Quantitative proteomic and phosphoproteomic analyses of the hippocampus reveal the involvement of NMDAR1 signaling in repetitive mild traumatic brain injury

The cumulative damage caused by repetitive mild traumatic brain injury can cause long-term neurodegeneration leading to cognitive impairment.This cognitive impairment is thought to result specifically from damage to the hippocampus.In this study,we detected cognitive impairment in mice 6 weeks after repetitive mild traumatic brain injury using the novel object recognition test and the Morris water maze test.Immunofluorescence staining showed that p-tau expression was increased in the hippocampus after repetitive mild traumatic brain injury.Golgi staining showed a significant decrease in the total density of neuronal dendritic spines in the hippocampus,as well as in the density of mature dendritic spines.To investigate the specific molecular mechanisms underlying cognitive impairment due to hippocampal damage,we performed proteomic and phosphoproteomic analyses of the hippocampus with and without repetitive mild traumatic brain injury.The differentially expressed proteins were mainly enriched in inflammation,immunity,and coagulation,suggesting that non-neuronal cells are involved in the pathological changes that occur in the hippocampus in the chronic stage after repetitive mild traumatic brain injury.In contrast,differentially expressed phosphorylated proteins were mainly enriched in pathways related to neuronal function and structure,which is more consistent with neurodegeneration.We identified N-methyl-D-aspartate receptor 1 as a hub molecule involved in the response to repetitive mild traumatic brain injury,and western blotting showed that,while N-methyl-D-aspartate receptor 1 expression was not altered in the hippocampus after repetitive mild traumatic brain injury,its phosphorylation level was significantly increased,which is consistent with the omics results.Administration of GRP78608,an N-methyl-D-aspartate receptor 1 antagonist,to the hippocampus markedly improved repetitive mild traumatic brain injury-induced cognitive impairment.In conclusion,our findings suggest that N-methyl-D-aspartate receptor 1 signaling in the hippocampus is involved in cognitive impairment in the chronic stage after repetitive mild traumatic brain injury and may be a potential target for intervention and treatment.

过表达NRF1减轻阿尔茨海默病模型小鼠的线粒体和认知功能障碍

目的探讨核呼吸因子1(NRF1)对阿尔茨海默病疾病(AD)模型小鼠线粒体及和认知功能障碍的影响。方法以5×FAD小鼠作为AD模型小鼠,并用脑立体定位注射稀疏标记的过表达NRF1的AAV病毒(AAV-NRF1)。Western blot法测定海马中NRF1的表达;用透射电镜观察海马中线粒体形态;用激光共聚焦显微镜观察CA1区稀疏标记神经元的树突棘并计数;Morris水迷宫实验评估小鼠认知和记忆功能;电生理法检测突触效能的长时程增强效应(LTP)。结果脑立体注射AAV-NRF1后,海马中NRF1表达升高(P<0.001),海马神经元中线粒体形态明显改善,小鼠的认知和记忆功能提高(P<0.01),海马CA1区神经元的树突棘密度增加(P<0.001)并产生持久稳定的LTP且fEPSP斜率增高(P<0.01)。结论在5×FAD小鼠AD模型中,NRF1过表达触发了线粒体功能障碍的修复,并改善了突触可塑性,推测这些改变参与到了过表达NRF1对AD认知功能障碍改善的治疗效果中。

Downregulation of caveolin-1 contributes to the synaptic plasticity deficit in the hippocampus of aged rats

Caveolin-1 is involved in the regulation of synaptic plasticity, but the relationship between its ex-pression and cognitive function during aging remains controversial. To explore the relationship be-tween synaptic plasticity in the aging process and changes in learning and memory, we examined caveolin-1 expression in the hippocampus, cortex and cerebellum of rats at different ages. We also examined the relationship between the expression of caveolin-1 and synaptophysin, a marker of synaptic plasticity. Hippocampal caveolin-1 and synaptophysin expression in aged （22-24 month old） rats was significantly lower than that in young （1 month old） and adult （4 months old） rats. Ex- pression levels of both proteins were significantly greater in the cortex of aged rats than in that of young or adult rats, and levels were similar between the three age groups in the cerebellum. Linear regression analysis revealed that hippocampal expression of synaptophysin was associated with memory and learning abilities. Moreover, synaptophysin expression correlated positively with caveolin-1 expression in the hippocampus, cortex and cerebellum. These results confirm that caveolin-1 has a regulatory effect on synaptic plasticity, and suggest that the downregulation of hippocampal caveolin-1 expression causes a decrease in synaptic plasticity during physiological aging.

