帕金森病大鼠黑质NurrlmRNA表达的动态变化

目的　探讨帕金森病大鼠黑质核内受体相关因子 1(Nurr1)mRNA表达的动态变化。方法　通过脑立体定位注射 6 羟基多巴胺 (6 OHDA)的方法建立大鼠帕金森病 (Parkinson’sdisease,PD)模型 ,采用HE染色 ,酪氨酸羟化酶 (TH)免疫组织化学染色、原位杂交技术 ,选择 6 OHDA注射术后 1d、3d、5d、7d、2 1d为研究时点 ,观察大鼠PD模型形成过程中黑质TH 多巴胺细胞数量及Nurr1mRNA表达的改变。结果　与健侧比较 ,注射 6 OHDA 5d组损毁侧黑质TH 细胞显著减少 (P <0 .0 1) ,2 1d时仅为健侧的 15 %且出现明显的旋转行为 ;同时 ,注射 6 OHDA 1d组损毁侧黑质Nurr1mRNA表达即开始下降 ,且以 3d组最为显著 (P <0 .0 1) ,7d以后各组完全消失。结论　本实验研究结果表明 ,6 OHDA能下调大鼠黑质Nurr1mRNA的表达早于诱导多巴胺细胞的死亡     

被动吸烟对帕金森病大鼠旋转行为和纹状体多巴胺含量的影响

目的：观察被动吸烟对帕金森病（PD）大鼠的影响,以验证流行病学研究的结论,为PD研制提供一新的线索。方法：用6－羟基多巴胺（6－OHDA）立体定向注入大鼠一侧黑质致密部和中脑被盖腹侧区建立侧侧PD模型,观察术前4周开始始予的被动吸烟（持续6周）和术后2周对成功模型给予的被动吸烟（持续2周）对阿朴吗啡诱发的旋转行为及纹状体DA含量的影响。结果：术前4周开始被动吸烟的大鼠旋转行为有减少趋势,受损侧纹状体DA含量较对照组升高,术后2周,成功模型给予的被动吸烟对PD大鼠的旋转行为及纹状体DA含量均无影响。结论;被动吸烟可减轻6－OHDA对黑质DNA能神经元的损伤。     

尼古丁对帕金森病大鼠纹状体GDNF和多巴胺含量的影响

目的 研究尼古丁对帕金森病（PD）大鼠纹状体脑胶质细胞源性神经营养因子(GDNF)和多巴胺（DA）含量的影响。方法 将6－羟多巴胺（6－OHDA）立体定向注射到大鼠右侧中脑腹侧背盖部（VTA）和黑质致密部（SNpc)，建立PD大鼠模型。采用生化、免疫组织化学方法观察不同剂量尼古丁对PD大鼠的作用，检测纹状体GDNF表达及DA含量的变化。结果 造模前及造模后皮下注射尼古丁的PD大鼠，纹状体GDNF表达及DA含量较PD组有明显改善（P＜0．05）。结论 尼古丁可减轻6－OHDA对黑质DA能神经元的损伤，对PD大鼠具有保护作用。     

侧脑室微量注射左旋多巴治疗大鼠帕金森病

目的观察经侧脑室注射左旋多巴对帕金森病（PD）大鼠的影响。方法应用“羟基多巴胺立体定向脑内注射制备偏侧损毁的PD大鼠模型，并用阿扑吗啡（APO）皮下注射诱发大鼠向健侧旋转。将24只PD大鼠随机分为4组（n=6），经侧脑室注入生理盐水组为对照组，余3组分别经侧脑室注射浓度为0．1μg／μl、1μg／μl和5μg／μl的左旋多巴1μl，4μl／d，连续1周；观察在注射后不同时间大鼠旋转行为以及中脑黑质多巴胺能神经元数量的变化。结果经侧脑室注射1μg/μl和5μg/μl的左旋多巴后。与对照组相比，PD大鼠向健侧的旋转圈数明显减少（P〈0．01），左旋多巴效果在2h左右达到高峰，且中脑黑质多巴胺能神经元的数量也明显增多（P〈0．01）。结论经侧脑室注射适当剂量的左旋多巴可有效地改善PD大鼠的旋转行为，并增加中脑黑质多巴胺能神经元数量。     

