胆囊收缩素对实验性神经细胞老化过程中脂褐素的影响

目的 观察 CCK8对实验性神经细胞老化过程中脂褐素的影响。方法 采用 NBA2 细胞无血清培养建立神经细胞老化实验模型 ,以显微荧光分光光度仪测定单个细胞内脂褐素自发荧光值作为细胞老化指标 ,观察 CCK8对细胞老化过程的影响。结果 在无血清培养条件下 ,细胞内脂褐素荧光值随培养时间的延长而累积性增加 (P<0 .0 1 )。将 CCK8加入无血清培养液 ,CCK8作用 1 0 d和 1 5 d都可显著降低细胞内脂褐素荧光值 (P<0 .0 1 )。结论 在无血清培养条件下 ,NBA2 细胞由分裂增殖变为分化成熟老化 ,反映了神经细胞的老化过程。而 CCK8可以延缓细胞的老化进程。

香菇多糖联合依地酸钙钠对铅中毒小鼠学习记忆功能及海马NO,nNOS的影响

将50只小鼠随机分成空白对照组、模型对照组、阳性对照组、香菇多糖低剂量组、香菇多糖高剂量组5个组,用Morris水迷宫检测小鼠学习记忆功能,微分电位溶出法测定血铅含量,硝酸还原酶法检测NO含量,免疫组化方法观察nNOS阳性细胞表达.结果表明,香菇多糖高剂量组能显著改善铅中毒小鼠的学习记忆功能.与模型对照组相比,香菇多糖高剂量组能显著降低血铅浓度(P<0.01),提高海马NO含量(P<0.01),且增强nNOS阳性神经元表达CA1(P<0.05),CA3(P<0.01).这提示香菇多糖联合依地酸钙钠能改善铅中毒小鼠的学习记忆功能,其作用机制可能与海马NO含量增高及nNOS神经元表达增强有关.

视皮层神经元活动的振荡和同步振荡现象

视皮层神经元电活动的振荡和同步振荡现象是神经生理学实验的最新发现之一。这一研究成果在认知科学界引起广泛关注。学术界对它在认知心理学上的解释、作用及意义有不同的评论。

栀子总环烯醚萜苷对脑出血大鼠炎症反应与神经元凋亡的影响

目的研究栀子总环烯醚萜苷对大鼠脑出血后炎症反应和神经元凋亡的影响。方法将SD大鼠随机分为假手术组、模型组、清开灵注射液组(3000mg/kg)和栀子总环烯醚萜苷高、中、低剂量组(30,15,7.5mg/kg),采用自体血注入诱发大鼠脑出血模型,在术后48h取脑组织标本,放射免疫法检测血肿周围脑组织TNF-α和IL-1β含量,免疫组化检测ICAM-1和Caspase-3的表达。结果与模型组相比较,栀子总环烯醚萜苷中、高剂量组血肿周围脑组织TNF-α和IL-1β含量明显降低,具有显著性差异(P<0.05或P<0.01),ICAM-1和Caspase-3表达明显下调,差异具有显著性(P<0.05或P<0.01)。结论栀子总环烯醚萜苷可以干预脑出血后炎症反应,阻止神经元凋亡。

The pathways by which mild hypothermia inhibits neuronal apoptosis following ischemia/reperfusion injury

Several studies have demonstrated that mild hypothermia exhibits a neuroprotective role and it can inhibit endothelial cell apoptosis following ischemia/reperfusion injury by decreasing casp- ase-3 expression, It is hypothesized that mild hypothermia exhibits neuroprotective effects on neurons exposed to ischemia/reperfusion condition produced by oxygen-glucose deprivation. Mild hypothermia significantly reduced the number of apoptotic neurons, decreased the expres- sion of pro-apoptotic protein Bax and increased mitochondrial membrane potential, with the peak of anti-apoptotic effect appearing between 6 and 12 hours after the injury. These findings indicate that mild hypothermia inhibits neuronal apoptosis following ischemia/reperfusion injury by protecting the mitochondria and that the effective time window is 6-12 hours after ischemia/reperfusion injury.