Effects of sericin on heme oxygenase-1 expression in the hippocampus and cerebral cortex of type 2 diabetes mellitus rats

Previous studies have demonstrated that sericin effectively reduces blood glucose, and protects islet cells, as well as the gonads and kidneys. However, whether sericin improves diabetes mellitus-induced structural and functional problems in the central nervous system remains poorly understood. Rat models of type 2 diabetes mellitus were established by intraperitoneal injection of streptozotocin. The present study observed histological changes in the hippocampus and cerebral cortex, as well as heme oxygenase-1 expression, and explored sericin effects on the central nervous system in diabetic rats. Pathological damage to neural cells in the rat hippocampus and cerebral cortex was relieved following intragastric administration of sericin at a dose of 2.4 g/kg for 35 consecutive days. Heme oxygenase-1 protein and mRNA expressions were decreased in the hippocampus and cerebral cortex of diabetes mellitus rats after sericin treatment. The results suggest that sericin plays a protective effect on the nervous system by decreasing the high expression of heme oxygenase-1 following diabetes mellitus.

Endothelin-1-induced mini-stroke in the dorsal hippocampus or lateral amygdala results in deficits in learning and memory

Functional and structural alterations in brain connectivity associated with brain ischemia have been extensively studied. However, the mechanism whereby local ischemia in deep brain region affect brain functions is still unknown. Here, we first established a mini-stroke model by infusion of endothelin-1 （ET-1） into the dorsal hippo- campus or the lateral amygdala, and then investigated how these mini-infarcts affected brain functions associated with these regions. We found that rats with ET-1 infusion showed deficit in recall of contextual fear memory, but not in learning process and recall of tone fear memory. In novel object task, ET-1 in the hippocampus also elimi- nated object identity memory. ET-1 in the lateral amygdale affected acquisition of fear conditioning and disrupted retention of tone-conditioned fear, but did not impair retention of contextual fear. These findings suggest that ET-1- induced mini-infarct in deep brain area leads to functional deficits in learning and memory associated with these regions.

Astrocytic endothelin-1 overexpression impairs learning and memory ability in ischemic stroke via altered hippocampal neurogenesis and lipid metabolism

Vascular etiology is the second most prevalent cause of cognitive impairment globally.Endothelin-1,which is produced and secreted by endothelial cells and astrocytes,is implicated in the pathogenesis of stroke.However,the way in which changes in astrocytic endothelin-1 lead to poststroke cognitive deficits following transient middle cerebral artery occlusion is not well understood.Here,using mice in which astrocytic endothelin-1 was overexpressed,we found that the selective overexpression of endothelin-1 by astrocytic cells led to ischemic stroke-related dementia(1 hour of ischemia;7 days,28 days,or 3 months of reperfusion).We also revealed that astrocytic endothelin-1 overexpression contributed to the role of neural stem cell proliferation but impaired neurogenesis in the dentate gyrus of the hippocampus after middle cerebral artery occlusion.Comprehensive proteome profiles and western blot analysis confirmed that levels of glial fibrillary acidic protein and peroxiredoxin 6,which were differentially expressed in the brain,were significantly increased in mice with astrocytic endothelin-1 overexpression in comparison with wild-type mice 28 days after ischemic stroke.Moreover,the levels of the enriched differentially expressed proteins were closely related to lipid metabolism,as indicated by Kyoto Encyclopedia of Genes and Genomes pathway analysis.Liquid chromatography-mass spectrometry nontargeted metabolite profiling of brain tissues showed that astrocytic endothelin-1 overexpression altered lipid metabolism products such as glycerol phosphatidylcholine,sphingomyelin,and phosphatidic acid.Overall,this study demonstrates that astrocytic endothelin-1 overexpression can impair hippocampal neurogenesis and that it is correlated with lipid metabolism in poststroke cognitive dysfunction.

