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ABSTRACT Objective: To assess the quantitative serum levels of tropomyosin receptor kinase receptor B, and to estimate its association with serum concentration of brain-derived neurotrophic factor and obesity in patients with painful and painless forms of diabetic polyneuropathy. Methods: We examined 70 patients with diabetic polyneuropathy with confirming peripheral nerve dysfunction by electroneuromyography and measuring of serum levels tropomyosin receptor kinase receptor B and brain-derived neurotrophic factor by enzyme immunoassay. Diabetic polyneuropathy was diagnosed using the modified Toronto Consensus (2011) criteria, while neuropathic pain was assessed using an 11-point Numerical Pain Rating Scale. The patients were divided into two groups according to presence or absence of neuropathic pain. Control Group consisted of 14 healthy persons. Results: The serum levels of tropomyosin receptor kinase receptor B and brain-derived neurotrophic factor in patients with diabetic polyneuropathy are significantly higher than healthy controls (p=0.000). Hyperexpression of brain-derived neurotrophic factor in serum was associated with painful form of diabetic polyneuropathy (R=0.392, p=0.012) and obesity (R=0.412, p=0.001). On the contrary high concentration of tropomyosin receptor kinase receptor B in serum associated with painless diabetic polyneuropathy by Pain DETECT (R=-0.354, p=0.015), low body weight (R=-0.354, p=0.015) and severe demyelization of nerve fibers (R=-0.574, p=0.001), indicated "non-working" receptor detected in serum. Conclusion: Tropomyosin receptor kinase receptor B signaling is involved in the modulation of neuropathic pain and obesity in diabetic polyneuropathy.
RESUMO Objetivo: Avaliar os níveis séricos quantitativos do receptor da tropomiosina quinase B, e estimar sua associação com os níveis séricos do fator neurotrófico derivado do cérebro e a obesidade, em pacientes com formas dolorosas e indolores de polineuropatia. Métodos: Examinamos 70 pacientes com polineuropatia diabética, com disfunção de nervo periférico confirmada por eletroneuromiografia e medida de níveis séricos do receptor da tropomiosina quinase B e do fator neurotrófico derivado do cérebro, por imunoensaio enzimático. Polineuropatia diabética foi diagnosticada através dos critérios modificados do Consenso de Toronto (2011), e a dor neuropática foi avaliada pela escala Numerical Pain Rating com 11 pontos. Os pacientes foram divididos em dois grupos, conforme presença ou ausência de dor neuropática. O Grupo Controle tinha 14 indivíduos saudáveis. Resultados: Os níveis séricos do receptor da tropomiosina quinase B e do fator neurotrófico derivado do cérebro em pacientes com polineuropatia diabética são significativamente mais elevados do que controles saudáveis (p=0,000). Hiperexpresssão do fator neurotrófico derivado do cérebro no soro foi associada à forma dolorosa da polineuropatia diabética (R=0,392, p=0,012) e obesidade (R=0,412, p=0,001). Por outro lado, alta concentração sérica de receptor da tropomiosina quinase B, associada à polineuropatia diabética indolor por PainDETECT (R=-0,354, p=0,015), baixo peso corporal (R=-0,354, p=0,015) e grave desmielização de fibras nervosas (R=-0,574, p=0,001), indicaram receptor "não funcionante" detectado no soro. Conclusão: A sinalização do receptor da tropomiosina quinase B está envolvida na modulação da dor neuropática e obesidade na polineuropatia diabética.
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Diabetes Mellitus , Diabetic Neuropathies , Neuralgia/etiology , Tropomyosin , Obesity/complicationsABSTRACT
Objective To evaluate the efficacy of sevoflurane in preventing depression-like behavior in mice and the relationship with brain-derived neurotrophic factor (BDNF)/tyrosine kinase B (TrkB) signaling pathway.Methods Forty-four clean-grade male C57BL/6 mice,weighing 18-22 g,aged 8-10 weeks,were divided into 2 groups (n =22 each) using a random number table method:control group (group C) and sevoflurane group (group S).Mice in group C inhaled oxygen for 30 min,and mice in group S inhaled 2.5％ sevoflurane for 30 min.The forced swimming test and novelty-suppressed feeding test were performed after the mice were fully awake.The brains were immediately removed under anesthesia at the end of inhalation of oxygen or sevoflurane,and the prefrontal cortex and hippocampus were isolated for detection of the expression of BDNF,TrkB and phosphorylated TrkB (p-TrkB) by Western blot.Results Compared to group C,the immobility time and feeding latency were significantly shortened,the expression of p-TrkB in the prefrontal cortex and hippocampus was up-regulated (P＜0.05),and no significant change was found in the feeding consumption or expression of BDNF and TrkB in the prefrontal cortex and hippocampus in group S (P＞0.05).Conclusion Sevoflurane produces a preventive effect on depression-like behavior in mice,and the mechanism is related to increased phosphorylation of TrkB in BDNF/TrkB signaling pathway.
