms. Moreover, the latter is more important.     

Effects of dexmedetomidine on behaviors and expression of BDNF and mTOR in hippocampus of depressive rats

AIM: To investigate the effects of dexmedetomidine (DEX) on the behaviors and the expression of brain-derived neurotrophic factor (BDNF) and mammalian target of rapamycin (mTOR) in the hippocampus of depressive rats. METHODS: Sprague-Dawley (SD) rats were randomly divided into 5 groups: sham operation group, model group, and DEX (2.5, 5 and 10 μg/kg) groups. The rats were randomly selected in each group (n=12). The rat depression model was established by chronic unpredictable mild stress and ovariectomy. The rats in DEX groups received daily DEX treatment via intraperitoneal injection for 21 d. The forced swimming immobility time (FSIT) and open-field test were used to evaluate the antidepressant effect of DEX. Escape latency and times of crossing the flat were evaluated by Morris water maze. The histological changes of hippocampal neurons were determined by Nissl staining. The mRNA levels of interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α) were detected by RT-qPCR. The protein expression of IL-1β, IL-6, TNF-α and BDNF, and the phosphorylation levels of protein kinase A (PKA), cAMP response element-binding protein (CREB), tropomyosin-related kinase B (TrkB), phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt) and mTOR in hippocampus were evaluated by Western blot. RESULTS: Compared with model group, the FSIT was significantly reduced and the spontaneous activity was markedly increased in DEX groups. The damage of the hippocampal neurons was obviously attenuated, the escape latency was obviously decreased, and times of crossing the flat were markedly increased (P<0.05 or P<0.01). The levels of IL-1β, IL-6 and TNF-α were obviously decreased, and the protein levels of p-PKA, p-CREB, BDNF, p-TrkB and p-PI3K, p-Akt, p-mTOR in hippocampal tissues were obviously increased (P<0.05 or P<0.01). CONCLUSION: Dexmedetomidine improves the behaviors and the spatial learning and memory ability of depressive model rats, which may be related to its anti-inflammatory effects, as well as up-regulating the protein levels of BDNF and p-TrkB, and activating PI3K/Akt/mTOR signaling pathway in the hippocampus.     

Effect of protein S-nitrosylation on cAMP response element-binding protein activity in RSC-364 cells

AIM: To investigate the effect of protein S-nitrosylation on cAMP response element-binding protein(CREB) activity in RSC-364 cells. METHODS: ① RSC-364 cells cytoplasmic extracts were incubated with 100 μmol/L GSH (control chemical), 100 μmol/L GSNO (a donor of NO) in the presence or absence of 10 mmol/L DTT (inhibitor of S-nitrosylation) for 15 min at room temperature. The S-nitrosylated proteins were determined by biotin switch assay. The expression of S-nitrosylated proteins was assayed by Western blotting. ② RSC-364 cell nuclear extracts were subjected to S-nitrosylation and electrophoretic mobility shift assay (EMSA) to analyze the CREB DNA binding activity after 1 h stimulation of rIL-1β (10 μg/L). RESULTS: GSNO obviously increased the expression of nitrosylated proteins and inhibited the CREB activity, which was reversed by DTT. CONCLUSION: S-nitrosylation may inhibit the CREB activity in RSC-364 cells.     

Construction of recombinant adenovirus expressing BDNF and its expression in expanded rat mesenchymal stem cells in vitro

AIM:To construct recombinant adenovirus vector containing brain derived neurotrophic factor, (BDNF) gene using bacterial homogenous recombination, and investigate the expression in expanded rat mesenchymal stem cells (rMSC) in vitro.METHODS:BDNF gene and proBDNF gene were subcloned into adenovirus shuttle plasmid pAdTrack-CMV containing enhanced green fluorescent protein gene (EGFP) expression cassette, forming shuttle vector of pAdTrack-BDNF, and pAdTrack-proBDNF, and co-transformed into BJ5183 bacterial cells with adenovirus backbone vector pAdEasy-1 using chemical transformation. After the recombinant adenovirus vector was obtained, the identified recombinant adenovirus plasmid DNA was digested with Pac I and transfected to 293 cells to package recombinant adenovirus particles. rMSC were infected by recombinant adenovirus and EGFP expression was detected using fluorescent microscope. Infection efficiency was assessed by flow cytometrics. Western blotting identified expression of Ad -proBDNF and Ad-BDNF in rMSC. rMSC infected with Ad -proBDNF and Ad-BDNF were induced to differentiate into neuron-like cells. rMSC infected with Ad -proBDNF and Ad-BDNF were injected into nude mice and assessd in vivo.RESULTS:We successfully constructed the recombinant adenovirus Ad -proBDNF and Ad-BDNF that expressed in expanded rMSC in vitro.CONCLUSION:Recombinant adenovirus high-effectively mediates Ad -proBDNF and Ad-BDNF expression in expanded rMSC in vitro and in vivo.     

