白藜芦醇通过SIRT1/AMPK信号通路减轻MPTP诱导的小鼠多巴胺能神经元丢失

目的观察白藜芦醇(RV)对帕金森病(PD)小鼠的神经保护作用,并探索其发挥神经保护作用的可能机制。方法将48只小鼠随机分为CON组、MPTP组、RV+MPTP组和EX527+RV+MPTP组,每组12只。腹腔注射MPTP建立PD小鼠模型,并给予RV灌胃、SIRT1特异性抑制剂EX257腹腔注射处理,利用免疫荧光、western blot等检测相关蛋白表达。结果给予RV后,与MPTP组相比,RV+MPTP组SIRT1蛋白表达显著增加(P0.001),p-AMPK蛋白水平显著升高(P0.01),Cleaved caspase 3蛋白水平显著下降(P0.01),小鼠黑质区TH阳性神经元丢失率明显降低,纹状体组织中TH蛋白表达显著增加(P0.01)。给予EX527后,阻断了RV的上述作用,p-AMPK蛋白水平显著降低(P0.01),Cleaved caspase 3显著升高(P0.01),小鼠黑质区TH阳性神经元丢失率明显升高,纹状体组织中TH蛋白表达显著下降(P0.001)。结论 RV可能通过激活SIRT1/AMPK信号通路,SIRT1与AMPK相互调控,减少MPTP小鼠黑质区多巴胺能神经元丢失。     

氯化锂对MPTP致帕金森病小鼠模型行为学及黑质多巴胺能神经元影响的研究

目的 探讨氯化锂对MPTP致帕金森病小鼠模型行为学及黑质多巴胺能神经元保护作用的影响.方法 实验小鼠随机分为MPTP组、NS(生理盐水)组、LM(LiCl +MPTP)组、PM(PBS+ MPTP)组;通过行为学观察各组震颤麻痹、移动格子数、站立次数、滚轴次数、游泳能力;免疫组织化学染色与免疫印迹技术观察各组酪氨酸羟化酶(TH)和钙结合蛋白(CB)的表达变化.结果 行为学检测LM组震颤麻痹评分、移动格子数、站立次数、滚轴实验、游泳能力都显著高于PM组(P＜0.05);免疫组织化学染色结果显示LM组黑质致密部TH与CB阳性神经元数量显著多于PM组;Western blot免疫印迹结果显示LM组TH、CB蛋白含量表达水平显著高于PM组(P＜0.01或0.05).结论 氯化锂可明显改善MPTP所致小鼠PD模型的运动障碍,且对其引起的DA神经元损伤起到保护作用,这种保护作用与细胞内CB表达增加有关;PD模型行为学与多巴胺能神经元的变化具有一致性.     

晚期糖基化终末产物受体对帕金森病模型小鼠脑内酪氨酸羟化酶表达的影响

目的探讨晚期糖基化终末产物受体(RAGE)对1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)诱导的帕金森病(PD)模型小鼠脑中酪氨酸羟化酶(TH)表达量的影响。方法采用12周龄的C57BL/6雄性小鼠依据不同处理方法分为6组(均n=10):对照组;MPTP组;空载病毒阴性对照(RAGE-NC)组;目的基因阴性对照(siRNA-RAGE)组;RAGE-NC+MPTP组;siRNA-RAGE+MPTP组。携带空载siRNA的慢病毒(RAGE-NC)与携带抑制RAGE表达的目的 siRNA-RAGE慢病毒经脑立体定位仪定向注射于小鼠两侧黑质,根据分组情况给予腹腔注射MPTP 30mg·kg~(-1)或等量生理盐水(每周2次×5周)。5周后予小鼠断头取脑,利用免疫组织荧光染色法检测各组小鼠脑组织黑质中TH数量变化情况,采用Western blot法分别检测各组RAGE、caspase-3、TH蛋白表达水平。结果与RAGENC+MPTP组比较,siRNA-RAGE+MPTP组RAGE蛋白表达减少(0.782 8±0.139 6 vs 1.039 0±0.146 4,P0.01),caspase-3蛋白表达减少(0.864 4±0.105 3 vs 1.240 0±0.080 7,P0.001),TH蛋白表达量显著升高(1.114 0±0.201 1vs 0.771 1±0.211 3,P0.05),差异有统计学意义。结论抑制RAGE表达可抑制凋亡反应,提高PD多巴胺能神经元模型中TH蛋白表达水平,有潜在的神经保护作用。     

