Brain-derived Neurotrophic Factor mRNA Expression Research Articles

OLAHRAGA DAPAT MENINGKATKAN FUNGSI KOGNITIF MELALUI MODULASI EPIGENETIK EKSPRESI GEN BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF)

ABSTRACTExercise may improve cognitive function and slow the onset of neurodegeneration, but the underlying mechanism had not yet known certainly. The purpose of this paper is to know the mechanism of exercise in improving cognitive function in terms of biomolecular aspects. The method of this paper is literature study of articles about the benefits of exercise in improving cognitive function in terms of biomolecular aspects. Cognitive function is a function related to perception, learning process, concentration, memory and problem solving. Exercise is useful for improving cognitive function mediated by a neurotropin-brain brain-derived neurotrophic factor (BDNF). BDNF has important role in neural plasticity, nerve excitability, and especially in learning process and memory improving. Exercise can improve cognitive function by inducing increased BDNF expression that occurs through the mechanism of epigenetic regulatory change. The change in epigenetic regulation caused by exercise through DNA methylation, which increase the expression of BDNF mRNA in the hippocampus. The change in epigenetic regulation caused by exercise, which also increase the expression of BDNF mRNA is a histone modification. The increased expression of mRNA in the hippocampus is not only increase synapse plasticity in the hippocampus area but also synapse transmission, which lead to the increasing of molecules expression related to learning and memory.Keywords: Sport, Brain-derived neurotrophic factor (BDNF), Epigenetic.

Riboflavin may ameliorate neurological motor disability but not spatial learning and memory impairments in murine model of multiple sclerosis

Summary Background & aims Riboflavin has an important role in myelin formation. This experimental study assesses the interactions between the effects of riboflavin and interferon beta-1a (INF-β1a) on motor disability, spatial learning and memory, and brain-derived neurotrophic factor (BDNF) in experimental autoimmune encephalomyelitis (EAE). Methods In the present research C57BL/6 mice (n = 56) were divided into sham and treatment groups. Riboflavin was administrated (10 mg/kg/day) orally for two weeks alone and/or combined with INF-β1a at 150 IU/g of body weight. After the induction of EAE, the animals were investigated for the clinical signs. Spatial learning and memory were assessed through the standard Morris water maze (MWM). The brain and spinal cord levels of BDNF were studied using real-time polymerase chain reactions and enzyme-linked immunosorbent assay. The data were analyzed using one-way ANOVA, repeated measures, and generalized estimating equations model. Results The results in the brain revealed that BDNF mRNA expression (P Conclusion The data highlighted the synergistic role of riboflavin and INF-β1a in improving the disability but not spatial learning and memory mediated by BDNF in EAE.

Effects of NaHS and hydroxylamine on the expressions of brain-derived neurotrophic factor and its receptors in rats after cardiac arrest and cardiopulmonary resuscitation

BackgroundH2S can also protect nerve cells. The objective of the study is to investigate the effects of hydrogen sulfide (H2S) on the expressions of brain-derived neurotrophic factor (BDNF) and its receptors, tyrosine protein kinase B (TrkB) and p75 neurotrophin receptor (p75NTR), in brain tissues of rats with cardiac arrest and cardiopulmonary resuscitation (CA/CPR) following the restoration of spontaneous circulation (ROSC).MethodsRats (n = 240) with CA/CPR were divided into three groups: Intervention (n = 80) that received sodium hydrosulfide (NaHS, 14 μmoL/kg·d) intervention after ROSC; Inhibition (n = 80) that received hydroxylamine (40 μmoL/kg·d) intervention after ROSC; and Control (n = 80) that received saline after ROSC. Kaplan-Meyer analysis was used to analyze the survival data. Quantitative real-time PCR (q-PCR), Western blot, immunohistochemistry and IODs (integrated optical density) were performed to determine the mRNA and protein expressions of BDNF, TrkB and p75NTR in rat brain tissues.ResultsSurvival rate of the three groups had significant difference (χ2 = 28.376, p = 0.000). The Intervention group had the highest survival rate (82.5%), while the Inhibition group had the lowest survival rate (62.5%). The mRNA and protein levels of BDNF and TrkB in the Intervention group were significantly higher compared to the Control group (p < 0.05); while the mRNA and protein levels of BDNF and TrkB in the Inhibition group was significantly lower than the Control group (p < 0.05) on days 1, 3, and 7. However, the mRNA and protein levels of p75NTR in the Intervention group were significantly lower than the Control group (p < 0.05); while the mRNA and protein levels of p75NTR in the Inhibition group were significantly higher than the Control group (p < 0.05) on days 1, 3, and 7.ConclusionNaHS treatment increases the survival rate of rats after CA and ROSC by upregulating the expression and activation of BDNF and its receptor TrkB, and down-regulating p75NTR expression.