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RESUMO Objetivo: determinar a expressão de neurotrofinas e seus receptores tirosina quinases em pacientes com osteossarcoma (OS) e sua correlação com desfechos clínicos. Métodos: biópsias de tumores primários de pacientes com OS tratados em uma única instituição, consecutivamente, entre 2002 e 2015, foram analisados através de imuno-histoquímica para expressão de receptores de tirosina quinase A e B (TrKA e TrKB), fator de crescimento neural (NGF) e fator neurotrófico derivado do cérebro (BDNF). De forma independente, dois patologistas classificaram os marcadores de imuno-histoquímica como negativos (negativos e focais fracos) ou positivos (moderado focal/difuso ou forte focal/difuso). Resultados: foram analisados dados de 19 pacientes (10 do sexo feminino e 9 do masculino) com mediana de idade de 12 anos (5 a 17,3 anos). Dos tumores, 83,3% estavam localizados em membros inferiores e 63,2% dos pacientes eram metastáticos ao diagnóstico. A sobrevida global em cinco anos foi de 55,3%. BDNF foi positivo em 16 pacientes (84%) e NGF em 14 pacientes (73%). TrKA e TrKB apresentaram coloração positiva em quatro (21,1%) e oito (42,1%) pacientes, respectivamente. A análise de sobrevida não demonstrou diferença significativa entre receptores TrK e neurotrofinas. Conclusão: amostras de OS primário expressam neurotrofinas e receptores TrK através de imuno-histoquímica. Estudos futuros podem auxiliar na identificação do papel das mesmas na patogênese do OS e determinar se há possível correlação prognóstica.
ABSTRACT Objective: to determine the expression of neurotrophins and their tyrosine-kinase receptors in patients with osteosarcoma (OS) and their correlation with clinical outcomes. Methods: we applied immunohistochemistry to biopsy specimens of patients consecutively treated for primary OS at a single institution between 2002 and 2015, analyzing them for expression receptors of tyrosine kinase A and B (TrKA and TrKB), neural growth factor (NGF) and brain derived neurotrophic factor (BDNF). Independently, two pathologists classified the immunohistochemical markers as negative (negative or weak focal) or positive (moderate focal/diffuse or strong focal/diffuse). Results: we analyzed data from 19 patients (10 females and 9 males), with median age of 12 years (5 to 17.3). Tumors' location were 83.3% in the lower limbs, and 63.2% of patients had metastases at diagnosis. Five-year overall survival was 55.3%. BDNF was positive in 16 patients (84%) and NGF in 14 (73%). TrKA and TrKB presented positive staining in four (21,1%) and eight (42,1%) patients, respectively. Survival analysis showed no significant difference between TrK receptors and neurotrophins. Conclusion: primary OS samples express neurotrophins and TrK receptors by immunohistochemistry. Future studies should explore their role in OS pathogenesis and determine their prognostic significance in larger cohorts.
