胚鼠腹侧中脑和胚肾联合移植治疗Parkinson病的实验研究

为了提高移植多巴胺(DA)能神经元的存活率和促进神经元生长,将胚鼠腹侧中脑和胚肾联合移植入Parkinson病(PD)模型大鼠脑内,检测胚肾对移植DA能神经元的影响。先用神经毒剂6 OHDA损毁大鼠左侧中脑被盖腹侧区和黑质致密部建立PD动物模型,再将胚脑的腹侧中脑(A组)、胚脑的腹侧中脑和胚肾(B组)分别移植入左侧纹状体尾壳核,C组为空白对照。于移植后3d、1月、3月将动物处死,采用酪氨酸羟化酶(TH)免疫组化法观察3组动物移植部位DA能神经元的存活和生长状况。在移植部位可见B组较A组的TH阳性神经元和纤维的数量明显增多,C组的移植部位未见TH阳性神经元和纤维;A、B两组的移植针道及其周围也有TH阳性神经元和纤维;B组的TH阳性神经元数量、体积和神经纤维的密度均大于A组。移植1个月和3个月后,A、B两组大鼠的旋转行为均较C组减少(P<0. 05)。以上结果提示胚肾具有良好的神经营养作用,能促进移植DA能神经元的存活和生长。     

转录因子Pitx3和Nurr1在中脑多巴胺能神经元终末分化中的表达特点

目的:探讨转录因子垂体同源盒家族因子3(Pitx3)和孤儿核受体相关因子1(Nurr1)在多巴胺(DA)能神经元终末分化中的表达特点。方法:采用免疫荧光方法检测体外培养的中脑源性神经干细胞(mNSCs)诱导分化后和大鼠胚胎发育至出生腹侧中脑Pitx3、Nurr1和酪氨酸羟化酶(TH)的表达。结果:(1)体外培养的mNSCs诱导分化48 h的Map-2阳性细胞不表达Pitx3、Nurr1和TH;分化7 d的TH阳性细胞均表达转录因子Pitx3和Nurr1;(2)在大鼠腹侧中脑黑质(SN)、腹侧被盖区(VTA)和中缝背核(DRN)可见大量TH与Pitx3(或Nurr1)共表达的神经元;(3)Pitx3和Nurr1阳性细胞主要分布于E16.5、P0大鼠SN、VTA和DRN区,其中Pitx3阳性细胞还少量分布于腹侧中脑非DA能神经元区域,Nurr1阳性细胞在腹侧中脑分布范围较Pitx3更广泛。结论:转录因子Pitx3、Nurr1在中脑DA能神经元的终末分化和生存维持中起重要作用。     

胚胎嗅鞘细胞和中脑腹侧细胞移植对帕金森病SD大鼠纹状体神经元存活和分化的影响

目的观察胚胎嗅球嗅鞘细胞(OECs)和胚胎中脑腹侧细胞(VMCs)联合移植对帕金森病(PD)SD大鼠纹状体神经元存活及分化的影响。方法 12只PD模型SD大鼠随机平均分成两组:单独VMCs组(在脑立体定位仪下将VMCs植入PD大鼠模型毁损侧纹状体内)和联合移植组(在脑立体定位仪下将OECs和VMCs植入PD大鼠模型毁损侧纹状体内)。OECs来源于5～7d绿荧光鼠的嗅球嗅鞘,VMCs来源于孕13～14d绿荧光胎鼠中脑腹侧的脑组织。于移植后4、14周灌注取脑,切片后做酪氨酸羟化酶(TH)免疫组织化学染色,检测胚胎中脑腹侧细胞的存活及分化状况。结果移植4周后单独VMCs组及联合移植组纹状体区都可检测到TH免疫阳性神经元,数量无统计学差异(P0.05)。移植14周后联合移植组纹状体区TH免疫阳性神经元数量比单独VMCs组明显增多(P0.05)。结论胚胎中脑腹侧细胞联合嗅鞘细胞移植入帕金森病大鼠纹状体促使纹状体神经元分化为多巴胺能神经元。     

