重组人改构体酸性成纤维细胞生长因子对帕金森病大鼠中脑腹侧被盖区酪氨酸羟化酶神经元的保护

目的:探讨重组人改构体酸性成纤维细胞生长因子(Mrh-aFGF)对帕金森病(PD)大鼠旋转行为和中脑腹侧被盖区酪氨酸羟化酶(TH)免疫阳性神经元的影响.方法:6-羟基多巴胺(6-OHDA)分别注入黑质和腹侧被盖区后建立PD大鼠模型,侧脑室内注射Mrh-aFGF,用阿扑吗啡诱导旋转行为,免疫组织化学显色观察TH免疫阳性神经元和纤维,并进行定量分析.结果:PD组术后旋转启动时间缩短,持续时间延长,速度加快;Mrh-aFGF处理组旋转行为有改善.各组大鼠组内健侧和损毁侧阳性神经元比较,对照组损毁侧无明显改变;PD组、NS处理组和Mrh-aFGF处理组损毁侧阳性神经元与健侧比较均减少.Mrh-aFGF处理组损毁侧中脑腹侧被盖区阳性神经元数量较PD组及对照组增加.结论:Mrh-aFGF能减少PD大鼠中脑腹侧被盖区TH免疫阳性神经元的丢失,并改善其旋转行为.     

Mrh-aFGF对帕金森病大鼠中脑腹侧被盖区神经元的保护

目的探讨重组人改构体酸性成纤维细胞生长因子(Mrh-a FGF)对帕金森病(PD)大鼠中脑腹侧被盖区神经元病变的影响。方法将54只SPF级雄性SD大鼠随机分为对照组、模型组和治疗组,每组18只。6-羟基多巴胺(6-OHDA)分别注入大鼠左侧黑质和中脑腹侧被盖区后建立PD模型,侧脑室内注射Mrh-a FGF,用阿扑吗啡诱导旋转行为;Nissl染色法观察大鼠中脑腹侧被盖区神经元病理学改变;电子显微镜观察中脑腹侧被盖区神经元及突触超微结构的变化。结果模型组大鼠损毁侧中脑腹侧被盖区神经元数目较健侧明显减少(P0.05);治疗组术后1周、2周、4周损毁侧神经元数目均较模型组明显增加(P0.05);模型组大鼠中脑腹侧被盖区神经元超微结构明显受损,出现核固缩,粗面内质网扩张、脱颗粒,线粒体肿胀、嵴消失,以及突触前后膜肿胀、突触间隙消失,治疗组中脑腹侧被盖区神经元超微结构有明显改善。结论 Mrh-a FGF能减少PD大鼠中脑腹侧被盖区神经元的丢失,并改善其神经元的超微结构。     

帕金森病模型大鼠中脑腹侧被盖区多巴胺能神经元改变的实验研究

目的：探讨帕金森病（Parkinson’s disease，PD）大鼠模型中脑腹侧被盖区（ventral tegmentalarea，VTA）多巴胺能神经元的改变。方法：应用6-羟基多巴胺（6-hydroxydopamine，6-OHDA）注射右侧黑质致密区（substantia nigra compacta，SNc）制作PD大鼠模型，进行阿朴吗啡（apomorphine，APO）诱发行为学观察、电镜、尼氏染色观察中脑VTA神经元的改变、酪氨酸羟化酶（tyrosine hydroxylase，TH）免疫组织化学ABC观察其DA能神经元的改变并进行图像分析。结果：APO诱发PD大鼠模型异常旋转行为，尼氏染色见PD大鼠中脑VTA有神经细胞肿胀、坏死等变化，VTA TH阳性神经元数量减少，形态学改变。结论：中脑VTA DA能神经参与PD模型大鼠的改变；APO能诱导6-OHDAPD模型大鼠的旋转行为，其强弱可能与TH^＋神经元数量直接相关。     

