TH基因修饰的神经干细胞移植治疗帕金森病的实验研究

目的 探讨TH基因修饰的神经干细胞脑内移植对帕金森病(PD)的治疗作用。方法 构建pN：ATH逆转录病毒载体质粒，用PA317细胞包装，G418筛选阳性克隆，病毒上清感染神经干细胞，将表达TH的神经干细胞植入：PD大鼠纹状体内，测定：PD大鼠旋转行为改善，DA和DOPAC含量变化，以及TH在纹状体的表达。结果 TH基因修饰的神经干细胞移植8周时能显著降低PD大鼠旋转行为，增加纹状体DA和DOPAC含量，TH在纹状体内的表达增加，疗效好于单纯神经干细胞移植组。结论 TH基因修饰的神经干细胞移植对PD大鼠有明显的治疗作用，可望为PD治疗提供新的途径。     

TH基因修饰细胞脑内移植治疗猴帕金森病的实验研究

目的 评价包囊化酪氨酸羟化酶（tyrosine hydroylase,TH）基因修饰的基因工程细胞脑内移植治疗帕金森病的疗效。方法 将pcDNA3/hTH质粒转染人神经母细胞瘤细胞系SYTY细胞，筛选出阳性克隆，微包囊化处理后的含有TH基因修饰细胞植入PD猴模型脑内，观察其行为、CSF中DA含量的变化，用免疫组化法检查移植细胞的存活情况。结果 （1）pcDNA3/hTH基因经亚克隆，提取纯化的质粒，经ECORI酶切后产生1.9Kb和5.5Kb的片段。转基因后的SY5Y细胞免疫细胞化学染色显示TH染色强阳性；（2）移植后PD猴症状明显改善，脑脊液中DA含量升高；（3）SABC免疫组化发现移植区存在大量TH阳／性细胞。结论 构建的TH基因工程细胞体外和体内均表达人类TH基因；微包囊化处理后的基因工程细胞在PD猴脑内存活并发挥治疗作用。     

胚胎干细胞分化的神经前体细胞移植治疗帕金森病的实验研究

目的探讨胚胎干细胞（embryonic stemcell,ESC）来源的神经前体细胞（Neural precursorcell）移植治疗帕金森病的可能性。方法将胚胎干细胞诱导分化到神经前体细胞阶段后移植到大鼠帕金森病模型纹状体中,并设生理盐水组做对照研究,观察两组移植后行为学改变及检查纹状体内DA、DOPAC的含量。结果移植组在2～4周后与对照组相比行为学上有明显改善（P〈0．01）,纹状体内DA、DOPAC的含量显著提高（P〈0．01）。结论胚胎干细胞经诱导分化成神经前体细胞可用于帕金森病的修复治疗,胚胎干细胞是良好的干细胞移植治疗用细胞来源。     

AADC和NURR1基因联合c17.2神经干细胞移植治疗帕金森病的实验研究

目的研究芳香族氨基酸脱羧酶(AADC)基因和NURR1基因联合c17．2神经干细胞脑内移植后对帕金森病模型大鼠的治疗效果。方法人类神经元性AADC基因和NURR1基因真核表达载体分别转染至c17．2神经干细胞内。将帕金森病(PD)模型大鼠随机分为4组,分别予以脑内毁损侧纹状区移植含空质粒的c17．2神经干细胞(A组),pCDNA3-AADC转染后的c17．2神经干细胞(B组),pCDNA3-NURR1转染后的c17．2神经干细胞(C组)以及含有pCDNA3-AADC和pCDNA3-NURR1转染后的c17．2 神经干细胞(D组)。观察其病理性旋转行为的改善,采用酪氨酸羟化酶(TH)的免疫组化方法研究脑内多巴胺含量的变化,并用荧光示踪方法观察c17．2细胞在PD模型脑内的移行。结果各组动物脑内移植后动物旋转行为较前均有改善(P<0．05),尤以D组改善最为明显,其行为学最大改善达73．7％,且同A、B、C组间差异具有显著性(P<0．05)。免疫组化可见各组移植TH阳性细胞明显增多,TH染色的神经元树突或轴突密集,体内TH阳性区域明显较PD模型组扩大,其中尤以D组病理学改善最为明显。荧光示踪观察c17．2神经干细胞有突触形成,并与临近的细胞建立突触联系。结论 AADC基因联合NURR1基因共转染c17．2神经干细胞脑内移植后改善了动物的旋转行为,增加了脑内多巴胺的表达,且植入的神经干细胞可同宿主神经元形成突触联接,为研究多基因联合神经干细胞移植治疗帕金森病提供了新方法。     

