帕金森病大鼠模型的行为学及神经元形态学评价

背景：由于黑质致密部体积狭小，应用6-羟基多巴胺(6-Hydroxydopamine，6-OHDA)损毁黑质多巴胺神经元(Nigral dopaminergic neuron，NDN)制作帕金森病大鼠模型的成功率较低，一般仅为30％～40％左右。目的：探讨帕金森病大鼠模型建立后的行为学及神经元形态学改变。设计：完全随机的实验研究。地点和材料：安徽省药物研究所，SD大鼠，6-OHDA，阿朴吗啡，兔抗TH血清，SR-6N大鼠脑立体定向仪等。干预：将6-OHDA立体定向注射于90只SD大鼠的左侧黑质区及黑质纹状体通路，观察大鼠行为及多巴胺神经元形态学变化。主要观察指标：旋转行为，震颇及其他异常行为，免疫组织化学观察，电镜观察。结果：经阿朴吗啡诱导共筛选出64只成功大鼠模型(占71％)；免疫组化观察发现注射侧黑质区NDN较对侧明显减少，电镜观察发现其普遍存在凋亡及坏死样改变。结论：本方法是建立帕金森病大鼠模型的有效方法，在行为学和神经元形态学等方面同帕金森病人有许多相似之处。     

应用6-羟基多巴胺建立帕金森病大鼠模型的稳定性评价

背景应用6-羟基多巴胺(6-Hydroxydopamine,6-OHDA)损毁黑质多巴胺神经元(nigral dopaminergic neuron,NDN)制作的大鼠模型,在目前帕金森病的研究中应用最广,但由于黑质致密部体积狭小,技术难度大,故模型制备成功率一般仅为30％～40％左右.目的探讨提高6-羟基多巴胺帕金森病大鼠模型成功率的方法,并对模型进行评价.设计完全随机的实验研究.地点和材料实验在安徽中医学院第一附属医院中心实验室完成,实验材料包括SD大鼠,6-OHDA,阿朴吗啡,兔抗TH血清,ABC试剂盒,SR-6N大鼠脑立体定向仪,JEM-100CX电镜.干预取SD大鼠90只,将6-OHDA立体定向微量注射于左侧黑质区及黑质纹状体通路,观察大鼠行为及黑质细胞形态学变化.主要观察指标旋转行为,免疫组织化学观察多巴胺能神经元数量,电镜观察多巴胺能神经元形态改变.结果90只大鼠中经阿朴吗啡诱导后有64只(占71％)恒定转向右侧且结果稳定,旋转圈数30 min＞210 r,被视为成功大鼠模型;免疫组化观察发现注射侧黑质区多巴胺能神经元较对侧明显减少,电镜观察发现其普遍存在凋亡及坏死样改变.结论应用本方法可较快建立稳定的成功率较高的大鼠模型,但在病理和行为学等方面同自然患者仍有较多差异.     

应用6-羟基多巴胺建立帕金森病大鼠模型的稳定性评价

背景：应用6-羟基多巴胺(6-Hydroxydopamine，6-OHDA)损毁黑质多巴胺神经元(nigral dopaminergic neuron，NDN)制作的大鼠模型，在目前帕金森病的研究中应用最广，但由于黑质致密部体积狭小，技术难度大，故模型制备成功率一般仅为30％-40％左右。目的：探讨提高6-羟基多巴胺帕金森病大鼠模型成功率的方法，并对模型进行评价。设计：完全随机的实验研究。地点和材料：实验在安徽中医学院第一附属医院中心实验室完成，实验材料包括SD大鼠，6-OHDA，阿朴吗啡，兔抗TH血清，ABC试剂盒，SR-6N大鼠脑立体定向仪，JEM-100CX电镜。干预：取SD大鼠90只，将6-OHDA立体定向微量注射于左侧黑质区及黑质纹状体通路，观察大鼠行为及黑质细胞形态学变化。主要观察指标：旋转行为，免疫组织化学观察多巴胺能神经元数量，电镜观察多巴胺能神经元形态改变。结果：90只大鼠中经阿朴吗啡诱导后有64只(占71％)恒定转向右侧且结果稳定，旋转圈数30min&;gt;210r，被视为成功大鼠模型；免疫组化观察发现注射侧黑质区多巴胺能神经元较对侧明显减少，电镜观察发现其普遍存在凋亡及坏死样改变。结论：应用本方法可较快建立稳定的成功率较高的大鼠模型，但在病理和行为学等方面同自然患者仍有较多差异。     

