红景天苷对MPTP诱导的帕金森病小鼠黑质多巴胺转运蛋白的影响

目的:探讨红景天苷(salidroside,Sal)对帕金森病(Parkinson’s disease,PD)小鼠黑质多巴胺转运蛋白(dopamine transporter,DAT)表达的影响。方法:将神经毒素1-甲基-4苯基-1,2,3,6-四氢吡啶(1-methyl-4-phen-yl-1,2,3,6-tetrahydropyridine,MPTP)注入C57BL/6小鼠腹腔内,制备PD模型,Rotarod实验和游泳实验观察小鼠行为学变化,免疫荧光组织化学法检测黑质DAT阳性神经元数目的变化。结果:行为学实验结果显示,Rotarod实验中模型组小鼠在滚轴上运动的时间明显短于正常组(P<0.01),给予不同剂量的Sal后,小鼠在滚轴上运动的时间有所延长,并呈剂量依赖性(P<0.05,P<0.01)。游泳实验结果与Rotarod结果一致,模型组小鼠游泳时间明显短于正常组(P<0.01),给予不同剂量Sal后,小鼠游泳时间不同程度增加(P<0.05,P<0.01)。免疫荧光结果显示,模型组小鼠黑质中DAT阳性神经元的数目明显少于正常组(P<0.01),而给予不同剂量Sal干预后,小鼠DAT阳性神经元数目的减少有所恢复(P<0.05,P<0.01)。结论:Sal可以改善PD小鼠行为协调能力,提高DAT阳性神经元存活的数目,并呈剂量依赖性,表明Sal对多巴胺(dopamine,DA)能神经元具有一定的保护作用。     

二苯乙烯苷对MPTP诱导的帕金森病小鼠模型黑质多巴胺转运体的影响

目的:研究2,3,5,4’-四羟基二苯乙烯-2-o-β-D-葡萄糖苷(2,3,5,4’-tetrahydroxystibene-2-o-β-D-gluco-side,TSG)对帕金森病(Parkinson’s disease,PD)小鼠黑质多巴胺转运体(dopamine transporter,DAT)表达的影响。方法:将1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)注入小鼠腹腔制作PD模型,然后采用爬杆实验和悬挂实验检测小鼠的行为学变化,免疫荧光组织化学法观察黑质DAT阳性神经元数目。结果:行为学检测结果表明:模型组小鼠较正常对照组爬杆时间延长,悬挂能力下降(P<0.01),而TSG干预后可有效缩短小鼠的爬杆时间,并提高其悬挂能力(P<0.05,P<0.01)。免疫荧光结果显示:模型组小鼠黑质DAT阳性神经元的数目明显少于正常对照组(P<0.01),而TSG干预后,小鼠DAT阳性神经元数目的减少降低(P<0.05,P<0.01)。结论:TSG可改善PD小鼠的行为学、提高黑质DAT阳性神经元的存活数目,表明TSG对黑质多巴胺能神经元有一定的保护作用。     

京尼平苷对MPTP所致帕金森病小鼠模型的神经保护作用研究

目的:观察京尼平苷对MPTP帕金森病小鼠黑质多巴胺能神经元的保护作用和对帕金森病的治疗作用。方法:制作MPTP帕金森病小鼠模型,将C57BL/6小鼠随机分为四组:对照组、京尼平苷组、MPTP组、和治疗组(MPTP+Geniposide)。通过行为学实验(转棒实验、游泳试验)、TH免疫组化实验和TUNEL染色,观察京尼平苷对MPTP小鼠行为学、黑质多巴胺能神经元数目和凋亡细胞数目的影响。结果:MPTP组出现了典型的PD行为学改变,小鼠掉落潜伏期和游泳行为评分均低于对照组(P0.01),黑质致密部TH阳性细胞数目较对照组明显减少(P0.001),凋亡细胞数目明显增多(P0.001)。治疗组与MPTP组相比,能明显改善MPTP诱导的C57BL/6小鼠的行为学异常,小鼠掉落潜伏期明显延长(P0.01),游泳行为评分亦显著提高(P0.01),同时,TH阳性细胞数目明显增多(P0.001),凋亡细胞数目明显减少(P0.001)。结论:京尼平苷能够明显改善MPTP引起的小鼠行为学改变,并能够抑制小鼠黑质TH阳性神经元的减少和凋亡细胞的增加。提示京尼平苷对MPTP帕金森病小鼠DA能神经元具有神经保护效应,这种保护作用可能与京尼平苷的抗凋亡作用有关。     

