Synergistic effects of brain-derived neurotrophic factor and retinoic acid on inducing the differentiation of bone marrow stromal cells into neuron-like cells in adult rats in vitro

BACKGROUND： Under induction of retinoic acid （RA）, bone marrow stromal cells （BMSCs） can differentiate into nerve cells or neuron-like cells, which do not survive for a long time, so those are restricted to an application. Other neurotrophic factors can also differentiate into neuronal cells through inducing BMSCs; especially, brain-derived neurotrophic factor （BDNF） can delay natural death of neurons and play a key role in survival and growth of neurons. The combination of them is beneficial for differentiation of BMSCs. OBJECTIVE： To investigate the effects of BDNF combining with RA on inducing differentiation of BMSCs to nerve cells of adult rats and compare the results between common medium group and single BDNF group. DESIGN： Randomized controlled animal study SETTING： Department of Neurology, Affiliated Hospital of Xuzhou Medical College MATERIALS： The experiment was carried out in the Clinical Neurological Laboratory of Xuzhou Medical College from September 2003 to April 2005. A total of 24 SD rats, of either gender, 2 months old, weighing 130-150 g, were provided by Experimental Animal Center of Xuzhou Medical College [certification： SYXK （su） 2002-0038]. Materials and reagents： low-glucose DMEM medium, bovine serum, BDNF, RA, trypsin, separating medium of lymphocyte, monoclonal antibody of mouse-anti-nestin, neuro-specific enolase, glial fibrillary acidic protein （GFAP） antibody, SABC kit, and diaminobenzidine （DAB） color agent. All these mentioned above were mainly provided by SIGMA Company, GIBCO Company and Boshide Company. METHODS： Bone marrow of SD rats was selected for density gradient centrifugation. BMSCs were undertaken primary culture and subculture; and then, those cells were induced respectively in various mediums in total of 3 groups, including control group （primary culture）, BDNF group （20 μg/L BDNF） and BDNF＋RA group （20 μg/L BDNF plus 20 μg/L RA）. On the 3^rd and the 7^th days after induction, BMSCs were stained immunocytochemically with nestin （sign of nerve stem cells）, neuron-specific enolase （NSE, sign of diagnosing neurons） and GFAP （diagnosing astrocyte）, and evaluated cellular property. MAIN OUTCOME MEASURES ： Induction and differentiation in vitro of BMSCs in 3 groups RESULTS： （1） Induction and differentiation of BMSCs： Seven days after induction, cells having 2 or more apophyses were observed. Soma shaped like angle or erose form, which were similar to neurons and glial cells having strong refraction. （2） Results of immunocytochemical detection： Three days after induction, rate of positive cells in BDNF＋RA group was higher than that in BDNF group and control group [（86.15±4.58）%, （65.43±4.23）%, （4.18±1.09）%, P 〈 0.01]. Seven days after induction, rate of positive cells was lower in BDNF group and BDNF＋RA group than that in both groups at 3 days after induction [（31.12±3.18）%, （29.35±2.69）%, P 〈 0.01]; however, amounts of positive cells of NSE and GFAP were higher than those at 3 days after induction （P 〈 0.01）; meanwhile, the amount in BDNF＋RA group was remarkably higher than that in BDNF group （P 〈 0.01）. CONCLUSION： Combination of BDNF and RA can cooperate differentiation of BMSCs into neurons and astrocyte, and the effect is superior to single usage of BDNF.

The Biological Actions and Mechanisms of Brain-Derived Neurotrophic Factor in Healthy and Disordered Brains

