Changes in Synapses and Axons Demonstrated by Synaptophysin Immunohistochemistry Following Spinal Cord Compression Trauma in the Rat and Mouse

Objective and methods To evaluate synaptic changes using synaptophysin immunohistochemstry in rat and mouse, which spinal cords were subjected to graded compression trauma at the level of Th8-9. Results Normal animals showed numerous fine dots of synaptophysin immunoreactivity in the gray matter. An increase in synaptophysin immunoreactivity was observed in the neuropil and synapses at the surface of motor neurons of the anterior horns in the ThS-9 segments lost immunoreactivity at 4-hour point after trauma. The immunoreactive synapses reappeared around motor neurons at 9-day point. Unexpected accumulation of synaptophysin immunoreactivity occurred in injured axons of the white matter of the compressed spinal cord. Conclusion Synaptic changes were important components of secondary injuries in spinal cord trauma. Loss of synapses on motor neurons may be one of the factors causing motor dysfunction of hind limbs and formation of new synapses may play an import,ant role in recovery of motor function. Synaptophysin immunohistochemistry is also a good tool for studies of axonal swellings in spinal cord injuries.

Effects of ephedrine on expression of Nogo-A and synaptophysin in neonatal rats following hypoxic-ischemic brain damage

BACKGROUND： Central nervous system axons regenerate poorly following neonatal hypoxic-ischemic brain damage （HIBD）, partly due to inhibitors, such as Nogo-A. Very few studies have addressed the regulation of Nogo-A in neonatal rats following HIBD. However, numerous studies have shown that ephedrine accelerates neuronal remodeling and promotes recovery of neural function in neonatal rats following HIBD. OBJECTIVE： To investigate the effects of ephedrine on expression of Nogo-A and synaptophysin in brain tissues of neonatal rats following HIBD. DESIGN, TIME AND SETTING： A completely randomized, controlled study was performed at the Immunohistochemistry Laboratory of the Research Institute of Pediatrics, Children＇s Hospital of Chongqing Medical University from August 2008 to March 2009. MATERIALS： Ephedrine hydrochloride （Chifeng Pharmaceutical Group, China）, rabbit anti-Nogo-A polyclonal antibody （Abcam, UK）, and rabbit anti-synaptophysin polyclonal antibody （Lab Vision, USA） were used in this study. METHODS： A total of 96 healthy, neonatal, Sprague Dawley rats were randomly assigned to three groups （n = 32）： sham operation, HIBD, and ephedrine. The HIBD model was established by permanent occlusion of the left common carotid artery, followed by 2 hours of hypoxia （8% oxygen and 92% nitrogen）. In the sham operation group, the left common carotid artery was exposed, but was not ligated or subjected to hypoxia. Rats in the ephedrine group were intraperitoneally injected with ephedrine immediately following HIBD, with 1.5 mg/kg each time. Rats in the sham operation and HIBD groups were injected with an equal volume of saline. All neonatal rats were treated once daily for 7 days. MAIN OUTCOME MEASURES： Histopathological damage to the cortex and hippocampus was determined by hematoxylin-eosin staining. Expression of Nogo-A and synaptophysin was detected using immunohistochemical staining. RESULTS： Neuronal degeneration and edema were observed in the hypoxJc-Jschemic cortex and hippocampus by hematoxylin-eosin staining. Compared with the sham operation group, the levels of Nogo-A significantly increased in the HIBD group at various time points （P 〈 0.01）. Nogo-A expression was significantly reduced in the ephedrine group compared with the HIBD group （P 〈 0.01）. Synaptophysin expression was significantly decreased in the hypoxic-ischemJc cortex, compared with the sham operation group （P 〈 0.01）. Synaptophysin levels were significantly increased in the ephedrine group, compared with the HIBD group （P 〈 0.01）. CONCLUSION： Altered Nogo-A expression was associated with inversely altered synaptophysin expression. The use of ephedrine normalized expression levels of Nogo-A and synaptophysin following HIBD.