大鼠腹侧中脑多巴胺能神经元的形态学发育与分布特征

目的:探讨大鼠腹侧中脑多巴胺能(mDA)神经元的形态学发育和分布特征。方法:取胚胎晚期至成年大鼠不同时期的腹侧中脑连续冠状切片,以酪氨酸羟化酶(TH)免疫荧光染色方法观察mDA神经元。结果:(1)在胚胎期,TH阳性细胞多为圆形或椭圆形,随着发育进程,其突起逐渐伸长,分支也逐渐增多;出生后28 d,TH阳性细胞表现为成熟mDA神经元的形态特征。(2)Map-2/TH免疫荧光检测显示,新生期大鼠腹侧中脑TH阳性神经元定位分布与成年期的mDA神经元分布趋向一致。(3)E16.5 d时腹侧中脑TH阳性细胞的数量和密度最大,此后逐渐下降。结论:大鼠mDA神经元的发育在出生前后,呈现先大量形成后又逐渐减少的过程,与此同时其形态趋向成熟;至P0 d时mDA神经元分布定位基本完成,至出生后28 d形态学发育成熟。     

同种异体神经干细胞脑内移植免疫排斥反应的实验研究

目的观察帕金森病(PD)模型大鼠同种异体神经干细胞(NSC)脑内移植是否存在免疫排斥反应。方法取E14.5d SD胚鼠腹侧中脑组织进行分离、培养、扩增,经Brdu、Nestin免疫组化染色鉴定确认为NSC后,借助脑立体定位仪移植到SD大鼠PD模型的纹状体内,分别于10、21、35、60d时检测其旋转行为后分批处死,再行HE、CD4、CD8、酪氨酸羟化酶(TH)和MHC-Ⅱ抗原免疫组化染色。结果移植组10d时,CD4、CD8、、MHC-Ⅱ少量表达,以21d时较为明显,35d时明显减少,60d消失;10d、21d时移植区未见明显TH阳性神经元,35d后数量显著增加。阳性对照组在10d、21d时见少量CD4、CD8、和MHC-Ⅱ阳性细胞,35d时消失,各时间点都未见TH阳性神经元。阴性对照组在各时间点都未见TH阳性神经元和CD4、CD8、MHC-Ⅱ阳性细胞。PD模型移植组旋转行为35d时出现改善。结论神经干细胞脑内移植未见明显免疫排斥反应。     

黑质多巴胺触液神经元

将30％ HRP 8—10μl或3％碘化丙啶(PI)3μl分别注入两组动物单侧侧脑室内,48小时后将鼠处死,检查中脑切片。发现双侧黑质均司见HRP标记细胞群,但以同侧为主。标记范围以中脑中上部为多。标记细胞主要分布在黑质致密带内侧部,网状带中仅少数散在。注射PI例所见类同,但标记细胞远较HRP标记细胞为多。TH免疫组化法发现黑质DA神经元投射纤维分散布于尾壳核,并见TH阳性投射纤维在室管膜上皮细胞的深面形成密集的膨大,个别地区还见阳性终末突入侧脑室。另外,在接受胚中脑黑质移植存活良好的受体鼠纹状体中,发现少数移植存活的TH阳性黑质DA神经元胞体或其突起伸入侧脑室室管膜上皮细胞间甚或突入室腔。实验表明部分黑质多巴胺神经元系触液神经元,提示可能直接释放DA入脑脊液。当胚黑质细胞被移植入受体脑纹状体后,部分黑质DA神经元重演其发育的规律,将其突起或胞体伸入室管膜上皮细胞间或突入侧脑室,以代偿其原有的功能。     

Laminin促进胚胎中脑多巴胺神经元生长发育的体外培养研究

本文在体外培养中,研究Laminin(LN)对大鼠胚胎中脑多巴胺(DA)神经元生长发育的影响。将胚胎鼠(胎龄15天)腹侧中脑细胞悬液,接种于底部涂有LN的24孔培养板中,培养2～6天后取出,以酪氨酸羟化酶(TH)免疫组织化学ABC法观察DA神经元的生长情况。培养48小时后,几乎所有TH免疫阳性细胞都有突起伸出,以双极细胞为主,有些突起分支末端有活跃生长的生长锥,后者又可发出多根丝状伪足。在培养3～6天的标本中,除见有单极、双极TH免疫阳性细胞外,每孔均见有     