Enhancement of BDNF Expression and Memory by HDAC Inhibition Requires BET Bromodomain Reader Proteins.

Histone deacetylase (HDAC) inhibitors may have therapeutic utility in multiple neurological and psychiatric disorders, but the underlying mechanisms remain unclear. Here, we identify BRD4, a BET bromodomain reader of acetyl-lysine histones, as an essential component involved in potentiated expression of brain-derived neurotrophic factor (BDNF) and memory following HDAC inhibition. In in vitro studies, we reveal that pharmacological inhibition of BRD4 reversed the increase in BDNF mRNA induced by the class I/IIb HDAC inhibitor suberoylanilide hydroxamic acid (SAHA). Knock-down of HDAC2 and HDAC3, but not other HDACs, increased BDNF mRNA expression, whereas knock-down of BRD4 blocked these effects. Using dCas9-BRD4, locus-specific targeting of BRD4 to the BDNF promoter increased BDNF mRNA. In additional studies, RGFP966, a pharmacological inhibitor of HDAC3, elevated BDNF expression and BRD4 binding to the BDNF promoter, effects that were abrogated by JQ1 (an inhibitor of BRD4). Examining known epigenetic targets of BRD4 and HDAC3, we show that H4K5ac and H4K8ac modifications and H4K5ac enrichment at the BDNF promoter were elevated following RGFP966 treatment. In electrophysiological studies, JQ1 reversed RGFP966-induced enhancement of LTP in hippocampal slice preparations. Last, in behavioral studies, RGFP966 increased subthreshold novel object recognition memory and cocaine place preference in male C57BL/6 mice, effects that were reversed by cotreatment with JQ1. Together, these data reveal that BRD4 plays a key role in HDAC3 inhibitor-induced potentiation of BDNF expression, neuroplasticity, and memory.SIGNIFICANCE STATEMENT Some histone deacetylase (HDAC) inhibitors are known to have neuroprotective and cognition-enhancing properties, but the underlying mechanisms have yet to be fully elucidated. In the current study, we reveal that BRD4, an epigenetic reader of histone acetylation marks, is necessary for enhancing brain-derived neurotrophic factor (BDNF) expression and improved memory following HDAC inhibition. Therefore, by identifying novel epigenetic regulators of BDNF expression, these data may lead to new therapeutic targets for the treatment of neuropsychiatric disorders.

Increased Calcium Influx through L-type Calcium Channels in Human and Mouse Neural Progenitors Lacking Fragile X Mental Retardation Protein.

SummaryThe absence of FMR1 protein (FMRP) causes fragile X syndrome (FXS) and disturbed FMRP function is implicated in several forms of human psychopathology. We show that intracellular calcium responses to depolarization are augmented in neural progenitors derived from human induced pluripotent stem cells and mouse brain with FXS. Increased calcium influx via nifedipine-sensitive voltage-gated calcium (Cav) channels contributes to the exaggerated responses to depolarization and type 1 metabotropic glutamate receptor activation. The ratio of L-type/T-type Cav channel expression is increased in FXS progenitors and correlates with enhanced progenitor differentiation to glutamate-responsive cells. Genetic reduction of brain-derived neurotrophic factor in FXS mouse progenitors diminishes the expression of Cav channels and activity-dependent responses, which are associated with increased phosphorylation of the phospholipase C-γ1 site within TrkB receptors and changes of differentiating progenitor subpopulations. Our results show developmental effects of increased calcium influx via L-type Cav channels in FXS neural progenitors.

Hemisphere-dependent Changes in mRNA Expression of GABAA Receptor Subunits and BDNF after Intra-prefrontal Cortex Allopregnanolone Infusion in Rats

Allopregnanolone is a neurosteroid implicated in mood disorders such as depression and anxiety. It acts as a GABAA receptor (GABAAR)-positive allosteric modulator and changes the expression of GABAAR subunits and of brain-derived neurotrophic factor (BDNF) in different brain regions. It has been demonstrated that such neurochemical changes may have an asymmetrical pattern regarding brain hemispheres. The aim of this study was to verify the behavioral and hemisphere-specific neurochemical effects of the bilateral intra-prefrontal cortex (intra-PFC) infusion of allopregnanolone in rats. Rats were exposed to the forced swim test and to the grooming microstructure test, followed by the right and left hemisphere-specific quantification of mRNA expression by Real-Time PCR of δ and γ2 GABAAR subunits and BDNF in the PFC and in the hippocampus. Though we did not observe any significant effects in the behavioral tests, intra-PFC allopregnanolone infusion bilaterally increased the mRNA expression of the δ subunit in the same area and of BDNF in the hippocampus. Both mRNA expressions of the γ2 subunit and BDNF were higher in the right than in the left PFC of control animals, and the hemisphere differences were not seen after allopregnanolone infusion. Overall hippocampal BDNF expression was also higher in the right hemisphere, but this asymmetry was not normalized by allopregnanolone. No asymmetries or changes were observed in the hippocampal mRNA expression of GABAAR subunits. These results point to a hemisphere-dependent regulation of GABAAR subunits and BDNF that can be modulated by intra-PFC allopregnanolone infusion, even in the absence of associated behavioral effects.