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Humans , Male , Female , Child, Preschool , Child , Adolescent , Bone Neoplasms/pathology , Osteosarcoma/pathology , Brain-Derived Neurotrophic Factor/analysis , Receptor, trkA/analysis , Receptor, trkB/analysis , Nerve Growth Factors/analysis , Reference Values , Bone Neoplasms/mortality , Immunohistochemistry , Biomarkers, Tumor , Osteosarcoma/mortality , Risk Factors , Statistics, Nonparametric , Kaplan-Meier EstimateABSTRACT
Objective To investigate the effects of brain-derived neurotrophic factor (BDNF) pretreatment on H9c2 myocardial hypoxia/reoxygenation (H/R) injury, and explore its mechanism. Methods The H9c2 myocardial cells were cul?tured in vitro and (95%O2+5%CO2) oxygen cultured 12 h after (95%N2+5%CO2) hypoxia cultured 4 h to establish the H/R model. The cells were divided into normal control group, H/R group, different concentrations (1, 10, 100μg/L) BDNF pre?treatment in H/R groups and TrkB-inhibitor group (with 100μg/L BDNF and 1∶1 000 TrkB inhibitor pre-treatment in H/R group). The cell survival rate was measured by MTT method in different groups. The lactate dehydrogenase (LDH), creatine kinase (CK), malondialdehyde (MDA) and superoxide dismutase (SOD) content and activity were detected after H/R injury. The apoptotic rate of H9c2 myocardial cells were detected by flow cytometry, and the expressions of TrkB, Bcl-2 and Bax protein were detected by Western blot assay. Results Compared with the normal control group, the survival rate of H9c2 myocardial cells was decreased significantly in H/R model group (P < 0.05), LDH, CK and MDA contents were increased and SOD activity was decreased (P<0.05). The cell apoptosis rate was increased significantly (P<0.05). The anti-apoptosis Bcl-2 protein expression was decreased, pro-apoptosis Bax protein expression was increased in H/R model group (P<0.05). Compared with the H/R model group, the cell survival rates of H9c2 myocardial cells were increased after pre-treatment with different concentrations of BDNF (P<0.05);LDH, CK and MDA contents were decreased and SOD activity were in?creased respectively (P < 0.05). The cell apoptotic rates were decreased (P < 0.05). The expressions of TrkB receptor and Bcl-2 protein gradually increased, while the expression of Bax protein was gradually decreased (P<0.05). The role of BDNF was inhibited by TrkB inhibitor. Conclusion BDNF pre-treatment can promote the cell survival rate of H9c2 myocardial cells after H/R injury, which plays a protective role by inhibiting the cell apoptotic rate and maintaining antioxidant capacity, and associates with BDNF-TrkB signaling pathways.
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ObjectiveToinvestigatetherolesofbrain-derivedneurotrophicfactor(BDNF)and tyrosine receptor kinase B (TrkB) in ischemic postconditioning. Methods Wistar rats w ere randomly assigned to three groups:a sham operation (9 rats), an ischemic postconditioning, and an ischemia-reperfusion group. According to the reperfusion time, the latter 2 groups w ere redivided into 6, 12, 24, 48, and 72 h subgroups (9 rats in each subgroups). A middle cerebral artery occluded by suture method for a cerebral ischemia-reperfusion model. Triphenyl tetrazolium staining w as used to detect infarct volume (P=4). Immunohisto-chemical staining w as used to detect the expression levels of BDNF and TrkB proteins (P=5). Results The infarct volumes in the ischemic postconditioning group w ere reduced significantly compared w ith those in the ischemia-reperfusion group (6 h:143.3 ±8.7 mm3 vs.166.8 ±7.5 mm3, t=4.104, P=0.006;12 h:151.7 ±7.8 mm3 vs.171.6 ±9.1 mm3, t=3.314, P=0.016; 24 h: 159.2 ±9.3 mm3 vs.177.1 ± 7.6 mm3, t=3.000, P=0.024;48 h:166.9 ±9.6 mm3 vs.184.9 ±9.0 mm3, t=2.732, P=0.034;72 h:172.0 ±9.1 mm3 vs.198.1 ±8.2 mm3, t=2.640, P=0.039), and the positive cel numbers of BDNF (6 h:23.98 ±4.07 vs.18.63 ±2.5, t=2.479, P=0.038;12 h:27.64 ±3.18 vs.22.01 ±3.14, t=2.817, P=0.023;24 h:34.82 ±4.17 vs.28.46 ±4.05, t=2.446, P=0.040; 48 h:34.30 ±3.27 vs.26.29 ± 3.26, t=3.872, P=0.005;72 h:28.77 ±3.53 vs.23.64 ±3.54, t=2.297, P=0.051) and TrkB (6 h:33.83 ±3.90 vs.21.51 ±3.86, t=5.012, P<0.001; 12 h:38.59 ±4.84 vs.23.41 ±3.67, t=5.586, P<0.001;24 h:46.07 ±3.06 vs.28.78 ±3.61, t=8.169, P<0.001; 48 h:47.90 ±3.30 vs.29.51 ± 3.81, t=8.160, P<0.001; 72 h:42.78 ±4.07 vs.27.46 ±3.19, t=6.623, P<0.001) per high-pow er field at each time point in the ischemic postconditioning group w ere significantly more than those in the ischemia-reperfusion group. Conclusions Ischemic postconditioning upregulates the expressions levels of BDNF and TrkB proteins after ischemia-reperfusion and reduces cerebral infarct volumes. BDNF/TrkB may play an important neuroprotective effect in ischemic postconditioning.