6-羟基多巴胺两点注射法建立帕金森病模型大鼠的行为学与组织病理学特征

目的:探讨提高6-羟基多巴胺(6-hydroxydopamine,6-OHDA)诱发帕金森病大鼠模型成功率,并能缩短其成模周期的方法。方法:实验于2004-05-08/07-12在暨南大学医学院解剖教研室进行。采用SD雄性大鼠24只,随机分为实验组(18只),对照组(6只),通过脑内立体定向术,将6-OHDA注入实验组大鼠左侧黑质致密部(substantianigraparscompacta,SNC)和中脑腹侧被盖区(ventraltegmentalarea,VTA)以建立帕金森病模型,观察大鼠行为变化及黑质细胞形态学改变。结果:实验组大鼠经APO诱导后,有15只(83.3%)向右侧旋转速度>7r/min(30min旋转>210r),术后2周与术后3,4周之间大鼠旋转行为差异无显著性意义(P>0.05)。成功模型鼠经Nissl染色可见左侧SNC和VTA区神经元数目较对侧明显减少,对照组无旋转行为和形态学改变。结论:应用6-OHDA于单侧SNC,VTA两点注射可明显提高帕金森病大鼠模型成功率,加大6-OHDA的注射剂量可以缩短其成模周期。同时,注射部位的准确性和注射速度及留针时间都至关重要。     

6-羟基多巴胺两点注射法建立帕金森病模型大鼠的行为学与组织病理学特征

目的：探讨提高6-羟基多巴胺(6-hydroxy dopamine，6-OHDA)诱发帕金森病大鼠模型成功率，并能缩短其成模周期的方法。方法：实验于2004-05-08／07-12在暨南大学医学院解剖教研室进行。采用SD雄性大鼠24只，随机分为实验组(18只)，对照组(6只)，通过脑内立体定向术，将6．OHDA注入实验组大鼠左侧黑质致密部(substantia nigra pars compacta,SNC)和中脑腹侧被盖区(ventral tegmental area，VTA)以建立帕金森病模型，观察大鼠行为变化及黑质细胞形态学改变。结果：实验组大鼠经APO诱导后，有15只(83．3％)向右侧旋转速度&;gt;7r／min(30min旋转&;gt;210r)，术后2周与术后3，4周之间大鼠旋转行为差异无显著性意义(|P&;gt;0．05)。成功模型鼠经Nissl染色可见左侧SNC和VTA区神经元数目较对侧明显减少，对照组无旋转行为和形态学改变。结论：应用6-OHDA于单侧SNC，VTA两点注射可明显提高帕金森病大鼠模型成功率，加大6-OHDA的注射剂量可以缩短其成模周期。同时，注射部位的准确性和注射速度及留针时间都至关重要。     

构建大鼠类似于人类帕金森病中晚期行为模型的实验研究

目的:探讨建立帕金森病模型过程中的关键步骤,摸索提高模型成功率的方法。方法:选择SD大鼠作为实验动物,随机分组为模型组和空白对照组。使用特异性的神经毒素6-羟多巴胺(6-OHDA)损伤一侧的黑质纹状体纤维,建立帕金森病动物模型,损伤后10d起,用阿朴吗啡可诱发大鼠向健侧旋转。结果:模型组诱发成功率达51%;病理学观察,损伤侧黑质致密部TH免疫阳性细胞、TH免疫阳性纤维严重缺失。空白对照组无旋转现象,病理学观察无异常现象。结论:用6-OHDA注射建立的大鼠帕金森病模型类似于人类帕金森病中晚期行为病理,制作方法科学、可靠、成功率高,可为医学研究提供依据。     

帕金森病模型大鼠行为学评价与黑质神经元凋亡的相关研究

目的检测帕金森病(PD)模型大鼠行为学及黑质神经元凋亡的相关指标。方法将6-羟基多巴胺(6-OHDA)通过立体定位仪注入大鼠右侧纹状体制备PD模型,5周后检测行为学指标;酪氨酸羟化酶(TH)组化染色观察各组大鼠右侧黑质神经元形态,Hoechst 33258染色了解其凋亡情况,Western blotting方法检测黑质内caspase-3蛋白表达。结果成功筛选的15只PD模型大鼠在露台Morris水迷宫实验中,与正常对照组及假手术组同侧相比,其寻台速度下降,时间延长(P<0-05);在平衡杆实验中,其潜伏期和过杆时间增加(P<0-05);模型组右侧黑质TH阳性神经元明显减少,该区域凋亡细胞明显增多,且caspase-3蛋白表达显著增高。结论6-OHDA诱导黑质内多巴胺(DA)神经元凋亡与其胞内caspase-3表达增高相关,模型大鼠在露台Morris水迷宫和平衡杆实验中行为学改变与TH免疫组化染色及Hoechst 33258染色结果吻合。     

