卒中后抑郁患者海马磁共振氢质子波谱分析

目的 探讨卒中后抑郁患者海马氢质子磁共振波谱（1H-MRS）的特点.方法 以32例卒中后抑郁患者为研究组,30例脑卒中患者为病例对照组,30名正常人为正常对照组.三组在入组24 h内采用多体素1 H-MRS检测双侧海马N-乙酰基天门冬氨酸（NAA）、胆碱复合物（Cho）与肌酸复合物（Cr）,完成NAA/Cr值和Cho/Cr值的计算.结果 研究组左右侧海马NAA/Cr值均低于病例对照组和正常对照组,P均＜0.05;研究组左侧海马Cho/Cr值均高于病例对照组和正常对照组,P均＜0.05;右侧海马Cho/Cr值高于正常对照组（P＜0.05）,但与病例对照组比较,P＞0.05.重度抑郁组左右侧海马NAA/Cr值均低于轻度抑郁组,P均＜0.05;不同抑郁程度的双侧海马Cho/Cr值比较,P均＞0.05;研究组双侧海马NAA/Cr值与HAMD评分呈负相关（P均＜0.05）,而双侧海马Cho/Cr值与HAMD评分不存在相关关系（P＞0.05）.三组左右两侧海马各研究指标比较,P均＞0.05.结论 海马神经元代谢的异常可能是卒中后抑郁的神经生物学基础;卒中后抑郁患者、脑卒中患者和正常人脑部NAA、Cho可能并不存在侧化现象.     

慢性脑缺血大鼠学习记忆损害与海马磁共振波谱分析

目的探讨慢性脑缺血对大鼠空间学习记忆功能及海马区神经细胞代谢物水平的影响及后两者的相关性。方法雄性10月龄SD大鼠30只,随机分为缺血组、假手术组和对照组,每组10只。行Morris水迷宫实验及质子磁共振波谱(~1H-MRS)扫描,计算左侧海马区N-乙酰天冬氨酸(NAA)/总肌酸(Cr)、胆碱复合物(Cho)/Cr的积分面积比值。结果缺血组大鼠定位航行的平均逃逸时间较假手术组和对照组明显延长,停留于平台所在区域的时间及穿越平台区域次数均较假手术组和对照组明显减少(P0.01)。缺血组大鼠左侧海马区Cho/Cr、NAA/Cr水平较假手术组和对照组明显降低(P0.05,P0.01)。各组大鼠左侧海马NAA/Cr、Cho/Cr水平与对应停留时间、穿越平台区域次数的变化趋势呈正相关。结论持续性低血流灌注可导致大鼠海马区神经元的功能代谢水平降低及学习记忆能力明显受损,海马区神经元的功能活性下降是认知障碍的重要机制之一。     

帕金森病模型大鼠海马mGluR5的表达变化及意义

目的探讨帕金森病(PD)模型大鼠海马mGluR5的表达变化及意义。方法将SD大鼠随机分为正常对照组(A组)、PD模型组(B组)和非竞争性NMDA受体拮抗剂D-AP-5+PD组(C组),通过免疫组织化学方法观察多克隆抗体mGluR5在大鼠海马的表达变化。结果正常对照组中大鼠海马有丰富的mGluR5表达;PD模型组中大鼠海马mGluR5表达明显下降;在非竞争性NMDA受体拮抗剂D-AP-5+PD组中,大鼠海马mGluR5表达又明显上调。结论帕金森病模型大鼠海马各区mGluR5表达下降,可能是神经细胞的一种自我保护作用。mGluR5可能与帕金森病认知和情感及记忆功能障碍有关。帕金森病模型大鼠海马各区经用非竞争性NMDA受体拮抗剂D-AP-5处理后,海马mGluR5表达明显上调,推测mGluR5表达下降可能在帕金森病长时程增强(LTP)诱导过程中具有重要作用,其作用机制可能为NMDA受体依赖性。     