脑源性神经生长因子抗体对小鼠坐骨神经损伤后脊髓与背根节内Synaptophysin表达的影响

目的探查小鼠坐骨神经压榨损伤后内源性脑源性神经营养因子(brainderivedneuroliophicfactor,BDNF)对Synaptophysin(SYN)在相应脊髓前角运动细胞与背根节神经元内表达的影响。方法在小鼠一侧坐骨神经压榨损伤后腹腔注射BDNF抗体,中和内源性BDNF,然后用免疫组织化学方法观察SYN在与坐骨神经相连的脊髓前角运动细胞与背根节神经元的表达。结果实验组SYN免疫反应阳性神经元的数目较对照组明显减少,阳性细胞的平均光密度也显著下降(P<0.01)。结论小鼠坐骨神经压榨损伤后内源性BDNF可能参与脊髓前角运动细胞与背根节神经元内SYN的表达。

猴垂体前叶Synaptophysin免疫反应性的光镜观察

目的：为神经纤维对哺乳动物尤其是灵长类动物垂体前叶腺细胞的直接调节作用提供形态学证据．方法：用抗Ｓｙｎａｐｔｏｐｈｙｓｉｎ（ＳＹＮ）单克隆抗体，对ＭａｃａｃａＭｕｌａｔａ猴垂体前叶进行了免疫组化染色．结果：猴垂体前叶ＳＹＮ的免疫反应性主要有膨体型和纤维型两种形式．膨体型表现为大小不等、深染的点状结构．纤维型表现为细、短浅染的ＳＹＮ免疫反应神经纤维，其上分布着大小不等、深染的膨体．ＳＹＮ免疫反应膨体和纤维均分布在腺细胞之间，或沿着细胞团边界走行，与腺细胞密切接触．结论：猴垂体前叶ＳＹＮ免疫反应膨体反映了神经末梢中突触小泡的存在，为“哺乳动物垂体前叶神经体液双重调节的假说”

Acupuncture accelerates neural regeneration and synaptophysin production after neural stem cells transplantation in mice

BACKGROUND Synaptophysin plays a key role in synaptic development and plasticity of neurons and is closely related to the cognitive process of Alzheimer’s disease(AD)patients.Exogenous neural stem cells(NSCs)improve the damaged nerve function.The effects of Sanjiao acupuncture on cognitive impairment may be related to the regulation of the NSC microenvironment.AIM To explore the anti-dementia mechanism of acupuncture by regulating the NSC microenvironment.METHODS NSCs were isolated from pregnant senescence-accelerated mouse resistant 1(SAMR1)mice,labeled with BrdU,and injected into the hippocampus of senescence-accelerated mouse prone 8(SAMP8)mice.Eight-month-old senescence-accelerated mice(SAM)were randomly divided into six groups:SAMR1(RC),SAMP8(PC),sham transplantation(PS),NSC transplantation(PT),NSC transplantation with acupuncture(PTA),and NSC transplantation with nonacupoint acupuncture(PTN).Morris water maze test was used to study the learning and memory ability of mice after NSC transplantation.Hematoxylin-eosin staining and immunofluorescence were used to observe the histopathological changes and NSC proliferation in mice.A co-culture model of hippocampal slices and NSCs was established in vitro,and the synaptophysin expression in the hippocampal microenvironment of mice was observed by flow cytometry after acupuncture treatment.RESULTS Morris water maze test showed significant cognitive impairment of learning and memory in 8-mo-old SAMP8,which improved in all the NSC transplantation groups.The behavioral change in the PTA group was stronger than those in the other two groups(P<0.05).Histopathologically,the hippocampal structure was clear,the cell arrangement was dense and orderly,and the necrosis of cells in CA1 and CA3 areas was significantly reduced in the PTA group when compared with the PC group.The BrdU-positive proliferating cells were found in NSC hippocampal transplantation groups,and the number increased significantly in the PTA group than in the PT and PTN groups(P<0.05).Flow cytometry showed that after co-culture of NSCs with hippocampal slices in vitro,the synaptophysin expression in the PC group decreased in comparison to the RC group,that in PT,PTA,and PTN groups increased as compared to the PC group,and that in the PTA group increased significantly as compared to the PTN group with acupointrelated specificity(P<0.05).CONCLUSION Acupuncture may promote nerve regeneration and synaptogenesis in SAMP8 mice by regulating the microenvironment of NSC transplantation to improve the nerve activity and promote the recovery of AD-damaged cells.