沉默信息调节因子1/p53信号通路参与MPTP诱导的帕金森病小鼠多巴胺能神经元丢失

目的研究沉默信息调节因子1(SIRT1)和p53在MPTP诱导的帕金森病(PD)小鼠模型多巴胺能神经元凋亡中的可能作用。方法将健康雄性C57BL/6小鼠随机分为对照组、MPTP组,采用行为学方法检测行为学改变,高效液相色谱(HPLC)检测多巴胺(DA)、二羟基苯乙酸(DOPAC)和高香草酸(HVA)的含量变化,免疫荧光染色法观察两组小鼠黑质酪氨酸羟化酶(TH)阳性神经元数目的变化及SIRT1表达情况,TUNEL法观察黑质细胞凋亡情况,Western blot法检测TH、SIRT1、p53、乙酰化p53 (ac-p53)、B淋巴细胞瘤-2基因(Bcl-2)和Bax的表达情况。结果行为学结果显示MPTP组小鼠爬杆转向时间及爬杆总时间均较对照组小鼠显著延长(P 0. 01)。HPLC结果提示MPTP组的DA、DOPAC及HVA含量较对照组显著下降(P 0. 01)。免疫荧光结果显示MPTP小鼠黑质区TH阳性神经元数目及SIRT1表达较对照组均显著减少。TUNEL检测结果显示,与对照组相比,MPTP组凋亡阳性细胞数明显增多。Western blot结果显示,与对照组相比,MPTP组的TH、SIRT1、Bcl-2蛋白表达显著下降(P 0. 01),p53、ac-p53、Bax蛋白表达显著升高(P 0. 01)。结论MPTP模型小鼠行为学异常、TH阳性神经元减少、DA及其代谢产物下降提示成功复制PD动物模型,同时MPTP模型小鼠的SIRT1、p53及凋亡相关蛋白表达异常,提示该信号通路可能参与了PD的疾病过程。     

姜黄素对帕金森病小鼠模型黑质多巴胺能神经元损伤的保护作用

目的研究姜黄素对由MPTP诱发的帕金森病小鼠模型的脑保护作用及其可能机制。方法应用免疫组织化学染色法和蛋白质印迹法(Western blotting)分别观察姜黄素干预前后帕金森病小鼠中脑黑质-纹状体系统中酪氨酸羟化酶、胶质纤维酸性蛋白阳性神经元数目的变化,以及酪氨酸羟化酶、诱导型一氧化氮合酶和胶质纤维酸性蛋白表达水平的变化。结果MPTP组小鼠中脑黑质酪氨酸羟化酶和胶质纤维酸性蛋白阳性神经元数目明显减少,与正常对照组及治疗组相比差异有统计学意义(均P<0.05)。经不同剂量(5mg/kg、50mg/kg和150mg/kg)的姜黄素干预治疗后,小鼠中脑纹状体中的酪氨酸羟化酶蛋白表达水平(相对灰度值)明显升高,而黑质中诱导型一氧化氮合酶和胶质纤维酸性蛋白表达水平明显降低,与MPTP组比较差异均有统计学意义(P<0.05);MPTP组与溶剂对照组(MPTP DMSO)之间差异无统计学意义(P>0.05)。结论姜黄素可以有效地拮抗MPTP诱导的帕金森病小鼠模型黑质多巴胺能神经元的丢失,其机制可能与姜黄素降低黑质多巴胺能神经元活性氧含量以及抑制炎症反应等作用有关。     