脑缺血后抑郁大鼠脑磁共振波谱研究及颐脑解郁方的干预作用

目的 采用在体磁共振波谱技术(1H-MRS)研究脑缺血后抑郁大鼠模型的脑内代谢变化及中药颐脑解郁方的干预作用.方法 采用去皮层血管结合孤养、慢性不可预知性应激的方法复制脑缺血后抑郁大鼠模型,采用在体磁共振波谱技术,观察大鼠左侧海马的代谢变化及颐脑解郁方的干预作用.结果 脑缺血后抑郁大鼠脑裂明显扩大(P<0.01);中药治疗组和西药对照组大鼠脑裂宽度较模型组有所减小趋势.模型组大鼠海马区域NAA/Cr较正常组降低(P<0.05);中药治疗组大鼠海马区域NAA/Cr与模型组相比有所增加(P<0.05);西药对照组大鼠海马区域NAA/Cr低于正常组(P<0.05),而与模型组相比则无明显变化.模型组、中药治疗组、西药对照组大鼠海马区域Cho/Cr明显低于正常组(P<0.01);而与模型组相比,中药治疗组、西药对照组大鼠海马区域Cho/Cr变化不明显.结论 脑缺血后抑郁大鼠存在脑萎缩,海马神经元的损伤和功能紊乱.中药颐脑解郁方具有保护和改善神经元功能的作用.     

急性坏死性胰腺炎大鼠胰腺代谢特征分析

目的 对急性坏死性胰腺炎(ANP)大鼠离体胰腺组织块行高分辨魔角旋转核磁共振波谱分析(HR-MASNMR),探索其代谢变化特征.方法 按完全随机法将30只Wistar大鼠分为ANP组(20只)和对照组(10只).ANP组大鼠经腹腔分2次注射L-精氨酸2.5 mg/g体重方法 制备,对照组仅注射等容积的生理盐水.运用HR-MASNMR分析两组离体胰腺组织代谢物的含量.结果 造模12 h后,胰腺水肿伴出血、实质内大片凝固性坏死、间质中炎性细胞浸润,并见胰周脂肪皂化;血清淀粉酶水平为(3527±429)U/L,显著高于对照组的(1250±188)U/L.波谱分析显示ANP组胰腺组织的牛磺酸(Tau)、乙酸(Ace)、丙氨酸(Ala)波峰下面积较对照组显著增加(P＜0.05);甜菜碱(Bet)、磷酸胆碱+甘油磷酸胆碱(Pc+Gpc)含量较对照组降低(P＜0.05);胆碱(Cho)、谷氨酸(Glu)、乳酸(Lac)波峰下面积与对照组无明显差异.结论ANP大鼠离体胰腺组织块具有显著的代谢特征,为进一步开展人类重症急性胰腺炎在体波谱研究奠定了实验基础.     

文拉法辛对老年抑郁大鼠海马血管内皮生长因子表达的影响

目的 探讨抗文拉法辛对老年抑郁大鼠海马血管内皮生长因子(VEGF)表达的影响.方法 老年雄性SD大鼠,随机分为3组,模型组、文拉法辛组各12只均给予慢性不可预测的温和多相应激结合孤养共5 w,文拉法辛组于应激第3周末开始同时给予文拉法辛(5 mg.kg-1.d-1)治疗持续14 d,模型组同时给予生理盐水14 d.对照组12只不给予任何处理.采用敞箱实验和糖水消耗实验观察大鼠抑郁建模情况.采用免疫印迹检测海马VEGF蛋白表达,逆转录聚合酶链反应(RT-PCR)检测VEGF mRNA表达.结果 敞箱实验、液体消耗实验显示模型组及文拉法辛组抑郁模型建立成功.与模型组比较,文拉法辛组垂直得分增高,蔗糖消耗增加(P均＜0.05).与对照组比较,文拉法辛组海马VEGF蛋白及VEGFmRNA表达均增加(P ＜0.05,P＜0.01);模型组海马VEGF蛋白及VEGF mRNA表达均下降(P＜0.05).文拉法辛组与模型组比较,文拉法辛组VEGF蛋白及VEGF mRNA表达均明显增加(P＜0.01).结论 文拉法辛可提高老年抑郁大鼠VEGF表达,并对血管新生可能起到促进作用.     