Brain-derived neurotrophic factor (BDNF) is a neurotrophin that elicits neuronal survival and differentiation, synaptic transmission, and the modulation of synaptic plasticity. The biological actions of BDNF are mediated via two distinct receptors: the high-affinity tropomyosin-related kinase B (TrkB) receptor and the low-affinity p75 neurotrophin receptor (p75NTR). Recent findings regarding the actions and mechanisms of BDNF are reviewed here. Activity-dependent synaptic plasticity, as exemplified by long-term potentiation (LTP) and long-term depression (LTD), underlies the cellular mechanism of learning and memory. An accumulating body of evidence shows that BDNF modulates synaptic plasticity. This function requires extracellular neurotrophin release, synaptic activity-dependent local protein synthesis. In addition, a precursor of BDNF, proBDNF, is emerging as a new ligand with biological activities that are distinct from those of BDNF. The proteolytic cleavage of proBDNF is also proposed as a mechanism that determines the direction of BDNF actions. This review discusses the post-translational processing of proBDNF, the modulatory roles of the human BDNF polymorphism Val66Met, recent reports of the novel mechanisms of BDNF expression, and clinical reports showing the roles of BDNF in the blood. Taken together, these data provide new insights into the biological roles of BDNF and its related molecules in the central nervous system.

Serum Levels of Brain-Derived Neurotrophic Factor in Patients with Obsessive-Compulsive Disorder in a Japanese Population

A role of lower brain-derived neurotrophic factor (BDNF) content in the pathogenesis of several mental illnesses has been suggested, especially in major depression. It is not known whether BDNF is involved in the pathogenesis of obsessive-compulsive disorder (OCD). Herein, we assessed the serum BDNF content and its correlation with symptom severity in a Japanese population with OCD. The serum BDNF levels of OCD patients (n = 39) and healthy controls (n = 37) were measured by ELISA. The severity of OCD symptoms was assessed by the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and the Beck Depression Inventory (BDI). The OCD patients’ BDNF levels were significantly higher than those of the controls (17.5 ± 7.3 vs. 12.7 ± 4.7) (p < 0.01). No correlation was observed between the OCD patients’ BDNF levels and their OCD symptoms as scored by the Y-BOCS. For all 76 subjects, the BDI scores were significantly negatively correlated with the serum BDNF levels. Our findings revealed that contrary to previous reports, the serum BDNF content in OCD patients could be higher than that of healthy subjects.

Research progress on brain-derived neurotrophic factor and non-suicidal self-injury addictive behavior associated with depressive disorders in adolescents

In recent years,non-suicidal self-injury(NSSI)behavior has emerged in a large number of adoles-cent depression.NSSI associated with adolescent depres-sion may be an addictive behavior,which has many sim-ilar neurobiological mechanisms to substance addiction.Brain-derived neurotrophic factor(BDNF)and precursor of BDNF(proBDNF)play an important role in addiction behavior,and they may be related to endogenous opioid receptors.The location and distribution of opioidμre-ceptors in the brain are related to reward,motivation and emotion regulated by behavioral addiction.The purpose of this paper is to review the general situation,mechanism and relationship between the characteristics of NSSI be-havior addiction and brain-derived nutritional factors in adolescents with depression.

Brain-derived neurotrophical factor after olfactory ensheathing cells transplantation in spinal cord injury of rats

Objective To observe the expression of brain - derived neurotrophical factor ( BDNF) in injury spinal cord after transplantation olfactory ensheathing cells ( OECs) , and to investigate the mechanism of OECs repairing spinal cord injury. Methods OECs from GFP transgenic rats were separated and cultured for transplantation. Spinal cord injury rats were separated two groups by

The roles of BDNF and ProBDNF in schizophrenia: possibilities for treatment

This review discusses the roles of brain-derived neurotrophic factor(BDNF)and precursor BDNF(proBDNF)in schizophrenia(SCZ).SCZ is associated with neuronal dysfunction,altered synaptic plasticity,and cognitive deficits.BDNF positively promotes neuronal growth,differentiation,and synapse forma-tion,and regulates synaptic transmission and plasticity.ProBDNF negatively affects neuronal survival and synaptic remodeling,however,by binding to its neurotroph-in receptor p75(p75NTR).A better understanding of the pathogenesis of SCZ vis-à-vis BDNF and proBDNF may provide new directions and strategies for its treatment.