High salt loading increases brain derived neurotrophic factor in supraoptic vasopressin neurones.

High salt loading (SL) is associated with inappropriate arginine vasopressin (AVP) release and increased mean arterial pressure. Previous work has shown that chronic high salt intake impairs baroreceptor inhibition of rat AVP neurones through brain-derived neurotrophic factor (BDNF) dependent activation of tyrosine receptor kinase B (TrkB) and down-regulation of K+/Cl- co-transporter KCC2. This mechanism diminishes the GABAA inhibition of AVP neurones in the supraoptic nucleus (SON) by increasing intracellular chloride. However, the source of BDNF leading to this ionic plasticity is unknown. In the present study, we used adeno-associated viral vectors with short hairpin RNA against BDNF to test whether SON is the source of BDNF contributing to increased AVP release and elevated mean arterial pressure in high salt loaded rats. Virally mediated BDNF knockdown (shBDNF) in the SON of salt loaded rats significantly blocked the increases in BDNF mRNA and AVP heterogeneous RNA expression. The observed increase in the activation of TrkB receptor during salt loading is consistent with previous studies. Western blot analysis of SON punches revealed that tyrosine phosphorylation of TrkB (pTrkBY515) was significantly decreased in salt shBDNF rats compared to the salt scrambled (SCR) rats. Injections of shBDNF in the SON also significantly prevented the increase in plasma AVP concentration associated with salt loading. However, the salt loading induced increase in mean arterial pressure was not decreased with BDNF knockdown in the SON. Average daily fluid intake and urine output were significantly elevated in both salt SCR and salt shBDNF rats compared to the euhydrated controls. Daily average urine sodium concentration was significantly higher in shBDNF injected salt rats than the other groups. These findings indicate that BDNF produced in the SON contributes to the increased AVP secretion during high salt loading but not with respect to the subsequent increase in mean arterial pressure.

Increase in Blood Levels of Growth Factors Involved in the Neuroplasticity Process by Using an Extremely Low Frequency Electromagnetic Field in Post-stroke Patients.

Background: Neuroplasticity ensures the improvement of functional status in patients after stroke. The aim of this study was to evaluate the effect of extremely low-frequency electromagnetic field therapy (ELF-EMF) on brain plasticity in the rehabilitation of patients after stroke.Methods: Forty-eight patients were divided into two groups underwent the same rehabilitation program, but in the study group, the patients additionally were exposed to a standard series of 10 ELF-EMF treatments. To determine the level of neuroplasticity, we measured the plasma level of the brain-derived neurotrophic factor (BDNF), the vascular-endothelial growth factor, as well as BDNF mRNA expression. Additionally, we determined the molecule levels for hepatocyte growth factor, stem cell factor, stromal cell-derived factor 1α, nerve growth factor β, and leukemia inhibitory factor, using 5plex cytokine panel in plasma. After 4 weeks, during which patients had undergone neurorehabilitation and neurological examinations, we assessed functional recovery using the Barthel Index, Mini-Mental State Examination (MMSE), Geriatric Depression Scale, National Institutes of Health Stroke Scale (NIHSS), and the modified Rankin Scale (mRS).Results: We observed that ELF-EMF significantly increased growth factors and cytokine levels involved in neuroplasticity, as well as promoted an enhancement of functional recovery in post-stroke patients. Additionally, we presented evidence that these effects could be related to the increase of gene expression on the mRNA level. Moreover, a change of BDNF plasma level was positively correlated with the Barthel Index, MMSE, and negatively correlated with GDS.Conclusion: Extremely low-frequency electromagnetic field therapy improves the effectiveness of rehabilitation of post-stroke patients by improving neuroplasticity processes.

Fatty Acid Lingual Application Activates Gustatory and Reward Brain Circuits in the Mouse.