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Objective To investigate the expression of Brain-derived neurotrophic factor (BDNF)and its receptors mRNAs in ovary tissues of letrozole-induced polycystic ovary syndrome (PCOS)in rats.Methods The SD rats were divided into two groups (moder group and control group),20 rats in each group.The rat models of PCOS were established by letrozole.Serum sex hormone levels were determined by radioimmunoassay.The histologic changes in ovaries were observed by Hematoxylin-eosin stai-ning,and the expression of BDNF and its receptors gene in ovary tissues was detected by Real-time PCR.Results Although the se-rum testosterone,follicle-stimulating hormone and luteinizing hormone levels in model group were markedly increased more than those in the control group (P < 0.01 ),estradiol and progesterone in model group showed a considerable reduction (P < 0.05 ). When compared with the control group,model group rats showed increased ovarian volume and high incidence of subcapsular ovari-an cysts together with decreased number of corpora lutea.The expression of BDNF and p75 mRNAs was significantly higher in model group than that in the control group(P <0.05),but the expression of TrkB mRNA reduced(P <0.05).Conclusion BDNF/TrkB/p75 expressed in ovarian tissues may play a specific role on follicular developmental disorders in letrozole-induced PCOS rats.
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Objective To investigate the effects of exercise on expressions of brain-derived neurotrophic factor (BDNF) and tyrosine kinase receptor B (TrkB) in spinal cord of spinal cord injury (SCI) rats. Methods Spinal cord injury models were produced by universal spinal cord impact system. Twenty-four Sprague-Dawley rats were randomly divided into 3 groups, exercise group (SCI-induction and exercises, n=8), control group (SCI-induction without exercises,n=8) and sham-operation group (no operation, without SCI nor exercises, n=8). Exercise training began from the 7th day after injury for 4 weeks. The locomotor function was assessed by Basso-Beattic-Bresnahan (BBB) scale before injury and at the 1st, 2nd, 3rd, 4th and 5th week post injury. The expressions level of BDNF and TrkB in spinal cords were detected by immunohistochemis-try and Western blot. Results Since the 3rd week after injury (after 2 weeks of exercise training), BBB scores in exercise group were higher than that in control group (P ＜ 0.05). In immunohistochemistry test, positive immunologic reaction to BDNF protein was mainly located in anterior horn of spinal cord, and the expression level in exercise group was significantly higher than that in sham-operation group and control group (P＜0.05). In immunohistochemistry test, positive immunologic reaction to TrkB protein was located in anterior horn and dorsal horn and central canal of spinal cord, and the expression lev-el in exercise group was significantly higher than that in sham-operation group and control group (P＜0.05). Expression of BDNF and TrkB in exercise group rats after exercise for 4 weeks were significantly increased, compared with that in control group. Conclusion Exercise training may effectively induce BDNF and TrkB expression in spinal cords and promote the re-covery of locomotor function of SCI rats.