基于Nrf2/HO-1通路探讨捏脊改善孤独症大鼠行为障碍的机制研究

目的从氧化应激及核因子NF-E2相关因子-2(nuclear factor erythroid 2-related factor 2,Nrf2)/血红素加氧酶-1(heme oxygenase-1,HO-1)通路探讨捏脊改善孤独症大鼠行为障碍的作用机制。方法将孤独症模型大鼠随机分为模型组、捏脊组,每组9只;同时纳入9只正常大鼠为空白组。捏脊组进行捏脊,21次/d,持续28 d。干预结束,各组大鼠进行行为学检测后处死取材,灌注固定后Nissl染色检测海马CA1、CA2区神经元损伤情况,取海马以生化试剂盒检测还原型谷胱甘肽(glutathione,GSH)、丙二醛(malondialdehyde,MDA)、超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)表达,Western blot检测Nrf2及其磷酸化指标p-Nrf2、HO-1、NAD(P)H:醌氧化还原酶1[NAD(P)H:quinone oxidoreductase 1,NQO1]表达。结果与空白组比较,模型组社交指数、站立次数均显著降低(P<0.01),理毛次数显著增多(P<0.01);与模型组比较,捏脊组社交指数、站立次数均明显提升(P<0.01),理毛次数减少(P<0.05)。空白组神经元细胞排列紧密,形态规则,尼氏体数量丰富;模型组有大量神经元受损,细胞核固缩深染,细胞膜破裂、边界模糊,尼氏体偏移、溶解,尼氏体阳性细胞数量减少;捏脊组细胞排列基本整齐,核固缩形态有所改善,细胞形态可,尼氏体阳性细胞数量增加。与空白组比较,模型组GSH、SOD、CAT、p-Nrf2/Nrf2、HO-1、NQO1表达量均降低(P<0.05或P<0.01),MDA表达量明显升高(P<0.01);与模型组比较,捏脊组GSH、SOD、CAT、p-Nrf2/Nrf2、HO-1、NQO1表达量均升高(P<0.05或P<0.01),MDA表达量显著下降(P<0.01)。结论捏脊能改善孤独症大鼠行为障碍,与其活化Nrf2/HO-1通路、引起抗氧化因子表达、改善氧化应激、减轻神经元损伤有关。

The β-amyloid protein induces S100β expression in rat hippocampus through a mechanism that involves IL-1

Objective To explore the effect of β-amyloid protein (Aβ) on S100β expression in rat hippocampus and its mechanisms. Methods At 7 days after bilateral stereotaxis injection of different dose of fibrillar Aβ 25-35 and interluekin-1 receptor antagonist (IL-1ra) into the rat CA1 region, the learning and memory abilities of rats were tested with passive avoidance task. Amyloid deposition was detected by using Congo red staining technique. Nissl staining and immunohistochemical techniques were used to analyze the number of neurons, and GFAP and the S100β expression in hippocampal CA1 region , respectively. Results After fibrillar Aβ injection, the step-through latency of rats was significantly shortened compared to that of the control group. The GFAP positive astrocytes were found surrounding amyloid deposition. Neuronal loss occurred in the pyramidal cell layer of CA1 region. The number of S100β positive cells in Aβ-treated group was significantly increased compared with that in the control group. After IL-1ra injection, the number of S100β positive cells was significantly decreased. Conclusion Intrahippocampal injection of Aβ 25-35 could cause similar pathologic changes of Alzheimer’s disease. Aβ 25-35 was capable of up-regulating S100β expression in a dose-dependent manner. The injection of IL-1ra could attenuate the effect of Aβ on S100β expression.

Repetitive traumatic brain injury–induced complement C1–related inflammation impairs long-term hippocampal neurogenesis

Repetitive traumatic brain injury impacts adult neurogenesis in the hippocampal dentate gyrus,leading to long-term cognitive impairment.However,the mechanism underlying this neurogenesis impairment remains unknown.In this study,we established a male mouse model of repetitive traumatic brain injury and performed long-term evaluation of neurogenesis of the hippocampal dentate gyrus after repetitive traumatic brain injury.Our results showed that repetitive traumatic brain injury inhibited neural stem cell proliferation and development,delayed neuronal maturation,and reduced the complexity of neuronal dendrites and spines.Mice with repetitive traumatic brain injuryalso showed deficits in spatial memory retrieval.Moreover,following repetitive traumatic brain injury,neuroinflammation was enhanced in the neurogenesis microenvironment where C1q levels were increased,C1q binding protein levels were decreased,and canonical Wnt/β-catenin signaling was downregulated.An inhibitor of C1 reversed the long-term impairment of neurogenesis induced by repetitive traumatic brain injury and improved neurological function.These findings suggest that repetitive traumatic brain injury–induced C1-related inflammation impairs long-term neurogenesis in the dentate gyrus and contributes to spatial memory retrieval dysfunction.

