Schisandrin C Ameliorates Learning and Memory Deficits by Aβ1–42‐induced Oxidative Stress and Neurotoxicity in Mice

Schisandrin C (SCH‐C) is a main and typical antioxidative lignan isolated from the fruits of Schisandra chinensis (Trucz.) Baill (a widely used traditional Chinese medicine). The present study aimed to characterize the effect of SCH‐C on memory impairment and further research on pathological changes in Aβ_1–42‐induced Alzheimer's disease mice. Mice were administration with SCH‐C daily for 5 days in the lateral cerebral ventricles using sterotaxically implanted cannula. Cognitive functions were assessed by Y‐maze test, active avoidance test and Morris water maze test in all groups, and the level of Aβ_1–42 and neuronal injury induced by Aβ_1–42 were reversed remarkably following SCH‐C treatment compared with sham group; meanwhile the impairment of short‐term or working memory was dramatically improved. In addition, SCH‐C significantly inhibited total cholinesterase (ChEtotal), and increased superoxide dismutase (SOD) and glutathione peroxidase (GSH‐px) activity glutathione (GSH) levels in the hippocampus and cerebral cortex. It can be speculated that SCH‐C offers protection against Aβ_1–42‐induced dysfunction in learning and memory by inhibiting ChEtotal and its antioxidant action. Copyright © 2015 John Wiley & Sons, Ltd.     

Brain‐derived Neurotrophic Factor Signaling Mediates the Antidepressant‐like Effect of the Total Flavonoids of Alpiniae Oxyphyllae Fructus in Chronic Unpredictable Mild Stress Mice

The present study verified the antidepressant‐like effects of the total flavonoids of Alpinia oxyphylla Miq. (AOF) using the chronic unpredictable mild stresses paradigm and explored the mechanism that underlies antidepressant‐like effects of AOF in mice. Previous research has shown that tropomyosin‐related kinase B (TrkB) receptor‐mediated extracellular regulated protein kinases (ERK) signaling pathways participate in depression pathophysiology. Therefore, we aimed to explore whether AOF improved depression‐like behaviors by increasing activity of ERK pathways mediated by TrkB. Results showed that AOF significantly reduced the immobility time in the forced swimming test and increased the sucrose preference in sucrose preference test. In addition, decreased phosphorylated cyclic adenosine monophosphate response element‐binding protein (pCREB)/CREB, pERK/ERK, and pTrkB/TrkB levels in the hippocampus induced by chronic unpredictable mild stresses were reversed by intragastric administration of AOF. Results suggested that AOF increased pCREB/CREB, pERK/ERK, and pTrkB/TrkB levels by acting on the TrkB receptor. To verify this hypothesis, mice were pretreated with the TrkB inhibitor K252a (or 0.1% dimethyl sulfoxide, intraperitoneally, 2 weeks), before the intragastric administration of AOF. This resulted in an absence of antidepressant‐like effects, as well as no activation of pERK/pCREB/BDNF signaling pathways. Results demonstrated that AOF might exert antidepressant‐like effects by targeting TrkB receptor‐mediated pERK/pCREB/BDNF signal systems, which could help to identify the AOF receptor. Copyright © 2016 John Wiley & Sons, Ltd.     

Schisandrae Chinensis Fructus inhibits behavioral deficits induced by sleep deprivation and chronic unpredictable mild stress via increased signaling of brain‐derived neurotrophic factor

The present study was undertaken to explore the interactions between sleep deprivation (SD) and Schisandrae Chinensis Fructus (SCF) treatment in the antidepressant‐like effects. We observed that SD aggravated the anxiety‐like behavior induced by chronic unpredictable mild stress (CUMS) in the elevated plus maze test. However, the forced swimming test and sucrose preference test showed that SD (12 hr) alleviated the depressive symptoms and SD (72 hr) has the opposite effects. Administration of SCF showed a promising therapeutic effect on depression and anxiety induced by CUMS and SD. Moreover, SCF could potential strengthen the antidepressant‐like effects of SD (12 hr) according to the behavioral tests. In addition, the BDNF level in hippocampus was elevated by SD (12 hr) and SCF treatment and together with the upregulation of TrkB/CREB/ERK and PI3K/AKT/GSK3β/mTOR signaling pathways. Besides, the protein levels of p70S6K and PSD95, which are downstream targets of mTOR, also increased by the treatment. These results indicated that the antidepressant‐like effect of SCF in the CUMS depends on the activation of BDNF and the modulation of TrkB/CREB/ERK and PI3K/AKT/GSK3β/mTOR signaling cascades, and SD (12 hr) shared a common etiology consisting of complex bidirectional interactions with SCF.     