重组人改构体酸性成纤维细胞生长因子减少帕金森病大鼠黑质酪氨酸羟化酶免疫阳性神经元丢失

目的 探讨重组人改构体酸性成纤维细胞生长因子(Mrh-aFGF)对帕金森病(PD)大鼠旋转行为和酪氨酸羟化酶(TH)免疫阳性神经元的影响.方法 6-OHDA分别注入黑质和腹侧被盖区后建立PD大鼠模型,侧脑室内注射Mrh-aFGF,用阿扑吗啡诱导旋转行为,免疫细胞化学染色观察TH免疫阳性神经元和纤维,并进行定量分析.结果 对照组均未引出旋转行为;PD组术后旋转启动时间缩短,持续时间延长,速度加快;生理盐水(NS)处理组旋转行为未见明显改善;Mrh-aFGF处理组旋转启动时间延长,持续时间缩短,速度减慢(P＜0.01).各组大鼠健侧黑质TH阳性神经元的数量维持在相近的水平.同组内健侧和损毁侧阳性神经元比较,对照组损毁侧无明显改变;PD组、NS处理组和Mrh-aFGF处理组损毁侧阳性神经元与健侧比较均明显减少(P＜0.01).其中PD组损毁侧黑质TH免疫阳性神经元数量随时问延长逐渐减少(P＜0.01).NS处理组损毁侧黑质TH免疫阳性神经元的变化与PD组相似;Mrh-aFGF处理组损毁侧黑质阳性神经元较PD组及NS处理组有明显改善,阳性神经元的数量明显增加(P＜0.01).结论 Mrh-aFGF能减少PD大鼠黑质TH免疫阳性神经元的丢失,并改善其旋转行为.     

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。     

阿朴吗啡诱导黑质毁损大鼠腹侧被盖区c-jun表达

目的：观察6-羟基多巴胺（6-hydroxydopamine，6-OHDA）毁损黑质DA能神经元后，不同时间点腹腔注射阿朴吗啡（Apomorphine，APO）大鼠行为学及中脑腹侧被盖区（ventral tagmental area，VTA）形态学、c-jun表达情况，探讨其可能机制。方法：6-OHDA单侧一点注射大鼠右黑质致密区（substantia nigra compacta，SNc），特异性毁损DA能神经元；术后1、3、7、14、21d腹腔注射APO，观察旋转行为；利用电镜、尼氏染色、免疫组织化学ABC法，观察各时间点VTADA能神经元形态学变化和酪氨酸羟化酶（TH）、c-jun表达情况。结果：毁损侧VTADA能神经元逐渐减少，超微结构损伤逐渐加重；DA神经元丢失≥75％时，APO诱导的旋转实验≥7r／min，VTA毁损侧c-jun表达。结论：APO能诱导毁损侧VTA表达c-jun；c-jun表达与DA能神经元毁损程度有一定的关系。     

Mrh-aFGF对帕金森病大鼠黑质神经元的保护

目的 探讨重组人改构体酸性成纤维细胞生长因子(Mrh-aFGF) 对帕金森病(PD) 大鼠黑质神经元病变的影响。 方法 SD大鼠72只,随机分为4组：对照组、PD组、生理盐水（NS）处理组、　Mrh-aFGF 处理组,每组18只。 6-OHDA 分别注入左侧黑质和腹侧被盖区后建立PD 大鼠模型,侧脑室内注射Mrh-aFGF,用阿扑吗啡诱导旋转行为;Nissl 染色法观察大鼠黑质神经元病理学改变;电子显微镜观察黑质神经元超微结构的变化。 结果 对照组均未出现旋转行为;PD组术后旋转速度逐渐加快;NS 处理组旋转行为未见明显改善;Mrh-aFGF 处理组旋转速度明显减慢(P<0.05);PD组及NS 处理组大鼠损毁侧黑质神经元数目较健侧显著减少(P<0.05);Mrh-aFGF 处理组术后1周、2周、4周损毁侧神经元数目均较PD组及NS 处理组明显增加(P<0.05);PD组大鼠黑质神经元超微结构明显受损,出现核固缩,线粒体肿胀、嵴消失,粗面内质网扩张、脱颗粒,以及突触前后膜肿胀,突触间隙消失,Mrh-aFGF处理组黑质神经元超微结构有明显改善。 结论 Mrh-aFGF能改善PD大鼠的旋转行为,减少PD大鼠黑质神经元的丢失,并改善其黑质神经元的超微结构。     