Activation of cerebral Ras-related C3 botulinum toxin substrate(Rac) 1 promotes post-ischemic stroke functional recovery in aged mice

Brain functional impairment after stroke is common;however,the molecular mechanisms of post-stroke recovery remain unclear.It is well-recognized that age is the most important independent predictor of poor outcomes after stroke as older patients show poorer functional outcomes following stroke.Mounting evidence suggests that axonal regeneration and angiogenesis,the major forms of brain plasticity responsible for post-stroke recovery,diminished with advanced age.Previous studies suggest that Ras-related C3 botulinum toxin substrate(Rac)1 enhances stroke recovery as activation of Rac1 improved behavior recovery in a young mice stroke model.Here,we investigated the role of Rac1 signaling in long-term functional recovery and brain plasticity in an aged(male,18 to 22 months old C57BL/6J)brain after ischemic stroke.We found that as mice aged,Rac1 expression declined in the brain.Delayed overexpression of Rac1,using lentivirus encoding Rac1 injected day 1 after ischemic stroke,promoted cognitive(assessed using novel object recognition test)and sensorimotor(assessed using adhesive removal tests)recovery on days 14–28.This was accompanied by the increase of neurite and proliferative endothelial cells in the periinfarct zone assessed by immunostaining.In a reverse approach,pharmacological inhibition of Rac1 by intraperitoneal injection of Rac1 inhibitor NSC23766 for 14 successive days after ischemic stroke worsened the outcome with the reduction of neurite and proliferative endothelial cells.Furthermore,Rac1 inhibition reduced the activation of p21-activated kinase 1,the protein level of brain-derived neurotrophic factor,and increased the protein level of glial fibrillary acidic protein in the ischemic brain on day 28 after stroke.Our work provided insight into the mechanisms behind the diminished plasticity after cerebral ischemia in aged brains and identified Rac1 as a potential therapeutic target for improving functional recovery in the older adults after stroke.

舒肝解郁汤改善去卵巢大鼠抑郁行为及作用机制研究

目的:探讨舒肝解郁汤对去卵巢(ovariectomy,OVX)模型大鼠抑郁样行为的干预作用及其机制。方法:将60只SPF级SD大鼠随机分为假手术组、模型组、氟西汀组(10 mg·kg^(-1))及舒肝解郁汤低剂量组(22.8 g·kg^(-1))、舒肝解郁汤高剂量组(45.6 g·kg^(-1)),每组10只。除假手术组外,其余大鼠进行双侧卵巢切除术建立OVX模型。模型建立完成后,各给药组给予相应药物干预6周后,采用旷场实验、糖水消耗实验评价大鼠的抑郁样行为;采用ELISA法检测大鼠脑组织中5-羟色胺(5-hydroxytryptamin,5-HT)、多巴胺(dopamine,DA)、去甲肾上腺素(norepinephrine,NE)水平及血清中皮质醇(cortisol)、促肾上腺皮质激素(adrenocorticotropic hormone,ACTH)、促肾上腺皮质激素释放激素(corti-cotropin-releasing hormone,CRH)水平;HE染色和尼氏染色观察大鼠海马区细胞与尼氏小体形态;Western Blot检测各组大鼠海马区中脑源性神经营养因子(brain-derived neurothrophic factor,BDNF)蛋白水平表达。结果:与假手术组比校,模型组大鼠的糖水偏好率、旷场实验活动能力、脑内神经递质与BDNF表达水平显著降低(P<0.05),血清HPA轴激素水平显著升高(P<0.05);与模型组比较,各给药组大鼠糖水消耗率、旷场实验活动能力、脑内神经递质与BDNF表达水平显著升高(P<0.05),血清HPA轴激素水平显著降低(P<0.05)。病理观察显示,各给药组大鼠神经元细胞形态及数量和尼氏小体数目得到明显改善。结论:舒肝解郁汤能够改善OVX大鼠抑郁状态,其作用机制与促进海马神经细胞中BDNF的表达有关。

THE GENE EXPRESSION OF BDNF IN NORMAL RABBIT RETINA

Objective To investigate the distribution of bra in-derived neurotrophic factor(BDNF) protein in the rabbit retina. Methods Immune response material in the retina was observed using BDNF antibody by the method of immunohistochemistry. Results BDNF gene expression was mainly found in the RGCs, a lso in innernuclei cells and outernuclei cells in rabbit retina. Conclusion RGC is not only the target cell of BDNF, but also express the BDNF protein. BDNF from multi-sources participates in the regulati on of RGCs.