Imperatorin ameliorates learning and memory deficits through BDNF/TrkB and ERK/CaMKIIα/CREB signaling in prenatally‐stressed female offspring

Prenatal stress (PS) can lead to impaired spatial learning and memory in offspring. Imperatorin (IMP) is a naturally occurring furanocoumarin with many pharmacological properties. However, the effects of IMP on cognitive impairment induced by PS and the underlying molecular mechanisms remain unclear. We investigated the protective effect of IMP treatment after PS on learning and memory deficits in female offspring at postnatal 60 days. After treating prenatally‐stressed offspring with IMP (15 and 30 mg/kg) for 28 days, we found that IMP increased body weight and ameliorated spatial learning and memory and working memory deficits in female offspring rats. Meanwhile, hippocampal Glu and serum corticosterone levels in prenatally‐stressed offspring were significantly decreased after IMP administration. Additionally, IMP treatment significantly increased BDNF, TrkB, CaMKII, and CREB mRNA expression in the hippocampus of offspring rats. Furthermore, PS‐mediated induction of RKIP protein and mRNA expression and glucocorticoid receptor protein expression in the hippocampus of offspring rats were significantly decreased by IMP treatment, and the protein expression of BDNF and TrkB and relative levels of p‐EKR/ERK, p‐CaMKIIα/CaMKIIα, and p‐CREB/CREB were remarkably increased after IMP treatment. Taken together, IMP can ameliorate PS‐induced learning and memory deficits through BDNF/TrkB and ERK/CaMKIIα/CREB signaling pathway and hypothalamic–pituitary–adrenal axis.     

Antidepressant‐like effects of 20(S)‐protopanaxadiol in a mouse model of chronic social defeat stress and the related mechanisms

20(S)‐Protopanaxadiol (PPD) is a basic aglycone of the dammarane triterpenoid saponins and exerts antidepressant‐like effects on behaviour in the forced swimming test (FST) and tail suspension test (TST) and in rat olfactory bulbectomy depression models. However, the antidepressant effects of PPD have not been studied thoroughly. The objective of the present study was first to investigate the effect of PPD on depression behaviours induced by chronic social defeat stress (CSDS) in mice. The results showed that CSDS was effective in producing depression‐like behaviours in mice, as indicated by decreased responses in the social interaction test, sucrose preference test, TST, and FST, and that this effect was accompanied by noticeable alterations in the levels of oxidative markers (superoxide dismutase, catalase, and lipid peroxidation) and monoamines (5‐HT and NE) in the hippocampus and serum corticosterone levels. Additionally, western blot analysis revealed that CSDS exposure significantly downregulated BDNF, p‐TrkB/TrkB, p‐Akt/Akt, and p‐mTOR/mTOR protein expression in the hippocampus. Remarkably, chronic PPD treatment significantly ameliorated these behavioral and biochemical alterations associated withCSDS‐induced depression. Our results suggest that PPD exerts antidepressant‐like effects in mice with CSDS‐induced depression and that this effect may be mediated by the normalization of neurotransmitter and corticosterone levels and the alleviation of oxidative stress, as well as the enhancement of the PI3K/Akt/mTOR‐mediated BDNF/TrkB pathway.     