脑内移植骨髓间质干细胞治疗帕金森病模型大鼠的实验研究

目的 探讨骨髓间质干细胞(mesenchymal stem cells,MSCs)移植治疗帕金森病(parkinson's disease,PD)大鼠的可行性及可能的机制.方法 移植Brdu标记的MSCs到模型大鼠的纹状体内.术后4个月中,定期对大鼠进行旋转行为学实验测试.并分别在术后2周和4个月时进行脑内针道处及移植区免疫组化检测TH和Brdu的表达.结果 Brdu标记的MSCs移植到模型大鼠的纹状体内,术后2周时移植针道处及针道周围可见Brdu阳性外源MSCs,并有外源性细胞表达TH,术后4个月时移植针道内仍可以看到MSCs存活.MSCs移植的PD模型大鼠症状较PBS注射组行为学明显改善.结论 移植MSCs到大鼠PD模型的纹状体内能成活,且分化细胞能表达TH蛋白,大鼠PD模型行为学症状明显改善.     

脑源性神经营养因子基因治疗对大鼠脑内多巴胺含量的影响

采用脑源性神经营养因子（BDNF）基因工程成肌细胞纹状体内移植观察其对帕金森病（PD）大鼠脑内纹状体多巴胺含量的影响，结果发现：基因工程成肌细胞脑内移植可使纹状体多巴胺含量明显增加，并可维持达两月之久，这为帕金森病的治疗提供了一种新的有效的治疗方法。     

GFP转基因小鼠神经干细胞移植治疗大鼠帕金森病的实验研究

目的观察GFP(绿色荧光蛋白)转基因小鼠胚胎神经干细胞植入帕金森病大鼠纹状体后的存活、分化情况及治疗作用。方法建立PD模型大鼠及体外培养神经干细胞,然后将GFP转基因小鼠神经干细胞定向植入帕金森病大鼠毁损侧纹状体内,于移植后不同时间诱发旋转行为,并与对照组相比,观察症状的改善,并用酪氨酸羟化酶(TH)免疫组织化学染色方法检测移植GFP转基因小鼠神经干细胞的存活及分化状况。结果 GFP转基因小鼠神经干细胞脑内移植后,帕金森病大鼠的旋转行为明显改善。移植后2至4周时可检测到成片或散在的TH免疫阳性细胞。结论 GFP转基因小鼠神经干细胞移植至帕金森病大鼠纹状体后,可分化为多巴胺能神经元并能改善旋转症状。     

基因修饰骨髓源性神经元样干细胞治疗帕金森大鼠的研究

目的 观察大鼠酪氨酸羟化酶(tyrosinehydroxylase,TH)修饰的骨髓基质源性神经元样干细胞(neuronoid stem cells derived from bone marrow stem cells,NdSCs-D-BMSCs)在脑室移植途径下对帕金森病(Parkinson disease,PD)大鼠的治疗作用.方法 将酶切鉴定后的新构建质粒pEGFP-C2-TH经电穿孔法转染培养第8天NdSCs-D-BMSCs,注射到PD大鼠模型右侧脑室,观察大鼠行为学变化,移植细胞在大鼠脑组织内的迁移,以及高效液相方法检测脑内DA含量.结果 质粒pEGFP-C2-TH转染NdSCs-D-BMSCs移植后10周,PD大鼠症状显著改善,DA恢复至正常水平33.0%,移植细胞可以在PD大鼠脑内存活,并出现远处迁移.结论 TH修饰的大鼠NdSCs-D-BMSCs经脑室移植对PD大鼠具有明显的治疗作用,为临床中腰椎穿刺干细胞移植的应用提供实验依据.     