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Objective To study the effect of miR-204 on BDNF/TrkB signaling and pathogenesis on the neuron model of epilepsy. Methods Primary hippocampal neurons were cultured in vitro for 7 days, and were divided into control group, control+BDNF group, epilepsy group, epilepsy+BDNF group , control+miR204 group, epilepsy+miR204 group and ep-ilepsy+miR204+BDNF group. The epilepsy model of hippocampal neurons was established by being exposed to Mg2+free me-dia for 3 hours. The miR-204 lentivirus vector was constructed. The effect of miR-204 on BDNF/TrkB expression was detect-ed by immunohistochemistry, patch clamp and Western blot technique. Results Compared with the control group, the TrkB phosphorylation level was higher in control+BDNF group. The TrkB phosphorylation level was lower in epilepsy+BDNF group than that of control+BDNF group, but it was higher than that of epilepsy group. The TrkB phosphorylation level was higher in epilepsy+miR204+BDNF group than that of epilepsy+BDNF group and epilepsy+ miR204 group. Conclusion BDNF and miR-204 can improve the inhibitory condition of BDNF/TrkB signaling and may play an important role in alleviat-ing epilepsy disease.
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Objective To investigate the mechanism of brain derived neurotrophic factor (BDNF) regulated by differ-ent isoforms of tyrosine kinase receptor B (TrkB) in epileptic hippocampal neurons. Methods Primary hippocampal neu-rons were cultured in vitro for 7 days, and divided into two groups, ALLN (calcineurin inhibitor) group and Anisomycin (trans-lation inhibitor) group. ALLN group included control group, control+BDNF group, epilepsy group, epilepsy+BDNF group, control+ALLN group, epilepsy+ALLN group and epilepsy+ALLN+BDNF group. Anisomycin group was sub-divided into con-trol group, control+BDNF group, epilepsy group, epilepsy+BDNF group, control+Anisomycin group, epilepsy+Anisomycin group and epilepsy+Anisomycin+BDNF group. The immunofluorescent technique was used to identificate the hippocampal neurons. Epileptiform discharges were detected by electrophysiological techniques. Western blot assay was used to deter-mine the protein expression of TrkB and phosphorylated TrkB (p-TrkB) in all cell groups. Results (1) In ALLN group, the gray value of p-TrkB/TrkB was higher in control+BDNF group compared with that of control group, the value was higher in epilepsy+BDNF group than that of epilepsy group but was lower than that of control+BDNF group. The gray value of p-TrkB/TrkB was lower in epilepsy+ALLN+BDNF group than that of epilepsy+BDNF group, but no significant difference compared with that of epilepsy+ALLN group. (2) In Anisomycin group:the gray value of p-TrkB/TrkB was higher in control+BDNF group than that of control group. The gray value of p-TrkB/TrkB was higher in epilepsy+BDNF group than that of epilepsy group, but which was lower than that of control+BDNF group. The gray value of p-TrkB/TrkB was higher in epilepsy+Aniso-mycin+BDNF group than that of epilepsy+BDNF group and epilepsy+Anisomycin group. Conclusion The decreased ex-pression of TrkB.T can improve the inhibition of BDNF/TrkB signaling, and BDNF can activate BDNF/TrkB signal pathway in epileptic hippocampal neurons. The increased TrkB.FL protein level by ALLN can’t improve the inhibition of BDNF/TrkB signal pathway.
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Brain-derived neurotrophic factor is the ligands of tyrosine kinase receptor B,for the binding of brain-derived neurotrophic factor to tyrosine kinase receptor B receptor,signal transmitted to the nucleus,resulting in a variety of biological effects.Lots of researchs had found that brain-derived neurotrophic factor and tyrosine kinase receptor B expression in malignant tumors more than non-cancerous adjacent tissue and normal tissue,and their effect can promote tumor blood vessel formation,suppress of cell anoikis,promote tumor growth,differentiation and metastasis.The relationship of brain-derived neurotrophic factor and tyrosine kinase receptor B provide a new therapeutic strategy for clinical treatment.From the current basic and clinical research,this treatment strategy has great prospect.