Expression of fibroblast growth factor-2 and fibroblast growth factor receptor-1 protein in the hippocampus in rats exhibiting chronic stress-induced depression

There is evidence that the expression of members of the fibroblast growth factor （FGF） protein family is altered in post-mortem brains of humans suffering from major depressive disorder. The present study examined whether the expression of fibroblast growth factor-2 （FGF2） and fibroblast growth factor receptor-1 （FGFR1） protein is altered following chronic stress in an animal model. Rats were exposed to 35 days of chronic unpredictable mild stress, and then tested using open-field and sucrose consumption tests. Compared with the control group, rats in the chronic stress group exhibited obvious depressive-like behaviors, including anhedonia, anxiety and decreased mobility. The results of western blot analysis and immunohistochemical analysis revealed a downregulation of the expression of FGF2 and FGFR1 in the hippocampus of rats, particularly in the CA1, CA3 and dentate gyrus. This decreased expression is in accord with the results of post-mortem studies in humans with major depressive disorder. These findings suggest that FGF2 and FGFR1 proteins participate in the pathophysiology of depressive-like behavior, and may play an important role in the mechanism of chronic stress-induced depression.

过表达海马LINGO-1对小鼠学习和记忆能力及海马各亚区Spinophilin+树突棘的影响

目的 脑立体定位注射腺相关病毒特异性过表达海马LINGO-1,探讨其对小鼠空间学习和记忆能力以及海马各亚区体积和Spinophilin+树突棘的影响。方法 将7月龄雄性C57小鼠按照简单随机法分为对照组和LINGO-1过表达组,对照组小鼠海马立体定位注射携带绿色荧光的空载腺相关病毒(adeno-associated virus, AAV),LINGO-1过表达组小鼠海马立体定位注射同时携带绿色荧光和LINGO-1过表达载体的AAV。运用Morris水迷宫评估小鼠的空间学习和记忆能力,荧光定量PCR及免疫荧光染色方法分别检测小鼠海马内LINGO-1基因表达水平和各亚区荧光强度,体视学三维定量小鼠海马各亚区体积及Spinophilin+树突棘总数。结果 对照组和LINGO-1过表达组病毒注射前后体质量差异无统计学意义;LINGO-1过表达诱导小鼠海马LINGO-1的mRNA水平升高、荧光强度增强(P<0.01);与对照组相比,LINGO-1过表达组小鼠在Morris水迷宫实验中的表现明显更差(P<0.05);LINGO-1过表达诱导小鼠海马各亚区体积显著下降(P<0.05,P<0.01),Spinophilin+树突棘密度显著降低(P<0.01,P<0.05),Spinophilin+树突棘数量显著减少(P<0.05)。结论 海马立体定位注射过表达LINGO-1腺相关病毒能够特异性上调小鼠海马内LINGO-1水平,海马LINGO-1的异常高表达可导致小鼠海马体积减小及Spinophilin+树突棘突触丢失,并在一定程度上损伤其空间学习与记忆能力。

