大鼠胚胎神经干细胞纹状体内移植后特性

观察大鼠胚胎神经干细胞移植入成年大鼠纹状体后的存活、迁移和分化状况。自14天胎鼠脑室下区分离获得神经干细胞,利用无血清培养基培养扩增并进行鉴定。经4～5代的扩增后,以BrdU标记的神经干细胞通过脑立体定位注射移植入成年大鼠纹状体内,然后分别于移植后2周、4周、6周和8周时做脑冰冻切片,通过免疫组织化学和免疫荧光方法检测移植细胞的数量、定位和分化情况。8周后移植细胞的检出率约16%;移植细胞向周围宿主组织有广泛的迁移表现,尤以沿着白质束向头尾方向的迁移最为显著,最远向后侧达到内囊;纹状体中移植细胞主要分化为神经元和星形胶质细胞。星形胶质细胞数量最多,主要位于移植区与宿主组织临界部位,而神经元处于移植区中央。培养的大鼠胚胎神经干细胞可以作为移植替代治疗神经退行性疾病研究的供体细胞源,而移植中的迁移现象值得注意。     

猕猴神经干细胞的诱导分化、干性维持及同种脑内移植

为探索猕猴神经干细胞分化及特性维持,推进神经干细胞临床应用研究,该实验以绿色荧光蛋白(green fluorescence protein,GFP)为标记探讨猕猴胚胎干细胞向玫瑰花环(rosettes)结构神经干细胞的分化及其碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF)和表皮生长因子(epidermal growth factor,EGF)的扩增培养。结果表明:1)建立了稳定高效的猕猴神经干细胞分化体系,在该分化体系下,GFP标记猕猴胚胎干细胞在分化的第12天时,95%以上的细胞分化为神经干细胞;2)分化得到的Rosettes结构神经干细胞经bFGF/EGF扩增后,能够较好地维持其Rosettes结构;3)经bFGF/EGF扩增后的rosettes结构神经干细胞移植到猕猴脑内后能够较好的存活并向神经元分化,即bFGF/EGF扩增培养能较好地维持Rosettes结构的神经干细胞,且移植到猕猴脑内的该细胞亦能够较好地存活并向神经元分化,该结果为神经干细胞应用于临床提供了基础理论依据。     

神经干细胞脑内移植后的存活、迁移和分化

从胚胎或成体大鼠脑组织、人胚脑组织均能分离到神经干细胞 ,将它们进行体外原代培养扩增或永生化后植入脑内 ,均能观察到其在脑内的迁移和分化现象。其分化能力主要取决于移植部位的脑内微环境 ,但这种影响作用是相对的。同时 ,体外培养环境如培养时间和细胞融合程度、维甲酸类诱导分化剂处理、NGF转导处理再移植或与嗜铬细胞 (分泌NGF)共移植等 ,也能决定神经干细胞脑内移植后向神经元方向分化的能力。神经干细胞移植为中枢神经系统功能重建和神经再生带来新的希望。     

纹状体内移植胚胎干细胞来源的神经前体细胞可升高帕金森病小鼠纹状体内多巴胺含量

目的探讨胚胎干细胞来源的神经前体细胞移植治疗帕金森病(Parkinson's disease,PD)的疗效及作用机制。方法以小鼠腹腔注射1-甲基-4-苯基-1,2,3,6-四氢吡啶(1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine,MPTP)建立PD小鼠模型;于体外将小鼠胚胎干细胞(embryonic stem cells,ESCs)向神经前体细胞(neural precursor cells,NPC)方向分化,经PCR与免疫荧光染色分析鉴定后将高纯度的NPC移植入PD小鼠纹状体内,2周和4周分别取纹状体制作冰冻切片并进行免疫荧光染色,用高效液相色谱法测定纹状体多巴胺的含量;对移植后死亡小鼠,取其脑进行常规石蜡切片、HE染色。结果移植的NPC可在移植部位存活,并分化为表达酪氨酸羟化酶(TH)的多巴胺能神经元;高效液相色谱法检测显示,PD小鼠纹状体内多巴胺含量明显降低,移植NPC 2周后的PD小鼠纹状体内多巴胺含量较未移植小鼠明显升高,但仍低于正常对照小鼠;移植4周后PD小鼠纹状体内多巴胺含量与未移植小鼠接近;有18.75%的PD小鼠移植NPC后形成畸胎瘤而死亡。结论 ESCs来源的NPC移植因可补充病变处多巴胺含量而对PD有一定治疗作用。     