Ca^(2+)诱导的synaptophysin Ⅰ蛋白的脂筏分布

文章研究了Ca2+对synaptophysin Ⅰ(Syp Ⅰ)蛋白的脂筏分布的影响。研究结果证明,Syp Ⅰ蛋白的脂筏分布明显受到Ca2+的特异性调控。在无Ca2+的条件下,Syp Ⅰ为典型的非脂筏蛋白;而在低浓度Ca2+的条件下,Syp Ⅰ可以转变为脂筏结合蛋白。文章还研究了SypⅠ在Ca2+的诱导下进入脂筏膜微区的分子机制。研究结果表明,Syp Ⅰ在Ca2+的诱导下进入脂筏这一现象依赖于其C末端胞质区,确定了Syp Ⅰ的胞质区在这种调节中的重要性。

Combined acupuncture and HuangDiSan treatment affects behavior and synaptophysin levels in the hippocampus of senescence-accelerated mouse prone 8 after neural stem cell transplantation

Sanjiao acupuncture and HuangDiSan can promote the proliferation, migration and differentiation of exogenous neural stem cells in senescence-accelerated mouse prone 8 （SAMP8） mice and can improve learning and memory impairment and behavioral function in dementia-model mice. Thus, we sought to determine whether Sanjiao acupuncture and HuangDiSan can elevate the effect of neural stem cell transplantation in Alzheimer’s disease model mice. Sanjiao acupuncture was used to stimulate Danzhong （CV17）, Zhongwan （CV12）,Qihai （CV6）, bilateral Xuehai （SP10） and bilateral Zusanli （ST36） 15 days before and after implantation of neural stem cells （5 × 10^5） into the hippocampal dentate gyrus of SAMP8 mice. Simultaneously, 0.2 mL HuangDiSan, containing Rehmannia Root and Chinese Angelica,was intragastrically administered. Our results demonstrated that compared with mice undergoing neural stem cell transplantation alone,learning ability was significantly improved and synaptophysin mRNA and protein levels were greatly increased in the hippocampus of mice undergoing both Sanjiao acupuncture and intragastric administration of HuangDiSan. We conclude that the combination of Sanjiao acupuncture and HuangDiSan can effectively improve dementia symptoms in mice, and the mechanism of this action might be related to the regulation of synaptophysin expression.

Effects of “Nourishing Liver and Kidney” Acupuncture Therapy on Expression of Brain Derived Neurotrophic Factor and Synaptophysin after Cerebral Ischemia Reperfusion in Rats

The aim of the present study was to investigate the effect of ＂nourishing liver and kidney＂ acupuncture therapy on motor and cognitive deficits,and the underlying mechanism following cerebral ischemia-reperfusion（I/R） via increasing the expression of brain derived neurotrophic factor（BDNF） and synaptophysin（SYN） in the hippocampus.Healthy adult male SD rats were randomly divided into sham operation group（n=51）,model group（n=51）,acupuncture group（n=51） and acupuncture control group（n=51）.The middle cerebral I/R model was established.Acupunctures were performed in the acupuncture group and acupuncture control group at acupoints of Taixi（K103）,Taichong（ST09） of both sides,for 30 min once daily every morning.The animals in the sham operation group and model group were conventionally fed in the cage,without any intervention therapy.The rats of each group were assessed with modified neurological severity scores（m NSS）.The expression of BDNF and SYN in the hippocampus was detected by immunohistochemical SP method and the synaptic structure in hippocampus area was assessed morphologically and quantitatively at the 3rd,7th and 14 th day.The Morris water Maze（MWM） test was used to evaluate the rats＇ learning and memory abilities on the 15 th day after acupuncture.The animals in the acupuncture control group and sham operation group presented no neurological deficit.In the acupuncture group,the nerve functional recovery was significantly better than that in the model group at the 7th and 14 th day after modeling.The average MWM escape latency in the acupuncture group was shorter than that in the model group at the 3rd,4th and 5th day.The number of crossings of the platform quadrant in the acupuncture group was significantly more than that in the model group.At the each time point,the expression levels of BDNF and SYN in the hippocampal regions increased significantly in the model group as compared with the sham operation group and the acupuncture control group.In the acupuncture group,the expression levels of BDNF at the 7th and 14 th day increased more significantly than those in the model group.In the acupuncture group,the expression levels of SYN at the each time point increased more significantly than those in the model group.The post-synaptic density（PSD） was significantly increased and the synapse cleft width was narrowed in the acupuncture group as compared with other groups.The synaptic curvatures were improved obviously in the acupuncture group in contrast to the model group.It was concluded that the ＂nourishing liver and kidney＂ acupuncture therapy has positive effects on behavioral recovery,as well as learning and memory abilities,probably by promoting the expression of BDNF and SYN,and synaptic structure reconstruction in the ipsilateral hippocampus after I/R in rats.The ＂nourishing liver and kidney＂ acupuncture therapy can promote the functional recovery in rats after cerebral ischemia injury.