改良帕金森病大鼠模型的建立及评价

目的:建立一种改进的帕金森病大鼠模型制作方法,并对模型进行综合评价。方法:实验于2004-02/2005-06在军事医学科学院干细胞研究中心完成。①选取Wistar大鼠60只,随机分为3组,传统组20只,改良组30只,对照组10只。②传统组向右侧中脑黑质致密部和中脑腹侧被盖区两点各注射6-羟基多巴胺8μg制作传统帕金森病大鼠模型,改良组向中脑腹侧被盖区单点6-羟基多巴胺12μg制作改良帕金森病大鼠模型。对照组向右侧中脑黑质致密部和中脑腹侧被盖区两点各注射含2g/L抗坏血酸的生理盐水4μL。③检测各组大鼠行为学变化及黑质多巴胺能神经元变化。结果:对照组和传统组术后分别有1只和4只动物在1周内死亡,改良组无动物死亡。行为学和免疫组化检测显示:①改良组30只大鼠有22只旋转稳定,平均转数>7r/min,成功率超过70%,与传统组相当。改良组大鼠死亡率低于传统组(20%)和对照组(10%)。②术后传统组和改良组均有部分动物出现震颤、活动迟缓、易激惹、竖毛、尾僵等异常行为。③成功帕金森病模型大鼠中脑黑质注射侧神经元数量明显减少,达90%以上,改良组与传统组比较差异无显著性(P>0.05),与对照组比较注射侧黑质多巴胺能神经元显著减少(P<0.001)。结论:改良帕金森病大鼠模型方法简便实用,动物死亡率低,模型成功率高,可以较快建立稳定的帕金森病大鼠模型。     

构建大鼠类似于人类帕金森病中晚期行为模型的实验研究

目的：探讨建立帕金森病模型过程中的关键步骤。摸索提高模型成功率的方法。方法：选择SD大鼠作为实验动物。随机分组为模型组和空白对照组。使用特异性的神经毒素6-羟多巴胺(6-OHDA)损伤一侧的黑质纹状体纤维。建立帕金森病动物模型。损伤后10d起，用阿朴吗啡可诱发大鼠向健侧旋转。结果：模型组诱发成功率达51％；病理学观察，损伤侧黑质致密部TH免疫阳性细胞、TH免疫阳性纤维严重缺失。空白对照组无旋转现象，病理学观察无异常现象。结论：用6-OHDA注射建立的大鼠帕金森病模型类似于人类帕金森病中晚期行为病理，制作方法科学、可靠、成功率高，可为医学研究提供依据。     

改良帕金森病大鼠模型的建立及评价

目的：建立一种改进的帕金森病大鼠模型制作方法，并对模型进行综合评价。 方法：实验于2004—02／2005—06在军事医学科学院干细胞研究中心完成。（1）选取Wistar大鼠60只，随机分为3组，传统组20只。改良组30只。对照组10只。（2）传统组向右侧中脑黑质致密部和中脑腹侧被盖区两点各注射6-羟基多巴胺8μg制作传统帕金森病大鼠模型。改良组向中脑腹侧被盖区单点6-羟基多巴胺12μg制作改良帕金森病大鼠模型。对照组向右侧中脑黑质致密部和中脑腹侧被盖区两点各注射含2g／L抗坏血酸的生理盐水4μL。（3）检测各组大鼠行为学变化及黑质多巴胺能神经元变化。 结果：对照组和传统组术后分别有1只和4只动物在1周内死亡，改良组无动物死亡。行为学和免疫组化检测显示：（1）改良组30只大鼠有22只旋转稳定。平均转数〉7r／min。成功率超过70％，与传统组相当。改良组大鼠死亡率低于传统组（20％）和对照组（10％）。（2）术后传统组和改良组均有部分动物出现震颤、活动迟缓、易激惹、竖毛、尾僵等异常行为。（3）成功帕金森病模型大鼠中脑黑质注射侧神经元数量明显减少．达90％以上，改良组与传统组比较差异无显著性（P〉0．05），与对照组比较注射侧黑质多巴胺能神经元显著减少（P〈0．001）。 结论：改良帕金森病大鼠模型方法简便实用，动物死亡率低，模型成功率高，可以较快建立稳定的帕金森病大鼠模型。     