AngⅡ诱导神经干细胞向多巴胺能神经元分化的时间效应

目的:体外分离培养神经干细胞(NSCs),探讨血管紧张素II(AngII)诱导NSCs向多巴胺(DA)能神经元分化的时间效应。方法:取第二代NSCs在含有AngII的诱导分化液中培养,根据诱导持续时间不同,分为A(10d),B(14d),C(17d)和D(21d)四组。终止诱导后,用免疫学法检测分化细胞中DA能神经元标志物酪氨酸羟化酶(TH)的表达,半定量-PCR测定THmRNA的相对表达量。结果:在AngII作用下,B,C组分化细胞数量均比A组增多,细胞胞体饱满,突起粗长,而D组细胞部分开始老化、脱壁悬浮。其中,C组TH阳性细胞率最高(15.64%),且THmRNA相对表达量(0.5047±0.0212)明显高于其他三组(P0.05)。结论:AngII诱导NSCs分化成DA能神经元存在分化的时间效应,诱导持续达17d时分化细胞中DA能神经元的比例最高。     

纹状体对体外培养中脑多巴胺神经元形态发育的影响

靶细胞在神经细胞的生长发育过程中起着重要的调节作用。本文通过胚胎腹侧中脑和纹状体联合培养研究纹状体对中脑多巴胺(DA)神经元形态发育的影响。纹状体(Str)和腹侧中脑(YMA)细胞悬液取自胚胎14天SD大鼠,联合培养3到14天后取出,用酪氨酸羟化酶(TH)免疫组化ABC法观察不同时期DA神经元的生长。与VMA单独培养相比,联合培养3天,发现细胞聚集程度较低,开始形成单层分布,培养7天TH阳性细胞数增加,多突起阳性细胞较易发现,细胞突起粗短,呈树枝状分枝。培养14天,TH阳性细胞数进一步增加,平均可达49个/25mm~2。本文对纹状体调节DA神经元生长发育的机制进行了讨论。     

胶质细胞源性神经营养因子对培养的胚鼠脑室下区神经干细胞表达Pitx3及酪氨酸羟化酶的影响

目的:观察胶质细胞源性神经营养因子(GDNF)对培养的胚鼠脑室下区(SVZ)神经干细胞(NSCs)表达Pitx3、酪氨酸羟化酶(TH)的影响。方法:取胚鼠SVZ组织,进行细胞培养。分为GDNF NSCs共培养组和NSCs单独培养对照组。用Pitx3、TH、Pitx3/TH免疫荧光单标和双标及Nestin免疫组化法进行检测。结果:共培养组5 d时形成神经球,10 d时球体积不断增大,12 d后开始贴壁生长,并向四周伸出突起并开始分化。对照组神经球明显少于共培养组。14 d共培养组Pitx3、TH、Pitx3/TH阳性细胞明显高于对照组。结论:GDNF能上调SVZ区NSCs表达Pitx3和TH,诱导NSCs向多巴胺(DA)能神经元分化。     

Experimental research on immunological rejection of brain tissue allograft]

AIM: To investigate the occurrence of rejection in brain tissue transplantation. METHODS: Ventral mesencephalon(VM) single cell suspensions from newborn rats were allografted into the striata of Parkinson's disease model recipient rats. Surviving animals were sacrificed at 2, 4 and 6 wk after transplantation, and the brain tissues were stained with HE or immunocytochemically to inspect the expression of tyrosine hydroxylase (TH) and major histocompatibility complex class II antigens (MHC II). RESULTS: High MHC II expression was observed within and around the allografts compared with control at 2 wk after grafting. MHC II expression then decreased at 4 wk and at 6 wk only few immunopositive cells remained. The number of TH positive neurons was low at 2 wk, but increased at 4 and 6 wk after transplantation. CONCLUSION: The brain is not an "immunologically privileged site" and graft rejection exists in brain tissue transplantation. This rejection maybe induced by MHC II. Therefore it is necessary to use immunosuppressants in brain transplantation.     