Effect of Panaxtriol Saponins on synaptophysin and postsynaptic density-95 expression at different periods of cerebral infarction

BACKGROUND： The change in expression of synaptophysin （Syp） and postsynaptic density-95 （PSD-95） alters after cerebral infarction, and the plasticity of synapses contributes greatly to nerve function recovery. Chinese medicinal substances may play an important role in the expression of Syp and PSD-95. OBJECTIVE： To observe the effect of Panaxtriol Saponins （PTS）, an active component in Sanqi tongshu capsules, on the expression of Syp and PSD-95 after cerebral infarction at different time points in rats, so as to examine the cerebral function remodeling mechanism. DESIGN, TIME AND SETTING： A randomized and controlled observation which was performed in Dongzhimen Hospital, Beijing University of Traditional Chinese Medicine from January to March, 2007. MATERIALS： Twenty-six healthy male Sprague Dawley rats were used to establish middle cerebral artery occlusion based on the Longa method. Sanqi tongshu capsules （containing 100 mg PTS per tablet） were provided by the Chengdu Huashen Group and nimodipine tablets （30 mg） by Tianjin Zhongyang Pharmaceutical Co., Ltd. METHODS： Twenty-six rats were randomly divided into an operation group （n = 21 ） and a control group （n = 5）. The operation group underwent the EZ Longa procedure to make the middle cerebral artery occlusion model. After surgery rats were randomly divided into a model group, a PTS group and a nimodipine group, with seven rats in each group. Rats were intragastrically administrated with saline （2 mL/d） in the model group, with Sanqi tongshu capsule （5.4 mg/100 g/d） in the PTS group, and with nimodipine （1.73 mg/100 g/d） in the nimodipine group. Rats in the control group did not undergo model establishment and drug administration. MAIN OUTCOME MEASURES： The expressions of Syp and PSD-95 were measured by immunohistochemical and image analysis at days 3, 7 and 28 after the operation. RESULTS： The expression of Syp and PSD-95 in the operation group was significantly lower than in the control group at days 3, 7, 28 postoperatively （P 〈 0.05）. The expression of Syp and PSD-95 in the PTS group and nimodipine group was significantly higher than in the model group at day 28 postoperatively （P 〈 0.05-0.01）. Additionally, after PTS and nimodipine treatment at different intervals, the expression of Syp and PSD-95 at day 28 postoperatively was significantly higher than those at days 3 and 7 postoperatively, respectively （P 〈 0.01）. CONCLUSION： PTS can promote the expression of Syp and PSD-95, i.e. the remodeling process of synapses, after cerebral infarction at different time points in rats, which contributes to cerebral function remodeling.

Influence of acupuncture with exercise training on learning and memory functions, as well as microtubule-associated protein-2 and synaptophysin expression in the hippocampal CA3 region, in a rat model of cerebral infarction

The present study was designed to determine microtubule-associated protein-2 and synaptophysin expression in the hippocampal CA3 region in a rat model of middle cerebral artery occlusion. The rats were treated with acupuncture at Baihui （GV 20）, Qubin （GB 7）, and Qianding （GV 21） points, in addition to exercise training. Results were compared with rats undergoing exercise training only. The Y-maze method and immunohistochemistry revealed decreased error frequency of passing through Y-maze, as well as significantly increased microtubule-associated protein-2 and synaptophysin expression, in the acupuncture with exercise training group compared with the model and exercise training groups after 5 weeks. Microtubule-associated protein-2 and synaptophysin expressions negatively correlated with error frequency of passing through the Y-maze. These results suggested that acupuncture combined with exercise training improved learning and memory functions in a rat model of cerebral infarction. The mechanisms of action were hypothesized to be associated with dendritic or synaptic plasticity in the ipsilateral hippocampal CA3 region.