脑卒中后抑郁与海马弥散加权成像表观弥散系数的关系

目的 探讨脑卒中后抑郁(PSD)患者海马弥散加权成像表观弥散系数(ADC)变化与PSD的关系.方法 选择60例脑卒中患者,其中合并PSD者30例(PSD组),无PSD者30例(无PSD组);另择30例查体健康者作为对照组.3组均行MRI检查,测定双侧海马ADC.结果 与对照组比较,PSD组双侧海马ADC明显升高(P均＜0.01);无PSD组与对照组比较无统计学差异(P均＞0.05).结论 PSD患者双侧海马ADC升高;ADC可作为判断PSD的重要参考指标之一.     

氟西汀对癫痫合并抑郁大鼠海马GFAP、NeuN表达的影响

目的探讨氟西汀对癫痫合并抑郁大鼠海马齿状回胶质纤维酸性蛋白(GFAP)、神经元核抗原(NeuN)表达的影响。方法SPF级SD大鼠60只,随机分为对照组、模型组、氟西汀低、中、高剂量组各12只。模型组和对照组给予等剂量生理盐水,1次/d,腹腔注射;氟西汀低、中、高剂量组给予氟西汀(5.0、7.5、10.0 mg/kg),1次/d,腹腔注射。治疗28 d,采用强迫游泳实验和旷场实验测试大鼠行为学表现,采用免疫组化、RT-PCR检测海马GFAP、NeuN表达。结果造模后,与对照组相比,模型组、氟西汀低、中、高剂量组不动时间延长,垂直运动次数、水平运动次数明显下降(P<0.05)。干预后,模型组不动时间明显长于对照组,垂直运动次数、水平运动次数明显低于对照组(P<0.01);与模型组相比,氟西汀低、中、高剂量组不动时间缩短,垂直运动次数、水平运动次数明显增加(P<0.05);尤其是氟西汀高剂量组,较氟西汀低、中剂量组相比有统计学意义(P<0.05)。免疫组化、RT-PCR显示,与对照组相比,模型组GFAP表达明显增加、NeuN表达明显下降(P<0.05);与模型组相比,氟西汀低、中、高剂量组GFAP表达明显下降、NeuN表达明显增加(P<0.05);尤其是氟西汀高剂量组,较氟西汀低、中剂量组相比有统计学意义(P<0.05)。结论氟西汀可能通过改变海马区GFAP、NeuN表达,并呈剂量依赖性,发挥神经保护作用,改善癫痫合并抑郁大鼠抑郁症状。     

脑卒中后抑郁大鼠海马、丘脑组织中BNDF、TrkB的表达变化及意义

目的观察脑卒中后抑郁(PSD)大鼠海马、丘脑组织中BDNF及其高亲和力受体原肌球蛋白受体激酶B(TrkB)的表达变化,并探讨其意义。方法将32只大鼠随机分为正常组、抑郁组、卒中组及PSD组各8只。正常组不干预;抑郁组采用孤养法制作抑郁模型;卒中组及PSD组采用线栓法致局灶性脑缺血(卒中);PSD组加慢性不可预见的中等应激刺激和孤养法制作PSD模型。采用RT-PCR法检测各组大脑海马及丘脑组织中的BNDF mRNA和TrkB mRNA。结果 PSD组海马BNDF mRNA、丘脑TrkB mRNA表达均明显低于对照组(P均<0.05);其余各组海马BNDF mRNA表达、丘脑TrkB mRNA表达比较均无统计学差异。结论 PSD大鼠海马、丘脑组织中BDNF及TrkB表达降低,二者可能参与了PSD的发病。     