外源性犬尿烯酸对黑质多巴胺能神经元损伤的保护性作用

背景帕金森病治疗方法有多种,多巴胺替代疗法、外科靶点永久毁损、脑深部核团高频电刺激术、脑移植和基因治疗.这些外科及药物治疗都有一些不足及难以弥补的缺陷,国内外学者将多巴胺能神经元保护剂的研究和应用提到了重要位置.目的观察评价预先应用谷氨酸受体拮抗剂犬尿烯酸对黑质多巴胺能神经元及神经传导纤维损伤的保护性作用.设计采用随机对照单盲实验研究.地点和材料研究地点为解放军总医院神经外科实验室;实验动物选取雌性SD大鼠(取自解放军总医院动物饲养室,40只,体质量210～240 g,平均228 g).干预雌性SD大鼠40只,随机分为4组,每组10只,应用江湾Ⅰ型C立体定向仪,在单侧黑质致密部及中脑被盖腹侧部,分别注射生理盐水,犬尿烯酸,犬尿烯酸加6-羟多巴胺,6-羟多巴胺.注射药物3 d后,进行症状观察,2周后处死大鼠.切片HE染色观察黑质细胞的形态特点,冷冻切片免疫组化特殊染色观察TH阳性细胞及TH阳性纤维着色情况,实验数据分别采用方差分析以及秩和检验进行统计分析.主要观察指标切片HE染色观察黑质细胞的形态特点,冷冻切片免疫组化特殊染色观察TH阳性细胞数及TH阳性纤维着色等级.结果正常黑质细胞体形较大,富含黑色素颗粒,可见尼氏体.数据统计分析结果提示犬尿烯酸组与生理盐水组之间差异无显著性意义(P＞0.05).实验组犬尿烯酸加6-羟多巴胺组与其他3组比较均差异有显著性意义(P＜0.01).结论外源性谷氨酸受体拮抗剂犬尿烯酸(kynurenic acid,KYNA)通过阻滞Glu受体能减轻6-羟多巴胺诱导的黑质多巴胺能神经元毒性损害.     

3-硝基丙酸预处理阻止黑质多巴胺神经元细胞凋亡

目的:观察3 硝基丙酸(3 NP)预处理时黑质多巴胺(DA)神经元细胞凋亡改变的作用机制及5 羟癸 酸(5 HD)对3 NP效果的影响。方法:25只雄性SD大鼠随机分为5组各5只。右侧黑质内立体定向注射6 羟多 巴胺(6 OHDA)建立帕金森病(PD)模型组,对照组大鼠立体定向和腹腔注射生理盐水,3 NP组在对照组的基础上 腹腔注射3 NP(20mg/kg),预处理组(CPC组)造模前24h给予3 NP(20mg/kg),5 HD组于造模前10min侧脑 室内给予5 HD(5mg/kg)。采用缺口末端标记原位检测法及免疫组化法检测黑质DA神经元细胞凋亡率及酪氨 酸羟化酶(TH)阳性细胞数。结果:PD组、CPC组及5 HD组与对照组和3 NP组比较细胞凋亡率均明显增高,损 毁侧TH阳性细胞数显著降低(P<0.01或P<0.05);CPC组与PD组比较细胞凋亡率降低,TH阳性细胞数增多 (P<0.05);5 HD组与PD组比较则差异无显著性意义(P>0.05)。结论:3 NP预处理可抑制细胞凋亡,而5 HD 可阻断3 NP预处理保护效应。线粒体ATP敏感性钾通道激活参与3 NP预处理神经元保护作用。     

Parkin gene therapy for alpha-synucleinopathy: a rat model of Parkinson's disease

Parkin is known to mitigate alpha-synuclein-induced neuronal cell death in vitro, which suggests that the parkin gene therapy is a candidate for therapeutic strategies for Parkinson's disease (PD). In the present study, the parkin gene therapy was investigated for its ameliorative effects on alpha-synucleinopathy in substantia nigra (SN) of rats. A recombinant adeno-associated viral (rAAV) vector system has frequently been used for the gene transfer to rat SN, and we have previously demonstrated that this technique induced the alpha-synucleinopathy, which closely resembles pathogenetic changes in PD. Therefore, in the present study, the effect of parkin was examined by co-infection of rAAV-parkin with rAAV-alpha-synuclein into dopaminergic neurons in SN. At 13 weeks post-rAAV infection, alpha-synuclein overexpression induced dopaminergic neuron loss, while co-expression of parkin mitigated the alpha-synuclein toxicity. Moreover, alpha-synuclein-induced dopaminergic neuron loss consequently resulted in motor dysfunction, which was also mitigated by parkin. Taken together, our results indicate that the parkin gene therapy is effective against alpha-synucleinopathy, suggesting its potential suitability for patients with PD.     