Perlecan and synaptophysin changes in denervated skeletal muscle

The present study observed sciatic nerve and gastrocnemius muscle changes in denervated rats using morphology methods, and assessed expression of perlecan, an extracellular matrix component, which is located at the skeletal muscle cell surface as acetylcholine esterase, as well as synaptophysin, a synaptic marker. Results showed degeneration and inflammation following transection of the sciatic nerve. In addition, the sciatic nerve-dominated skeletal muscle degenerated with mild inflammation, indicating that skeletal muscle atrophy primarily contributed to denervation-induced nutritional disturbances. With prolonged injury time （1-4 weeks post-injury）, perlecan expression gradually decreased and reached the lowest level at 4 weeks, but synaptophysin expression remained unchanged after denervation. Results suggested that perlecan expression was more sensitive to denervation and reflected regional extracellular matrix changes following denervation.

Effects of genistein and 17 beta-estradiol on hippocampal synaptophysin expression in ovariectomized rats

BACKGROUND： Phytoestrogen, derived from plants, is an estrogen-like element, and is effective and safe for estrogen replacement. OBJECTIVE： To compare the interventional effects of genistein and 17 S-estradiol on learning and memory and synaptophysin （SYN） expression in the hippocampus of ovariectomized rats.DESIGN： Randomized controlled animal study.SETTING： Department of Neurology, the Third Affiliated Hospital, Xiangya Medical College, Central South University. MATERIALS： 130 healthy female Sprague Dawley （SD） rats, 6 months old and weighing （293.1 ± 10.2） g, were provided by the Second Xiangya Hospital of Central South University. This animal experiment received confirmed consent from the local ethics committee. All rats were randomly divided into 5 groups, including baseline group （n= 10）, sham operation group （n = 30）, ovariectomized group （n = 30）, genistein group （n = 30）, and 17 β -estradiol group （n = 30）. Rats in the latter four groups were observed for 3 weeks （n = 10） and for 15 weeks （n = 20） after model establishment. METHODS： This study was performed at the Department of Endocrinology, the Second Affiliated Hospital, Xiangya Medical College, Central South University from August 2005 to January 2006. Animals were not submitted to any treatment in the baseline group, but anesthetized and sacrificed at the 7 months of age. After anesthesia in the ovariectomized, genistein, and 17 S-estradiol groups, both ovaries were separated and resected to establish an ovariectomized model. The same volume of fat was resected in the sham operation group. After surgery, rats were intraperitoneally injected with 5 mg/kg genistein in the genistein group,10μg/kg 17 β -estradiol in the 17 β-estradiol group, and 0.1 mL/100 g dimethyl sulfoxide （DMSO）/polyethylene glycol （PEG）-200 stock solution in the sham operation and ovariectomized groups once a day until one day before sacrifice. MAIN OUTCOME MEASURES：① Learning and memory changes of SD rats were detected using water maze behavioral testing 3 and 15 weeks after surgery. ② SYN expression in the hippocampus was measured using immunohistochemistry. RESULTS： A total of 16 out of 130 rats died due to infection, and 114 rats were included in the final analysis. ① Comparison of water maze results from the five groups： by 3 and 15 weeks after surgery, escape latency was prolonged and platform-crossing times decreased in the ovariectomized group compared to the baseline, genistein, 17 β-estradiol, and sham operation groups （t = 4.17 14.64, P 〈 0.05）. However, there were no significant differences in escape latency and platform-crossing times among the sham operation, genistein, and 17 S-estradiol groups （P 〉 0.05）. ② Distribution and quantity of SYN immunoreactive products in hippocampus： SYN-immunoreactive cells stained darkly in the baseline and sham operation groups, but were lightly stained in the genistein, 17 S -estradiol, and ovariectomized groups. In particular, SYN-immunoreactive cells stained lightly in the ovariectomized group 15 weeks after surgery. SYN correction gray values in hippocampal sub-regions, especially in the mossy fiber layer of the CA3 region, of the ovariectomized group was lower compared to the baseline, sham operation, 17 β -estradiol, and genistein groups （t = 12.57 23.92, P 〈 0.05） 15 weeks after surgery. However, there were no significant differences in SYN correction gray values among the baseline, sham operation, 17 β -estradiol and genistein groups （P 〉 0.05）. CONCLUSION： Genistein or 17 β -estradiol supplemental therapy antagonizes memory deterioration, due to endogenous estrogen deficiency and blocks the decrease of SYN expression in the hippocampus. The effect of genistein is similar to 17 β -estradiol.