脂多糖对多巴胺能神经元的损毁作用及其机制研究

目的观察脂多糖(1ipopolysaccharide．LPs)对黑质多巴胺(dopamine，DA)能神经元的损毁作用，探讨免疫机制与帕金森病(Parkinsondisease，PD)发病的相关性。方法采用立体定向术将LPS注人大鼠单侧黑质后分别于注射后2、3、4周经腹腔注射阿朴吗啡诱发动物旋转行为；采用高效液相色谱一电化学法(high performanee liquid chromatography，HPLC)测定纹状体和黑质部位DA等单胺类递质含量；采用免疫组化法检测黑质酪氨酸羟化酶(tyrosine hydroxylase，TH)阳性细胞数；采用尼(氏)染色(Nissl)观察小胶质细胞的活化和以双重免疫酶染色法观察小胶质细胞活化和诱导型一氧化氮合酶(inducible nitric oxide，iNOS)合成。结果大鼠单侧黑质注人LPS后2、3、4周，以阿朴吗啡诱发大鼠均出现旋转行为，其损伤侧纹状体和黑质DA及其代谢物含量降低了30%～70%，注射侧的黑质TH阳性细胞数减少，尤以3周和4周为甚．尼(氏)染色和双重免疫酶染色法也分别显示LPS注射侧小胶质细胞活化，同时伴有iNOS合成的增加。结论LPS对DA能神经元具有一定的损毁作用，小胶质细胞的活化及其释放的NO有可能参与该细胞死亡，提示免疫机制与PD的发病可能存在相关性。     

尼古丁对帕金森病大鼠纹状体多巴胺及黑质自由基含量的影响

目的 :研究尼古丁对帕金森病大鼠的影响 ,探讨其对 PD的作用机制。方法 :通过 6 - OHDA脑立体定向注射术建立大鼠帕金森病模型。采用生化方法观察不同剂量尼古丁对帕金森病大鼠的作用 ,检测黑质自由基、抗氧化剂及多巴胺含量的变化。结果 :造模前及造模后皮下注射尼古丁的 PD大鼠 ,黑质自由基及抗自由基酶及多巴胺含量较PD组有明显改善 (P<0 .0 5 )。结论 :尼古丁可减轻 6 - OHDA对黑质 DA能神经元的损伤 ,对 PD大鼠具有保护作用     

镁对帕金森病大鼠黑质多巴胺神经元的影响

目的观察镁对帕金森病(PD)大鼠黑质多巴胺神经元影响及其作用机制。方法应用6-羟基多巴胺(6-OHDA)制备偏侧PD大鼠模型后分为硫酸镁组、美多巴组、混合组(硫酸镁+美多巴)和对照组(生理盐水),并给予相应药物灌胃治疗28d。观察治疗后各组大鼠旋转行为的变化;免疫组化法检测黑质酪氨酸羟化酶(TH)阳性神经元数量;生化法测定损毁侧纹状体超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性及丙二醛(MDA)含量;逆转录聚合酶链反应检测损毁侧黑质caspase-3 mRNA表达;Western Blot法检测核因子(NF)-кBP65水平。结果治疗后仅混合组出现较稳定的向对侧的旋转行为;TH阳性神经元数混合组较其他各组明显增加(均P<0.05);与对照组和美多巴组比较,硫酸镁组和混合组SOD、GSH-Px活性显著增高,MDA、caspase-3 mRNA、NF-кBP65水平显著降低(均P<0.05);硫酸镁组与混合组间差异无统计学意义。结论镁及美多巴联合治疗可提高PD模型脑内多巴胺神经元存活、降低氧化应激损伤、减少神经元凋亡,改善PD大鼠症状。     

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.     

大鼠行为学改变与黑质多巴胺能神经元的相关性研究

目的　观察毁损黑质多巴胺能神经元大鼠行为学及其形态学变化特点 ,探讨两者之间的相关性。方法　利用 6 -羟基多巴胺 (6 - OHDA)单侧一点注射大鼠黑质致密区 (SNc) ,特异毁损多巴胺 (DA )能神经元 ,采用开野实验观察术后 1d、3d、5 d、7d、14 d、2 1d行为学变化 ;利用 Nissl染色、HE染色、免疫组织化学方法和电镜的方法 ,观察各时间点黑质形态学变化。结果　毁损侧 DA能神经元逐渐减少 ,超微结构损伤逐渐加重 ;开野实验中旋转、探究、后肢站立和穿梭行为在术后 1d即有显著改变 (与对照组比较 P<0 .0 5 ) ,其中 ,旋转行为与毁损程度呈正相关 (r=0 .4 71,P <0 .0 1) ,探究、后肢站立和穿梭行为与毁损程度呈负相关 (r分别为 - 0 .719、- 0 .5 89、- 0 .5 94 ,P <0 .0 1) ,修饰行为与毁损程度无相关性 (r=- 0 .2 2 7,P>0 .0 5 )。结论　黑质 DA能神经元丢失是毁损大鼠行为改变的病理学基础 ,开野实验可作为丢失程度的敏感行为学观察指标。     