Effect of resveratrol on level of brain-derived neurotrophic factor in hippocampus of obese rats induced by ovariectomy and high-fat diet

AIM：To explore the effects of resveratrol on the level of brain-derived neurotrophic factor (BDNF) and the mRNA expression of estrogen receptor α (ERα) and estrogen receptor β (ERβ) in hippocampus of obese rats induced by ovariectomy and high-fat diet. METHODS：Fifty female Wistar rats, aged 3 months, were randomly divided into 5 groups: control (C) group, sham operation plus high-fat diet (H) group, ovariectomy plus normal diet (O) group, ovariectomy plus high-fat diet (O+H) group, and ovariectomy plus high-fat diet and treated with resveratrol (40 mg·kg-1·d-1) (O+H+R) group. Three months later, the blood was collected from the femoral artery to detect the serum concentrations of total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and estradiol (E2). The mRNA expression of ERα, ERβ and BDNF in the hippocampus was determined by real-time PCR. The protein level of BDNF in hippocampal tissues was detected by ELISA and Western blotting. RESULTS：Compared with C group, the serum levels of TC and LDL-C in H group were increased, and the hippocampal level of BDNF was decreased. The rats in O group had higher concentration of serum TC, and lower levels of serum E2 and the mRNA expression of ERα, ERβ and BDNF in the hippocampus than those in C group. Compared with C,H and O groups, the level of serum TC was higher, and the level of serum E2 and the expression of BDNF in the hippocampus was lower in O+H group. The mRNA expression of ERα and ERβ in hippocampus was also reduced as compared with C group and H group. After treated with resveratrol, the rats in O+H+R group showed lower level of serum TC, and higher levels of serum E2, hippocampal BDNF and mRNA expression of ERα and ERβ than those in O+H group. CONCLUSION：Ovariectomy combined with high-fat diet decreases the mRNA expression of ERαand ERβ and the level of BDNF in the rat hippocampus. Resveratrol improves the blood lipid metabolism and up-regulates the mRNA expression of ERα/ERβ and the level of BDNF in the hippocampus in obese rats induced by ovariectomy and high-fat diet.     

Variation of brain derived neurotrophic factor and its mRNA expression in infancy rats after experimental bacterial meningitis

AIM: To investigate the expression and effect of brain derived neurotrophic factor (BDNF) mRNA and its protein in infancy rats after exposure to bacterial meningitis. METHODS: Three week old rats were used to construct the models of bacterial meningitis (n=30) and mormal(n=18). At 24 h, 48 h, 5 d after inoculating, the expression of BDNF mRNA and its protein were detected by in situ hybridization and immunohistochemical staining methods, respectively. RESULTS: The increase in BDNF mRNA expression was detected by in situ hybridization at 24 h in experiment(0.13320±0.02750) compared to control(0.06269±0.01147)(P＜0.01). Expression of BDNF mRNA was declined at 48 h, but its expression was still stronger than that in controls at 5 d(P＜0.05). The expression of BDNF protein was enhanced and reached to its zenith at 24 h in this experiment (0.16896±0.02717) (P＜0.01), compared to controls(0.08700±0.03413), and it declined after 48 h, then restored to the control levels at 5 d(P＞0.05). Meanwhile, in the brain from the experiment rats, strong positive hybridization and immunoreactivity were observed in the infiltrated inflammatory cells in leptomeninges, subarachnoid cavity, ventricles and brain parenchyma. CONCLUSIONS: These results support the hypothesis that BDNF might play a neuroprotective role in brain damage process in bacterial meningitis attacked rats. BDNF might take part in imune response. These results also support the hypothesis that BDNF has some relationships with other inflammatory mediators during acute inflammatory response of bacterial meningitis.     

Effect of Ganoderma lucidum spores on cytochrome C,mitochondrial Ca2+, HSP70 and BDNF in brain of epilepsy rats

AIM: To investigate the effects of Ganoderma lucidum spores on superoxide dismutase(SOD),malondialdehyde(MDA),total antioxidative capacity(T-AOC), cytochrome C, heat-shock protein 70 (HSP70), mitochondrial Ca²⁺ and brain-derived neurotrophic factor(BDNF) in the brain tissues of epilepsy rats.METHODS: The rat chronic epilepsy model was by intraperitoneal injection of pentetrazole(PTZ) at a subconvulsant dose (32 mg/kg).Flame atomic absorption method was used to detect the content of mitochondrial Ca²⁺,and spectrophotometer colorimetry was used to measure SOD activity,MDA content,T-AOC and cytochrome C levels in rat brain tissues. HSP70 and BDNF were determined by immunohistochemical method.RESULTS: The contents of mitochondrial Ca²⁺ and cytochrome C were higher, and the content of intracytoplasmic cytochrome C in the rat brain tissues was obviously lower in Ganoderma lucidum spores group than that in epileptic model group. Compared to epileptic model group, the activity of SOD and T-AOC in cytoplasm of the rat brain tissues decreased while MDA increased, and the numbers of BDNF-positive cells in cerebral cortex and hippocampus were significantly increased in Ganoderma lucidum spores group. The positive neuron population of HSP70 in hippocampus, basal nucleus and cortex was significantly higher in Ganoderma lucidum spores group than that in epilepsy model group.CONCLUSION: Ganoderma lucidum spores attenuate the impairment of neuronal mitochondria induced by seizure, and accelerate the expression of BDNF, resulting in restoring the energy metabolism in mitochondrion, thus alleviating the impairment and apoptosis of the brain tissues.     