骨髓基质干细胞的诱导分化及其治疗癫痫的实验研究

目的探讨骨髓基质干细胞诱导分化为神经元样细胞的方法及脑内移植治疗大鼠癫痫模型的作用。方法无菌条件下分离纯化BMSCs,用bFGF 10ng/ml、RA0.5μmol/L的DMEM/F12诱导72h后,部分用于免疫荧光检测nestin,其余的继续用bFGF 10ng/ml、RA 0.5μmol/L及神经营养因子NT-3 20ng/ml、BDNF 20ng/ml的DMEM/F12诱导4d,检测GAD67。皮下注射匹罗卡品建立癫痫大鼠模型,采用行为学分析筛选模型。通过立体定位仪,用微量注射器将BMSCs来源的神经干细胞和神经营养因子移植入癫痫鼠海马内,观察大鼠行为变化,存活2、4周后,心脏灌注取脑,冰冻切片免疫组化双标检测移植细胞的存活、迁移、分化情况。结果BMSCs诱导72h后,nestin表达阳性,4d后GAD67检测60%阳性。采用匹罗卡品造模,方法简便,但死亡率较高,仅15%-20%的动物造模成功。BMSCs源神经干细胞移植后可在海马内存活,向周围的脑区内迁移和整合。结论BMSCs源的神经干细胞在体外可诱导为γ-氨基丁酸能神经元并且对慢性癫痫有一定的治疗作用。     

肾上腺素受体在大鼠中枢神经系统发育中的作用研究

去甲肾上腺素和肾上腺素受体在大鼠中枢神经系统（CNS）的发育早期开始表达,且受体表达的时空模式与脑发育过程中某些脑区神经元的迁移和分化相一致,这提示去甲肾上腺素在中枢神经系统的发育中具有重要作用。本文论述了胚胎和新出生的大鼠不同脑区肾上腺素受体mRNA的表达模式以及这些受体对体外培养的成熟细胞和相应的前体细胞的调控效应,通过离体和在体研究的实验证据,阐述肾上腺素受体介导了去甲肾上腺素对神经前体细胞的增殖、生长、迁移、分化和存活的调控作用。进一步明确了去甲肾上腺素在CNS发育中所起的作用,使其可作为成体脑修复的助动剂而赋予新的意义。     

阿尔茨海默氏病大鼠海马内植入神经干细胞后效果观察

目的：观察神经干细胞植入阿尔茨海默氏病（AD）大鼠海马内的存活和增殖情况,以及对学习记忆能力的影响一方法：从新生大鼠海马齿状回分离、培养神经干细胞,经Hoechst33258标记后植入AD模型大鼠海马,2周和4周后,行Y迷宫实验检测大鼠的学习记忆能力,然后取脑进行荧光观察和PCNA免疫组织化学染色。结果：与AD组相比,2周移植组和4周移植组大鼠的学习能力和记忆能力有明显提高一移植的神经干细胞能在海马存活,与周围组织建立良好的整合,还可沿海马CAl区迁移,而且在海马CAl区内可见许多PCNA阳性细胞：结论：新生大鼠海马齿状回神经干细胞移植到AD大鼠海马内能够存活、增殖,并能改善AD大鼠的学习能力和记忆能力。     

PKH26示踪神经干细胞移植急性脑损伤的初步观察

严重的颅脑损伤导致神经细胞和神经组织坏死,无法再生恢复,致残率高,至今缺乏有效疗法。本实验将体外培养的神经干细胞（NSC）移植入急性脑损伤大鼠模型脑内,观察移植后NSC在宿主鼠脑内的自然存活、迁移及分化情况。实验用NSC来源于孕15d Wister胎鼠脑组织,于DMEM／F12（1：1）培养基（含有bFGF,EGF和N2添加剂）中获取生长旺盛的神经干细胞球,     

LincRNA1230抑制小鼠胚胎干细胞向神经前体细胞分化

胚胎干细胞是一类具有多向分化潜能的细胞.胚胎干细胞可以模拟体内发育过程,在无外界信号分子刺激的情况下,自发向神经前体细胞分化.有研究表明,这一体外发育过程受神经分化相关转录因子和表观遗传修饰的共同调控,然而该过程中的分子机制尚不清楚.本研究发现长链非编码RNA1230(LincRNA1230)参与了小鼠(Mus musculus)胚胎干细胞向神经前体细胞的分化过程.在小鼠的胚胎干细胞中过表达LincRNA1230可以显著抑制其神经分化效率;反之,干扰LincRNA1230可以提高分化效率.进一步研究表明,LincRNA1230通过结合Wdr5,降低神经分化相关基因启动子区H3K4me3的修饰水平,从而抑制相关基因的表达活性.这些发现揭示了LincRNA1230在小鼠胚胎干细胞神经分化过程中的重要作用.     