纳米二氧化锰对大鼠腹侧中脑的损伤作用

目的:探讨纳米二氧化锰(nano-MnO2)对大鼠腹侧中脑的损伤作用。方法:大鼠在脑立体定位下,实验组脑内注射nano-MnO2,对照组脑内注射生理盐水(NS),各组分别于注射1周后用免疫组织化学方法检测酪氨酸羟化酶(tyrosine hydroxylase,TH)、胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)及诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)的表达变化。结果:免疫组织化学染色结果显示,实验组大鼠注射1周后,腹侧中脑损毁侧与对侧相比,TH阳性细胞明显减少(P<0.05),GFAP及iNOS阳性细胞明显增多(P<0.05);对照组大鼠注射1周后,腹侧中脑损毁侧与对侧相比,TH、GFAP和iNOS免疫反应阳性细胞均无明显变化(P>0.05)。结论:脑内注射nano-MnO2能引起大鼠中脑多巴胺能神经元的破坏,GFAP和iNOS的表达增加。     

不同时程吗啡依赖对大鼠中脑腹侧被盖区多巴胺能神经元的影响

目的:观察不同时程吗啡依赖对大鼠中脑腹侧被盖区(ventral tegmental area,VTA)多巴胺能神经元的影响。方法:建立吗啡慢性依赖大鼠模型,石蜡包埋组织连续切片,免疫组织化学染色观察多巴胺能神经元特异性标记物酪氨酸羟化酶(tyrosine hydroxylase,TH)的表达变化。结果:TH免疫组化结果显示随着吗啡依赖时间的延长VTA区内TH阳性细胞逐渐减少,吗啡依赖6周组阳性细胞减少明显。结论:较长时程吗啡依赖大鼠VTA多巴胺能神经元损伤明显。     

垂体同源盒家族因子3和孤儿核受体相关因子1基因在帕金森病模型大鼠腹侧中脑表达显著下调

目的:探讨垂体同源盒家族因子3(Pitx3)和孤儿核受体相关因子1(Nurr1)基因在帕金森病(PD)模型大鼠腹侧中脑的表达变化。方法:(1)采用免疫荧光方法检测PD模型组、成年正常组和假手术组大鼠腹侧中脑TH、Pitx3/TH和Nurr1/TH阳性细胞并计数;(2)分别采用半定量RT-PCR和Western Blot方法检测Pitx3和Nurr1基因在PD模型组、成年正常组和假手术组大鼠腹侧中脑转录和翻译水平的变化。结果:(1)免疫荧光检测显示PD大鼠模型组腹侧中脑多巴胺能神经元数目显著减少;(2)半定量RT-PCR和Western Blot检测显示PD大鼠模型组腹侧中脑左侧Pitx3和Nurr1表达显著下调,其中Pitx3表达下调更明显。结论:Pitx3和Nurr1基因的持续表达与腹侧中脑多巴胺能神经元的生存维持密切相关,为探索PD的病因诊断及基因治疗提供可能的新途径。     

GFR-α1在Parkinson病大鼠黑质区的表达

本文观察了胶质细胞源性神经营养因子受体-α1(GFR-α1)在Parkinson病(PD)大鼠黑质区的表达变化。分别向大鼠左侧尾壳核和黑质致密部、中脑腹侧被盖区内注射6-羟基多巴胺(6-OHDA)建立部分损伤模型和完全损伤模型后,取大鼠黑质区脑组织作冰冻切片,行GFR-α1和TH免疫组织化学染色,用图像分析系统进行细胞计数。结果表明,在部分损伤组和完全损伤组中,GFR-α1在黑质区神经元及胶质细胞中均有表达,且部分损伤组GFR-α1阳性细胞的分布、数量随受损时程的不同出现差异。TH阳性神经元形态学改变,数量的变化与GFR-α1阳性细胞的分布、数量有着密切的关系。以上结果提示,GFR-α1的表达可能与脑内受损部位细胞的营养、修复、再生有关。     

损毁Parkinson病大鼠腹侧苍白球对纹状体内多巴胺的影响

应用6羟基多巴胺(6OHDA)制备Parkinson病(PD)大鼠模型,插入电极通过直流电毁损腹侧苍白球(VP),观察毁损术后PD大鼠旋转行为的变化,并应用高压液相色谱检测纹状体内多巴胺(DA)及3,4二羟甲基苯丙氨酸(DOPAC)和去甲肾上腺素(NA)的含量。结果显示:直流电毁损VP可使PD模型大鼠的旋转行为明显减少;毁损侧纹状体内DA的含量减少,DOPAC和NA的含量增加。上述结果提示VP毁损可明显改善PD大鼠的旋转行为,此效应可能与抑制VP的异常兴奋有关。     