Protective effect of ginsenoside Rh2 on scopolamine‐induced memory deficits through regulation of cholinergic transmission,oxidative stress and the ERK‐CREB‐BDNF signaling pathway

Rh2 is a rare ginsenoside and there are few reports of its effect on cognition compared with other similar molecules. This study aimed to establish the impact of Rh2 treatment on improving scopolamine (Scop)‐induced memory deficits in mice and illuminate the underlying mechanisms. First, memory‐related behavior was evaluated using two approaches: object location recognition (OLR), based on spontaneous activity, and a Morris water maze (MWM) task, based on an aversive stimulus. Our results suggested that Rh2 treatment effectively increased the discrimination index of the mice in the OLR test. In addition, Rh2 elevated the crossing numbers and decreased the escape latency during the MWM task. Moreover, Rh2 markedly upregulated the phosphorylation of the extracellular signal‐regulated kinase (ERK)‐cAMP response element binding (CREB)‐brain derived neurotrophic factor (BDNF) pathway in the hippocampus. Meanwhile, the administration of Rh2 significantly promoted the cholinergic system and dramatically suppressed oxidative stress in the hippocampus. Taken together, Rh2 exhibited neuroprotective effects against Scop‐induced memory dysfunction in mice. Rh2 activity might be ascribed to several underlying mechanisms, including its effects on modulating the cholinergic transmission, inhibiting oxidative stress and activating the ERK‐CREB‐BDNF signaling pathway. Consequently, the ginsenoside Rh2 might serve as a promising candidate compound for Alzheimer's disease.     

Rapid antidepressant‐like effect of Fructus Aurantii depends on cAMP‐response element binding protein/Brain‐derived neurotrophic facto by mediating synaptic transmission

Several studies reported the relative antidepressant effects of Fructus Aurantii (FRA) with repeated treatment, the rapid antidepressant effects of FRA and the underlying mechanisms remained unclear. We, therefore, examined the rapid antidepressant actions of FRA in behavioral tests in mice and tested the underlying molecular mechanisms. We found FRA, like ketamine, reversed the behavioral deficits both in lipopolysaccharide(LPS)‐induced and learned helplessness (LH) models at 1 day after a single administration. FRA was also capable of increasing the expressions of protein kinase A/cAMP‐response element‐binding protein/brain‐derived neurotrophic factor (PKA/CREB/BDNF) signaling in hippocampus. Consistent with ketamine, FRA up‐regulated the expressions of GABAergic receptor (GAD67) and glutamatergic receptor 1 (GluR1) in mouse hippocampus both exposed to LPS and LH. Moreover, synaptic proteins such as postsynaptic density‐95 (PSD95) and synapsin1 were also up‐regulated by a single dose of FRA both in LH and LPS models, like ketamine. Finally, metadoxine (an antagonist of CREB) inhibited the antidepressant effects of FRA in tail suspension test (TST) and forced swimming test (FST) in LPS‐induced mice, which also blocked the phosphorylation of CREB and the expressions of neurotransmitters and synaptic molecules. Therefore, FRA had rapid antidepressant effects, which depended on PKA/CREB/BDNF pathway, subsequently regulated the downstream synaptic transmission.     

Silibinin protects rat pancreatic β‐cell through up‐regulation of estrogen receptors' signaling against amylin‐ or Aβ1–42‐induced reactive oxygen species/reactive nitrogen species generation

Amylin and amyloid‐β (Aβ) were found to induce reactive oxygen species (ROS) and reactive nitrogen species (RNS) in rat pancreatic β‐cell line, INS‐1 cells, leading to cell death. In this study, we report on reciprocal relationship between the expression of estrogen receptors (ERs) α and β (ERα and ERβ) and generation of ROS/RNS in amylin/Aβ_1–42‐treated INS‐1 cells. That is, pharmacological activation of ERs in INS‐1 cells significantly decreases ROS/RNS generation, but blockage of ERs increases ROS/RNS generation. Silibinin is a natural polyphenolic flavonoid isolated from milk thistle with phytoestrogen activities, also known as silybin. Treatment with silibinin down‐regulated ROS/RNS production induced by treatment with amylin/Aβ_1–42 in the cells. Silencing ERs expression with siRNAs targeting ERs showed that the protective effect of silibinin was markedly weakened, indicating that silibinin protection is largely attributed to activation of ERs' signaling. The binding of silibinin to ERs implies that the protective effect of silibinin on amylin/Aβ_1–42‐treated INS‐1 cells owes to down‐regulation of ROS/RNS through the activation of ERs phosphorylation. Amylin and Aβ_1–42 cotreatment enhanced furthermore ROS/RNS generation and cytotoxicity through further down‐regulation of ERs phosphorylation, and this was reversed by silibinin. Silibinin also protects INS‐1 cells from amylin and Aβ_1–42 cotreatment. These results indicate that protective effect of silibinin is mediated by enhancement of ERs phosphorylation that depresses ROS/RNS generation in amylin/Aβ_1–42‐treated INS‐1 cells.     