Effects of electroacupuncture versus nimodipine on long-term potentiation and synaptophysin expression in a rat model of vascular dementia

The present study stimulated Baihui （DU 20） and Dazhui （DU 14） acupoints in a rat model of vascular dementia with electroacupuncture to investigate changes in long-term potentiation and synaptophysin expression in the hippocampus. The results revealed that synaptophysin expression in brain tissues was increased after electroacupuncture. After high4requency stimulation, the population spike latency was shortened and the excitatory postsynaptic potential slope and population spike amplitude were increased. In addition, cognitive function was enhanced, similar to the effects of intragastric perfusion of nimodipine. The results indicated that electroacupuncture at Baihui and Dazhui acupoints can improve learning and memory functions of a rat model of vascular dementia by promoting synaptophysin expression, enhancing hippocampal synaptic plasticity and accelerating synaptic transmission.

Xuefu Zhuyu decoction improves neurological dysfunction by increasing synapsin expression after traumatic brain injury

Xuefu Zhuyu decoction has been used for treating traumatic brain injury and improving post-traumatic dysfunction, but its mechanism of action needs further investigation. This study established rat models of traumatic brain injury by controlled cortical impact. Rat models were intragastrically administered 9 and 18 g/kg Xuefu Zhuyu decoction once a day for 14 or 21 days. Changes in neurological function were assessed by modified neurological severity scores and the Morris water maze. Immunohistochemistry, western blot assay, and re- verse-transcription polymerase chain reaction were used to analyze synapsin protein and mRNA expression at the injury site of rats. Our results showed that Xuefu Zhuyu decoction visibly improved neurological function of rats with traumatic brain injury. These changes were accompanied by increased expression of synaptophysin, synapsin I, and postsynaptic density protein-95 protein and mRNA in a dose-de- pendent manner. These findings indicate that Xuefu Zhuyu decoction increases synapsin expression and improves neurological deficits alder traumatic brain injury.

An enriched environment promotes synaptic plasticity and cognitive recovery after permanent middle cerebral artery occlusion in mice

Cerebral ischemia activates an endogenous repair program that induces plastic changes in neurons. In this study, we investigated the effects of environmental enrichment on spatial learning and memory as well as on synaptic remodeling in a mouse model of chronic cerebral ischemia, produced by subjecting adult male C57 BL/6 mice to permanent left middle cerebral artery occlusion. Three days postoperatively, mice were randomly assigned to the environmental enrichment and standard housing groups. Mice in the standard housing group were housed and fed a standard diet. Mice in the environmental enrichment group were housed in a cage with various toys and fed a standard diet. Then, 28 days postoperatively, spatial learning and memory were tested using the Morris water maze. The expression levels of growth-associated protein 43, synaptophysin and postsynaptic density protein 95 in the hippocampus were analyzed by western blot assay. The number of synapses was evaluated by electron microscopy. In the water maze test, mice in the environmental enrichment group had a shorter escape latency, traveled markedly longer distances, spent more time in the correct quadrant(northeast zone), and had a higher frequency of crossings compared with the standard housing group. The expression levels of growth-associated protein 43, synaptophysin and postsynaptic density protein 95 were substantially upregulated in the hippocampus in the environmental enrichment group compared with the standard housing group. Furthermore, electron microscopy revealed that environmental enrichment increased the number of synapses in the hippocampal CA1 region. Collectively, these findings suggest that environmental enrichment ameliorates the spatial learning and memory impairment induced by permanent middle cerebral artery occlusion. Environmental enrichment in mice with cerebral ischemia likely promotes cognitive recovery by inducing plastic changes in synapses.