转基因星形胶质细胞脑内移植治疗帕金森病大鼠的研究

目的　评价酪氨酸羟化酶 (TH)基因转染的星形胶质细胞移植入帕金森病 (PD)模型大鼠脑内后对旋转行为改善作用。方法　用pcDNA3 1/TH质粒转染原代培养的星形胶质细胞 ,采用免疫组化及RT PCR方法检测到TH表达后 ,将转基因的星形胶质细胞移植入PD模型大鼠脑纹状体内 ,观察PD大鼠的旋转行为变化情况。结果　移植后共观察 12周 ,转基因细胞移植组PD大鼠 (n =10 )的旋转行为明显改善 (P <0 0 5 ) ,改善情况在 2～ 8周最显著 ,对照组大鼠 (n =10 )的旋转行为无变化。结论　转基因的星形胶质细胞脑内移植后可短期改善PD大鼠的旋转行为 ,星形胶质细胞有可能作为有效的载体细胞。     

人羊膜上皮细胞侧脑室移植对帕金森病大鼠模型行为、多巴胺能神经元、神经递质影响的实验研究

目的 观察人羊膜上皮细胞(HAECs)移植入帕金森病(PD)大鼠模型侧脑室后的存活及分化情况,及其对PD大鼠模型旋转行为、纹状体区多巴胺及其代谢产物的影响.方法 采用6-羟多巴立体定向脑内注射制作PD大鼠模型,将制模成功大鼠随机分成3组:人羊膜上皮细胞移植组(HAECs组)、磷酸缓冲组(PBS组)和帕金森组(PD组),1w后腹腔注射阿朴吗啡观察各组大鼠旋转行为的变化,连续观察10w,HAECs组5w后用人特异性抗体Nestin和Vimentin检测人羊膜细胞的存活情况,10w后酪氨酸羟化酶(TH)染色观察各组PD大鼠模型黑质部TH阳性神经元的变化情况及HAECs的分化情况,高效液相色谱--电化学仪测定纹状体多巴胺(DA)、高香草酸(HVA)、3,4-二羟基苯乙酸(DOPAC)等神经递质的水平.结果 HAECs在PD大鼠侧脑室内移植可以长期存活达10w,并且可以分化为DA能神经元,HAECs组大鼠旋转数较PBS组及PD组明显降低(P<0.01),黑质部TH阳性神经元数量较PD组及PBS组升高(P<0.01),HAECs组大鼠纹状体区DA及其代谢产物DOPAC、HVA含量较PBS组明显升高(P<0.05).结论 人羊膜上皮细胞移植入PD大鼠侧脑室可以改善PD大鼠的旋转行为,其机制可能与增加纹状体区DA等神经递质有关.     

An experimental study on intracerebroventricular transplantation of human amniotic epithelial cells in a rat model of Parkinson's disease

Abstract

Objectives: Human amniotic epithelial (HAE) cells are formed from amnioblasts, separated from the epiblast at about the eighth day after fertilization. In the present study, we attempt to investigate the effects of intracerebroventricular transplantation of HAE cells on Parkinson's disease (PD) rats.

Methods: A PD rat model was induced by 6-OHDA injections. Then the rats were transplanted intracerebroventricularly with HAE cells. Apomorphin-induced turns were used to assess the neurobehavioral deficit in rats. Immunofluorescence cytochemistry was used to track the survival of HAE cells. Tyrosinehydroxylase (TH) immunohistochemistry was used to determine the density of TH-positive cells in rat substantia nigra and the differentiation of HAE cells. High performance liquid chromatography (HPLC) was used to measure the levels of dopamine (DA) and its metabolites 3, 4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in rat striatum. HVA levels in the cerebrospinal fluid of rats were also determined by HPLC.