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INTRODUCCIÓN: La epilepsia del lóbulo temporal se desarrolla como consecuencia de insultos cerebrales como trauma, infartos, infección o convulsiones. Los circuitos neuronales del lóbulo temporal, incluyendo al hipocampo, se reorganizan generando redes hiperexcitables, el foco epiléptico, proceso denominado epileptogénesis; en cambio, la corteza cerebral es más resistente a la reorganización. La epileptogénesis en el hipocampo está mediada en parte por óxido nítrico, sintetizado por la óxido nítrico sintasa neuronal y por la neurotrofina BDNF, cuyo receptor es TrkB. Estas proteínas están localizadas en las sinapsis excitadoras y podrían estar implicadas en la sensibilidad diferencial entre el hipocampo y corteza cerebral a la epileptogénesis. OBJETIVO: Lograr un acercamiento a los mecanismos que participan en la sensibilidad diferencial a la epileptogénesis entre el hipocampo y la corteza, después de convulsiones. MATERIAL Y MÉTODO: Se indujeron convulsiones en ratas mediante inyección de kainato. Se obtuvieron membranas sinápticas reselladas (sinaptosomas) de corteza e hipocampo. En ellas, se cuantificó la co-localización de óxido nítrico sintasa neuronal, TrkB y un marcador de sinapsis excitadoras (Prosap2) mediante técnicas inmunohistoquímicas. Los resultados expresados como por ciento promedio +/- error estándar se sometieron a prueba de t-student. RESULTADOS: TrkB y óxido nítrico sintasa neuronal aumentaron de 20,6 +/- 3,5 por ciento a 35,7 +/- 2,6 por ciento (p = 0,0008) y de 32,4 +/- 3,8 por ciento a 51,5 +/- 3,5 por ciento (p = 0,0003), respectivamente, en sinaptosomas excitadores hipocampales después de convulsiones. En sinaptosomas excitadoras de cerebro corteza no se observaron cambios significativos. DISCUSIÓN: óxido nítrico sintasa neuronal y TrkB se asocian a sinapsis excitadoras hipocampales después de convulsiones, pudiendo contribuir así a la epileptogénesis. La cerebrocorteza es resistente a esta reorganización molecular.
INTRODUCTION: Temporal lobe epilepsy develops as a consequence of brain insults such as trauma, stroke, infection, or seizures. The temporal lobe circuit, including the hippocampus, reorganizes generating hyper-excitable networks and, therefore, the epileptic focus, process called epileptogenesis. Where as, the cerebral cortex is more resistant to the reorganization. Temporal lobe epileptogenesis is mediated partly by neuronal nitric oxide synthase and the neurotrophin BDNF with its receptor TrkB. These proteins are localized at excitatory synapses and might be involved in the differential sensitivity of the hippocampus and cerebral cortex to epileptogenesis. OBJECTIVE: Getting closer to mechanisms involved in epileptogenesis differential sensitivity between the hippocampus and cortex after seizures. MATERIAL AND METHOD: Seizures were induced in rats by injection of kainic acid. Resealed synaptic membranes (synaptosomes) were obtained from cortex and hippocampus. Then the co-localization of neuronal nitric oxide synthase, TrkB and a marker of excitatory synapses (Prosap2/Shank3) was quantified by immunohistochemistry. The results were expressed as mean +/- standard error and subjected to t-student test. RESULTS: TrkB and neuronal nitric oxide synthase increased from 20.6 +/- 3.5 percent to 35.7 +/- 2.6 percent (p = 0.0008) and from 32.4 +/- 3.8 percent to 51.5 +/- 3.5 percent (p = 0.0003), respectively in excitatory hippocampal synaptosomes after seizures. In excitatory cerebrocortical synaptosomes no significant changes were observed. DISCUSSION: neuronal nitric oxide synthase and TrkB associate to excitatory hippocampal synapses after seizures, thereby probably contributing to epileptogenesis. The cerebral cortex is resistant to this molecular reorganization.