小鼠脑室内注射神经干细胞裂解液促进谷氨酸盐诱导的兴奋性神经元损伤的修复

先前的研究已经证实,阿魏酸钠诱导分化的PC12细胞裂解液的无细胞滤液具有改善抑郁症样模型大鼠的行为学障碍、上调其海马和大脑皮质神经生长因子(nerve growth factor,NGF)和脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)的表达、增加海马神经干细胞(neural stem cells,NSCs)/神经前体细胞(neural progenitor cells)增殖的效果。该研究的目的在于探讨神经干细胞裂解液的无细胞滤液(cell-free filtrate ofneural stem cell lysates,FNSCL)脑室内注射促进谷氨酸盐诱导的成年小鼠兴奋性神经元损伤修复的可能性。成年小鼠谷氨酸单钠(monosodiumglutamate,MSG,2.0g/(kg·d))灌胃,连续10日,造成兴奋性神经元损伤模型。自孕15 d的昆明种小鼠取胎脑,分离、培养神经干细胞,免疫细胞化学法检测巢蛋白(nestin)抗原,制备神经干细胞裂解液的无细胞滤液。MSG+NSCs组动物在MSG灌胃后接收脑室内NSCs移植,MSG+FNSCL组动物在MSG灌胃...     

Region-specific generation of functional neurons from naive embryonic stem cells in adult brain

Embryonic stem (ES) cells are multipotent progenitors with unlimited developmental potential, and in vitro differentiated ES cell-derived neuronal progenitors can develop into functional neurons when transplanted in the central nervous system. As the capacity of naive primary ES cells to integrate in the adult brain and the role of host neural tissue therein are yet largely unknown, we grafted low densities of undifferentiated mouse ES (mES) cells in adult mouse brain regions associated with neurodegenerative disorders; and we demonstrate that ES cell-derived neurons undergo gradual integration in recipient tissue and acquire morphological and electrophysiological properties indistinguishable from those of host neurons. Only some brain areas permitted survival of mES-derived neural progenitors and formed instructive environments for neuronal differentiation and functional integration of naive mES cells. Hence, region-specific presence of microenvironmental cues and their pivotal involvement in controlling ES cell integration in adult brain stress the importance of recipient tissue characteristics in formulating cell replacement strategies for neurodegenerative disorders.     

Effects of prolonged delivery of brain-derived neurotrophic factor on the fate of neural stem cells transplanted into the developing rat retina

One of the major roles of brain-derived neurotrophic factor (BDNF) is to promote the differentiation and support the survival of neurons in the central nervous system. The objective of the present study was to evaluate the effect of BDNF on the fate of adult rat hippocampus-derived neural stem cells (AHPCs) transplanted into the developing rat retina. Immunohistochemical analysis showed a significant increase in the ratio of grafted AHPCs stained for MAP2ab (P<0.05) and a marked decrease in the ratio of nestin-positive grafted cells in the slow-releasing BDNF group compared with the control group. The respective changes in the ratios of MAP5 and GFAP-positive grafted cells were comparable for the two groups. The results reported here suggest a potentially beneficial role for extended delivery of BDNF in the differentiation of grafted neural stem cells, which may lead to a novel modification of stem cell transplantation.     

Green fluorescent protein-labeled mapping of neural stem cells migrating towards damaged areas in the adult central nervous system

Neural stem cells, which are clonogenic cells with multilineage differentiation properties from regions of the fetal brain, cortex and hippocampus, are currently considered as powerful candidates for cell replacement therapy in neurodegenerative disorders, such as Parkinson's disease. A key issue is whether stem cells can survive, migrate and differentiate following transplantation into the adult CNS. Here, enhanced green fluorescent protein plasmid electroporation-transfected neural stem cells from the fetal cortex were grafted into the striatum of a rat model of Parkinson's disease. We found most of the grafted cells could survive in the adult parkinsonian rat brain and migrated towards damaged areas, while they moved randomly in the normal brain. Several grafted cells differentiated into neurons.     