丁苯酞对帕金森病大鼠模型的疗效研究

目的研究丁苯酞对帕金森病(PD)大鼠行为学、中脑氧化应激水平及黑质多巴胺能神经元的影响并探讨其可能的疗效。方法采用鱼藤酮立体定向注射方法制作偏侧PD大鼠模型。将造模成功的大鼠随机分为按体质量丁苯酞20、40、80 mg/kg 3个治疗组及对照组,观察各组大鼠经丁苯酞干预前后旋转行为情况,采用分光光度计检测中脑还原型谷胱甘肽(GSH)、丙二醛(MDA)水平及超氧化物歧化酶(SOD)活性,另用免疫组化染色测定黑质酪氨酸羟化酶(TH)阳性细胞数量。结果 (1)与治疗前相比,按体质量丁苯酞80 mg/kg治疗组治疗后旋转圈数明显减少(P0.05);(2)与对照组损毁侧相比,各治疗组损毁侧中脑GSH水平增高,MDA水平降低,SOD活性增强(P0.05,P0.01);(3)与对照组损毁侧相比,按体质量丁苯酞80 mg/kg治疗组损毁侧黑质TH阳性细胞计数增多(P0.05)。结论丁苯酞可显著改善PD大鼠旋转行为,增强抗氧化能力,提高黑质多巴胺能神经元残存率,提示其可能具有治疗和保护作用。     

Chronic levodopa is not toxic for remaining dopamine neurons,but instead promotes their recovery,in rats with moderate nigrostriatal lesions

Orally administered levodopa remains the most effective symptomatic treatment for Parkinson's disease (PD). The introduction of levodopa therapy is often delayed, however, because of the fear that it might be toxic for the remaining dopaminergic neurons and, thus, accelerate the deterioration of patients. However, in vivo evidence of levodopa toxicity is scarce. We have evaluated the effects of a 6-month oral levodoapa treatment on several dopaminergic markers, in rats with moderate or severe 6-hydroxydopamine-induced lesions of mesencephalic dopamine neurons and sham-lesioned animals. Counts of tyrosine hydroxylase (TH)-immunoreactive neurons in the substantia nigra and ventral tegmental area showed no significant difference between levodopa-treated and vehicle-treated rats. In addition, for rats of the sham-lesioned and severely lesioned groups, immunoradiolabeling for TH, the dopamine transporter (DAT), and the vesicular monoamine transporter (VMAT2) at the striatal level was not significantly defferent between rats treated with levodopa or vehicle. It was unexpected that quantification of immunoautoradiograms showed a partial recovery of all three dopaminergic markers (TH, DAT, and VMAT2) in the denervated territories of the striatum of moderately lesioned rats receiving levodopa. Furthermore, the density of TH-positive fibers observed in moderately lesioned rats was higher in those treated chronically with levodopa than in those receiving vehicle. Last, that chronic levodopa administration reversed the up-regulation of D2 dopamine receptors seen in severely lesioned rats provided evidence that levodopa reached a biologically active concentration at the basal ganglia. Our results demonstrate that a pharmacologically effective 6-month oral levodopa treatment is not toxic for remaining dopamine neurons in a rat model of PD but instead promotes the recovery of striatal innervation in rats with partial lesions.     

Responses of substantia nigra pars reticulata neurons to GABA and SKF 38393 in 6-hydroxydopamine-lesioned rats are differentially affected by continuous and intermittent levodopa administration

Systemic administration of the selective D1 agonist, SKF 38393, to rats with unilateral 6-hydroxydopamine-induced lesion of the nigrostriatal dopamine pathway induces contralateral turning and reduces firing rates of substantia nigra pars reticulata neurons. Previous studies have shown that chronically administered levodopa diminishes the contralateral turning induced by SKF 38393 in these animals. The present study demonstrates that twice daily injections (45-50 mg/kg, i.p.) of levodopa for 19 days also diminishes the effects of SKF 38393 on substantia nigra pars reticulata activity. Concomitant with this change, chronic levodopa injections reversed the lesion-induced supersensitivity of substantia nigra pars reticulata neurons to iontophoresed GABA. Neither of these effects were produced by the continuous infusion of levodopa (90-100 mg/kg/day, i.p. by osmotic pump) for 19 days, a treatment that produces average daily blood levodopa levels similar to those produced by chronic levodopa injection. These results suggest that large variations in circulating levodopa levels in 6-hydroxydopamine lesioned rats may desensitize the behavioral responses to D1 dopamine agonist administration by down-regulating D1 and GABA receptor-mediated mechanisms of basal ganglia output through the substantia nigra pars reticulata.     