七氟烷对β淀粉样蛋白_(1-40)诱导的大鼠认知功能障碍影响及机制

目的 探讨七氟烷吸入对β淀粉样蛋白(Aβ)_(1-40)诱发的大鼠认知功能障碍影响及其可能的机制。方法 于2021年8月至2022年8月,将32只成年雄性Sprague-Dawley大鼠以随机数字表法分为生理盐水(NS)+氧气组、NS+七氟烷组、Aβ+氧气组和Aβ+七氟烷组,每组8只,分别给予双侧海马内注射NS或Aβ_(1-40)。吸入30%氧气或2.5%七氟烷过程中监测生命体征,采用Morris水迷宫实验检测大鼠认知功能;酶联免疫吸附测定检测海马Aβ_(1-40)水平;免疫组织化学法检测胶质纤维酸性蛋白(GFAP)和离子钙接头蛋白分子1(IBA1)的表达;实时荧光定量逆转录聚合酶链反应检测白细胞介素-1β(IL-1β)、核因子-κB(NF-κB)、诱导型一氧化氮合酶(iNOS)的mRNA表达;蛋白质印迹法检测B淋巴细胞瘤-xL(Bcl-xL)、胱天蛋白酶-9(caspase-9)、脑源性神经营养因子(BDNF)和晚期糖基化终末产物受体(RAGE)的蛋白表达。结果 维持吸入2.5%七氟烷在4个不同时间点(1、2、3和4 h)对大鼠生命体征无影响。与NS+氧气组比较,Aβ+氧气组大鼠原始平台探索时间减少,逃逸潜伏期增加;与Aβ+氧气组相比,Aβ+七氟烷组大鼠原始平台探索时间减少,逃逸潜伏期增加(P<0.05)。Aβ+七氟烷组大鼠海马区Aβ_(1-40)水平[(42.18±5.72)ng/L],GFAP和IBA1阳性细胞数[(24.33±1.21)个和(37.82±3.23)个],caspase-9和RAGE蛋白表达(0.74±0.11和0.81±0.07),IL-1β、NF-κB和iNOS mRNA表达(28.98±12.32、25.91±12.31和43.92±17.21)均高于NS+七氟烷组[(18.13±2.89)ng/L、(10.51±0.96)个、(17.17±1.77)个、0.23±0.02、0.29±0.03、1.35±0.04、1.37±0.05、1.42±0.06]和Aβ+氧气组[(32.61±4.82)ng/L、(15.76±1.25)个、(24.76±2.31)个、0.45±0.08、0.68±0.08、10.23±6.56、6.51±2.34、13.23±4.81];Bcl-xL和BDNF蛋白表达(0.13±0.04和0.18±0.04)低于NS+七氟烷组(1.07±0.31和0.58±0.07)和Aβ+氧气组(0.46±0.11和0.33±0.04)(P<0.05)。而NS+氧气组和NS+七氟烷组之间各指标差异无统计学意义(P>0.05)。结论 七氟烷通过启动大鼠海马的神经毒性、神经炎症和神经元凋亡,加剧了Aβ_(1-40)诱发的大鼠认知功能障碍。

Movement and behavior analysis using neural spike signals in CA1 of rat hippocampus

The hippocampus which lies in the temporal lobe plays an important role in spatial navigation,learning and memory.Several studies have been made on the place cell activity,spatial memory,prediction of future locations and various learning paradigms.However,there are no attempts which have focused on finding whether neurons which contribute largely to both spatial memory and learning about the reward exist.This paper proposes that there are neurons that can simultaneously engage in forming place memory and reward learning in a rat hippocampus' s CA1 area.With a trained rat,a reward experiment was conducted in a modified 8-shaped maze with five stages,and utterance information was obtained from a CA1 neuron.The firing rate which is the count of spikes per unit time was calculated.The decoding was conducted with log-maximum likelihood estimation(Log-MLE) using Gaussian distribution model.Our outcomes provide evidence of neurons which play a part in spatial memory and learning regarding reward.

Increased hippocampal Disrupted-In-Schizophrenia 1 expression in mice exposed prenatally to lead

Disrupted-in-Schizophrenia 1 is a susceptibility gene for schizophrenia and other psychiatric disorders. Developmental lead exposure can cause neurological disorders similar to hyperactivity disorder, dyslexia and schizophrenia. In the present study, we examined the impact of developmental lead exposure, administered in vitro and in vivo, on hippocampal Disrupted-In- Schizophrenia 1 expression. Our results show that in cultured hippocampal neurons, in vitro exposure to 0.1-10 pM lead, inhibited neurite growth and increased Disrupted-In-Schizophrenia 1 mRNA and protein expression dose-dependently. In addition, blood lead levels in mice were increased with increasing mouse maternal lead （0.01-1 mM） exposure. Hippocampal neurons from these mice showed a concomitant increase in Disrupted-in-Schizophrenia 1 mRNA and protein expression. Overall our findings suggest that in vivo and in vitro lead exposure increases Disrupted-In-Schizophrenia 1 expression in hippocampal neurons dose-dependently, and consequently may influence synapse formation in newborn neurons.