The origin of spontaneous preference for dietary lipids in humans and rodents is debated, though recent compelling evidence has shown the existence of fat taste that might be considered a sixth taste quality. We investigated the implication of gustatory and reward brain circuits, triggered by linoleic acid (LA), a long-chain fatty acid. The LA was applied onto the circumvallate papillae for 30 min in conscious C57BL/6J mice, and neuronal activation was assessed using c-Fos immunohistochemistry. By using real-time reverse transcription polymerase chain reaction (RT-qPCR), we also studied the expression of mRNA encoding brain-derived neurotrophic factor (BDNF), Zif-268, and Glut-1 in some brain areas of these animals. LA induced a significant increase in c-Fos expression in the nucleus of solitary tract (NST), parabrachial nucleus (PBN), and ventroposterior medialis parvocellularis (VPMPC) of the thalamus, which are the regions known to be activated by gustatory signals. LA also triggered c-Fos expression in the central amygdala and ventral tegmental area (VTA), involved in food reward, in conjunction with emotional traits. Interestingly, we noticed a high expression of BDNF, Zif-268, and Glut-1 mRNA in the arcuate nucleus (Arc) and hippocampus (Hipp), where neuronal activation leads to memory formation. Our study demonstrates that oral lipid taste perception might trigger the activation of canonical gustatory and reward pathways.

Abstract P205: Age-dependent Alteration in Expression of Brain-derived Neurotrophic Factor and its Receptors in Central Nervous System of Spontaneously Hypertensive Rats.

Background and Aim: Essential hypertension is a cause unknown disease leading to heart disease, stroke and renal failure. Spontaneously hypertensive rats (SHR) are animal model of human essential hypertension and develop hypertension at 7-15-week-old. Several studies reported expression pattern of brain-derived neurotrophic factor (BDNF) changes in central nervous system (CNS) in SHR, suggesting that BDNF and its receptors might be related to increased blood pressure. However, age-dependent change in BDNF and receptors (TrkB and p75NTR) remains to be elucidated. This study aimed to clarify it. Method: Isolated brain tissues from SHR and control Wistar Kyoto Rats (WKY) at 4-, 7- and 15-week-old were dissected into five regions (cerebral cortex: CC; cerebellum: CB; brainstem: BS; hypothalamus: HT; hippocampus: HC). Protein and mRNA expression of BDNF, TrkB isoforms (FL, T1 and T2) and p75NTR as well as an inflammatory marker NOX-2 was examined by Western blotting and real-time PCR. Results: The following data showed significant difference in SHR compared with WKY (n = 4): pro-BDNF protein was lower by 49.9% (4-week, p &lt; 0.05) and 38.2% (7-week, p &lt; 0.05) in HT, while mature BDNF protein was lower by 21.9% in HC (15-week, p &lt; 0.05). TrkB FL mRNA was higher by 32.5% in CB (7-week, p &lt; 0.05) and 43.1% in BS (7-week, p &lt; 0.05), while TrkB FL protein was higher by 51.4% in BS (15-week, p &lt; 0.05). TrkB T1 mRNA was higher by 22.8% in BS (7-week, p &lt; 0.05) and 17.2% in HT (15-week, p &lt; 0.05), while TrkB T1 protein was higher by 56.1% in BS (4-week, p &lt; 0.01). p75NTR protein was higher by 46.9% in CB (7-week, p &lt; 0.05). NOX-2 mRNA was higher by 29.1% (4-week, p &lt; 0.01), 104.2% (7-week, p &lt; 0.01) and 75.8% (15-week, p &lt; 0.05) in CC, 27.0% in CB (15-week, p &lt; 0.05), 34.6% in BS (4-week, p &lt; 0.05), 326.1% in HT (15-week, p &lt; 0.01) and 29.8% in HC (7-week, p &lt; 0.05). Conclusion: We for the first time revealed age-dependent changes in expression of BDNF and its receptors in CNS of SHR. Specifically, our results suggest that alteration of BDNF and TrkB expression is already occurred at juvenile before a stable blood pressure increase. The upregulation of NOX-2 was also identified. Further detailed study might identify whether and how BDNF-receptor-oxidative stress axis is related to pathogenesis of essential hypertension.

Sympathetic nervous remodeling is induced in the intermediolateral nucleus after myocardial infarction – Role of BDNF-TrkB axis-

Several studies have shown that neural remodeling in stellate ganglia (SG) is induced by myocardial infarction (MI). It remains unclear whether neural remodeling after MI is limited in SG within the sympathetic nervous system (SNS). MI was induced in a rat model by ligation of the left anterior descending artery. Neural remodeling in the intermediolateral nucleus (IML) and SG was assessed by immunohistochemistry 2 weeks after MI. The mRNA and protein expressions of brain-derived neurotrophic factor (BDNF), tropomyosin-related kinase receptor (TrkB) and extracellular signal-regulated kinase (ERK) were measured by quantitative RT-PCR, immunohistochemistry and Western blotting 1 week after MI. The neuronal size and axonal density of IML were increased after MI compared to sham. The density of growth-associated protein-43, a protein upregulated in axons undergoing nerve sprouting, was increased after MI compared to sham. The fluorescence intensity of BDNF and TrkB in IML were significantly higher in the MI group than in the sham group. In addition, mRNA expressions of BDNF and TrkB in the spinal cord at the Th2 level was increased after MI. Finally, the percentage of phospho-ERK-immunoreactive cells in IML was significantly higher in the MI group than in the sham group. In conclusion, neural remodeling after MI in IML is associated with the activation of BDNF-TrkB axis. Morphological remodeling throughout the SNS may be involved in sustained activation of sympathetic tone after MI.