Results: The results showed that transplanted HAE cells can survive for at least 10 weeks and differentiate into TH-positive cells in PD rats. The grafts significantly ameliorated apomorphine-induced turns in PD rats. TH immunohistochemistry showed that HAE cells attenuated the loss of TH-positive cells in rat substantia nigra. In addition, HAE cells prevented the fall of DA and its metabolites DOPAC and HVA in PD rats. Increased HVA levels in the cerebrospinal fluid of PD rats were also observed.

Conclusion: These results demonstrate that HAE cells have beneficial effect on 6-OHDA-induced PD rats, which may be due to the neurotrophic factors secrete by HAE cells.     

The ability of grafted human sympathetic neurons to synthesize and store dopamine: a potential mechanism for the clinical effect of sympathetic neuron autografts in patients with Parkinson's disease

We have investigated the potential of autologous sympathetic neurons as a donor for cell therapy of Parkinson's disease (PD). Our recent study demonstrated that sympathetic neuron autografts increase the duration of levodopa-induced “on” periods with consequent reduction in the percent time spent in “off” phase. We also found that human sympathetic neurons grown in culture have the ability to convert exogenous levodopa to dopamine and to store the synthesized dopamine. This may explain the clinically observed prolongation in the duration of levodopa effects. To further analyze the mechanism for the graft-mediated effect, the present study investigated the metabolic function of human sympathetic ganglionic neurons xenografted into the dopamine (DA)-denervated striatum of rats by monitoring striatal levels of DA and its primary metabolite, 3,4-dihydroxyphenylacetic acid (DOPAC), after systemic administration of levodopa. We also explored whether the graft-mediated effect above may last in four PD patients who had been given the grafts and followed for 12-36 months postgrafting. Clinical evaluations showed that an increase in the duration of levodopa-induced “on” phase is detected during a follow-up period of 12-36 months postgrafting in all the four patients tested. Accordingly, the percent time spent in “off” phase exhibited a 30-40% reduction as compared to the pregrafting values. The animal experiment showed that a significant increase in striatal DA levels is noted after systemic levodopa treatment, and that the DA levels remain high for longer periods of time in the grafted rats than in control animals. When given reserpine pretreatment, the levodopa-induced rise of striatal DA levels was significantly attenuated with concomitant increase in DOPAC levels. Histological examinations demonstrated that the grafts contain some tyrosine hydroxylase (TH)-positive cells. These cells were also found to express aromatic-l-amino acid decarboxylase (AADC) and vesicular monoamine transporter-2 (VMAT), both of which are important molecules for the synthesis and the storage of DA, respectively. These results indicate that grafted sympathetic neurons can provide a site for both the conversion of exogenous levodopa to DA and the storage of the synthesized DA in the DA-denervated striatum, explaining a mechanism by which sympathetic neuron autografts can increase the duration of levodopa-induced “on” phase in PD patients.     

Neuroprotective and neurorescue effect of black tea extract in 6-hydroxydopamine-lesioned rat model of Parkinson's disease