Effect of electroacupuncture on glial fibrillary acidic protein and nerve growth factor in the hippocampus of rats with hyperlipidemia and middle cerebral artery thrombus

Electroacupuncture(EA)has been shown to reduce blood lipid level and improve cerebral ischemia in rats with hyperlipemia complicated by cerebral ischemia.However,there are few studies on the results and mechanism of the effect of EA in reducing blood lipid level or promoting neural repair after stroke in hyperlipidemic subjects.In this study,EA was applied to a rat model of hyperlipidemia and middle cerebral artery thrombosis and the condition of neurons and astrocytes after hippocampal injury was assessed.Except for the normal group,rats in other groups were fed a high-fat diet throughout the whole experiment.Hyperlipidemia models were established in rats fed a high-fat diet for 6 weeks.Middle cerebral artery thrombus models were induced by pasting 50%FeCl3 filter paper on the left middle cerebral artery for 20 minutes on day 50 as the model group.EA1 group rats received EA at bilateral ST40(Fenglong)for 7 days before the thrombosis.Rats in the EA1 and EA2 groups received EA at GV20(Baihui)and bilateral ST40 for 14 days after model establishment.Neuronal health was assessed by hematoxylin-eosin staining in the brain.Hyperlipidemia was assessed by biochemical methods that measured total cholesterol,triglyceride,low-density lipoprotein and high-density lipoprotein in blood sera.Behavioral analysis was used to confirm the establishment of the model.Immunohistochemical methods were used to detect the expression of glial fibrillary acidic protein and nerve growth factor in the hippocampal CA1 region.The results demonstrated that,compared with the model group,blood lipid levels significantly decreased,glial fibrillary acidic protein immunoreactivity was significantly weakened and nerve growth factor immunoreactivity was significantly enhanced in the EA1 and EA2 groups.The repair effect was superior in the EA1 group than in the EA2 group.These findings confirm that EA can reduce blood lipid,inhibit glial fibrillary acidic protein expression and promote nerve growth factor expression in the hippocampal CA1 region after hyperlipidemia and middle cerebral artery thrombosis.All experimental procedures and protocols were approved by the Animal Use and Management Committee of Beijing University of Chinese Medicine,China(approval No.BUCM-3-2018022802-1002)on April 12,2018.

Similar effects of substance P on learning and memory function between hippocampus and striatal marginal division

Substance P is an endogenous neurokinin that is present in the central and peripheral nervous systems. The neuropeptide substance P and its high-affinity receptor neurokinin 1 receptor are known to play an important role in the central nervous system in inflammation, blood pressure, motor behavior and anxiety. The effects of substance P in the hippocampus and the marginal di- vision of the striatum on memory remain poorly understood. Compared with the hippocampus as a control, immunofluorescence showed high expression of the substance P receptor, neuro- kinin 1, in the marginal division of the striatum of normal rats. Unilateral or bilateral injection of an antisense oligonucleotide against neurokinin 1 receptor mRNA in the rat hippocampus or marginal division of the striatum effectively reduced neurokinin 1 receptor expression. Indepen- dent of injection site, rats that received this antisense oligonucleotide showed obviously increased footshock times in a Y-maze test. These results indicate that the marginal division of the striatum plays a similar function in learning and memory to the hippocampus, which is a valuable addi- tion to our mechanistic understanding of the learning and memory functions of the marginal division of the striatum.

沉默海马LINGO-1对小鼠学习记忆以及有髓神经纤维的影响

目的:研究沉默海马含亮氨酸重复序列和免疫球蛋白结构域的蛋白-1(LINGO-1)对APP/PS1小鼠空间学习和记忆能力以及海马有髓神经纤维的影响。方法:随机选取18只雄性APP/PS1小鼠,随机分为对照组和rAAV-LINGO-1-shRNA组,通过海马立体定位注射表达LINGO-1-shRNA的重组腺相关病毒rAAV-LINGO-1-shRNA,运用Morris水迷宫方法测试小鼠的空间学习和记忆能力;运用免疫荧光染色和real time RT-PCR分析小鼠海马内LINGO-1表达水平;运用real time RT-PCR分析小鼠海马内LINGO-1下游分子RhoA和ROCK的表达水平;运用无偏体视学方法结合透射电子显微镜技术对小鼠海马(CA1~3和齿状回)的体积,海马内有髓神经纤维的长度、髓鞘体积及其损伤情况进行定量研究。结果:与对照组小鼠相比,rAAV-LINGO-1-shRNA组小鼠的逃避潜伏期显著性缩短,穿台次数显著增多,而目标象限游泳时间及目标象限游泳路程比无显著性改变;与对照组相比,rAAV-LINGO-1-shRNA组海马内LINGO-1显著下调,同时其下游RhoA和ROCK的表达水平降低;对照组和rAAV-LINGO-1-shRNA组海马体积无显著性差异;与对照组相比,rAAV-LINGO-1-shRNA组海马内有髓神经纤维的长度和正常髓鞘的体积显著性增加,受损的有髓神经纤维占比和受损的髓鞘占比均显著降低。结论:沉默海马LINGO-1能够有效改善APP/PS1小鼠海马依赖的空间学习和记忆能力,抑制RhoA/ROCK的表达,减轻海马内有髓神经纤维及其髓鞘的损伤,这将为阿尔茨海默病的发病及治疗提供新的方向。