毛蕊花糖苷对MPTP制备的帕金森病模型小鼠的神经保护作用及机制研究

目的 探讨毛蕊花糖苷对帕金森病（PD）模型小鼠脑的神经保护作用及其可能的机制。 方法 选取 75 只 C57/BL 小鼠（SPF 级、健康雄性、24～26 g）为实验对象,随机分为空白对照组、模型组 （1- 甲基 -4- 苯基 -1,2,3,6- 四氢吡啶 /MPTP 组）、实验组（低剂量组：MPTP+30 mg/kg 毛蕊花糖苷;中剂 量组：MPTP+60 mg/kg 毛蕊花糖苷;高剂量组：MPTP+120 mg/kg 毛蕊花糖苷）,每组 15 只。造模完成后采 用爬杆、悬挂实验检测各组小鼠的行动能力,采用超微电镜检测多巴胺能神经元细胞亚细胞结构变化, 采用免疫组织化学染色法检测酪氨酸羟化酶（TH）阳性细胞数量,采用 Western blotting 检测 TH、α- 突出 核蛋白（α-syn）、核因子红细胞-2相关因子2（Nrf2）、血红素加氧酶-1（HO-1）、谷胱甘肽过氧化物酶4（GPX4） 蛋白的表达情况,采用酶联免疫吸附试验（ELISA）检测各组小鼠黑质的谷胱甘肽、总铁离子、超氧化物 歧化酶（SOD）、脑组织丙二醛等。结果 模型组小鼠完成爬杆实验的时间较空白对照组长,实验组小鼠 完成爬杆实验的时间较模型组短,差异均有统计学意义（均P＜ 0.05）;模型组小鼠的悬挂实验评分低于 空白对照组,实验组小鼠的悬挂实验评分高于模型组,差异均有统计学意义（均P＜ 0.05）。电镜下模型 组较实验组小鼠中脑黑质区多巴胺能神经元细胞的变性、坏死更明显;免疫组织化学染色结果显示,模 型组小鼠黑质 TH 阳性神经元数目较空白对照组减少,实验组小鼠黑质 TH 阳性细胞数目较模型组增加, 差异均有统计学意义（均P＜ 0.05）。Western blotting 结果显示,模型组小鼠黑质 TH、Nrf2、HO-1、GPX4 的蛋白表达量低于空白对照组,实验组小鼠黑质 TH、Nrf2、HO-1、GPX4 的蛋白表达量高于模型组,差异 均有统计学意义（均P＜ 0.05）;模型组小鼠黑质 α-syn 表达量高于空白对照组,实验组小鼠黑质 α-syn 表达量低于模型组,差异均有统计学意义（均P＜ 0.05）。ELISA 结果显示,模型组小鼠黑质的谷胱甘肽、 SOD 表达量低于空白对照组,实验组小鼠黑质的谷胱甘肽、SOD 表达量高于模型组,差异均有统计学意 义（均P＜ 0.05）;模型组小鼠黑质的的丙二醛、总铁离子表达量高于空白对照组,实验组的丙二醛、总铁 离子表达量低于模型组,差异均有统计学意义（均P＜ 0.05）。结论 毛蕊花糖苷可能是通过抑制 PD 模 型小鼠中脑黑质区的多巴胺能神经元细胞的铁死亡起到神经保护作用。     

MPTP小鼠脑沉默信息调节因子1和缺氧诱导因子-1α的表达及行为学检测

目的本研究旨在研究MPTP模型小鼠中沉默信息调节因子1(SIRT1)和缺氧诱导因子1α(HIF-1α)的表达情况以及行为学的变化。方法选用MPTP处理C57BL/6小鼠构建PD动物模型,采用行为学实验、高效液相色谱(HPLC)、免疫组化等方法检验模型的建立是否成功,并在小鼠模型中检测SIRT1和HIF-1α的表达情况。结果 MPTP处理的小鼠表现出显著的行为学异常,主要体现在自主活动减少(P0.001)、步距缩短(P0.001),且有显著运动迟缓(P0.001)。HPLC结果发现,模型组小鼠纹状体区域多巴胺(DA)及其代谢产物减少(P0.001)。免疫组化结果提示黑质区域多巴胺能神经元标志物酪氨酸羟化酶(TH)和多巴胺转运体(DAT)的表达明显下调(P0.01)。分子生物学方面,PD模型小鼠的SIRT1表达降低(P0.05),HIF-1α表达增加(P0.05)。结论 PD模型小鼠表现出明显的行为学异常,多巴胺能神经元标志物检测提示成功复制PD动物模型,同时发现模型小鼠的SIRT1/HIF-1α的表达异常,提示该信号通路可能参与了PD的疾病过程。     