MPTP诱导的帕金森病模型小鼠味觉偏好变化

目的:探讨1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)对帕金森病(PD)模型小鼠味觉的影响。方法:将雄性C57BL/6J小鼠分成对照组(control)和MPTP组,通过转棒、爬杆、嗅觉和悬尾实验检测小鼠行为,组织免疫荧光染色检测小鼠黑质致密部(SNpc)多巴胺(DA)能神经元。采用双瓶偏好实验检测小鼠对蔗糖、糖精、氯化钠及奎宁溶液的偏好率。利用real time RT-PCR检测小鼠舌上皮TAS1R1、TAS1R2和TAS1R3的mRNA表达的变化。结果:与control组相比,MPTP组小鼠转棒时间显著性降低,爬杆时间、找到隐藏食物的时间以及悬尾实验中静止时间均显著增加,免疫荧光结果显示MPTP处理可显著减少SNpc的DA能神经元数量。通过双瓶偏好实验发现MPTP可诱导小鼠对蔗糖、糖精、氯化钠的偏好率增加;但对苦味剂奎宁的偏好率没有影响。qRT-PCR分析发现MPTP抑制了小鼠舌上皮味觉受体TAS1R1和TAS1R2 mRNA的表达,而对TAS1R3 mRNA的表达没有影响。结论:MPTP诱导的PD模型小鼠对蔗糖、糖精、氯化钠的饮用偏好率增加,而对奎宁的偏好率没有影响,...     

硫辛酸对MPTP诱导的小鼠帕金森病模型的神经保护作用

目的:探讨α-硫辛酸(alpha-lipoic acid,ALA)在1-甲基-4-苯基-1,2,3,6-四氢吡啶(1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine,MPTP)诱导的小鼠帕金森病(Parkinson disease,PD)模型中的神经保护作用。方法:建立MPTP诱导的PD小鼠模型后,通过旷场实验、悬绳实验和转棒实验评估ALA对PD小鼠运动缺陷的影响;通过免疫组化检测ALA对PD小鼠黑质和纹状体多巴胺能神经元的影响;通过高效液相色谱检测ALA对PD小鼠纹状体多巴胺(dopamine,DA)及其代谢产物3,4-二羟基苯乙酸(3,4-dihydroxyphenylacetic acid,DOPAC)释放的影响;通过免疫荧光检测ALA对PD小鼠黑质中小胶质细胞活化以及小胶质细胞中诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)表达的影响;通过Western blot检测ALA对PD小鼠纹状体中酪氨酸羟化酶(tyrosine hydroxylase,TH)和促炎分子白细胞介素1β(interleu...     

MPTP诱导的小鼠PD模型中相关脑区小胶质细胞反应性差异研究

为了探讨Parkinson病(PD)小鼠相关脑区的小胶质细胞反应性是否存在差异,本研究采用MPTP诱导的小鼠PD模型,用GSA I-B4-HRP组织化学染色方法对黑质致密部(SNc)、尾壳核(CPu)、腹侧被盖区(VTA)和额叶联合皮层(FrA)四个部位中小胶质细胞的形态和数量进行了观察;同时用免疫荧光染色检测了SNc和VTA中TH阳性神经元的数量,用Western blot方法检测CPu和FrA内TH蛋白含量的变化情况。结果显示:SNc中TH阳性神经元的数量和CPu中TH蛋白的含量在MPTP腹腔注射后1 d即大幅度降低(降幅约为68%);在MPTP腹腔注射后3 d起SNc中TH阳性神经元的数量和CPu中TH蛋白的含量逐步增加;小胶质细胞在MPTP腹腔注射后1～3 d的反应明显,然后逐渐减弱。VTA中TH阳性神经元的数量和FrA中TH蛋白的含量在MPTP腹腔注射后降幅不明显(降幅约在15%),小胶质细胞在MPTP腹腔注射后1 d的反应较为明显,其它时段的变化不显著。本研究结果提示:PD模型小鼠SNc和CPu中的小胶质细胞反应明显强于VTA和FrA区,反应性小胶质细胞在SNc中的多巴胺(DA)能神经元损伤过程中扮演了重要角色。     