Research progress on whether BDNF can be used as a predictive biomarkerfor suicidal behavior

In recent years,the serious social phe-nomenon of suicide has been of great concern to society and academia.However,the study and early risk assess-ment of suicide have been limited by multiple aspects.Therefore,researchers have started to search for a reliable marker for early diagnosis of suicide risk,and one of the widely studied neurotransmitters associated with suicide is the brain-derived neurotrophic factor(BDNF).This re-view aims to summarize the current scientific knowledge on the relevance of BDNF and psychiatric disorders to suicide and to infer whether neurotrophic factors could be a reliable marker for early diagnosis of suicide risk.Based on the results of these studies,a link between BDNF and suicide may exist and act independently of mental illness.However,there is still controversy and further studies may provide researchers with useful information.

Research progress on the relationship between proBDNF and alcohol dependence and its related cognitive impairment

Brain-derived neurotrophic factor(BDNF)plays an important role in the growth,develop-ment,differentiation,injury,repair,survival and apoptosis of nerve cells.Precursor of BDNF(proBDNF)is an im-portant regulator of neurodegeneration,long-term hippo-campal inhibition and synaptic plasticity.Alcohol depen-dence syndrome(ADS)is a group of chronic recurrent diseases with unknown etiology.Current studies believe that proBDNF plays an important role in the occurrence,development and outcome of ADS.Alcohol dependence patients,like other neurodegenerative diseases,will also have different degrees of cognitive impairment.This arti-cle reviews the research progress on the relationship be-tween BDNF,proBDNF,alcohol dependence and cogni-tive impairment.

Research progress on BDNF in Sjogren's syndrome with depressive disorder

Brain-derived neurotrophic factor(BDNF)is a widely studied neurotrophic factor,which plays an important role in the growth,development,dif-ferentiation,injury,repair,survival and apoptosis of nerve cells.More and more studies have found that there is a high prevalence of depressive disorders in patients with autoimmune diseases.Sjogren's syndrome is a chronic autoimmune exocrine disease characterized by lympho-cytic infiltration and exocrine gland destruction.Depres-sive disorders are common in patients with Sjogren's syndrome.The quality of life of patients with Sjogren's syndrome with depression was generally lower than that of patients with Sjogren's syndrome without depres-sion.In this article,we reviewed the research progress of BDNF and depression in Sjogren's syndrome at home and abroad.

Brain-derived neurotrophic factor protects neurons from GdCl_3-induced impairment in neuron-astrocyte co-cultures

Gadolinium (Gd3+) complexes are important contrast agents in medical magnetic resonance imaging (MRI) and of great potential value in brain research. In order to better understand the mechanisms of the action of Gd3+ on neurons in the complex central nervous system (CNS), the neurotoxic actions of GdCl3 have been investigated in both neuron monoculture and astrocyte-neuron co-culture systems. Measurements of lactate dehydrogenase release showed that GdCl3 causes significant cell death of monocultured neurons as a result of reactive oxygen species (ROS) generation and down-regulation of brain-derived neurotrophic factor (BDNF). However, GdCl3 does not affect the viability and BDNF expression of astrocytes. Both co-culturing of neurons with astrocytes and addition of BDNF ameliorated GdCl3-induced neurotoxicity by decreasing ROS generation and facilitating recovery of BDNF levels. The results obtained suggest that astrocytes in the CNS may protect neurons from GdCl3-induced impairment through secreting BDNF and thus up-regulating BDNF expression and interfering with Gd3+-induced cell signaling in neurons. A possible molecular mechanism is suggested which should be helpful in understand- ing the neurotoxic actions of gadolinium probes .

Regulatory role of CREB/BDNF signaling pathway in acute sleep deprivation-induced anxiety-like behavior mice

Objective:To investigate the regulatory role of cyclic adenosine monophosphate responsive element binding protein(CREB)/brain-derived neurotrophic factor(BDNF)signaling pathway in acute sleep deprivation(SD)-induced anxiety-like behavior mice(SD group)to study the mechanism of anxiety-like behavior better.Methods:The SD chamber was used to deprive the mice of sleep,and the anxiety-like behavior of the mice was verified using an open field test(OFT),elevated plus maze(EPM),forced swim test(FST),and tail suspension test(TST).Finally,proteins were detected by Western blotting.Result:OFT showed that the active distance and the time of stay in the central area were significantly reduced(P<0.05).EPM showed that the time and number of open arms in the SD group were significantly lower than in the control group(P<0.05).The FST showed that the forced swimming immobility time of the SD group was significantly lower than that of the control(P<0.05).Moreover,the TST showed that the immobility time of the tail suspension experiment in the SD group was significantly higher than that in the control group(P<0.05).Conclusion:Acute SD can regulate anxiety-like behavior in mice through the CREB/BDNF signaling pathway.