Contributions of the mesencephalic dopaminergic system and the trigeminal sensory pathway to the ventral tegmental aphagia syndrome in rats

Four experiments examined the neural substrates for the aphagia and adipsia syndrome resulting from damage of the ventral tegmental region. Radiofrequency (RF) lesions at the level of the mesencephalon in rats showed that the most effective site for producing aphagia and adipsia was in an intermediate zone between the substantia nigra and the ventral tegmental area. Injection of the neurotoxin 6-hydroxydopamine (6-OHDA) into this intermediate zone led to a less severe feeding deficit, suggesting that both dopaminergic and non-dopaminergic neurons are involved in the mesencephalic aphagic syndrome. As the lemniscus trigeminalis was destroyed after the RF lesion of the intermediate zone, the hypothesis of trigeminal projection involvement was tested by lesioning (RF) the sensory trigeminal nucleus. These rats were aphagic but they recovered and their deficit was less severe than after RF lesion of the mesencephalic intermediate zone. In the last experiment, a combined 6-OHDA lesion of the mesencephalic intermediate zone and RF lesion of the trigeminal sensory nucleus led to a more severe deficit in feeding behavior than either lesion alone. These results further demonstrate that feeding behavior is under the control of a complex system involving several neural pathways.     

Effects of orally administered levodopa on mesencephalic dopaminergic neurons undergoing a degenerative process

Although the issue of in vivo levodopa toxicity appears to be settled by now in the light of recent findings, a crucial aspect was not accounted for the experiments designed to tackle that question. Levodopa could in fact be non-toxic on surviving dopamine neurons, but that could not be the case when the drug is administered at the same time those neurons are undergoing degeneration, which is what happens in the clinical setting. Dopaminergic neurons could in that situation be more vulnerable to levodopa's potential toxic action. Our aim was to determine if oral administration of levodopa is toxic for mesencephalic dopaminergic neurons that are actively involved in a degenerative process. We induced delayed retrograde degeneration of the nigrostriatal system in rats by injecting 6-hydroxydopamine (6-OHDA) intrastriatally. Treatment was started the day after the injection. Dopaminergic markers were histologically studied at the striatal and nigral levels, to determine degree of damage of the nigrostriatal dopaminergic system in levodopa- and vehicle-treated rats. No significant differences between levodopa or vehicle-treated rats were found in: (i) striatal immunoautoradiographic labeling for tyrosine hydroxylase (TH) and the membrane dopamine transporter (DAT); (ii) cell counts of TH-immunoreactive (TH-ir) neurons remaining in the substantia nigra and ventral tegmental area (VTA); (iii) surface area of remaining TH-immunoreactive neurons in the substantia nigra. The present experiments demonstrate that levodopa does not enhance delayed retrograde degeneration of dopaminergic neurons induced by intrastriatal administration of 6-OHDA.     

阿扑吗啡对6-羟基多巴胺毁损纹状体鼠的神经保护和神经营养作用

目的在6-羟基多巴胺毁损纹状体鼠模型上,探讨阿扑吗啡的神经保护和神经营养作用。方法用6-羟基多巴胺毁损大鼠单侧纹状体,在毁损前15 m in注射阿扑吗啡(10 mg/kg,s.c.),连续注射11 d。毁损2周后,分别进行行为学(苯丙胺引起的旋转数目)、组织学(黑质和腹侧被盖区的酪氨酸羟化酶阳性细胞计数)的观察。结果阿扑吗啡降低苯丙胺引起的向损伤侧旋转的次数,显著降低黑质神经元的损伤(从50%降至30%)。且多巴胺细胞形状可恢复到类似正常组;阿扑吗啡对正常鼠黑质细胞数无影响,但可使腹侧被盖区细胞数显著增高37%。结论阿扑吗啡对6-羟基多巴胺毁损纹状体模型鼠的黑质和腹侧被盖区神经细胞具有显著的保护作用,且改善运动功能。同时,对正常鼠的腹侧被盖区也显示神经营养作用。     