色钉菇乙酸乙酯提取物对帕金森病模型小鼠黑质多巴胺神经元的保护作用

目的:探讨色钉菇乙酸乙酯提取物能否改善帕金森病(PD)小鼠的行为症状以及对黑质多巴胺(DA)能神经元保护作用。方法:以成年C57BL/6小鼠为对象,设置空白对照组、MPTP模型组和100 mg/kg、200 mg/kg、400 mg/kg三个剂量的色钉菇乙酸乙酯提取物的干预组。通过站立次数和爬杆得分等指标评价行为症状,以TH的免疫荧光方法检测存活的黑质DA能神经元,FJC染色法显示黑质致密部变性的DA能神经元。结果:在行为上,实验处理之前各组之间无显著性差异(P0.05);而实验处理后,于站立次数指标上,400 mg/kg剂量干预组显著地高于实验对照组(P0.05),与空白对照组无显著性差异(P0.05);在爬杆得分指标上,200 mg/kg组和400 mg/kg组均显著地高于实验对照组(P0.05),但与空白对照组无显著性差异(P0.05)。在TH标记的黑质多巴胺能神经元数量上,只有400 mg/kg组显著地高于实验对照组(P0.05),与空白对照组无显著性差异(P0.05)。而FJC标记的变性细胞只在MPTP组、100 mg/kg和200 mg/kg组表达,空白对照组和400 mg/kg组未见FJC阳性细胞。结论:色钉菇乙酸乙酯提取物能显著地改善PD的行为症状和保护黑质DA能神经元,且呈剂量依赖性。     

利用MPTP建立帕金森病动物模型的安全与防护策略

帕金森氏病 (Parkinsondisease,PD)是一种常见的神经系统变性性疾病。该病的主要临床表现为 :静止性震颤、僵硬、动作迟缓和姿势不稳。 1917年英国医学帕金森 (JameParkinson)首先描述了这一临床症状。该病主要由于黑质致密部多巴胺能神经元的减少 ,致使纹状体多巴胺的含量降低所致。近年来 ,研究者利用 6 OHDA(六羟多巴胺 )、MPTP(1 甲基 4 苯基 1,2 ,3,6 四氢吡啶 )等成功建立了帕金森病动物模型 ,对多巴胺能神经元死亡的病因进行了大量的研究 ,但由于MPTP是一种很强的神经毒素 ,在使用过程中极易对研究者造成潜在的影响 ,因此本文对MPTP的安全使用和研究者的自身防护进行了探讨。     

血管活性肠肽在MPTP帕金森病模型小鼠的抗氧化应激作用

目的:研究血管活性肠肽(VIP)对1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)诱导的帕金森病(PD)模型小鼠发挥抗氧化应激和神经保护作用。方法:雄性C57BL/6J小鼠随机分为生理盐水(NS)组、MPTP组和MPTP+VIP组。Elisa法检测纹状体丙二醛(MDA)以及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)的变化;免疫组织化学法观察中脑黑质纹状体系统酪氨酸羟化酶(TH)、星形胶质细胞特异性标记物胶质细胞纤维酸性蛋白(GFAP)和小胶质细胞标志物离子钙结合蛋白(Iba-1)的表达变化;透射电子显微镜观察中脑黑质多巴胺能神经元的超微结构变化。结果:MPTP组与对照组相比,MDA水平显著增高,SOD和CAT的表达显著降低;给予VIP可显著抑制MDA的水平(P0.01),增强SOD和CAT的表达(P0.05)。与对照组相比,MPTP组小鼠GFAP和Iba-1的表达明显上升,TH表达明显下降;给予VIP可显著降低GFAP和Iba-1的表达(P0.05),而TH表达明显增强。透射电镜观察显示:NS组神经细胞和细胞器结构清晰完整;MPTP组神经细胞核膜内陷,线粒体空泡样变;MPTP+VIP组神经细胞和细胞器结构基本正常。结论:VIP能够抑制MPTP诱导PD小鼠中脑黑质星形胶质细胞和小胶质细胞的活化,对抗氧化应激,发挥神经保护作用。     