Protective effects of Dendrobium nobile Lindl. alkaloids on amyloid beta(25–35)-induced neuronal injury

Dendrobium nobile Lindl.alkaloids（DNLA）,the active ingredients of a traditional Chinese medicine Dendrobium,have been shown to have anti-oxidative effects,anti-inflammatory action,and protective effect on neurons against oxygen-glucose deprivation.However,it is not clear whether DNLA reduces amyloid-beta（Aβ）-induced neuronal injury.In this study,cortical neurons were treated with DNLA at different concentrations（0.025,0.25,and 2.5 mg/L）for 24 hours,followed by administration of Aβ（25-35）（10μM）.Aβ（25-35） treatments increased cell injury as determined by the leakage of lactate dehydrogenase,which was accompanied by chromatin condensation and mitochondrial tumefaction.The damage caused by Aβ（25-35） on these cellular properties was markedly attenuated when cells were pretreated with DNLA.Treatment with Aβ（25-35）down-regulated the expressions of postsynaptic density-95 mRNA and decreased the protein expression of synaptophysin and postsynaptic density-95,all changes were significantly reduced by pretreatment of cells with DNLA.These findings suggest that DNLA reduces the cytotoxicity induced by Aβ（25-35） in rat primary cultured neurons.The protective mechanism that DNLA confers on the synaptic integrity of cultured neurons might be mediated,at least in part,through the upregulation of neurogenesis related proteins synaptophysin and postsynaptic density-95.

Repetitive transcranial magnetic stimulation promotes neurological functional recovery in rats with traumatic brain injury by upregulating synaptic plasticity-related proteins

Studies have shown that repetitive transcra nial magnetic stimulation(rTMS)can enhance synaptic plasticity and improve neurological dysfunction.Howeve r,the mechanism through which rTMS can improve moderate traumatic brain injury remains poorly understood.In this study,we established rat models of moderate traumatic brain injury using Feeney's weight-dropping method and treated them using rTMS.To help determine the mechanism of action,we measured levels of seve ral impo rtant brain activity-related proteins and their mRNA.On the injured side of the brain,we found that rTMS increased the protein levels and mRNA expression of brain-derived neurotrophic factor,tropomyosin receptor kinase B,N-methyl-D-aspartic acid receptor 1,and phosphorylated cAMP response element binding protein,which are closely associated with the occurrence of long-term potentiation.rTMS also partially reve rsed the loss of synaptophysin after injury and promoted the remodeling of synaptic ultrastructure.These findings suggest that upregulation of synaptic plasticity-related protein expression is the mechanism through which rTMS promotes neurological function recovery after moderate traumatic brain injury.

Beta 2-adrenergic receptor activation enhances neurogenesis in Alzheimer's disease mice

Impaired hippocampal neurogenesis is one of the early pathological features of Alzheimer＇s disease. Enhancing adult hippocampal neuro- genesis has been pursued as a potential therapeutic strategy for Alzheimer＇s disease. Recent studies have demonstrated that environmental novelty activates β2-adrenergic signaling and prevents the memory impairment induced by amyloid-β oligomers. Here, we hypothesized that β2-adrenoceptor activation would enhance neurogenesis and ameliorate memory deficits in Alzheimer＇s disease. To test this hypothe- sis, we investigated the effects and mechanisms of action of β2-adrenoceptor activation on neurogenesis and memory in amyloid precursor protein/presenilin 1 （APP/PS1） mice using the agonist clenbuterol （intraperitoneal injection, 2 mg/kg）. We found that β2-adrenoceptor ac- tivation enhanced hippocampal neurogenesis, ameliorated memory deficits, and increased dendritic branching and the density of dendritic spines, lhese effects were associated with the upregulation of postsynaptic density 95, synapsin 1 and synaptophysin in APP/PS1 mice. Furthermore, β2-adrenoceptor activation decreased cerebral amyloid plaques by decreasing APP phosphorylation at Thr668. These findings suggest that β2-adrenoceptor activation enhances neurogenesis and ameliorates memory deficits in APP/PS 1 mice.