Effect of unilateral injection of MK-801 into the area of A10 cells on feeding evoked by stimulation of homologous area in the contralateral hemisphere

It was found previously that unilateral electrolytic and 6-OHDA lesions of the ventral tegmental area (VTA) and unilateral intra-VTA injection of bicuculline resulted in facilitation of behavioral responses evoked by electrical stimulation of the symmetrical VTA area in the contralateral hemisphere. We postulated that "the contralateral facilitation effect", which may reflect the yet unexplored mechanism of immediate compensation after acute unilateral brain injury, is attributable to the A10 DA neurons and their regulatory inputs. The present study was aimed at examining the possible involvement of NMDA-mediated glutamatergic transmission in VTA in the "contralateral facilitation effect". The behavioral model of the VTA stimulation-induced feeding in rats was used. Latency to eat was measured as a function of stimulation frequency before and after unilateral intra-VTA injection of non-competitive NMDA receptors antagonist, MK-801, (doses 0.0, 1.25 and 2.5 micrograms). MK-801 caused a dose-dependent augmentation of feeding evoked by stimulation of the contralateral VTA, which manifested as a decrease in the reaction frequency threshold and a leftward shift of the latency/frequency curve. Dose 2.5 micrograms replicated the facilitatory effect of electrolytic and 6-OHDA lesions. The results are interpreted in terms of MK-801-evoked depression of excitatory glutamatergic tone over A10 DA cells and compensatory increase in DA release in the contralateral hemisphere.     

Enhanced glutamatergic phenotype of mesencephalic dopamine neurons after neonatal 6-hydroxydopamine lesion

There is increasing evidence that a subset of midbrain dopamine (DA) neurons uses glutamate as a co-transmitter and expresses vesicular glutamate transporter (VGLUT) 2, one of the three vesicular glutamate transporters. In the present study, double in situ hybridization was used to examine tyrosine hydroxylase (TH) and VGLUT2 mRNA expression during the embryonic development of these neurons, and postnatally, in normal rats and rats injected with 6-hydroxydopamine (6-OHDA) at P4 to destroy partially DA neurons. At embryonic days 15 and 16, there was a regional overlap in the labeling of TH and VGLUT2 mRNA in the ventral mesencephalon, which was no longer found at late embryonic stages (E18-E21) and postnatally. In normal pups from P5 to P15, only 1-2% of neurons containing TH mRNA in the ventral tegmental area (VTA) and substantia nigra, pars compacta, also displayed VGLUT2 mRNA. In contrast, after the cerebroventricular administration of 6-OHDA at P4, 26% of surviving DA neurons in the VTA of P15 rats expressed VGLUT2. To search for a colocalization of TH and VGLUT2 protein in axon terminals of these neurons, the nucleus accumbens of normal and 6-OHDA-lesioned P15 rats was examined by electron microscopy after dual immunocytochemical labeling. In normal rats, VGLUT2 protein was found in 28% of TH positive axon terminals in the core of nucleus accumbens. In 6-OHDA-lesioned rats, the total number of TH positive terminals was considerably reduced, and yet the proportion also displaying VGLUT2 immunoreactivity was modestly but significantly increased (37%). These results lead to the suggestion that the glutamatergic phenotype of a VTA DA neurons is highly plastic, repressed toward the end of normal embryonic development, and derepressed postnatally following injury. They also support the hypothesis of co-release of glutamate and DA by mesencephalic neurons in vivo, at least in the developing brain.     

Intracerebral dopaminergic transplants are not activated by electrical footshock stress activating in situ mesocorticolimbic neurons

Male rats received a dopaminergic implant aimed either at the nucleus accumbens or the ventral tegmental area (VTA) following 6-hydroxydopamine lesion of their mesocorticolimbic dopaminergic system. Exposure to electrical footshock stress 6 months later markedly activated the mesocorticolimbic neurons in control animals as shown by the increase of dihydroxyphenylacetic acid (DOPAC) levels both in the nucleus accumbens and the VTA. However, no stress-induced activation was seen for the grafted neurons, irrespective of the area of implantation. These results indicate the lack of reinnervation and modulation of the grafted dopaminergic neurons by one of the important afferent systems regulating the activity of endogenous mesencephalic dopaminergic neurons.