运动锻炼对更年期抑郁模型大鼠行为学影响及机制研究

目的观察运动锻炼对更年期抑郁模型大鼠的行为学及血清和海马中脑源性神经营养因子(BDNF)表达的影响。方法建立更年期抑郁大鼠模型40例,随机分成空白组、假手术组、去卵巢组和去卵巢+运动组4组,每组10只。各组给予相应处理后,观察大鼠的行为学变化,酶联免疫吸附剂测定(ELISA)法检测血清BDNF的含量,蛋白质印迹技术检测海马BDNF的表达。结果去卵巢+运动组大鼠的抑郁行为得到明显改善,在强迫游泳实验中悬浮时间明显缩短,其血清和海马中BDNF含量明显增加。结论更年期抑郁模型大鼠的抑郁行为通过运动锻炼可得到明显改善,其机制与BDNF表达上调有关。

Effects of electroacupuncture on urodynamics,intramedullary apoptosis and bidirectional regulation of neurotrophic factors in neurogenic bladder rats after supersacral spinal cord injury

Objective:To observe the effects of electroacupuncture on urodynamics and intramedullary apoptosis related factor B cell lymphoma gene-2(Bcl-2),Bcl-2 related protein X(Bax)and brain-derived neurotrophic factor(BDNF)in neurogenic bladder rats after supersacral spinal cord injury.Methods:A total of 60 female SD rats,SPF grade,were randomly selected,12 rats in the blank group and 12 rats in the sham operation group,and the remaining 36 rats were made models.Of these 36 rats,24 rats meeting the model standard were randomized into the model group and electroacupuncture group,with 12 rats in each group.The neurogenic bladder models after supracacral spinal cord injury were prepared by the Hassan Shaker spinal cord transection method,via combining the previous model study experience.At the end of spinal shock stage,"Dazhui(大椎GV14)""Zhongji(中极CV 3)""Ciliao(次髎BL 32)",and"Sanyinjiao(三阴交SP 6)"were selected for electroacupuncture.Observation on the histomorphological changes of bladder detrusor and spinal cord in rats was conducted by HE staining.The apoptosis rate of spinal cord cells was measured by TUNEL assay.The maximum bladder volume and compliance were measured by urodynamics test.The protein expressions of Bcl-2,Bax,and BDNF in spinal cord tissues were measured by Western blot assay.The expressions of Bcl-2,Bax,and BDNF mRNA were measured by RT-PCR assay.Results:(1)The results of HE staining showed that compared with the blank group and sham operation group,in the model group the bladder epithelial cell structure was destroyed,the detrusor muscle fibers proliferated,and there were severe bleeding changes,the spinal cord tissue was disordered,the structure was destroyed,the cell space was enlarged,and accompanied by a large number of inflammatory cell infiltration and cystic cavity formation.Compared with the model group,in the electroacupuncture group,the intact bladder epithelial cells increased,the detrusor muscle fiber proliferation decreased,the bleeding changes decreased,the complete structural area of spinal cord tissues increased,the cell space decreased,the levels were clearer,and the cystic cavity decreased.(2)The results of TUNEL assay indicated that the TUNEL positive rate of spinal cord cells in the model group was significantly higher than that in the blank group and sham group(both P<0.05).Compared with the model group,the TUNEL positive rate of spinal cord cells in the electroacupuncture group was significantly reduced(P<0.05).(3)The results of urodynamics test suggested that compared with the blank group and sham operation group,the maximum bladder volume and compliance of the model group were significantly reduced(all P<0.05).Compared with the model group,the maximum bladder volume and compliance were significantly increased in the electroacupuncture group(both P<0.05).(4)The results of Western blot assay indicated that,compared with the blank group and sham operation group,in the model group the protein contents of Bcl-2 and BDNF were significantly reduced(all P<0.05),while the protein content of Bax in the model group was significantly increased(both P<0.05).(5)The results of RT-PCR assay indicated that,compared with blank group and sham operation group,in the model group the intramedullary Bcl-2 and BDNF mRNA were significantly reduced(all P<0.05),and Bax mRNA was significantly increased(both P<0.05).Conclusion:Electroacupuncture at"GV14""CV3""BL32",and"SP6"can promote the repair of bladder detrusor,improve the maximum bladder volume and compliance of bladder,promote morphological repair of bladder detrusor,reduce spinal cord cell apoptosis rate,thus to restore the function of bladder.This is maybe related with the electroacupuncture’s two-way regulatory mechanism of increased expression of protein and gene of Bcl-2 and BDNF and decreased expression of protein and gene of Bax in spinal cord tissues.