Neural stem cells transplanted into intact brains as neurospheres form solid grafts composed of neurons, astrocytes and oligodendrocyte precursors

Neural stem cells (NSCs) are tissue-specific stem cells with self-renewal potential that can give rise to neurons and glia in vivo and in vitro. The aim of this study was to transplant NSCs as whole neurospheres into intact brain and assess the fate and phenotype of their progeny generated in vivo. We isolated NSCs from E14 foetal rat forebrains and cultured them in basic fibroblast and epidermal growth factor-supplemented serum-free medium in the form of neurospheres in vitro. Neurospheres were transplanted into the intact brains of 2 Wistar rats and after a period of 3 weeks, grafted brains were examined immunohistochemically. Neurospheres formed solid grafts that were found in the lateral ventricle and in the velum interpositum under the hippocampus. The majority of cells in the transplanted tissue were identified as beta-III-tubulin(+), NeuN(+), PanNF(+) and synaptophysin(+) neurons and were accumulated throughout the graft centre. GFAP(+) astrocytes were scattered throughout the entire graft and astrocyte processes delimited the outer and perivascular surfaces. A great number of NG2(+) oligodendrocyte precursors was detected. Nestin(+) endothelial cells were found to line capillaries growing in the transplant. These data indicate that nestin(+) NSCs prevailing in neurospheres differentiate following transplantation into nestin(-) neuronal and glial cells which confirms the multipotency of NSCs. Three weeks posttransplantation neuronal and astrocyte cells reached terminal differentiation (formation of synaptic vesicles and superficial and perivascular limiting membranes) while elements of oligodendroglial cell lineage remained immature. Grafting stem cells as non-dissociated neurospheres provide cells with favourable conditions which facilitate cell survival, proliferation and differentiation. However, in the intact brain, grafted neurosphere cells were not found to integrate with the brain parenchyma and formed a compact structure demarcated from its surroundings.     

Transplanted neuronal precursors migrate and differentiate in the devel-oping mouse brain

The subventricular zone (SVZ), lining the lateral ventricle in forebrain, retains a population of neuronal precursors with the ability of proliferation in adult mammals. To test the potential of neuronal precursors in adult mice, we transplanted adult SVZ cells labeled with fluorescent dye PKH26 into the lateral ventricle of the mouse brain in different development stages. The preliminary results indicated that the grafted cells were able to survive and migrate into multiple regions of the recipient brain, including SVZ, the third ventricle, thalamus, superior colliculus, inferior colliculus, cerebellum and olfactory bulb etc; and the amount of survival cells in different brain regions was correlated with the development stage of the recipient brain. Immunohistochemical studies showed that most of the grafted cells migrating into the specific target could express neuronal or astrocytic marker. Our results revealed that the neuronal precursors in adult SVZ still retained immortality and ability of prolife     

Neural precursor cells differentiated from mouse embryonic stem cells relieve symptomatic motor behavior in a rat model of Parkinson’s disease

Pluripotent embryonic stem (ES) cells are the most versatile cells, with the potential to differentiate into all types of cell lineages including neural precursor cells (NPCs), which can be expanded in large numbers for significant periods of time to provide a reliable cell source for transplantation in neurodegenerative disorders such as Parkinson’s disease (PD). In the present study, we used the MESPU35 mouse ES cell line, which expresses enhanced green fluorescent protein that enables one to distinguish between transplanted cells and cells of host origin. Embryoid bodies (EBs) were formed and were induced to NPCs in N2 selection medium plus fibronectin. Praxiology and immunohistochemistry methods were used to observe the survival, differentiation, and therapeutic effect of NPCs after grafted into the striatum of PD rats. We found that mouse ESc were differentiated into nestin-positive NPCs 6 days after the EBs formed and cultured in the N2 selection medium. The number of survival NPCs was increased significantly by fibronectin. About 23.76 ± 2.29% of remaining cells were tyrosine hydroxylase (TH)-positive 12 days after NPCs were cultured in N2 selective medium. The survival rates of NPCs were 2.10 ± 0.41% and about 90.90 ± 3.00% of the engrafted NPCs were TH-positive 6 weeks after transplantation into the striatum of PD rats. The rotation of PD rats was relieved 3 weeks after the NPCs transplantation and this effect was kept for at least 6 weeks. It suggests that most of the survival NPCs derived from ES cells differentiated into TH-positive neurons after grafted into the striatum of PD rats, which produces therapeutic effect on PD.     