Alantolactone and Isoalantolactone Prevent Amyloid β25–35‐induced Toxicity in Mouse Cortical Neurons and Scopolamine‐induced Cognitive Impairment in Mice

Given the evidence for detoxifying/antioxidant enzyme‐inducing activities by alantolactone (AL) and isoalantolactone (IAL), the purpose of this study was to investigate the effects of AL and IAL on Aβ_25–35‐induced cell death in mouse cortical neuron cells and to determine their effects on scopolamine‐induced amnesia in mice. Our data demonstrated that both compounds effectively attenuated the cytotoxicity of Aβ_25–35 (10 μM) in neuronal cells derived from the mouse cerebral cortex. It was also found that the production of intracellular reactive oxygen species, including superoxide anion induced by Aβ_25–35, was inhibited. Moreover, the administration of the sesquiterpenes reversed scopolamine‐induced cognitive impairments as assessed by Morris water, Y‐maze, and the passive avoidance tests, and the compounds decreased acetylcholinesterase (AChE) activities in a dose‐dependent manner. Interestingly, AL and IAL did not improve scopolamine‐induced cognitive deficit in Nrf2 ^?/? mice, suggesting that memory improvement by sesquiterpenes was mediated not only by the activation of the Nrf2 signaling pathway but also by their inhibitory activity against AChE. In conclusion, our results showed that AL and IAL had neuroprotective effects and reversed cognitive impairments induced by scopolamine in a mouse model. Therefore, AL and IAL deserve further study as potential therapeutic agents for reactive oxygen species‐related neurodegenerative diseases. Copyright © 2017 John Wiley & Sons, Ltd.     

Catalpol provides a protective effect on fibrillary Aβ1–42‐induced barrier disruption in an in vitro model of the blood–brain barrier

Excessive amyloid beta (Aβ) deposition in brain is mainly responsible for cell damage and blood–brain barrier (BBB) disruption in Alzheimer's disease (AD). Catalpol, an iridoid glucoside extracted from the root of Rehmannia glutinosa Libosch, has neuroprotective effect against AD. It is unclear whether catalpol has a protective effect on Aβ‐induced BBB leakage. We employed an immortalized endothelial cell line (bEnd.3) and astrocytes co‐culture to mimic a BBB model in vitro and investigated the effect of catalpol on BBB. We found that treatment with catalpol decreased BBB hyperpermeability induced by fibrillar Aβ_1–42. Data from western blotting showed that catalpol prevented fibrillar Aβ_1–42‐induced bEnd.3 cell apoptosis through mitochondria‐dependent and death receptor pathways; decreased the levels of matrix metalloproteinases (MMPs), MMP‐2, MMP‐9, and the receptor for advanced glycation end products; and increased the levels of tight junction proteins (ZO‐1, occludin, and claudin‐5), low‐density lipoprotein receptor‐related protein 1, and P‐glycoprotein in fibrillar Aβ_1–42‐treated bEnd.3 cells. Moreover, catalpol also enhanced soluble Aβ efflux across the fibrillar Aβ_1–42‐treated bEnd.3 cells BBB monolayer model. Altogether, our results suggest that catalpol alleviate fibrillar Aβ_1–42‐induced BBB disruption, enhance soluble Aβ clearance, and offer a feasible therapeutic application in AD treatment.     