Role of BDNF in the taste system

Neurotrophins are a family of proteins that regulate neural survival, development, function and plasticity in the central and the peripheral nervous system. There are four neurotrophins： NGF, BDNF, NT-3 and NT-4. Among them, BDNF is mostly studied in the taste system due to its high expression. Recent studies have shown BDNF play an important role in the developmental and mature taste system, by regulating survival of taste cells and geniculate ganglion neurons, and maintaining and guiding taste nerve innervations. These studies imply BDNF has great potentialities for therapeutic usage to enhance sensory regeneration following nerve injury, with aging, and in some neurodegenerative diseases.

Protective effects of parecoxib on rat primary astrocytes from oxidative stress induced by hydrogen peroxide

Objective： To investigate the protective effects of parecoxib from oxidative stress induced by hydrogen peroxide （H202） in rat astrocytes in vitro. Methods： All experiments included 4 groups： （1） negative control （NC） group, without any treatment; （2） H202 treatment group, 100 μmol/L H202 treatment for 24 h; （3） and （4） parecoxib pre- treatment groups, 80 and 160 μmol/L parecoxib treatment for 24 h, respectively, and then treated with 100 μmol/L H202. Several indices were investigated, and the expressions of Bax, Bcl-2, and brain-derived neurotrophic factor （BDNF） were quantified. Results： Compared to the NC group, exposure to H202 resulted in significant morphological changes, which could be reversed by pretreatment of parecoxib. In addition, H202 treatment led to loss of viability （P=0.026） and increased intracellular reactive oxygen species （ROS） levels （P〈0.001）, and induced apoptosis （P〈0.01） in the primary astrocytes relative to the NC group. However, in the parecoxib pretreatment groups, all the above changes reversed significantly （P〈0.05） as compared to the H202 treatment group, and were nearly unchanged when compared to the NC group. Mechanical investigation showed that dysregulated Bax, Bcl-2, and BDNF could be im- plicated in these changes. Conclusions： Our results indicated that parecoxib provided a protective effect from oxidative stress induced by exposure to H202.

Research progress of the role and mechanism of extracellular signal-regulated protein kinase 5(ERK5) pathway in pathological pain

Extracellular signal-regulated protein kinase 5 （ERK5）, also known as big mitogen-activated protein kinase 1 （MAPK1）, is an important member of ERK family, which is a subfamily of the large MAPK family. ERK5 is expressed in many tissues, including the dorsal root ganglion （DRG） neurons and the spinal cord. In this review, we focus on elaborating ERK5-associated pathway in pathological pain, in which the ERK5/CREB （cyclic adenosine monophos- phate （cAMP）-response element-binding protein） pathway plays a crucial role in the transduction of pain signal and contributes to pain hypersensitivity. ERK5 activation in the spinal dorsal horn occurs mainly in microglia. The activation of ERK5 can be mediated by N-methyI-D-aspartate （NMDA） receptors. We also elaborate the relationship between ERK5 activation and nerve growth factor-tyrosine kinase A （NGF-TrkA）, and the connection between ERK5 activation and brain-derived neurotrophic factor （BDNF） in pathological pain in detail.