丁基苯酞对帕金森模型小鼠中脑黑质多巴胺能神经元数及TH、TNF-α蛋白表达的影响

目的研究丁基苯酞(dl-3n-butylphthalide,NBP)对由MPTP诱导的C57BL/6小鼠帕金森模型中脑黑质多巴胺能神经元数及TH、TNF-α蛋白表达的影响,进一步探讨其保护机制。方法 24只C57BL/6小鼠,随机分成3组:正常对照组,MPTP组,NBP治疗组。MPTP腹腔注射法制备帕金森模型,免疫组织化学法观察中脑黑质TH阳性神经元细胞数,蛋白质印迹法观察中脑黑质TH、TNF-α蛋白含量的变化。结果 (1)与正常对照组比较,MPTP组可见帕金森病小鼠中脑黑质TH阳性神经元明显减少(P0.01);与MPTP组比较,NBP治疗组帕金森病小鼠中脑黑质TH阳性神经元数目明显增加(P0.01);(2)与正常对照组比较,MPTP组帕金森病模型小鼠中脑黑质TH蛋白表达减少(P0.01),而TNF-α蛋白表达增加(P0.05);(3)与MPTP组比较,NBP治疗组帕金森病模型小鼠中脑黑质TH蛋白表达明显增加(P0.01),而TNF-α蛋白表达减少(P0.05)。结论丁基苯酞可能通过提高中脑黑质中TH的含量及减少TNF-α炎性介质表达发挥对MPTP所致C57BL/6小鼠帕金森模型的神经元保护作用。     

罗格列酮通过抗凋亡机制保护帕金森病模型小鼠多巴胺神经元

目的研究罗格列酮在1-甲基-4-苯基-1,2,3,6四氢吡啶(MPTP)所致帕金森病(PD)模型小鼠中对多巴胺能神经元的保护作用。方法采用MPTP制备PD小鼠模型,观察各组小鼠行为学变化,免疫组织化学和免疫印迹法观察中脑黑质TH、caspase-9、caspase-6、Bcl-2和Bax的表达变化,TUNEL检测细胞凋亡情况,并观察给予罗格列酮后对上述变化的影响。结果模型组小鼠出现竖毛、翘尾、震颤、肌肉强直和运动变缓等PD样症状,黑质区TH阳性神经元缺失,并伴有Caspase-9、caspase-6、Bax高表达及TUNEL阳性细胞增加,而Bcl-2的表达与对照组相比下降;经罗格列酮处理后,上述情况得到一定程度逆转。结论罗格列酮可通过阻抑凋亡调控蛋白的异常表达,发挥对PD模型小鼠多巴胺能神经元保护作用。     

MicroRNA-124对帕金森病中多巴胺能神经元的神经保护作用

目的 研究microRNA(miR)-124对帕金森病模型小鼠中脑多巴胺能神经元的神经保护作用,并探讨其免疫炎性调控机制. 方法 采用小胶质细胞系BV2细胞制备炎性反应的细胞模型,实时荧光定量PCR (qRT-PCR)检测miR-21、miR-124、miR-155、miR-146a、miR-181c、miR-221-3p等中枢炎性相关rniRNAs表达;腹腔内注射1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)制备帕金森病小鼠模型,尾静脉注射miR-124治疗,免疫组织化学染色观察治疗前后多巴胺能神经元凋亡情况(TH蛋白表达)、小胶质细胞活化情况(Iba1蛋白表达),Western blotting及qRT-PCR检测治疗前后细胞凋亡相关蛋白酶caspase-3、caspase-8的表达情况. 结果 miR-124在BV2细胞中表达量明显高于其他5种miRNAs,差异有统计学意义(P＜0.05),且致炎后表达下调幅度最大;与帕金森病模型鼠相比,miR-124治疗后黑质区TH阳性细胞数明显增多,而Iba1阳性细胞数明显减少,caspase-3、caspase-8的表达量亦明显减少,差异有统计学意义(P＜0.05). 结论 miR-124可通过抑制黑质区小胶质细胞活性缓解多巴胺能神经元凋亡进程,可能是帕金森病发病机制中的一个关键因子.     