经颅超声对电针治疗帕金森病模型大鼠的效果评价

目的采用经颅超声（TCS）观察6-OHDA诱导的PD模型大鼠电针治疗前后中脑黑质区高回声（SNH）面积,结合黑质酪氨酸羟化酶（TH）免疫组化及血清、十二指肠和黑质炎症因子IL-1β和TNF-α等,探讨TCS在PD诊断和疗效评价中的应用价值。 方法60只雄性SD大鼠,随机分为假手术组15只,6-OHDA造模45只,通过向黑质区单侧输注6-OHDA诱导PD模型,模型成功33只,随机分为模型组（16只）和电针组（17只）,并于造模后第15 d和45 d进行行为学评估及超声观察,造模后第45 d,每组选取4只大鼠进行脑组织免疫组化染色,余下大鼠取心脏血后,根据解剖位置迅速分离出黑质及十二指肠,进行ELISA法检测,采用方差分析及t检验比较各组间的指标差异。 结果造模15 d后的大鼠损伤侧黑质区均出现明显的大面积片状SNH;超声观察第45 d时电针组损伤侧SNH面积比模型组减少,差异有统计学意义（t=4.01,P<0.05）;电针组TH阳性面积与模型组相比显著增加,差异有统计学意义（t=2.84,P<0.05）;电针组血清和十二指肠TNF-α及十二指肠IL-1β较模型组有所下降,差异均有统计学意义（t=8.88,7.64、10.86,P均<0.05）;模型组、电针组SNH面积与TH阳性面积之间存在显著相关性（r=-0.698、-0.723,P<0.05）。 结论TCS可以成功观测PD模型大鼠电针治疗前后SNH的面积变化,可作为PD诊断和疗效评价的指标之一。     

Asymmetry of sympathetic activity in a rat model of Parkinson’s disease induced by 6-hydroxydopamine: haemodynamic,electrocardiographic and biochemical changes

We studied the effects of experimental hemiparkinsonism upon sympathetic function in rat. The rats were divided into three groups: a group given intact control, one given lesioning with 6-hydroxydopamine (6-OHDA), and one given sham operation. One day after apomorphine testing following lesioning of the substantia nigra (SN) with 6-OHDA, heart rate (HR), mean arterial blood pressure (MAP), and electrocardiogram (ECG) were monitored. Plasma norepinephrine (NE), epinephrine (E), and dopamine (DA) levels were measured. Thereafter, immunohistochemical examination was performed to detect the extent of 6-OHDA lesions, using the avidinbiotinylated peroxidase complex (ABC) method. There was no difference in the total number of tyrosine hydroxylase (TH)-positive cells and rotation responses between the right- and left-sided 6-OHDA-treated groups. On the other hand, injury of rats with unilateral 6-OHDA resulted in haemodynamic, electrocardiographic, and biochemical changes. A significant difference was found between the right-sided 6-OHDA-treated rats and the left-sided treated ones. The MAP increased in the group given left 6-OHDA treatment and to lesser extent in the sham-operated group. In contrast, MAP did not increase in the group given right 6-OHDA treatment and was significantly lower than values in both the intact control rats and the sham-treated rats. Also, only the group given right 6-OHDA injury showed a fall in the value of HR. The plasma NE level was significantly decreased in the group given right 6-OHDA treatment compared with all other groups (PS< 0.005). Our results indicate that right-sided lesioning of the nigrostriatal DA pathway in the central nervous system (CNS) has greater sympathetic consequences than left-sided ones. These results also suggest that there is a differential effect of right-sided SN lesions on sympathetic cardiac innervation. The mechanism behind the confronting impairment of autonomic nervous system (ANS) could in this experiment be attributable to an asymmetric representation of sympathetic function in the brain. However, further studies will be needed before final conclusions can be made.     