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Male , Animals , Rats , Cerebral Cortex/metabolism , Epilepsy/metabolism , Hippocampus/metabolism , Nitric Oxide Synthase/metabolism , Receptor, trkB , Kainic Acid/administration & dosage , Carrier Proteins , Epilepsy/chemically induced , Brain-Derived Neurotrophic Factor/metabolism , Temporal Lobe/metabolism , Rats, Sprague-Dawley , SynaptosomesABSTRACT
Objective To investigate the mechanisms of methylglyoxal(MG)-induced injury of hippocam-pal neurons. Methods Primary cultured of hippocampal neurons from 1-day-old Sprague-Dawley rats were incuba-ted with MG for different time and dose period. Cells proliferation were assayed by methyl thiazolyl tetrazolium (MTT),and apoptosis was quantified by flow cytometer using annexin V-FITC and propidium iodide (PI) stai-ning. The protein and mRNA levels of brain-derived neurotrophie factor (BDNF) and tyrosine kinase B(TrkB) were assayed with Western Blotting and real-time PCR. Results Treatment with MG resulted in a concentration-dependent (r=0.946, P < 0.01) and time-dependent (r=0.993, P < 0.01) decreasing neurons viability. Com-pared with Oh group(1. 633±0. 153)%, 100 μM MG treatment for 2h,6h, 12h and 24h,the cellular apeptosis rate were significantly increased ((2. 833±0. 153)%, (3. 367±0. 153)%, (4. 433±0. 404)% and (8. 833± 0. 306)% respectivdy,all P<0.01). MG also increased the BDNF mRNA and protein expression after 12h treat-ment (P<0.05 or P<0.01),but decreased the TrkB mRNA and protein expression in the cells after 6h treatment (P<0.05 or P < 0.01). Conclusion MG has direct toxic effect on hippocampal neurons and can impaire the BD-NF-TrkB signal pathway by inhibiting the expression of TrkB,and increasing the apoptosis of hippocampal neurons.
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Objective To study the relationship between tyrosine kinase receptor B (TrkB)expression and anoikis-suppression and invasion in OVCAR3 ovarian cancer ceils. Methods The expression of TrkB mRNA in OVCAR3 ovarian cancer cells under two culture conditions :adhesive cells and ceil-spheroids were evaluated by RT-PCR and real-time PCR.The relationship between TrkB expression and anoikis-suppression of OVCAR3 ovarian cancer ceils was examined by RNA interference (RNAi) technic,anchorage independent culture and fluorescence-activated ceil sorting analysis.The difference in invasion and metastatic ability of OVCAR3 cells under two culture conditions and with or without TrkB silenced by small interfering RNA (siRNA) was investigated by matrigel invasion assay and in vivo studies.Results The expression of TrkB mRNA was highest in OVCAR3 ovarian cancer ceils,0.0240 ~ 0.0017,compared with the other three cell lines,0.0030±0.0006,0.0027±0.0009 and 0.0087±0.0003 respectively,andthe expression in OVCAR3 multicellular spheroids was significantly higher than that in ceils under monolayer adhesive culture,0.0437±0.0021 versus 0.0240±0.0017 (P＜0.01) . TrkB mediated anoikissuppression in OVCAR3 ovarian cancer ceils.OVCAR3 multiceilular spheroids had a higher invasion ability than OVCAR3 cells under monolayer adhesive culture,and the penetrating cells of the two groups were 71.8± 0.8 and 47.7±0.8 respectively (P＜0.01 ).The metastatic ability of OVCAR3 cells was attenuated when TrkB was silenced,and the volume of the tumors developed by OVCAR3 adhesive cells and OVCAR3 adhesive cells with TrkB silenced were (16.3±4.7) mm3 and(6.0±1.4) mm3 respectively (P＜0.01).Conclusion As an anoikis-suppressur,TrkB may increase the invasion and metastasis of OVCAR3 ovarian cancer cells.
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OBJECTIVE To investigate the role of brain-derived neurotrophic factor(BDNF) and its receptor TrkB in the development of allergic rhinitis(AR). METHODS SD rats were randomly divided into allergic rhinitis group(AR group, n=20) and control group (Con group, n=10) . A model of allergic rhinitis in health SD rat was established by using ovalbumin intraperitoneal immunization and nasal antigen challenge. The nasal mucosa obtained from 18 out of 20 AR models as well as 10 normal controls were studied with immunohistochemistry (Envision System) method to observe the expression and distribution of BDNF and TrkB. RESULTS Immunohistochemical staining showed that the distribution of BDNF and TrkB in nasal mucosa from normal rats was in accordance with that in the nasal mucosa from rats with allergic rhinitis on the whole. The study showed that immunoreactivity to BDNF (or to TrkB) was present both on the surface and in the cytoplasm of epithelial cells, glandular cells and their duct cells. The statistical analysis of imumunohistochemical staining showed that the IOD of BDNF in rat nasal mucosa with allergic rhinitis (77344.17?8567.02) was obviously higher than that in the normal rat nasal mucosa (54124.82? 18515). There was a statistical significance between the two groups (t=3.053, P