Intrastriatal glial cell line-derived neurotrophic factors for protecting dopaminergic neurons in the substantia nigra of mice with Parkinson disease

BACKGROUND: Substantia nigra is deep in position and limited in range, the glial cell line-derived neurotrophic factor (GDNF) injection directly into substantia nigra has relatively greater damages with higher difficulty. GDNF injection into striatum, the target area of dopaminergic neuron, may protect the dopaminergic neurons in the compact part of substantia nigra through retrograde transport. OBJECTIVE: To investigate the protective effect of intrastriatal GDNF on dopaminergic neurons in the substantia nigra of mice with Parkinson disease (PD), and analyze the action pathway. DESIGN: A controlled observation. SETTING: Neurobiological Laboratory of Xuzhou Medical College. MATERIALS: Twenty-four male Kunming mice of 7–8 weeks old were used. GDNF, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were purchased from Sigma Company (USA); LEICAQWin image processing and analytical system. METHODS: The experiments were carried out in the Neurobiological Laboratory of Xuzhou Medical College from September 2005 to October 2006. The PD models were established in adult KunMing mice by intraperitoneal injection of MPTP. The model mice were were randomly divided into four groups with 6 mice in each group: GDNF 4-day group, phosphate buffer solution (PSB) 4-day group, GDNF 6-day group and PSB 6-day group. Mice in the GDNF 4 and 6-day groups were administrated with 1 μL GDNF solution (20 μg/L, dispensed with 0.01 mol/L PBS) injected into right striatum at 4 and 6 days after model establishment. Mice in the PSB 4 and 6-day groups were administrated with 0.01 mol/L PBS of the same volume to the same injection at corresponding time points. ② On the 12th day after model establishment, the midbrain tissue section of each mice was divided into 3 areas from rostral to caudal sides. The positive neurons of tyroxine hydroxylase (TH) and calcium binding protein (CB) with obvious nucleolus and clear outline were randomly selected for the measurement, and the number of positive neurons in unit area was counted. MAIN OUTCOME MEASURES: Number of positive neurons of TH and CB in midbrain substantia nigra of mice in each group. RESULTS: All the 24 mice were involved in the analysis of results. The numbers of TH+ and CB+ neurons in the GDNF 4-day group (54.33±6.92, 46.33±5.54) were obviously more than those in the PBS 4-day group (27.67±5.01, 21.50±5.96, P < 0.01). The numbers of TH+ and CB+ neurons in the GDNF 6-day group (75.67±5.39, 69.67±8.69) were obviously more than those in the PBS 6-day group (27.17±4.50, 21.33±5.72, P < 0.01) and those in the GDNF 4-day group (P < 0.01). CONCLUSION: Intrastriatal GDNF can protect dopaminergic neurons in substantia nigra of PD mice, and it may be related to the increase of CB expression.     