Brain and spinal cord trauma:what we know about the therapeutic potential of insulin growth factor 1 gene therapy

Although little attention has been paid to cognitive and emotional dysfunctions observed in patients after spinal co rd injury,several reports have described impairments in cognitive abilities.Our group also has contributed significantly to the study of cognitive impairments in a rat model of spinal co rd injury.These findings are very significant because they demonstrate that cognitive and mood deficits are not induced by lifestyle changes,drugs of abuse,and combined medication.They are related to changes in brain structures involved in cognition and emotion,such as the hippocampus.Chronic spinal cord injury decreases neurogenesis,enhances glial reactivity leading to hippocampal neuroinflammation,and trigge rs cognitive deficits.These brain distal abnormalities are recently called te rtiary damage.Given that there is no treatment for Tertiary Damage,insulin growth factor 1 gene therapy emerges as a good candidate.Insulin growth factor 1 gene thera py recove rs neurogenesis and induces the polarization from pro-inflammato ry towards anti-inflammatory microglial phenotypes,which represents a potential strategy to treat the neuroinflammation that supports te rtiary damage.Insulin growth factor 1 gene therapy can be extended to other central nervous system pathologies such as traumatic brain injury where the neuroinflammatory component is crucial.Insulin growth factor 1 gene therapy could emerge as a new therapeutic strategy for treating traumatic brain injury and spinal cord injury.

Therapeutic effect of bone marrow mesenchymal stem cells on cold stress induced changes in the hippocampus of rats

The present study aims to evaluate the effect of bone marrow mesenchymal stem cells on cold stress induced neuronal changes in hippocampal CA1 region of Wistar rats. Bone marrow mes- enchymal stem cells were isolated from a 6-week-old Wistar rat. Bone marrow from adult femora and tibia was collected and mesenchymal stem cells were cultured in minimal essential medium containing 10% heat-inactivated fetal bovine serum and were sub-cultured. Passage 3 cells were analyzed by flow cytometry for positive expression of CD44 and CD90 and negative expression of CD45. Once CD44 and CD90 positive expression was achieved, the cells were cultured again to 90% confluence for later experiments. Twenty-four rats aged 8 weeks old were randomly and evenly divided into normal control, cold water swim stress （cold stress）, cold stress ＋ PBS （intra- venous infusion）, and cold stress ＋ bone marrow mesenchymal stem cells （1 x 106; intravenous infusion） groups. The total period of study was 60 days which included 1 month stress period followed by 1 month treatment. Behavioral functional test was performed during the entire study period. After treatment, rats were sacrificed for histological studies. Treatment with bone marrow mesenchymal stem cells significantly increased the number of neuronal cells in hippocampal CA 1 region. Adult bone marrow mesenchymal stem cells injected by intravenous administration show potential therapeutic effects in cognitive decline associated with stress-related lesions.

11β-羟化类固醇脱氢酶敲除对高脂饮食喂养小鼠认知功能的影响

目的:探究11β-羟化类固醇脱氢酶1(11β-hydroxysteroid dehydrogenase,11β-HSD1)基因敲除对小鼠整体代谢和认知功能的影响。方法:将C57BL/6J为遗传背景的野生对照组及11β-HSD1基因敲除组各15只小鼠高脂喂养20周,代谢笼评估能量代谢,行为学评估观察小鼠认知功能,电镜评估海马体的线粒体结构,免疫荧光及PCR确定其认知功能、线粒体功能相关基因及炎症基因的变化。结果:11β-HSD1基因敲除能够提高高脂喂养小鼠学习和记忆能力,改善握力,改善海马体的微结构、线粒体含量变多,认知相关基因、线粒体呼吸功能相关基因上调,炎症相关基因改变。结论:11β-HSD1敲除后高脂饮食喂养小鼠认知功能显著改善,握力显著提高,可能是治疗认知功能障碍的有效靶点。