Ginseng Protein Reverses Amyloid Beta Peptide and H2O2 Cytotoxicity in Neurons,and Ameliorates Cognitive Impairment in AD Rats Induced by a Combination of D‐Galactose and AlCl3

Ginseng (Panax ginseng C.A. Meyer) is one of the most widely used herbal medicines worldwide. The present study evaluated the neuroprotective effects of ginseng protein (GP) and its possible mechanisms in a cellular and animal model of AD. The results demonstrated that GP (10–100 µg/mL) significantly improved the survival rate of neurons and reduced the cells' apoptosis and the mRNA expression of caspase‐3 and Bax/Bcl‐2. In addition, GP (0.1 g/kg) significantly shortened the escape latency, prolonged the crossing times and the percentage of residence time; reduced the level of Aβ_1–42 and p‐tau, the activity of T‐NOS and iNOS, and the content of MDA and NO, improved the activity of SOD, the concentration of cAMP and the protein expression of p‐PKA/PKA and ‐CREB/CREB. The results demonstrated that GP significantly inhibited Alzheimer‐like pathophysiological changes induced by Aβ_25–35 or H₂O₂ in cells or those induced by D‐gal/ Al in animals. These neuroprotective effects of GP may be associated with the cAMP/PKA/CREB pathway. Also, in combination with our previous studies, these results indicate that the anti‐AD mechanism of GP was likely to activate the CREB pathway through multiple channels. Copyright © 2016 John Wiley & Sons, Ltd.     

基于BDNF/TrkB/PI3K/Akt信号通路的滋肾醒脑汤对阿尔茨海默病大鼠学习记忆能力的影响

目的基于BDNF/TrkB/PI3K/Akt信号通路观察滋肾醒脑汤对阿尔茨海默病(AD)大鼠学习记忆能力的影响,探讨其可能的作用机制。方法采用侧脑室注射β-淀粉样蛋白制备AD大鼠模型,假手术组注射等体积生理盐水,将成模大鼠随机分为模型组、中药组及阳性对照组,每组6只,中药组及阳性对照组分别予滋肾醒脑汤(16.74 g/kg)和盐酸多奈哌齐混悬液(0.45 mg/kg)灌胃,假手术组和模型组灌胃等体积蒸馏水,每日1次,连续4周。采用Morris水迷宫实验进行大鼠行为学检测,TUNEL染色检测海马组织神经细胞凋亡情况,Western blot检测海马组织脑源性神经营养因子(BDNF)、酪氨酸激酶受体B(TrkB)蛋白表达,免疫组化检测海马组织PI3K、Akt蛋白表达。结果与假手术组比较,模型组大鼠逃避潜伏期明显延长,跨越平台次数减少,目标象限停留时间缩短(P<0.05,P<0.01),海马组织神经细胞凋亡率明显升高,BDNF、TrkB、PI3K、Akt蛋白表达明显降低(P<0.05);与模型组比较,中药组及阳性对照组大鼠逃避潜伏期明显缩短,跨越平台次数增加,目标象限停留时间延长(P<0.01,P<0.05),海马组织神经细胞凋亡率明显降低,BDNF、TrkB、PI3K、Akt蛋白表达明显升高(P<0.05,P<0.01),中药组与阳性对照组差异无统计学意义(P>0.05)。结论滋肾醒脑汤可改善AD大鼠学习记忆能力,其机制可能与上调BDNF/TrkB/PI3K/Akt信号通路蛋白表达,减少神经细胞凋亡有关。     