帕金森病小鼠模型黑质纹状体通路的形态学改变

目的 观察帕金森病小鼠模型黑质纹状体通路随病程进展而发生的形态学变化,从新的视角探讨帕金森病的病理生理机制。方法 正常C57小鼠36只,随机分为生理盐水组和1-甲基-4-苯基-1,2,3,6-四氢吡啶（MPTP）组,每组18只,于注射后第7、14、21、25、28、35天取材,利用免疫组织化学、免疫荧光技术和激光扫描共焦显微镜观察黑质多巴胺能神经元的数量、在纹状体内投射的神经纤维密度及其在纹状体直接通路和间接通路神经元（D1R/D2R阳性神经元）上的分布比例。结果 注射MPTP后,黑质多巴胺能神经元减少40%～50%;纹状体内多巴胺能神经纤维数量呈现先减少后增加的过程：第21天最少,仅为正常的20%;第35天最高,达到正常的45%;多巴胺能神经纤维在纹状体D1R/D2R阳性神经元上的分布比例也有先低后高的表现：第21天最低,第35天最高,与生理盐水组相比差异有显著性。结论 MPTP帕金森病模型小鼠的黑质纹状体通路呈现多巴胺能神经纤维再生现象,再生的多巴胺能神经纤维更多地分布于其直接通路的神经元上。     

Tumor necrosis factor-alpha receptor ablation in a chronic MPTP mouse model of Parkinson's disease

Recently, we demonstrated that mice deficient of the pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) were partly protected against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxicity. Here we extended the study and investigated TNF-alpha receptor 1 (-/-) (TNFR1) and TNF-alpha receptor 2 (-/-) (TNFR2) mice using a chronic MPTP dosing regimen (15 mg/kg MPTP on 8 consecutive days). One week after the last MPTP treatment, HPLC determination of striatal dopamine (DA) and immunostaining for the dopamine transporter (DAT) in the substantia nigra pars compacta (SNpc) was performed. MPTP treatment reduced striatal DA levels significantly; nigral DAT immunoreactivity was reduced to a lower extent. However, there was no difference in DA levels and the number of DAT positive neurons between TNFR1 (-/-), TNFR2 (-/-) and wild type mice after MPTP treatment. In contrast to TNF-alpha deficiency neither TNFR1 nor TNFR2 gene ablation showed protection against MPTP neurotoxicity, which argues for a protective mechanism of TNF-alpha not mediated by TNFR1 and TNFR2 signaling.     

Exposure to varenicline protects against locomotor alteration in a MPTP mouse model of Parkinson's disease

The beneficial effects of drugs that act via nicotinic acetylcholine receptors (nAChRs) on Parkinson''s disease (PD) symptomatology may explain the negative correlation between cigarette smoking and risk of this neurological condition. Varenicline, an α4β2 nAChR partial agonist approved for smoking cessation treatments, could be valuable for PD treatment. Here, we investigated varenicline effects in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) PD mouse model. From postnatal day (PN) 90 to PN119, male C57BL/6 mice were exposed daily to varenicline (2 mg/kg) by gavage. After that, MPTP was injected (30 mg/kg, ip) once a day for five days. At PN125, locomotor and anxiety-like effects were assessed with the open field test. At PN126, immobile behavior was assessed with the forced swimming test. At PN127, the frontal cerebral cortex was collected to evaluate dopamine and DOPAC levels. To verify whether varenicline was protective during the MPTP insult, a separate group of MPTP animals received varenicline from PN90 to PN124. MPTP reduced cortical dopamine content and increased dopamine turnover. Those effects were not reversed by varenicline treatment. Interestingly, varenicline reversed the MPTP-induced hyperactivity in the open field. Both maintenance of varenicline treatment during MPTP exposure or its interruption before MPTP exposure elicited similar results. No alterations were observed in anxiety-like behavior or in immobility time. Altogether, these findings suggested that varenicline treatment reduced the MPTP-induced hyperactivity, but did not protect against dopaminergic damage. Based on this partial protective effect, varenicline could exert neuroprotective effects on circuits that control motor activity in PD.     

帕金森病MPTP模型小鼠海马内星形胶质细胞活化和p-CREB的表达下降

目的:通过检测帕金森病(Parkinson's disease,PD)MPTP模型小鼠海马内GFAP和p-CREB的表达,探讨PD认知障碍发生的原因。方法:雄性C57BL/6小鼠随机分为对照组和PD模型组,每组12只。PD模型组经腹腔注射MPTP和丙磺舒,3.5 d注射1次,共10次,持续5周,对照组小鼠注射等量生理盐水。在第6周,旷场试验和爬杆试验评价运动功能。免疫组化检测黑质、纹状体TH的表达及海马GFAP和p-CREB的表达;Western Blot检测p-CREB的表达。结果:旷场实验和爬杆实验结果显示PD模型组小鼠运动能力明显低于对照组(P0.001)。免疫组化显示PD模型组黑质TH阳性神经元和纹状体TH阳性神经纤维均明显低于对照组(P0.001),海马的GFAP阳性细胞的面积明显多于对照组。而Western Blot和免疫组化染色均显示PD模型组海马p-CREB的表达明显少于对照组(P0.001)。结论:慢性PD模型小鼠海马内星形胶质细胞激活和p-CREB表达降低,可能参与了PD认知损害的病理过程。     