Ⅱ组代谢型谷氨酸受体阻断剂对大鼠海马神经元凋亡的影响

目的观察Ⅱ组代谢型谷氨酸受体阻断剂对大鼠海马神经元凋亡的影响。方法 SD大鼠24只随机分为假手术组、痴呆组和阻断剂组,每组8只。大鼠脑室注射凝聚肽Aβ_(25-35)5建立痴呆大鼠模型,阻断剂组1周后行阻断剂脑室注射,另2组等量注射人工脑脊液4周行Morris水迷宫测试;测试1周后取材行病理观察,采用TUNEL法检测海马CA1区锥体细胞凋亡情况。结果与假手术组比较,痴呆组大鼠平均潜伏期明显延长,平台象限滞留时间明显缩短(P0.05);与痴呆组比较,阻断剂组大鼠上述指标明显提高(P0.05)。与假手术组比较,痴呆组大鼠海马CA1区可见大量的凋亡锥体细胞,阳性锥体细胞数、总面积、平均吸光度(A)值明显升高(P0.05);与痴呆组比较,阻断剂组大鼠海马CA1区可见明显的阳性细胞和核固缩,但其阳性染色锥体细胞数、总面积、平均A值明显降低(P0.05)。结论Ⅱ组代谢型谷氨酸受体阻断剂可明显抑制痴呆引起的海马CA1区锥体细胞的凋亡,提示其可能通过影响细胞凋亡,参与痴呆的发病过程。     

Energy metabolism in rat hippocampus during and following seizure activity

The hippocampus exhibits a post-ictal phenomenon in which it is unresponsive to further stimulation. It has been suggested that this loss of excitability is the basis of post-seizure amnesia. The biochemical events associated with this phenomenon are unclear. In the present study, energy metabolites were measured in the stratum oriens, stratum pyramidale and stratum radiatum in rat hippocampus, and correlated with field potential recordings. Wistar rats were anesthetized and the calvarium removed. Following removal of the cortex by aspiration, the hippocampus was covered with oil, and stimulating and recording electrodes were placed. Stimulation consisted of a train of stimuli at 100 Hz (10–20 m Amps). This stimulation was found to be effective in evoking self-sustaining after-discharges and post-ictal depression. Tissues for metabolite analysis were taken from a series of controls, from animals during active self-sustaining seizures, and from animals which were totally unresponsive to further electrical stimulation. Hippocampal tissue for metabolite analysis was obtained by pouring liquid N2 on the exposed tissue, then removing the frozen tissue. Glucose, ATP, and phosphocreatine were measured in hippocampal layers of CA1 using fluorescence techniques and enzymatic cycling. Results showed that during seizure activity, glucose, ATP, and phosphocreatine were all decreased from 40–80% in the three layers of the hippocampus, whereas from 60 seconds after the onset of hippocampal shutdown, energy metabolites had returned toward normal. Thus, at a time when the hippocampus was unresponsive, energy metabolites were at control levels. These data suggest that the shutdown phenomenon occurs in the presence of adequate energy stores.     

轻度阿尔茨海默病海马各区磁共振T_2信号的研究

目的探讨轻度阿尔茨海默病(AD)患者左右侧海马头体尾各部磁共振T2信号强度的变化,为AD的临床早期诊断及早期治疗提供影像学帮助。方法选择轻度AD患者(轻度AD组)20例和老年健康体检者(对照组)20例。所有受试者均行快速自旋回波T2序列,并在工作站手工勾绘海马各部感兴趣区,测量其T2信号强度。并分析各部磁共振T2信号强度与简易智能状态检查量表(MMSE)评分的相关性。应用ROC曲线计算海马磁共振T2信号作为轻度AD临床诊断指标的阈值,并评价其价值。结果轻度AD组双侧海马头部磁共振T2信号强度较对照组明显增高,差异有统计学意义(P<0.05)。MMSE评分与轻度AD双侧海马头部呈负相关。左侧海马头部磁共振T2信号强度最佳诊断阈值为563.0,敏感性为87.0%,特异性为94.0%;右侧海马头部磁共振T2信号强度最佳诊断阈值为562.2,敏感性为89.0%,特异性为93.0%。结论轻度AD患者双侧海马头部磁共振T2信号强度存在异常,并可作为AD早期诊断有价值的辅助指标之一。     

阿尔茨海默病认知功能与磁共振成像测量海马和侧脑室颞角的相关性

目的探讨轻、中度阿尔茨海默病(AD)认知功能和MRI测量海马和侧脑室颞角的相关性。方法对31例AD患者(AD组)及30例健康体检者(对照组)进行认知功能量表的检测,包括简易智能状态检查表(MMSE)、日常生活能力量表(ADL)、Pfeffer功能活动调查表(POD)、Fuld物体记忆测验(FOM)、快速词汇测验(RVR)、数字广度测验(DS)、积木测验(BD)等,同时应用MRI测量颅腔的海马体积和侧脑室颞角宽度。结果海马体积、侧脑室颞角宽度AD组与对照组比较差异显著(P<0.01)。海马体积、侧脑室颞角宽度与MMSE、ADL、POD、FOM有相关性,其与DS、BD无相关性,其中海马体积与MMSE、FOM密切相关。结论AD患者的认知功能评定与MRI脑结构测量有一定的相关性,认知功能和MRI脑结构测量可为临床诊断和治疗提供可靠依据。     