Hippocampal expression of synaptic structural proteins and phosphorylated cAMP response element-binding protein in a rat model of vascular dementia induced by chronic cerebral hypoperfusion

The present study established a rat model of vascular dementia induced by chronic cerebral hypoperfusion through permanent ligation of bilateral common carotid arteries.At 60 days after modeling,escape latency and swimming path length during hidden-platform acquisition training in Morris water maze significantly increased in the model group.In addition,the number of accurate crossings over the original platform significantly decreased,hippocampal CA1 synaptophysin and growth-associated protein 43 expression significantly decreased,cAMP response element-binding protein expression remained unchanged,and phosphorylated cAMP response element-binding protein expression significantly decreased.Results suggested that abnormal expression of hippocampal synaptic structural protein and cAMP response element-binding protein phosphorylation played a role in cognitive impairment following chronic cerebral hypoperfusion.

Effect of Panax notoginseng saponins on the expression of beta-amyloid protein in the cortex of the parietal lobe and hippocampus, and spatial learning and memory in a mouse model of senile dementia

BACKGROUND： The pharmacological actions of Panax notoginseng saponins （PNS） lie in removing free radicals, anti-inflammation and anti-oxygenation. It can also improve memory and behavior in rat models of Alzheimer＇s disease. OBJECTIVE： Using the Morris water maze, immunohistochemistry, real-time PCR and RT-PCR, this study aimed to measure improvement in spatial learning, memory, expression of amyloid precursor protein （App） and β -amyloid （A β ）, to investigate the mechanism of action of PNS in the treatment of AD in the senescence accelerated mouse-prone 8 （SAMP8） and compare the effects with huperzine A. DESIGN, TIME AND SETTING： A completely randomized grouping design, controlled animal experiment was performed in the Center for Research ＆ Development of New Drugs, Guangxi Traditional Chinese Medical University from July 2005 to April 2007. MATERIALS： Sixty male SAMP8 mice, aged 3 months, purchased from Tianjin Chinese Traditional Medical University of China, were divided into four groups： PNS high-dosage group, PNS low-dosage group, huperzine A group and control group. PNS was provided by Weihe Pharmaceutical Co., Ltd. （batch No.： Z53021485, Yuxi, Yunan Province, China）. Huperzine A was provided by Zhenyuan Pharmaceutical Co., Ltd. （batch No.： 20040801, Zhejiang, China）. METHODS： The high-dosage group and low-dosage group were treated with 93.50 and 23.38 mg/kg PNS respectively per day and the huperzine A group was treated with 0.038 6 mg/kg huperzine A per day, all by intragastric administration, for 8 consecutive weeks. The same volume of double distilled water was given to the control group. MAIN OUTCOME MEASURES： After drug administration, learning and memory abilities were assessed by place navigation and spatial probe tests. The recording indices consisted of escape latency （time-to-platform）, and the percentage of swimming time spent in each quadrant. The number of A β 1-40, A β 1-42 and App immunopositive neurons in the brains of SAMP8 mice was analyzed by immunohistochemistry. The mRNA content ofApp, tau, acetylcholinesterase, and synaptophysin （Syp） was tested by real time PCR and RT-PCR. RESULTS： The PCR results show that PNS can downregulate the expression of the App gene and upregulate the expression of the Syp gene in the parietal cortex and hippocampus of SAMP8 mice. The therapeutic effects of the PNS high-dosage group were greater than those of the PNS low-dosage group and the huperzine A group （P 〈 0.05）. The results of the Morris water maze and immunohistochemistry indicated that PNS can improve the capacity for spatial learning and memory in SAMP8 mice, and reduce the content of A β 1-40, A β 1-42 and expression of App in the brains of SAMP8 mice. The therapeutic effects of the PNS high-dosage group were greater than that of the PNS low-dosage group and the huperzine A group （P 〈 0.05）. CONCLUSION： These results support the hypothesis that PNS plays a therapeutic and protective role on the pathological lesions and learning dysfunction of Alzheimer＇s disease. The therapeutic effects of PNS for Alzheimer＇s disease are possibly achieved through downregulating the expression of the App gene and upregulating the expression of the Syp gene. The therapeutic effects of PNS are dose-dependent and are greater than the effect of huperzine A.