Post-weaning Environmental Enrichment in Male CD-1 Mice: Impact on Social Behaviors, Corticosterone Levels and Prefrontal Cytokine Expression in Adulthood.

Environmental enrichment is typically associated with enhanced well-being, improved cognitive function and stress resilience. However, in some instances grouping adult male mice in enriched conditions promoted a stressful environment, which resulted in elevated endocrine, monoamine and inflammatory outcomes in response to subsequent stressor exposure. The current investigation examined whether raising male mice in an enriched environment (EE) would modulate social and anxiety-like behaviors in early adulthood and influence brain expression of pro-inflammatory cytokines and brain-derived neurotrophic factor (BDNF). Immediately after weaning (postnatal day [PD] 21), CD-1 male mice were housed with their siblings (3/cage) for 6 weeks in an EE or a standard (SE) environment. Body weights and aggressive interactions were monitored weekly. Social avoidance behaviors in the social interaction test and anxiety-like behaviors in the elevated-plus maze were examined in early adulthood. Ninety minutes following the behavioral tests, mice were sacrificed and a blood sample and the prefrontal cortex (PFC) were collected for the determination of plasma corticosterone levels as well as cytokine and BDNF mRNA expression. Mice raised in an EE exhibited more wounds and gained less weight than mice housed in a SE. Enriched mice also spent a greater amount of time in proximity of a social target in the social interaction test and made fewer transitions into the closed arms of the elevated-plus maze. Interestingly, the elevated plasma corticosterone and upregulated prefrontal interleukin (IL)-1β expression observed after the social interaction test among the SE mice were not apparent among those housed in an EE. Enrichment also increased prefrontal BDNF expression, especially among mice that experienced the social interaction test. These results suggest that although raising male mice in an EE may elicit aggressive interactions between sibling cage-mates (as indicated by a high number of wounds), this environment also enhances social behaviors and limits the corticosterone and cytokine impacts of mild social stressors encountered in early adulthood.

Exercise and low-level GABAA receptor inhibition modulate locomotor activity and the expression of BDNF accompanied by changes in epigenetic regulation in the hippocampus

Aerobic exercise is known to increase expression of brain-derived neurotrophic factor (BDNF) in the hippocampus and to improve cognitive function. The inhibition of GABAergic synapses enhances hippocampal plasticity as well as learning and memory. The objective of the present study was to examine the interactive effect of low-level GABAA receptor inhibition and exercise on behavior tests (cognitive function and locomotor activity), expression of BDNF and epigenetic regulations including the activity levels of histone acetyltransferases (HATs) and histone deacetylases (HDACs) in the hippocampus.ICR mice were divided into two groups: those who did not participate in exercise and those who participated in exercise. Each group was subdivided into two other groups: the one who received vehicle and the one who received GABAA receptor antagonist, bicucullin. We administered saline or bicuculline intraperitoneally to the mice at a non-epileptic dose of 0.25 mg/kg, whereas the mice were exercised on a treadmill for approximately 1 h a day, 5 days a week for 4 weeks. Novel-object recognition test and locomotor activity were assessed at a rest day approximately 4 days before the euthanasia. The mice were euthanized 4 h after the last exercise session.Aerobic exercise for 4 weeks increased mRNA and protein expression of BDNF in the hippocampus, accompanied by enhanced HAT activity. Alternatively, bicuculline administration increased HDAC activity in the hippocampus. Furthermore, exercise in the presence of bicuculline administration increased locomotor activity, indicating that exercise combined with low-level GABAA receptor inhibition potentiated the activity of the mice. Altogether, the present study suggested that exercise beneficially contributes to neuroprotection in the hippocampus accompanied by the up-regulation of BDNF expression and epigenetic regulation, whereas the chronic inhibition of GABAA receptor potentiates exercise-induced behavioral activity.

Role of Brain-Derived Neurotrophic Factor in Endometriosis Pain.