铁筷子挥发油对慢性脑缺血致血管性认知功能障碍大鼠的作用及机制研究

目的 探究苗药铁筷子[腊梅Chimonanthus praecox及山腊梅C. nitens的干燥根]挥发油对慢性脑缺血（chronic cerebral hypoperfusion,CCH）致血管性认知功能障碍（vascular cognitive impairment,VCI）大鼠的作用及机制。方法 采用改良的双侧颈总动脉结扎（bilateral common carotid artery occlusion,BCCAO）法建立CCH模型,将造模成功大鼠随机分为模型组及铁筷子挥发油高、中、低剂量（80、40、20 mg/kg）组和丁苯酞（63 mg/kg）组,另设假手术组,给予相应药物干预28 d,采用水迷宫实验检测各组大鼠学习记忆能力;采用旷场实验、Y迷宫实验检测各组大鼠自主活动性和新奇事物探索能力;采用苏木素-伊红（HE）染色、Nissl染色、TUNEL染色观察各组大鼠大脑皮层及海马CA1区神经细胞结构变化、尼氏小体以及凋亡细胞数量变化;采用ELISA法检测各组大鼠血清中脑源性神经营养因子（brain-derived neurotrophic factor,BDNF）水平;采用比色法检测各组大鼠海马组织中乙酰胆碱酯酶（acetylcholinesterase,AChE）和乙酰胆碱转移酶（cholineacetyltransferase,ChAT）的活性;采用Western blotting法检测各组大鼠海马组织中BDNF、酪氨酸激酶受体B（tyrosine kinase receptor B,TrkB）、磷酸化TrkB（phosphorylated TrkB,p-TrkB）、磷脂酰肌醇-3-激酶（phosphatidylin-ositol-3-kinase,PI3K）、蛋白激酶B（Akt）、p-Akt和半胱氨酸天冬氨酸蛋白酶-3（cystein-asparate protease-3,Caspase-3）蛋白表达。结果 与模型组比较,铁筷子挥发油组大鼠逃避潜伏期缩短（P＜0.05、0.01）,穿越平台次数和跨格次数提高（P＜0.05、0.01）,在新异臂所待时间延长（P＜0.05）;神经细胞结构的变性得到改善,脑组织中尼氏小体的数量提高（P＜0.05）,细胞凋亡减少（P＜0.05）;血清中BDNF水平及海马组织中ChAT活性升高（P＜0.05、0.01）,海马组织中AChE活性降低（P＜0.05）;海马组织中BDNF、TrkB、p-TrkB、PI3K和p-Akt蛋白表达水平均显著升高（P＜0.05、0.01）,Caspase-3蛋白表达水平降低（P＜0.05）。结论 苗药铁筷子挥发油可以改善CCH致VCI大鼠认知功能障碍,其作用机制可能与激活BDNF/TrkB/PI3K/Akt信号通路有关。     

Effects of Ginsenoside Rg1 on Learning and Memory in a Reward‐directed Instrumental Conditioning Task in Chronic Restraint Stressed Rats

Ginsenoside Rg1 is one of the major active ingredients of Panax ginseng and has showed notable improving learning and memory effects in several behavioral tasks, such as water maze, shuttle‐box, and step‐through, based on avoidance. However, there was no report about the role of Rg1 on the performance of reward‐directed instrumental conditioning, which could reflect the adaptive capacity to ever‐changing environments. Thus, in this study, the reward devaluation test and conditional visual discrimination task were conducted to study the ameliorating effects of Rg1 on cognitive deficits, especially the loss of adaptation capacity in chronic restraint stress (CRS) rat model. Our results showed that rat subjected to CRS became insensitive to the changes in outcome value, and it significantly harmed the rat's performance in conditional visual discrimination task. Moreover, the levels of BDNF, TrkB, and Erk phosphorylation were decreased in the prefrontal cortex of CRS rats. However, these changes were effectively reversed by Rg1 (5 and 10 mg/kg, i.p.). Therefore, it demonstrated that Rg1 has a good ability to improve learning and memory and also ameliorate impaired adaptive capacity induced by CRS. This amelioration effect of Rg1 might be mediated partially by BDNF/TrkB/Erk pathway in prefrontal cortex. Copyright © 2016 John Wiley & Sons, Ltd.     

Genistein inhibits Aβ25–35‐induced SH‐SY5Y cell damage by modulating the expression of apoptosis‐related proteins and Ca2+ influx through ionotropic glutamate receptors

In this study, we investigated the protective effects of genistein against SH‐SY5Y cell damage induced by β‐amyloid 25–35 peptide (Aβ_25–35) and the underlying mechanisms. Aβ‐induced neuronal death, apoptosis, glutamate receptor subunit expression, Ca²⁺ ion concentration, amino acid transmitter concentration, and apoptosis‐related factor expression were evaluated to determine the effects of genistein on Aβ‐induced neuronal death and apoptosis. The results showed that genistein increased the survival of SH‐SY5Y cells and decreased the level of apoptosis induced by Aβ_25–35. In addition, genistein reversed the Aβ_25–35‐induced changes in amino acid transmitters, α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionate (AMPA) receptors, and N‐methyl‐d ‐aspartate (NMDA) receptor subunits in SH‐SY5Y cells. Aβ_25–35‐induced changes in Ca²⁺ and B‐cell lymphoma‐2 (Bcl‐2) and Bcl‐2‐associated X (Bax) protein and gene levels in cells were also reversed by genistein. Our data suggest that genistein protects against Aβ_25–35‐induced damage in SH‐SY5Y cells, possibly by regulating the expression of apoptosis‐related proteins and Ca²⁺ influx through ionotropic glutamate receptors.     