Ontogenesis of the central serotonin neuron system of the rat--an immunohistochemical study

The peroxidase-antiperoxidase technique was used to study the ontogenesis of serotonin-containing neurons in fetal, neonatal and adult rats. Serotonin-containing neurons were first detected in a rat embryo of crown-rump length (CRL) 5 mm, bilaterally distributed in the ventral metencephalon near the isthmus rhombencephali. Serotonin fibers were first detected in CRL 6 mm embryos. There was a rapid increase in serotonin-immunoreactive neurons of embryos of 7-8 mm CRL. Serotonin neurons appeared initially as independent, bilateral groups of neurons, but as early as CRL 16 mm, the adult mid-line distribution was present, while the neurons that occurred as single groups in the adult already existed as single groups or at least were only partially connected across the mid-line. A continuous distribution of serotonin neurons was observed in the mesencephalic and pontine reticular formation from CRL 13 mm to the adult stage. It is suggested that the rapid increase in serotonin neurons at 7 and 8 mm CRL is associated with the completion of mitosis which occurs at this time.     

Early fetal development of the human cerebellum

Early cerebellum development in humans is poorly understood. The present study histologically examined sections from 20 human embryos and fetuses at 6 weeks (12-16 mm crown-rump length (CRL); 4 specimens), 7-9 weeks (21-39 mm CRL; 8 specimens), 11-12 weeks (70-90 mm CRL; 4 specimens) and 15-16 weeks (110-130 mm CRL; 4 specimens). During 7-9 weeks (approximate CRL 28 mm), the rhombic lip (a pair of thickenings of the alar plate) protruded dorsally, bent laterally, extended ventrolaterally and fused with the medially located midbrain. During that process, the primitive choroid plexus appeared to become involved in the cerebellar hemisphere to form a centrally located eosinophilic matrix. At that stage, the inferior olive had already developed in the thick medulla. Thus, the term 'bulbo-pontine extension' may represent an erroneous labeling of a caudal part of the rhombic lip. The cerebellar vermis developed much later than the hemisphere possibly from a midline dark cell cluster near the aqueduct. In the midline area after 12 weeks (80 mm CRL), the growing bilateral hemispheres seem to provide mechanical stress such as rotation and shear that cause the development of several fissures much deeper than those on the hemisphere. The rapidly growing surface germinal layer may be a minor contributor to this vermian fissure formation. The vermian fissures seem to enable inside involvement of the surface germinal cells, and to induce cytodifferentiation of the vermis. Consequently, in the early stages, it appears that the cerebellar hemisphere and vermis develop independently of each other.     

Fetal porcine ventral mesencephalon graft. Determination of the optimal gestational age for implantation in Parkinsonian patients

Human fetal ventral mesencephalon tissue has been used as dopaminergic striatal implants in Parkinsonian patients, so far with variable effects. Fetuses from animals that breed in large litters, e.g., pigs, have been considered as alternative donors of dopaminergic tissue. The optimal gestational age of the porcine fetal donors has not been studied systematically. We collected ventral mesencephalic (VM) tissue from fetal pigs, embryonal ages E21, E28, E42, and E70, and examined the viability of the fetal VM cells after dissociation, the expression of tyrosine hydroxylase (TH) in culture, the presence of catecholamines, and the cellular survival and outgrowth up to 10 months after intrastriatal implantation in rats. The highest viability was found in suspensions prepared from E28 fetuses. The highest number of TH-positive cells was found in cell cultures prepared from E28 VM tissue. Explants with a gestational age of 28 and 42 days contained the largest amount of dopamine. Only E28-derived grafts showed TH-cell survival after implantation in rat striatum. Our results show that a gestational age of 28 days must be considered to be the optimal age for dopaminergic tissue derived from pig fetuses for therapeutic use as intrastriatal grafts in Parkinsonian patients.     