Brain-derived neurotrophic factor (BDNF) is a regulator for the formation and maintenance of chronic pain in various chronic disorders and has been shown to increase in the serum of women with endometriosis. However, BDNF expression in the peritoneal fluid (PF) and ectopic lesions and its role in endometriosis pain remain unclear. Thus, this study aims to determine the BDNF concentrations in serum and PFs and BDNF expression levels in ectopic lesions and endometriotic stromal cells (ESCs) of women with endometriosis (n = 60). The obtained results were then compared with those of women without endometriosis (n = 38). Brain-derived neurotrophic factor concentrations in serum and PF, as well as the BDNF expression levels in ectopic lesions and endometriotic cells, were evaluated through enzyme-linked immunosorbent assay, immunohistochemical staining, quantitative real-time polymerase chain reaction, and Western blot analysis. As a result, BDNF concentrations in serum and PF were significantly higher in women with endometriosis with pain (2284.3 ± 51.5 pg/mL, n = 23; 58.8 ± 6.4 pg/mL, n = 16) than in women with endometriosis without pain (1999.8 ± 61.1 pg/mL, n = 37; 31.7 ± 2.9 pg/mL, n = 25; P < .01). Moreover, BDNF messenger RNA (mRNA) expression levels in ectopic lesions (8.97 ± 1.44, n = 29) were significantly higher than eutopic (0.97 ± 0.14, n = 16; P < .01) and control endometrium (1.23 ± 0.19, n = 18; P < .01) and were correlated with endometriosis pain ( P < .05). Furthermore, increased BDNF mRNA and protein expression levels in ESCs induced by estradiol or interleukin 1β were removed using a phosphorylated extracellular-regulated protein kinase 1/2 inhibitor. These results suggest that BDNF may play an important role in the pathogenesis of endometriosis pain.

Honokiol Exerts Antidepressant Effects in Rats Exposed to Chronic Unpredictable Mild Stress by Regulating Brain Derived Neurotrophic Factor Level and Hypothalamus-Pituitary-Adrenal Axis Activity.

Honokiol (HNK), the main active component of Magnolia officinalis, has shown a variety of pharmacological activities. In the present study, we measured the antidepressant-like effects of HNK in a rat model of chronic unpredictable mild stress (CUMS) and explored its possible mechanisms. The antidepressant-like effects of HNK were assessed in rats by an open field test (OFT), sucrose preference test (SPT) and forced swimming test (FST). Then, serum levels of corticotrophin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and corticosterone (CORT) and hippocampal brain-derived neurotrophic factor (BDNF) and glucocorticoid receptor α (GRα) levels were assessed to explore the possible mechanisms. We identified that HNK treatment (2, 4, and 8mg/kg) alleviated the CUMS-induced behavioural deficits. Treatment with HNK also normalized the CUMS-induced hyperactivity of the limbic hypothalamic-pituitary-adrenal (HPA) axis, as indicated by reduced CRH, ACTH and CORT serum levels. In addition, HNK increased the expression of GRα (mRNA and protein) and BDNF (mRNA and protein) in the hippocampus. These data confirmed the antidepressant-like effects of HNK, which may be related to its normalizing the function of the HPA axis and increasing the BDNF level in the hippocampus.

BDNF contributes to the neonatal incision-induced facilitation of spinal long-term potentiation and the exacerbation of incisional pain in adult rats

Neonatal surgical injury exacerbates spinal microglial reactivity, modifies spinal synaptic function, leading to exaggerated pain hypersensitivity after adult repeated incision. Whether and how the alteration in microglial reactivity and synaptic plasticity are functionally related remain unclear. Previously, we and others have documented that spinal brain-derived neurotrophic factor (BDNF), secreted from microglia, contributes to long-term potentiation (LTP) in adult rodents with neuropathic pain. Here, we demonstrated that the mRNA and protein expression of spinal BDNF are significantly upregulated in adult rats subjected to neonatal incision and adult repeated incision (nIN-IN). Neonatal incision facilitates spinal LTP induced by BDNF or high frequency electrical stimulation after adult incision, including a decreased induction threshold and an increased magnitude of LTP. Coincidently, inhibition of spinal BDNF abrogates the LTP facilitation, alleviates the mechanical allodynia and thermal hyperalgesia in nIN-IN rats. By contrast, spinal application of exogenous BDNF in the adult rats with a single neonatal incision mimics the LTP facilitation and pain hypersensitivity, which have been found in nIN-IN rats. Exogenous BDNF-induced exacerbation of pain hypersensitivity could be blocked by BDNF inhibitor. In addition, blockade of microglial reactivity by intrathecal application of minocycline attenuates the elevation of BDNF and the LTP facilitation, and also, alleviates pain hypersensitivity in nIN-IN rats. In conclusion, spinal BDNF, at least partly derived from microglia, contributes to the neonatal incision-induced facilitation of spinal LTP and to the exacerbation of incisional pain in adult rats. Thus, spinal BDNF may combine the changes of microglial reactivity and synaptic plasticity in nIN-IN rats.