Electrophysiological characterization of substantia nigra dopaminergic neurons in partially lesioned rats: effects of subthalamotomy and levodopa treatment

Progressive degeneration of dopaminergic neurons in the substantia nigra pars compacta is the main histopathological characteristic of Parkinson's disease. We studied the electrophysiological characteristics of the spontaneous activity of substantia nigra pars compacta dopaminergic neurons in rats with a partial, unilateral, 6-hydroxydopamine lesion of the nigrostriatal pathway. In addition, the effects of subthalamotomy and prolonged levodopa treatment on the activity of dopaminergic neurons were investigated. As a result of the lesion ( approximately 50% neuronal loss), the number of spontaneously active neurons was significantly reduced. Basal firing rate, burst firing and responsiveness to intravenously administered apomorphine remained unchanged. In contrast, the variation coefficient, a measure of interspike interval regularity, was significantly increased. Ibotenic acid (10 microg) lesion of the ipsilateral subthalamic nucleus in lesioned rats did not modify the electrophysiological parameters. However, prolonged levodopa treatment (100 mg/kg/day + benserazide 25 mg/kg/day, 14 days) reversed the irregularity observed in cells from lesioned rats, while it induced an irregular firing pattern in cells from intact rats. Our results using an experimental model of moderate Parkinson's disease indicate that surviving substantia nigra pars compacta dopaminergic neurons fire irregularly. In this model, subthalamotomy does not modify the firing pattern while levodopa treatment efficiently restores normal firing of SNpc neurons and does not appear to be toxic to them.     

KDI tripeptide of gamma1 laminin protects rat dopaminergic neurons from 6-OHDA induced toxicity

Our previous studies indicate that the KDI (Lys-Asp-Ile) tripeptide of gamma1 laminin protects central neurons from mechanical trauma and excitotoxicity. At least part of the neuroprotective effect of the KDI tripeptide may be mediated by its inhibitory function on ionotropic glutamate receptors. We studied the protective effect of the KDI tripeptide against 6-hydroxy-dopamine (6-OHDA) induced neurotoxicity in a rat experimental model of Parkinson's disease (PD). We found that a single unilateral injection of the KDI tripeptide into the substantia nigra before an injection of 6-OHDA protected the dopaminergic neurons from the neurotoxicity of 6-OHDA. Compared to rats treated with 6-OHDA alone, the KDI + 6-OHDA-treated substantia nigra was relatively intact with large numbers of dopaminergic neurons present at the injection side. In the rats treated with 6-OHDA alone, no dopaminergic neurons were detected, and the substantia nigra-area at the injection side was filled with blood-containing cavities. Quantification of the rescue effect of the KDI tripeptide indicated that, in animals receiving KDI before 6-OHDA, 33% of tyrosine hydroxylase-positive dopaminergic neurons of the substantia nigra were present as compared to the contralateral non-injected side. In animals receiving 6-OHDA alone, only 1.4% of the tyrosine hydroxylase expressing dopaminergic neurons could be verified. If this much protection were achieved in humans, it would be sufficient to diminish or greatly alleviate the clinical symptoms of PD. We propose that the KDI tripeptide or its derivatives might offer a neuroprotective biological alternative for treatment of PD.     

Regulation of neurotensin-containing neurons in the rat striatum and substantia nigra. Effects of unilateral nigral lesion with 6-hydroxydopamine on neurotensin content and its binding site density

The effect of unilateral lesion of the rat substantia nigra with 6-hydroxydopamine (6-OHDA) was investigated on the endogenous contents of neurotensin (NT) and its binding site densities in the striatum and substantia nigra. Tyrosine hydroxylase (T-OH) activity, γ-aminobutyric acid (GABA) content, binding site densities of dihydrotetrabenazine (TBZOH), a marker of dopaminergic synaptic vesicles, and of iodosulpride, a ligand for dopamine D₂ receptors, were also determined. Fourteen days following nigral lesions, these markers were analyzed by means of radioimmunoassay for NT levels, fluoremetric method for GABA content, radiochemical method for T-OH activity and quantitative autoradiography for NT, TBZOH and iodosulpiride binding site densities. Unilateral nigral lesion with 6-OHDA provoked only ipsilateral modifications in dopamine markers. T-OH activity and TBZOH binding site densities significantly decreased in both the ipsilateral striatum and substantia nigra. Iodosulpiride binding sites decreased in the substantia nigra and increased in the striatum on the ipsilateral side. In contrast to these unilateral changes observed for dopamine markers, dramatic increases in NT contents were found in both the ipsi- and contralateral striata. No change was found in nigral NT levels on either side. On the other hand, NT binding sites decreased in the ipsilateral striatum and substantia nigra, which reflected the destruction of dopaminergic elements in these regions. The present results strongly suggest a dopaminergic control of striatal NT systems and demonstrate that a unilateral loss of this control may lead to strong bilateral alterations in NT levels.     