Host striatal projections into fetal ventral mesencephalic tissue grafted to the striatum of immature or adult rat

We have previously reported that few striatal axons from adult host brain innervate intrastriatal grafts of fetal ventral mesencephalic tissue. To see whether the immature rat brain would favor striatal innervation of the graft, unilateral implantation of fetal ventral mesencephalic tissue was carried out at 7 (P7), 14 (P14), or 60 (adults) days of age in neonatally dopamine- (DA)-lesioned and nonlesioned rats. Immunocytochemistry for tyrosine hydroxylase (TH), and/or dopamine- and adenosine 3′,5′-monophosphate-regulated phosphoprotein-32 (DARPP-32) was performed 2–6 months later. In the great majority of immature and in all adult recipients, the resulting graft consisted of a distinct intrastriatal mass of tissue surrounded by the host parenchyma. Most TH-immunopositive neurons were found within the confines of such grafts, although some were lying at short distances into the host striatal tissue, particularly in immature recipients. In a few immature recipients, there was, however, extensive intermingling of TH-positive neurons with the adjacent host brain tissue. In all recipients grafted at P7, P14, or as adults, the distinct, intra-parenchymal grafts contained moderate numbers of DARPP-32-positive processes, mainly at their periphery. These results indicate that the limited capacity of host striatal neurons to grow axons into transplanted fetal ventral mesencephalic tissue is not markedly different in young versus adult rats. A better integration of the ventral mesencephalic graft into the striatal circuitry of immature — as opposed to adult — recipients should therefore rely more on the higher tendency of DA neurons to become located into the host tissue following transplantation in young rats.     

基底前脑NOS神经元移植至成年鼠海马内的发育

目的 研究基底胶脑ＮＯＳ神经元移植成年鼠海马内后,ＮＯＳ的发育变化规律,同时观察移植的与宿主海马间发生联系的情况。方法 将大鼠１４－１６ｄ胚胎的基底前脑移植到单侧穹隆海马伞切断的成的大鼠海马内,动物在移植后存活５,７,１４,３０,６０,９０,１５０和１８０ｄ分别取脑,经ＮＡＤＰＨ－ｄ法和尼氏染色观察。结果 在移植后第７ｄ时ＮＡＤＰＨ－ｄ阳性染色才出现在ＮＯＳ阳性神经元内,随着移植物成活时间的延长,     

缺损运动神经元的大鼠脊髓内胚胎脊髓移植物的存活与生长

ＳＤ大鼠于出生２４ｈ内行左侧坐骨神经钳压术，造成左侧腰段脊髓前角运动神经元缺损。５￣１２周后，作为脊髓移植的受体鼠。供体为胚龄１３￣１４ｄ的ＳＤ大鼠胚胎，取其脊髓腹侧组织块作为移植物，植入受体鼠左侧腰段脊髓的背外侧部。将受体鼠右侧带神经的Ｍｕ长伸肌移放到脊椎旁，神经的断端插入胚胎移植物处。术后动物存活６￣８周，行组织学（包括电镜）、ＡＣｈＥ组织化学、ＣｈＡＴ免疫组织化学和ＨＲＰ逆行追踪等观察。结果     

BDNF、SDNF、GM_1对体外培养的多巴胺神经元的影响

本研究在体外培养的条件下研究了BDNF、SDNF、GM1对大鼠胚腹侧中脑多巴胺神经元生长发育的影响。取孕15d鼠胚腹侧中脑细胞悬液将之接种于24孔培养板中进行培养。实验分4组；对照组及分别向培养液中加入BDNF、SDNF、GM1等的三个实验组。培养7d后取出。用酪氨酸羟化酶免疫组织化学ABC法观察和比较了多巴胺神经元的生长状态。发现加入BDNF、SDNF、GM1的培养孔内的酪氨酸羟化酶阳性神经元明显增多，细胞突起的长度增加且数量增多，与单纯培养组相比均有显著性差异，但三个实验组之间无显著性差异。研究结果表明，BDNF、SDNF、GM1可促进体外培养的鼠胚腹侧中脑多巴胺神经元的存活及突起的延伸。