The memory ameliorating effects of INM-176, an ethanolic extract of Angelica gigas, against scopolamine- or Aβ(1-42)-induced cognitive dysfunction in mice

Ethnopharmacological relevance

Alzheimer’s disease is a neurodegenerative disorder associated with cognitive impairment and cholinergic neuronal death. INM-176 is a standardized ethanolic extract of Angelica gigas Nakai that has been traditionally used in herbal medicine in China, Japan, and Korea to treat anemia or as a sedative. We investigated whether INM-176 exhibits anti-amnesic effects.

Materials and methods

Memory impairment was induced by scopolamine, a cholinergic muscarinic receptor antagonist, or amyloid β_1–42 (Aβ_1–42) protein. Anti-amnesic effects of INM-176 were measured by the passive avoidance and the Morris water maze tasks in mice. We also examined the effect of INM-176 on the acetylcholinesterase activity, as well as Aβ_1–42 protein-induced astrogliosis or cholinergic neuronal loss in the brain.

Results

Scopolamine-induced cognitive dysfunction was significantly attenuated by a single or sub-chronic administration of INM-176 in the passive avoidance and the Morris water maze tasks. A single or sub-chronic administration of INM-176 also ameliorated memory impairments induced by Aβ_1–42 protein. INM-176 inhibited acetylcholinesterase activity in the hippocampal tissue in vitro and ex vivo. In addition, INM-176 attenuated the Aβ_1–42 protein-induced astrocyte activation in the hippocampus as well as cholinergic neuronal damage in the CA3 region of the hippocampus and the nucleus basalis of Meynert.

Conclusion

These results suggest that the memory ameliorating effects of INM-176 on scopolamine- or Aβ_1–42 protein-induced memory impairment are mediated, in part, via acetylcholinesterase inhibition and neuroprotective activities.     

合欢花总黄酮对抑郁模型大鼠海马CA3区BDNF和TrkB表达的影响

目的:观察合欢花总黄酮对抑郁模型大鼠海马CA3区脑源性神经营养因子(BDNF)及其受体酪氨酸激酶B(TrkB)表达的影响.方法:将90只SD大鼠随机分为正常组、模型组、盐酸文拉法辛组(12.5 mg·kg-1)、合欢花总黄酮(100,50,25 mg·kg-1)剂量组.应用孤养加慢性不可预见性应激建立抑郁症模型,造模同时ig给药,每天1次,连续给药21 d,正常组、模型组ig等体积蒸馏水.用Morris水迷宫法测定各组大鼠学习记忆能力,免疫组织化法检测大鼠海马CA3区BDNF及TrkB表达.结果:与正常组比较,模型组大鼠Morris水迷宫试验逃避潜伏期时间增加、成功次数减少(P ＜0.05,P＜0.01);海马CA3区BDNF及受体TrkB的表达降低(P＜0.01).与模型组比较,盐酸文拉法辛组、合欢花总黄酮3个剂量组Morris水迷宫试验逃避潜伏期时间缩短、成功次数增加(P＜ 0.05或P＜0.01),海马CA3区BDNF及受体TrkB的表达明显增高(P＜0.05或P＜0.01).结论:合欢花总黄酮能够提高抑郁模型大鼠学习记忆能力,其作用机制可能与增加抑郁模型大鼠海马CA3区BDNF及其受体TrkB的表达,进而保护海马神经元有关.     