A proteomic approach in the study of an animal model of Parkinson's disease

BACKGROUND: The aetiology of Parkinson's disease (PD), an age-related disorder characterized by a progressive degeneration of dopaminergic neurons of the substantia nigra (SN) pars compacta, remains unclear. Current treatments, such as administration of L-DOPA, are only symptomatic and do not stop or delay the progressive loss of neurons. In fact, it has been suggested that the dopamine precursor L-DOPA, increases generation of reactive oxygen species (ROS) leading to further neuronal damage. A similar loss in nigrostriatal dopaminergic neurons is produced on intracerebral administration of the catecholaminergic neurotoxin 6-hydroxydopamine (6-OHDA). In an animal model of PD, termed 'the hemiparkinsonian rat', unilateral injection of 6-OHDA into the nigrostriatal pathway results in extensive loss of dopaminergic cells in the ipsolateral SN. In an attempt to identify some of the proteins that are involved in dopaminergic neuronal death, we used the proteomic methods to analyze this animal model of PD. METHODS: Five hemiparkinsonian rats were obtained by intranigral stereotaxic injection of 6-OHDA.The right 6-OHDA-lesioned substantia nigra and striatum tissues along with the left, unlesioned controlateral tissues, were excised and homogenized, using urea-based buffer, to extract the tissues protein. The separation of the protein mixtures and the visualization of the protein patterns obtained were performed using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Protein profiles of control and treated tissues were compare by the PDQuest 2D-gel analysis software (BIO-Rad laboratory). The protein spots showing differential expression were analysed by matrix assisted laser desorption/ionizing time of flight (MALDI-TOF) mass spectrometry. RESULTS: The brain protein extraction and solubilization protocol was validated obtaining a satisfactory protein profile. In comparison to the normal rats, hemiparkinsonian animals exhibited a different expression in alpha-enolase and beta-actin in substantia nigra and striatum, respectively. CONCLUSION: The proteomic study of 6-OHDA-induced lesions in the nigrostriatial pathway allowed us to identify two proteins, alpha-enolase and beta-actin, showing increased levels in the 6-OHDA-lesioned brain tissues compared to control. Previous studies described the same proteins as oxidized and proteins in Alzheimer's disease (AD) brain. Our preliminary data could mirror those results pointing out a common mechanism of neurodegenerative diseases.     

颈动脉体球细胞块移植治疗帕金森病大鼠行为学的实验研究

探讨帕金森病（ＰＤ）大鼠颈动脉体球细胞块移植后其行为学的变化。采用６－羟多巴胺（６－ＯＨＤＡ）损毁大鼠一侧黑质细胞制成ＰＤ样大鼠模型。在右侧纹状体内分别移植入胚胎黑质和自、异体颈动脉体球细胞块。在移植后２、４、８和１２周记录阿朴吗啡诱发大鼠的旋转行为,同步分析存活酪氨酸羟化酶（ＴＨ）阳性细胞数目。结果：在１２周时与胚胎中脑组织移植相比较,自、异体颈动脉体球细胞移植组大鼠旋转行为改善更为明显。存活ＴＨ＾＋细胞显著增多（分别Ｐ〈０．０５）,但自、异体颈动脉体球细胞移植组间比较差异无显著性,提示：颈动脉体球细胞块移植后ＰＤ大鼠行为学显著改善。效果优于胚胎中脑组织块的移植。     

Delayed delivery of AAV-GDNF prevents nigral neurodegeneration and promotes functional recovery in a rat model of Parkinson's disease

Glial cell line-derived neurotrophic factor (GDNF) is a strong candidate agent in the neuroprotective treatment of Parkinson's disease (PD). We investigated whether adeno-associated viral (AAV) vector-mediated delivery of a GDNF gene in a delayed manner could prevent progressive degeneration of dopaminergic (DA) neurons, while preserving a functional nigrostriatal pathway. Four weeks after a unilateral intrastriatal injection of 6-hydroxydopamine (6-OHDA), rats received injection of AAV vectors expressing GDNF tagged with FLAG peptide (AAV-GDNFflag) or beta-galactosidase (AAV-LacZ) into the lesioned striatum. Immunostaining for FLAG demonstrated retrograde transport of GDNFflag to the substantia nigra (SN). The density of tyrosine hydroxylase (TH)-positive DA fibers in the striatum and the number of TH-positive or cholera toxin subunit B (CTB, neuronal tracer)-labeled neurons in the SN were significantly greater in the AAV-GDNFflag group than in the AAV-LacZ group. Dopamine levels and those of its metabolites in the striatum were remarkably higher in the AAV-GDNFflag group compared with the control group. Consistent with anatomical and biochemical changes, significant behavioral recovery was observed from 4-20 weeks following AAV-GDNFflag injection. These data indicate that a delayed delivery of GDNF gene using AAV vector is efficacious even 4 weeks after the onset of progressive degeneration in a rat model of PD.