Toxicity of MPTP on neurotransmission in three mouse models of Parkinson's disease

Parkinson's disease (PD) is recognized as the second most common neurodegenerative disorder after Alzheimer's disease. PD is mainly characterized by a selective degeneration of the dopaminergic neurons in the substantia nigra. Also, it is observed imbalances in some nondopaminergic systems, including the serotonergic system. Serotonergic dysfunction appears to play a role in some parkinsonian symptoms, including motor function, l-dopa-induced dyskinesia, mood, psychosis, and constipation.The fact that 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) causes a parkinsonian syndrome was discovered in 1982 and has been used extensively and successfully in various mammalian species, including monkeys and mice, to produce an experimental model of PD.Three common dosing regimens of the MPTP-induced mice model of PD were compared on dopaminergic neurotransmission and serotonin levels in various brain regions.Results showed that tyrosine hydroxylase activity and dopaminergic transporter density were reduced in striatum and substantia nigra of mice and that this reduction was dependent on the cumulative dose of MPTP injected. Furthermore, for the three protocols, a decrease of dopamine (DA) level was observed in striatum, associated with a significant diminution of DA concentration in frontal cortex only for the chronic treatment. Moreover, a decrease of serotonin level was observed in midbrain and hippocampus of acute and sub-acute intoxicated-mice.In all, the results suggested that dosing regimen should be carefully pre-considered. Furthermore, the acute and sub-acute MPTP protocols represent good models of early, subclinical stages of PD, ideal in the development of neuroprotective strategies.     

MRI/SPECT-based diagnosis and CT-guided high-intensity focused-ultrasound treatment system in MPTP mouse model of Parkinson's disease

Single-photon emission computed tomography (SPECT) of dopamine transporters with ^99mTc-TRODAT-1 has recently been proposed to offer valuable information for the diagnosis of Parkinson's disease (PD). Furthermore, High-intensity focused ultrasound (HIFU) is a newly developed technique in which the energy of ultrasound wave is directed to a focused spot for the purpose treatment of PD. This study presents a diagnosis and image-guided system using HIFU to treat the mouse with PD under a designed stereotactic frame. The system comprises two key components: an automatic atlas-based SPECT/MRI image registration module for diagnosis and a stereotactic CT-guided module for HIFU treatment. The SPECT/MR image registration here is important in the non-invasive examination of the dopamine concentration in vivo. From the experimental results, the image registration module proves to have comparable performance to that derived from manual drawing by experts. In addition, the stereotactic CT-guided module achieved a positioning accuracy to within 2 mm on the average, which is acceptable for the purpose of HIFU treatment.     

Cyclooxygenase-2 mediates microglial activation and secondary dopaminergic cell death in the mouse MPTP model of Parkinson's disease

Background  

Accumulating evidence suggests that inflammation plays an important role in the progression of Parkinson's disease (PD). Among many inflammatory factors found in the PD brain, cyclooxygenase (COX), specifically the inducible isoform, COX-2, is believed to be a critical enzyme in the inflammatory response. Induction of COX-2 is also found in an experimental model of PD produced by administration of 1-methy-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP).     

Lithium and oxidative stress lessons from the MPTP model of Parkinson's disease

Lithium has been successfully employed therapeutically for treatment of bipolar depressive illness; however, its mechanism of action is poorly understood. Recently, it has been demonstrated by us that lithium can prevent 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) dopaminergic neurotoxicity in mice. From analyzing the pattern of protection in various parameters, we suggest that lithium protects against MPTP-induced depletion of striatal dopamine (DA) by preventing free radical-induced inactivation of tyrosine hydroxylase (TH), the rate limiting enzyme in dopamine synthesis. Possible neuroprotective effect of lithium against H₂O₂-induced cell death was assessed in human neuroblastoma; SH-SY5Y cell line. Pretreatment with LiCl (2 mM and 4 mM) for 7 days protected against H₂O₂ neurotoxicity in a dose-dependent manner. However, this protection could not be achieved through short-term incubation with LiCl. In agreement; we found that lithium lacks immediate antioxidant activity using the in vitro lipid peroxidation essay indicating that not acute but chronic treatment with lithium allows cells to deal better with oxidative stress.