Melatonin and the human hippocampus, a time dependent interplay

Melatonin serves as a signal of darkness and participates in sleep/wake regulation. Animal studies demonstrated effects of melatonin in the hippocampus, particularly suggesting involvement in synaptic plasticity. We used functional magnetic resonance imaging to identify and investigate effects of melatonin in the human hippocampus. Activity in the hippocampal complex during a memory task was examined at 22:00 hr (when endogenous melatonin levels are normally increasing) and compared with 16:00 hr (when endogenous melatonin levels are minimal). The relationship between observed activation patterns and endogenous melatonin was assessed. Finally, the effects of exogenous melatonin administered at 22:00 hr were studied in a double-blind, placebo-controlled crossover manner. Our findings indicate that activation in the left hippocampus at 22:00 hr is significantly reduced compared with afternoon hours compatible with diurnal variation in hippocampal activity. Exogenous melatonin further reduced activation in this region, only in subjects who already crossed the melatonin onset phase at this hour and in correlation with endogenous melatonin levels. As such an effect was not demonstrated with afternoon administration of melatonin, a time depended effect is suggested. Contrary, activation in the left para-hippocampus at 22:00 hr was higher in subjects that crossed the melatonin onset phase. Parahippocampal activation correlated with individual endogenous melatonin levels and was not further affected by exogenous melatonin. These results demonstrate that memory related activation in the hippocampus and para-hippocampus are affected by time of day and melatonin in a differential manner and may implicate the circadian clock and melatonin in human memory processing during the night.     

Exercise induces age-dependent changes on epigenetic parameters in rat hippocampus: A preliminary study

Regular exercise improves learning and memory, including during aging process. Interestingly, the imbalance of epigenetic mechanisms has been linked to age-related cognitive deficits. However, studies about epigenetic alterations after exercise during the aging process are rare. In this preliminary study we investigated the effect of aging and exercise on DNA methyltransferases (DNMT1 and DNMT3b) and H3-K9 methylation levels in hippocampus from 3 and 20-months aged Wistar rats. The animals were submitted to two exercise protocols: single session or chronic treadmill protocol. DNMT1 and H3-K9 methylation levels were decreased in hippocampus from aged rats. The single exercise session decreased both DNMT3b and DNMT1 levels in young adult rats, without any effect in the aged group. Both exercise protocols reduced H3-K9 methylation levels in young adult rats, while the single session reversed the changes on H3-K9 methylation levels induced by aging. Together, these results suggest that an imbalance on DNMTs and H3-K9 methylation levels might be linked to the brain aging process and that the outcome to exercise seems to vary through lifespan.     

Proteomic analysis of hippocampus in the rat

Objective To analyze the protein expression in the rat hippocampus by the proteomic approach. Methods Proteins from hippocampal tissue homogenates of the rat were separated by two-dimensional gel electrophoresis (2-DE), and stained with colloidal Coomassie blue to produce a high-resolution map of the rat hippocampus proteome. Selected proteins from this map were digested with trypsin, and the resulting tryptic peptides were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) The mass spectrometric data were used to identify the proteins through searches of the NCBI protein sequence database. Results 37 prominent proteins with various functional characteristics were identified. The identified brain protein classes covered metabolism enzymes, cytoskeleton proteins, heat shock proteins, antioxidant proteins,signalling proteins, proteasome-related proteins, neuron-specific proteins and glial-associated proteins. Furthermore,3 hypothetical proteins, unknown proteins so far only proposed from their nucleic acid structure, were identified.Conclusion This study provides the first unbiased characterization of proteins of the rat hippocampus and will be used for future studies of differential protein expression in rat models of neurological disorders.