The Role of Apolipoprotein E and Ethanol Exposure in Age-Related Changes in Choline Acetyltransferase and Brain-Derived Neurotrophic Factor Expression in the Mouse Hippocampus.

Disruption of apolipoprotein E (APOE) is responsible for age-dependent neurodegeneration and cognitive impairment. Elderly individuals are more sensitive than young individuals to the effects of ethanol (EtOH), particularly those affecting cognition. We investigated the role of APOE deficiency and EtOH exposure on age-dependent alterations in choline acetyltransferase (ChAT) and brain-derived neurotrophic factor (BDNF) mRNA and protein expression in the mouse hippocampus. Three-month-old (young) and 12-month-old (aged) ApoE-knockout (ApoE-KO) and wild-type (WT) mice were treated with saline or 2g/kg EtOH, and the bilateral hippocampus was collected after 60min for real-time PCR and western blotting analyses. ChAT (P < 0.01) and BDNF (P < 0.01) expression were significantly decreased in both young and aged saline- and EtOH-treated ApoE-KO mice versus young and aged saline- and EtOH-treated WT mice. Aged saline- and EtOH-treated ApoE-KO mice exhibited greater differences in ChAT and BDNF expression (P < 0.01) than young saline- and EtOH-treated ApoE-KO mice. Aged EtOH-treated WT mice also exhibited larger decreases in BDNF expression (P < 0.01)-but not in ChAT expression-than young EtOH-treated WT mice. EtOH decreased ChAT and BDNF expression in both young (P < 0.01) and aged (P < 0.01) ApoE-KO mice versus EtOH-free ApoE-KO mice of the same age. EtOH also decreased BDNF expression in aged (P < 0.01) WT mice versus EtOH-free aged WT mice. In summary, these results suggest that APOE deficiency and EtOH exposure cause age-dependent decreases in ChAT and BDNF in the hippocampus. Importantly, the decreases in ChAT and BDNF were greater in aged EtOH-treated mice, particularly those lacking APOE, raising the possibility that APOE-deficient individuals who consume alcohol may be at greater risk of memory deficit.

Effects of postnatal handling on adult behavior and brain mRNA expression of serotonin receptor, brain-derived neurotrophic factor and GABA-A receptor subunit

Development of brain and behavior is influenced by the interaction of genetic and environmental factors. Postnatal handling, a manipulation that briefly separates mouse offspring from their mother during the postnatal period, has been reported to yield beneficial effects on the behavior of adult offspring. However, brain mechanisms underlying the effects on the behavior have not been well understood. Here we first examined effects of postnatal handling on the behavior of adult male BALB/c mice. Offspring were separated for 15 min every day between postnatal day 1 (P1) and P14 and then various behaviors were tested in the adulthood. Postnatal handling reduced anxiety-like behavior in elevated plus maze and improved spatial learning and memory in Morris water maze without effects on depression-like behavior in forced swim test. Next, to elucidate mechanisms underlying the behavioral effects, we evaluated mRNA expression of the serotonin 1A (5-HT1A) receptor, brain-derived neurotrophic factor (BDNF), and GABA-A receptor subunits in the medial prefrontal cortex, amygdala, dorsal and ventral hippocampi, and dorsal raphe nucleus by quantitative RT-PCR, since these genes and brain regions have been shown to be involved in cognition and emotion. Postnatal handling up-regulated mRNA expression of the 5-HT1A receptor in the dorsal raphe nucleus and down-regulated 5-HT1A receptor mRNA expression in the amygdala on P15 and P71. In adulthood, mRNA expression of BDNF was up-regulated in the amygdala and dorsal hippocampus and down-regulated in the dorsal raphe nucleus, whereas that of GABA-A receptor α2 subunit was down-regulated in the amygdala. Taken together, the present study suggests that postnatal handling reduced anxiety-like behavior and improved learning and memory, which were accompanied by changes in mRNA expression of 5-HT1A receptor, BDNF and GABA-A receptor α2 subunit in the amygdala, 5-HT1A receptor in the dorsal raphe nucleus and BDNF in the dorsal hippocampus.