In the present study, an attempt has been made to explore the neuroprotective and neuroreparative (neurorescue) effect of black tea extract (BTE) in 6-hydroxydopamine (6-OHDA)-lesioned rat model of Parkinson's disease (PD). In the neuroprotective (BTE + 6-OHDA) and neurorescue (6-OHDA + BTE) experiments, the rats were given 1.5% BTE orally prior to and after intrastriatal 6-OHDA lesion respectively. A significant recovery in d-amphetamine induced circling behavior (stereotypy), spontaneous locomotor activity, dopamine (DA)-D2 receptor binding, striatal DA and 3-4 dihydroxy phenyl acetic acid (DOPAC) level, nigral glutathione level, lipid peroxidation, striatal superoxide dismutase and catalase activity, antiapoptotic and proapoptotic protein level was evident in BTE + 6-OHDA and 6-OHDA + BTE groups, as compared to lesioned animals. BTE treatment, either before or after 6-OHDA administration protected the dopaminergic neurons, as evident by significantly higher number of surviving tyrosine hydroxylase immunoreactive (TH-ir) neurons, increased TH protein level and TH mRNA expression in substantia nigra. However, the degree of improvement in motor and neurochemical deficits was more prominent in rats receiving BTE before 6-OHDA. Results suggest that BTE exerts both neuroprotective and neurorescue effects against 6-OHDA-induced degeneration of the nigrostriatal dopaminergic system, suggesting that possibly daily intake of BTE may slow down the PD progression as well as delay the onset of neurodegenerative processes in PD.     

Intranigral transplantation of solid tissue ventral mesencephalon or striatal grafts induces behavioral recovery in 6-OHDA-lesioned rats

Parkinson's disease (PD) is characterized by a degeneration of the dopamine (DA) pathway from the substantia nigra (SN) to the basal forebrain. Prior studies in unilateral 6-hydroxydopamine (6-OHDA)-lesioned rats have primarily concentrated on the implantation of fetal ventral mesencephalon (VM) into the striatum in attempts to restore DA function in the target. We implanted solid blocks of fetal VM or fetal striatal tissue into the SN to investigate whether intra-nigral grafts would restore motor function in unilaterally 6-OHDA-lesioned rats. Intra-nigral fetal striatal and VM grafts elicited a significant and long-lasting reduction in apomorphine-induced rotational behavior. Lesioned animals with ectopic grafts or sham surgery as well as animals that received intra-nigral grafts of fetal cerebellar cortex showed no recovery of motor symmetry. Subsequent immunohistochemical studies demonstrated that VM grafts, but not cerebellar grafted tissue expressed tyrosine hydroxylase (TH)-positive cell bodies and were associated with the innervation by TH-positive fibers into the lesioned SN as well as adjacent brain areas. Striatal grafts were also associated with the expression of TH-positive cell bodies and fibers extending into the lesioned SN and an induction of TH-immunolabeling in endogenous SN cell bodies. This finding suggests that trophic influences of transplanted fetal striatal tissue can stimulate the re-expression of dopaminergic phenotype in SN neurons following a 6-OHDA lesion. Our data support the hypothesis that a dopaminergic re-innervation of the SN and surrounding tissue by a single solid tissue graft is sufficient to improve motor asymmetry in unilateral 6-OHDA-lesioned rats.     

Activation of striatal dopaminergic grafts by haloperidol

The effect of haloperidol (0.5 mg/kg, 60 min) on striatal dopamine metabolism of intact rats and of rats bearing a dopaminergic graft implanted into the previously denervated striatum was investigated. The dopaminergic grafts increased dopamine and dihydroxyphenylacetic acetic acid (DOPAC) contents to 6.2 and 9.6% of their respective control levels (lesioned striatum: 0.5 and 0.7% respectively). Haloperidol increased both the DOPAC content and the DOPAC:DA ratio in the grafted striatum, and the magnitude of these increases were similar to those seen in intact controls. Furthermore a tendency for the high striatal DOPAC:DA ratio seen in lesioned striata to revert toward control values could also be observed in grafted animals. The significance of these results is discussed in terms of the in vivo regulation of graft activity.     