丘脑底核高频电刺激对大鼠纹状体多巴胺代谢影响的研究

目的研究丘脑底核(STN)高频电刺激(HFS)对大鼠纹状体多巴胺(DA)代谢的影响。方法给予正常大鼠一侧STN-HFS,应用微透析观察其对纹状体DA及其代谢产物的影响,应用免疫组化观察其对黑质DA能神经元的影响。结果微透析检测发现刺激侧纹状体DA代谢产物明显增高(P<0.05),DA水平无变化(P>0.05);免疫组化检测发现刺激组和对照组酪氨酸羟化酶(TH)阳性神经元数量无差异(损毁侧分别为24.00±6.81、23.43±5.49,P>0.05)。结论STN-HFS可能通过影响黑质-纹状体DA代谢发挥作用,STN-HFS对黑质DA能神经元可能无保护作用。     

神经节苷脂对帕金森病鼠旋转行为、纹状体多巴胺浓度及黑质病理的影响

目的观察神经节苷脂对帕金森病（Ｐａｒｋｉｎｓｏｎｄｉｓｅａｓｅ，ＰＤ）鼠模型的旋转行为、纹状体多巴胺浓度及黑质病理的影响。方法将６－羟基多巴胺用立体定向法注入大鼠一侧中脑被盖腹侧区制作ＰＤ大鼠模型，并于同侧侧脑室注射混合型神经节苷脂（ａｍｉｘｅｄｇａｎｇｌｉｏｓｉｄｅｐｒｅｐａｒａｔｉｏｎ，ＧＭ），观察ＧＭ对由阿朴吗啡所诱发的旋转行为、受损侧纹状体多巴胺浓度及黑质病理的影响。结果ＧＭ能减轻ＰＤ大鼠模型的旋转行为、使受损侧纹状体多巴胺浓度下降和黑质神经细胞减少。结论ＧＭ可减轻６－羟基多巴胺对黑质多巴胺能神经元的损伤。     

Chronic lesions differentially decrease tyrosine hydroxylase messenger RNA in dopaminergic neurons of the substantia nigra

Long-term effects of lesions were analyzed in terms of gene expression. Nine months after unilateral 6-hydroxydopamine (6-OHDA) lesions of the substantia nigra pars compacta (s. nigra), the remaining dopaminergic (DAergic) neurons (tyrosine hydroxylase (TH) cells determined by immunocytochemistry (ICC] on the lesioned side were atrophic with smaller nucleoli. By in situ hybridization, the DAergic neurons on the lesioned side had a 50% smaller TH-mRNA concentration than on the contralateral non-lesioned side. However, beta-tubulin mRNA concentration in DAergic neurons was unaffected by the lesion. The lesions did not alter TH-mRNA concentration in the contralateral non-lesioned side by comparison with unoperated controls. We propose that chronic lesions have long-term effects on gene expression because of damage sustained during compensatory hyperactivity after the lesion, or because of decreased trophic support from other neurons.     

黑质内注射脂多糖对不同年龄大鼠DA能神经元和小胶质细胞活性的影响

目的 探讨青年和老年大鼠黑质DA能(DA)神经元对脂多糖(LPS)所诱导的损伤作用的敏感性差异和对小胶质细胞活性的影响.方法 采用立体定向技术向大鼠单侧黑质内注入LPS建立PD大鼠模型;采用免疫组化法观察黑质酪氨酸羟化酶(TH)阳性细胞和OX6阳性小胶质细胞变化;采用Fluoro-Jade B染色法检测黑质的变性神经元.结果 黑质内注射LPS后,老年组大鼠黑质区TH阳性神经元数量较青年组明显减少(P<0.01);老年组大鼠黑质区Fluoro-Jade B阳性神经元明显多于青年组(P<0.01);青年组大鼠黑质部位的OX6阳性小胶质细胞主要是处在激活期的;而老年组大鼠黑质部位的OX6阳性小胶质细胞主要是活化期的(阿米巴样或巨噬细胞样).结论 老年大鼠的黑质DA能神经元对于LPS所诱导的损伤作用较青年大鼠更为敏感.