Relationship between hippocampal structure and high incidence of depression after spinal cord injury in mice

AIM: To explore whether the high risk of depression caused by spinal cord injury is related to structural changes of hippocampus. METHODS: Mouse spinal cord injury model was established. The Basso Mouse Scale (BMS) was used to evaluate the postoperative motor function of mice at different periods after injury. The depression of mice was evaluated by behavior experiment. The morphological changes of cells in hippocampal tissue were observed by HE staining. The structural changes of hippocampal subcellular synapses were observed by electron microscopy. RT-qPCR was used to detect the changes of synaptic protein markers synaptophysin (SYP) and postsynaptic density protein 95 (PSD-95) at the mRNA level. RESULTS: The mice had significant depressive behaviors in model group, and the depression degree was the most serious on the 7th day (P<0.01). Compared with control group, the arrangement of hippocampal cells was disordered, the cell number was decreased, and the shape was irregular in model group. Compared with control group, the observation results of electron microscopy showed that the number of synapses in the hippocampal ultrastructure was decreased, the length of synaptic activity zone was shortened, the thickness of postsynaptic density was thinned, the width of synaptic gap was increased, and the curvature of synaptic interface was decreased in the model group (P<0.05). The mRNA expression levels of SYP and PSD-95 in model group were lower than those in control group (P<0.05). CONCLUSION: The change of hippocampal structure is one of the important reasons leading to high risk of depression caused by spinal cord injury.     

Effects of Xiaoyaosan on imiquimod induced psoriatic lesions and depression neurotransmitters in mouse model

AIM: To observe the effect of Xiaoyaosan decoction on the psoriatic lesions and depression neurotransmitters induced by imiquimod in mice. METHODS: BALB/c male mice were randomly divided into control group, model group, methotrexate group and Xiaoyaosan high, medium and low dose groups, 6 mice in each group. Imiquimod (IMQ, 5%) was used on the back of the animals to induce psoriasis-like lesions in the mice. The psoriasis area and seve-rity index (PASI) were evaluated for daily scoring. The sugar water preference experiment was conducted to explore the behavioral differences in the mice. The morphological changes and epidermal thickness of the lesions were observed under light microscopy. Immunohistochemical method was used to detect the expression of CD3 on T lymphocyte surface. The expression of Ki67 in the skin lesions was detected by immunofluorescence. The contents of monoamine neurotransmitters such as adrenaline (AD), gamma-aminobutylic acid (GABA), glutamate (Glu), dopamine (DA) and their metabolites in the hippocampus and hypothalamus of mice were detected by high performance liquid chromatography-mass spectrometry (HPLC-MS). RESULTS: Compared with model group, the back skin lesions of Xiaoyaosan each dose group and methotrexate group were significantly improved, and the PASI score and epidermal thickness were both lower than those in model group (P<0.05). The expression levels of Ki67 and CD3⁺ T cells in Xiaoyaosan group and methotrexate group were lower than those in model group (P<0.05). Compared with model group, the body mass change range of Xiaoyaosan high-dose group and blank control group was significantly smaller than that in model group (P<0.05). The sugar water preference rate in blank control group was significantly higher than that in model group (P<0.01). Compared with model group, the sugar water preference rate in methotrexate and Xiaoyaosan groups showed a certain increase trend, but no statistical diffe-rence was observed. Compared model group, the levels of 3, 4-Dihydroxypheny-lacetic acid (DOPAC), AD, GLU and GABA levels in the mouse hippocampus in blank control group were decreased significantly (P<0.01), while the levels of DA and homovanillic acid (HVA) had no significant difference (P>0.05). No significant difference of DA, DOPAC, HVA and GLU levels in the mouse hypothalamus was observed between blank control group and model group (P>0.05), while the content of AD and GABA in the mouse hypothalamus in blank control group was lower than that in model group. The AD content of the hypothalamus in high-dose Xiaoyaosan group was significantly higher than that in model group (P<0.01), and the HVA content of the hypothalamus in low-dose Xiaoyaosan group was significantly higher than that in model group (P<0.01). PASI score was negatively correlated with the content of DOPAC, AD, GLU and GABA in the hippocampus and the content of AD, GLU and GABA in the hypothalamus, those were, the more severe the back skin lesion was, the lower the expression of depression-related neurotransmitters were, indicating the aggravation of depression in the mice. CONCLUSION: Xiaoyaosan improves the skin lesions induced by imiquimod in the mice with psoriasis, improves the behavior of depression in the mice with psoriasis, and up-regulates the expression of depression-related monoamine neurotransmitters. The expression of depression-related neurotransmitters is negatively correlated with the skin lesions induced by imiqumod in the mice with psoriasis. The degree of depression is increased with the aggravation of psoriatic lesions.