逍遥散抗抑郁作用的BDNF/CREB信号机制

目的:探讨逍遥散抗抑郁作用的BDNF/CREB信号机制。方法:采用小鼠慢性温和不可预知应激(CUMS)结合孤养抑郁模型,逍遥散水煎液30g/kg灌胃给药4周,测定小鼠体重、自主活动及糖水消耗量的变化以评价药物的抗抑郁效应。ELISA法测定血清BDNF水平,实时荧光定量聚合酶链式反应(real-time PCR)测定小鼠海马及皮质部位CREB、BDNF mRNA表达,Western-blot方法测定小鼠脑内ERK1/2及磷酸化ERK1/2(pERK1/2)的蛋白表达量。结果:与模型组比较,逍遥散30g/kg能提高模型小鼠体重、自主活动及糖水消耗量,并有提高模型动物血清BDNF含量的趋势;逍遥散30g/kg显著增加模型小鼠海马BDNF、CREB mR-NA及皮质BDNF mRNA的表达量,对模型动物海马部位pERK1/2的表达量有提高趋势。结论:逍遥散对CUMS结合孤养的小鼠抑郁模型具有抗抑郁效应,作用机制与干预BDNF/CREB信号途径的关键分子的表达与功能有关。     

电针对阿尔茨海默病模型大鼠海马区BDNF TrkB的影响

目的:观察电针对阿尔茨海默病(AD)模型大鼠海马区BDNF、TrkB的影响,探讨针刺风府穴治疗AD的作用机理。方法:选取Wistar大鼠,随机分为正常组、假手术组、模型组、电针组,以双侧海马注射微量Aβ25-35制备AD动物模型,电针组选取风府穴行电针治疗,以Morris水迷宫评价大鼠学习记忆能力,免疫组化法观察海马区BDNF、TrkB的表达。结果:与正常组比较,模型组学习记忆能力减退,海马区BDNF、TrkB的表达明显减少(P0.01);经电针治疗后,学习记忆能力增强,BDNF、TrkB的表达较模型组增加。结论:针刺风府穴可显著改善AD模型大鼠的学习记忆能力,增加海马区BDNF、TrkB的表达。     

Antidepressant-like action of the bark ethanolic extract from Tabebuia avellanedae in the olfactory bulbectomized mice

Ethnopharmacological relevance

Tabebuia avellanedae Lorentz ex Griseb is a plant employed in tropical America folk medicine for the treatment of several diseases, including depressive disorders.

Aim of the study

To investigate the ability of Tabebuia avellanedae ethanolic extract (EET) administered chronically to cause an antidepressant-like effect in the tail suspension test (TST), a predictive test of antidepressant activity, and to reverse behavioral (hyperactivity, anhedonic-like behavior and increased immobility time in the TST) and biochemical changes induced by olfactory bulbectomy (OB), a model of depression, in mice.

Materials and methods

Mice were submitted to OB to induce depressive-related behaviors, which were evaluated in the open-field test (hyperactivity), splash test (loss of motivational and self-care behavior indicative of an anhedonic-like behavior) and TST (increased immobility time). Phosphorylation levels of Akt, GSK-3β, ERK1/2 and CREB, as well as BDNF immunocontent, were evaluated in the hippocampus of bulbectomized mice or sham-operated mice treated for 14 days by p.o. route with EET or vehicle.

Results

EET (10 and 30 mg/kg) given 14 days by p.o route to mice reduced the immobility time in the TST without altering locomotor activity, an indicative of an antidepressant-like effect. EET per se increased both CREB (Ser¹³³) and GSK-3β (Ser⁹) phosphorylation (at doses of 10–30 and 30 mg/kg, respectively) in sham-operated mice. OB caused hyperactivity, loss of motivational and self-care behavior, increased immobility time in the TST and an increase in CREB and ERK1 phosphorylation, as well as BDNF immunocontent. EET abolished all these OB-induced alterations except the increment of CREB phosphorylation. Akt (Ser⁴⁷³) and ERK2 phosphorylation levels were not altered in any group.

Conclusions

EET ability to abolish the behavioral changes induced by OB was accompanied by modulation of ERK1 and BDNF signaling pathways, being a promising target of EET. Results indicate that this plant could constitute an attractive strategy for the management of depressive disorders, once more validating the traditional use of this plant.