Protective effect of astaxanthin against cognitive impairment in offspring prenatally exposed to maternal epilepsy

Objective To investigate the protective effect of prenatal astaxanthin treatment against cognitive impairment in adult offspring induced by exposure to maternal seizures in utero. Methods Female adult Sprague-Dawley rats were randomly divided into four groups: control group, astaxanthin group, kindling group and kindling+astaxanthin group. Each rat was implanted with electrodes. Those in the kindling and kindling+astaxanthin groups were kindled once a day by electrical stimulation of the amygdala. All rats were allowed to mate after one week's amygdala kindling. Rats in the kindling and kindling+astaxanthin groups continued to be treated with electrical stimulation every 48 hours from gestational day 1 to 20, and those in the astaxanthin and kindling+astaxanthin groups were injected intraperitoneally with 30 mg/(kg·d) of astaxanthin simultaneously. Naturally delivered offspring were raised till 12 weeks of age. Morris water maze test was performed to assess the cognitive function of adult offspring. Changes in the morphology of hippocampus were observed with Nissal's staining and transmission electron microscope. Expression of cyclic adenosine monophosphate response element binding protein (CREB) and brain-derived neurotrophic factor (BDNF) in adult offsprings' hippocampus tissues at protein and mRNA levels were determined using Western-blotting and reverse transcription-polymerase chain reaction. Analysis of variance and LSD test were used as statistical methods. Results Morris water maze test showed that from the 3rd day to the 5th day, the kindling group had significantly longer escape latency [(36.33±7.85), (28.80±8.41), (29.50±11.72) s] than the control [(28.90±7.46), (17.59±9.12), (10.40±3.69) s] and kindling+astaxanthin groups [(28.30±5.75), (18.37±3.39), (15.23±6.63) s] (F=3.601, 9.811 and 14.226, all P<0.05). In probe trials, the kindling group had significantly fewer platform crossings as compared with the control and kindling+astaxanthin groups [(4.40±1.71) vs (7.20±1.62) and (6.50±1.84) times, F=6.586, P=0.001]. The kindling group spent dramatically less time in the target quadrant than the control and kindling+astaxanthin groups [(27.35±7.63) vs (58.29±10.48) and (40.41±7.06) s, F=25.825, P<0.001]. Nissl staining showed that hippocampal neurons of offspring in the control group were normal, but there was hippocampal damage in the kindling group and the damage was more severe than that in the kindling+astaxanthin group. Electron microscope observation showed that neurons and synapses in the hippocampal CA1 area of offspring in the control group were normal. However, obvious damage to neurons and synapses was induced in the kindling group and that was worse than the damage induced in the kindling+astaxanthin group. Expression of CREB and BDNF protein in the kindling group (0.19±0.06 and 0.32±0.04, respectively) were significantly lower than those in the control (0.81±0.11 and 0.93±0.04, respectively) and kindling+astaxanthin groups (0.60±0.07 and 0.80±0.06, respectively) (F were 34.015 and 71.074, both P<0.001). Moreover, the kindling group showed decreased expression of CREB and BDNF mRNA (0.48±0.11 and 0.43±0.08, respectively) as compared with the control (1.02±0.65 and 0.99±0.09, respectively) and kindling+astaxanthin groups (0.89±0.15 and 0.96±0.13, respectively) (F were 13.447 and 21.912, both P<0.01). Conclusion Treatment with astaxanthin could ameliorate the cognitive impairment and pathological damage in hippocampus of adult offspring induced by exposure to maternal seizures in utero through regulating the CREB-BDNF signal pathway. Key words: Pregnancy complications; Epilepsy; Xanthophylls; Oxidative stress; Rats

Effect of electro-acupuncture on the BDNF-TrkB pathway in the spinal cord of CCI rats

Microglia, which comprise a sensor for pathological events in the central nervous system, may be triggered by nerve injury and transformed from a quiescent state into an activated state; ionised calcium binding adaptor molecule 1 (Iba1) is a sensitive marker associated with activated microglia. Accumulated evidence suggests that spinal activated microglia and the brain-derived neurotrophic factor (BDNF)-tyrosine kinase receptor B (TrkB) signalling pathway play major roles in the production and development of neuropathic pain. Electro-acupuncture (EA) has a positive effect on relieving chronic neuropathic pain; however, the underlying mechanisms remain unclear. To determine the significance of EA in the treatment of neuropathic pain mediated by activated microglia and the BDNF-TrkB signalling pathway in the spinal cord, the mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) values were recorded to assess hyperalgesia and allodynia. In addition, the amount of activated microglia and BDNF were assessed via immunofluorescence. Iba1, BDNF and TrkB mRNA expression levels were examined using qPCR; the protein levels of BDNF, p-TrkB and TrkB in the spinal cord were analysed via western blotting. The present study demonstrated that EA treatment increased the MWT and TWL values. EA significantly inhibited the proportion of activated microglia and BDNF expression in the spinal cord after chronic constrictive injury (CCI). Furthermore, EA decreased the expression of BDNF and TrkB at both the mRNA and protein levels in the spinal cord of CCI rats. These findings suggest that the analgesic effect of EA may be achieved by inhibiting the activation of spinal microglia and subsequently blocking the BDNF-TrkB signalling pathway.