Co-grafted embryonic striatum increases the survival of grafted embryonic dopamine neurons

To enhance the current therapeutic benefit of dopamine (DA) neuron grafts in Parkinson's disease, strategies must be developed that increase both DA neuron survival and fiber outgrowth into the denervated striatum. Previous work in our laboratory has demonstrated that dopaminergic neurons grow to greater size when co-grafted with striatal cell suspensions and display extensive tyrosine hydroxylase-positive (TH+) projections, but no conclusion could be reached concerning enhancement of survival of grafted DA neurons. The aim of the present study was to characterize further the potential trophic effects of striatal co-grafts on grafted mesencephalic DA neuron survival. Unilaterally lesioned male Fischer 344 rats were grafted with either a suspension of mesencephalic cells or with both mesencephalic and striatal cell suspensions. Co-grafts were either mixed together or placed separately into the striatum. Lesioned rats receiving no graft served as controls. Rotational behavior was assessed following amphetamine challenge at 2 weeks prior to grafting and at 4 and 8 weeks following grafting. Only rats receiving co-grafts of nigral and striatal suspensions separated by a distance of 1 mm showed significant behavioral recovery from baseline rotational asymmetry. Both mixed and separate striatal co-grafts were associated with a doubling of DA neuron survival compared with solo mesencephalic grafts. In the mixed co-graft experiment, DA neurite branching appeared enhanced and TH-rich patches were observed, whereas with co-grafts that were separated, TH+ innervation of the intervening host striatum was increased significantly. These results provide the first evidence suggesting that nigral-striatal co-grafts, particularly those placed separately and in proximity to each other, increase both DA neuron survival and neurite extension from the mesencephalic component of the grafts. J. Comp. Neurol. 399:530–540, 1998. © 1998 Wiley-Liss, Inc.     

人羊膜上皮细胞移植治疗帕金森病鼠的研究

目的 观察人羊膜上皮细胞在帕金森病鼠移植后的存活情况,以及它对帕金森病鼠旋转行为的改善作用.方法 采用6-羟多巴胺立体定向纹状体注射制作帕金森病鼠模型;51只大鼠随机分三组:人羊膜上皮细胞移植组、假手术PBS对照组以及空白模型对照组.制模成功后第5周用人特异性抗体Nestin和Vimentin检测人羊膜细胞的存活情况,第10周切片观察黑质部TH阳性神经元的变化情况,高效液相色谱--电化学仪测定纹状体多巴胺(DA),高香草酸(HVA),3,4-二羟基苯乙酸(DOPAC)等浓度以及脑脊液DA的含量.结果 人羊膜上皮细胞帕金森病鼠侧脑室内移植可以存活达10周;移植组大鼠旋转数较对照组明显降低(P≤0.01);黑质部TH阳性神经元数量较对照组升高(P≤0.01),纹状体区DA、HVA和DOPAC含量较PBS对照组明显升高(P＜0.01～0.05),移植组脑脊液DA含量较PBS对照组也显著增加(P＜0.01).结论 人羊膜上皮细胞侧脑室移植可以改善帕金森病鼠的旋转行为,其机制可能与其增加纹状体区多巴胺等递质水平有关.     

Transplantation of neural stem cells co-transfected with Nurr1 and Brn4 for treatment of Parkinsonian rats

Neural stem cells (NSCs) tranplantation has great potential for the treatment of neurodegenerative disease such as Parkinson's disease (PD). However, the usage of NSCs is limited because the differentiation of NSCs into specific dopaminergic neurons has proven difficult. We have recently demonstrated that transgenic expression of Nurr1 could induce the differentiation of NSCs into tyrosine hydroxylase (TH) immunoreactive dopaminergic neurons, and forced co-expression of Nurr1 with Brn4 caused a dramatic increase in morphological and phenotypical maturity of these neurons. In this study, we investigated the effect of transplanted NSCs in PD model rats. The results showed that overexpression of Nurr1 promoted NSCs to differentiate into dopaminergic neurons in vivo, increased the level of dopamine (DA) neurotransmitter in the striatum, resulting in behavioral improvement of PD rats. Importantly, co-expression of Nurr1 and Brn4 in NSCs significantly increased the maturity and viability of dopaminergic neurons, further raised the DA amount in the striatum and reversed the behavioral deficit of the PD rats. Our findings provide a new potential and strategy for the use of NSCs in cell replacement therapy for PD.