Transplanted neuronal precursors migrate and differentiate in the developing mouse brain

The subventricular zone (SVZ), lining the lateral ventricle in forebrain, retains a population of neuronalprecursors with the ability of proliferation in adult mammals. To test the potential of neuronal precursorsin adult mice, we transplanted adult SVZ cells labeled with fluorescent dye PKH26 into the lateral ventricleof the mouse brain in different development stages. The preliminary results indicated that the graftedcells were able to survive and migrate into multiple regions of the recipient brain, including SVZ, the thirdventricle, thalamus, superior colliculus, inferior colliculus, cerebellum and olfactory bulb etc; and the amountof survival cells in different brain regions was correlated with the development stage of the recipient brain.Immunohistochemical studies showed that most of the grafted cells migrating into the specific target couldexpress neuronal or astrocytic marker. Our results revealed that the neuronal precursors in adult SVZstill retained immortality and ability of proliferation, which is likely to be induced by some environmentalfactors.     

Comparison of intracerebral transplantation effects of different stem cells on rodent stroke models

In the present study, induced pluripotent stem cells (iPSCs), induced neural stem cells (iNSCs), mesenchymal stem cells (MSCs) and an immortalized cell line (RMNE6), representing different characteristics of stem cells, were transplanted into normal and/or injured brain areas of rodent stroke models, and their effects were compared to select suitable stem cells for cell replacement stroke therapy. The rat and mice ischaemic models were constructed using the middle cerebral artery occlusion technique. Both electrocoagulation of the artery and the intraluminal filament technique were used. The behaviour changes and fates of grafted stem cells were determined mainly by behaviour testing and immunocytochemistry. Following iPSC transplantation into the corpora striata of normal mice, a tumour developed in the brain. The iNSCs survived well and migrated towards the injured area without differentiation. Although there was no tumourigenesis in the brain of normal or ischaemic mice after the iNSCs were transplanted in the cortices, the behaviour in ischaemic mice was not improved. Upon transplanting MSC and RMNE6 cells into ischaemic rat brains, results similar to iNSCs in mice were seen. However, transplantation of RMNE6 caused a brain tumour. Thus, tumourigenesis and indeterminate improvement of behaviour are challenging problems encountered in stem cell therapy for stroke, and the intrinsic characteristics of stem cells should be remodelled before transplantation. Copyright © 2015 John Wiley & Sons, Ltd.     

Transplanted neuronal precursors migrate and differentiate in the developing mouse brain

The subventricular zone (SVZ), lining the lateral ventricle in forebrain, retains a population of neuronal precursors with the ability of proliferation in adult mammals. To test the potential of neuronal precursors in adult mice, we transplanted adult SVZ cells labeled with fluorescent dye PKH26 into the lateral ventricle of the mouse brain in different development stages. The preliminary results indicated that the grafted cells were able to survive and migrate into multiple regions of the recipient brain, including SVZ, the third ventricle, thalamus, superior colliculus, inferior colliculus, cerebellum and olfactory bulb etc; and the amount of survival cells in different brain regions was correlated with the development stage of the recipient brain. Immunohistochemical studies showed that most of the grafted cells migrating into the specific target could express neuronal or astrocytic marker. Our results revealed that the neuronal precursors in adult SVZ still retained immortality and ability of proliferation, which is likely to be induced by some environmental factors.     

Effect of neurotrophic factors on neuronal stem cell death

Neural cell survival is an essential concern in the aging brain and many diseases of the central nervous system. Neural transplantation of the stem cells are already applied to clinical trials for many degenerative neurological diseases, including Huntington\'s disease, Parkinson\'s disease, and strokes. A critical problem of the neural transplantation is how to reduce their apoptosis and improve cell survival. Neurotrophic factors generally contribute as extrinsic cues to promote cell survival of specific neurons in the developing mammalian brains, but the survival factor for neural stem cell is poorly defined. To understand the mechanism controlling stem cell death and improve cell survival of the transplanted stem cells, we investigated the effect of plausible neurotrophic factors on stem cell survival. The neural stem cell, HiB5, when treated with PDGF prior to transplantation, survived better than cells without PDGF. The resulting survival rate was two fold for four weeks and up to three fold for twelve weeks. When transplanted into dorsal hippocampus, they migrated along hippocampal alveus and integrated into pyramidal cell layers and dentate granule cell layers in an inside out sequence, which is perhaps the endogenous pathway that is similar to that in embryonic neurogenesis. Promotion of the long term-survival and differentiation of the transplanted neural precursors by PDGF may facilitate regeneration in the aging adult brain and probably in the injury sites of the brain.