Differentiation of GDNF and NT-3 Dual Gene-modified Rat Bone Marrow Mesenchymal Stem Cells into Enteric Neuron-like Cells

Bone marrow mesenchymal stem cells (BMSCs) have been shown to be multipotent cells that possess high self-replicating capacity.The purpose of our study was to investigate the feasibility of using enteric neuron-like cells obtained by in vitro induction and differentiated from rat BMSCs for the treatment of Hirschsprung’s disease (HD).Glial cell-derived neurotrophic factor (GDNF) and neurotrophin-3 (NT-3) are neurotrophic factors that play important roles in neuronal development,differentiation,survival and function.Meanwhile,GDNF mutations are a major cause of HD.In this study,BMSCs were transfected with eukaryotic expression plasmids co-expressing GDNF and NT-3,and the trans-fected cells displayed neuron-like changes after differentiation induced by fetal gut culture medium (FGCM).Immunofluorescence assay showed positive expression of the neuronal marker NSE and the enteric neuronal markers PGP9.5,VIP and nNOS.Reverse transcription-polymerase chain reaction (RT-PCR) revealed the expression of GDNF and NT-3 in transfected BMSCs.The present study indicates that genetically modified BMSCs coexpressing GDNF and NT-3 are able to differentiate into en-teric neuronal cells and express enteric nerve markers when induced by FGCM.This study provides an experimental basis for gene therapy to treat enteric nervous system-related disorders,such as HD.

实验性脑梗死后突触体[Ca^(2+)]_i改变及神经生长因子治疗的影响

目的:探讨RHR脑梗死后病灶边缘额、顶叶皮层脑组织突触体内[Ca^(2+)]_i水平及其对神经生长因子(NGF)治疗的变化。方法:用Fura-2荧光标记,测定分离突触体内[Ca^(2+)]_i。结果:在RHR脑梗死后,静息状态下病灶边缘额、顶叶皮层脑组织突触体内[Ca^(2+)]_i在第3、7及14d明显升高,NGF脑室内注射12d后明显降低,同时减少运动障碍评分。结论:病灶边缘皮层突触体内[Ca^(2+)]_i的升高不利于神经运动功能的恢复,NGF降低突触体内[Ca^(2+)]_i促进运动功能恢复。

Plasma membrane calcium ATPase 4b inhibits nitric oxide generation through calcium-induced dynamic interaction with neuronal nitric oxide synthase

The activation and deactivation of Ca^(2+)- and calmodulindependent neuronal nitric oxide synthase (nNOS) in the central nervous system must be tightly controlled to prevent excessive nitric oxide (NO) generation. Considering plasma membrane calcium ATPase (PMCA) is a key deactivator of nNOS, the present investigation aims to determine the key events involved in nNOS deactivation of by PMCA in living cells to maintain its cellular context. Using time-resolved Förster resonance energy transfer (FRET), we determined the occurrence of Ca^(2+)-induced protein-protein interactions between plasma membrane calcium ATPase 4b (PMCA4b) and nNOS in living cells. PMCA activation significantly decreased the intracellular Ca 2+ concentrations ([Ca^(2+)]_(i)), which deactivates nNOS and slowdowns NO synthesis. Under the basal [Ca^(2+)]_(i) caused by PMCA activation, no protein-protein interactions were observed between PMCA4b and nNOS. Furthermore, both the PDZ domain of nNOS and the PDZ-binding motif of PMCA4b were essential for the protein-protein interaction. The involvement of lipid raft microdomains on the activity of PMCA4b and nNOS was also investigated. Unlike other PMCA isoforms, PMCA4 was relatively more concentrated in the raft fractions. Disruption of lipid rafts altered the intracellular localization of PMCA4b and affected the interaction between PMCA4b and nNOS, which suggest that the unique lipid raft distribution of PMCA4 may be responsible for its regulation of nNOS activity. In summary, lipid rafts may act as platforms for the PMCA4b regulation of nNOS activity and the transient tethering of nNOS to PMCA4b is responsible for rapid nNOS deactivation.

Induced pluripotency and direct reprogramming:a new window for treatment of neurodegenerative diseases

Human embryonic stem cells(hESCs)are pluripotent cells that have the ability of unlimited self-renewal and can be differentiated into different cell lineages,includ-ing neural stem(NS)cells.Diverse regulatory signaling pathways of neural stem cells differentiation have been discovered,and this will be of great benefit to uncover the mechanisms of neuronal differentiation in vivo and in vitro.However,the limitations of hESCs resource along with the religious and ethical concerns impede the pro-gress of ESCs application.Therefore,the induced pluri-potent stem cells(iPSCs)via somatic cell reprogramming have opened up another new territory for regenerative medicine.iPSCs now can be derived from a number of lin-eages of cells,and are able to differentiate into certain cell types,including neurons.Patient-specifi c iPSCs are being used in human neurodegenerative disease modeling and drug screening.Furthermore,with the development of somatic direct reprogramming or lineage reprogramming technique,a more effective approach for regenerative medicine could become a complement for iPSCs.