抗帕颗粒对帕金森病模型小鼠酪氨酸羟化酶神经元的影响

目的 探讨抗帕颗粒对1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)帕金森病(PD)模型小鼠黑质纹状体酪氨酸羟化酶(TH)阳性神经元的影响。方法 90只健康雄性C57BL/6小鼠,鼠龄8～12周,并随机分为3组,即正常对照组30只、PD模型对照组30只、PD模型干预组30只; MPTP腹腔注射(40 mg·kg^-1·d^-1×7 d)制备小鼠PD模型; 正常对照组及PD模型对照组予生理盐水1 mL·d^-1灌胃,PD模型干预组给予抗帕颗粒40 mg·kg^-1·d^-1灌胃,连续喂养4个月; 黑质纹状体切片、HE染色、免疫组织化学染色TH神经元及Western blotting检测TH蛋白的表达量。结果 ①正常对照组30只(30/30只)最终均存活,PD模型对照组4个月存活27只(27/30只),PD模型干预组4个月存活28只(28/30只); ②PD模型对照组、PD模型干预组小鼠每次注射MPTP后先有短暂兴奋[持续(7.61±2.17)min],表现为四处窜跳,随即出现全身中重度震颤,皮毛及尾巴时有竖立,活动减少,持续(24.23±3.89)min后震颤消失,随后出现活动减少; ③HE染色显示正常对照组大量褐色TH阳性细胞,PD模型对照组TH阳性细胞数明显减少,PD模型干预组TH阳性细胞数有所增加; ④免疫组织化学染色后经Imagepro-Plus 5.1系统分析,正常对照组TH阳性细胞面积为64 145 μm²,高倍镜下可见大量胞质为褐色颗粒的TH阳性细胞; PD模型对照组TH阳性细胞染色面积为40 012 μm²,高倍镜下见TH细胞数明显减少; PD模型干预组TH阳性细胞染色面积为60 952 μm²,高倍镜下见TH阳性细胞数较PD模型对照组增加; ⑤Western blotting检测显示正常对照组TH蛋白表达量与PD模型对照组和PD模型干预组比较均有明显差异(P<0.001),PD模型对照组TH蛋白表达量与PD模型干预组比较也有明显差异(P<0.05)。结论 抗帕颗粒可使PD小鼠黑质纹状体中多巴胺能神经元一定程度地减少丢失,对多巴胺能神经元的数量、形态及功能具有一定的保护作用。     

CX3CR1 Disruption Differentially Influences Dopaminergic Neuron Degeneration in Parkinsonian Mice Depending on the Neurotoxin and Route of Administration

Parkinson’s disease (PD) is characterized by progressive degeneration of dopaminergic neurons accompanied by an inflammatory reaction. The neuron-derived chemokine fractalkine (CX3CL1) is an exclusive ligand for the receptor CX3CR1 expressed on microglia. The CX3CL1/CX3CR1 signaling is important for sustaining microglial activity. Using a recently developed PD model, in which the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxin is delivered intranasally, we hypothesized that CX3CR1 could play a role in neurotoxicity and glial activation. For this, we used CX3CR1 knock-in mice and compared results with those obtained using the classical PD models through intraperitonal MPTP or intrastriatal 6-hydroxydopamine (6-OHDA). The striatum from all genotypes (CX3CR1^+/+, CX3CR1^+/GFP and CX3CR1-deficient mice) showed a significant dopaminergic depletion after intranasal MPTP inoculation. In contrast to that, we could not see differences in the number of dopaminergic neurons in the substantia nigra of CX3CR1-deficient animals. Similarly, after 6-OHDA infusion, the CX3CR1 deletion decreased the amphetamine-induced turning behavior observed in CX3CR1^+/GFP mice. After the 6-OHDA inoculation, a minor dopaminergic neuronal loss was observed in the substantia nigra from CX3CR1-deficient mice. Distinctly, a more extensive neuronal cell loss was observed in the substantia nigra after the intraperitoneal MPTP injection in CX3CR1 disrupted animals, corroborating previous results. Intranasal and intraperitoneal MPTP inoculation induced a similar microgliosis in CX3CR1-deficient mice but a dissimilar change in the astrocyte proliferation in the substantia nigra. Nigral astrocyte proliferation was observed only after intraperitoneal MPTP inoculation. In conclusion, intranasal MPTP and 6-OHDA lesion in CX3CR1-deficient mice yield no nigral dopaminergic neuron loss, linked to the absence of astroglial proliferation.     

Altered regulation of iron transport and storage in Parkinson's disease

Parkinson's disease (PD) is characterized by the death of dopaminergic neurons in the substantia nigra. This neuronal degeneration is associated with a strong microglial activation and iron accumulation in the affected brain structures. The increased iron content may result from an increased iron penetration into the brain parenchyma due to a higher expression of lactoferrin and lactoferrin receptors at the level of the blood vessels and dopaminergic neurons in the substantia nigra in PD. Iron may also accumulate in microglial cells after phagocytosis of dopaminergic neurons. These effects may be reinforced by a lack of up-regulation of the iron storage protein ferritin, as suggested by an absence of change in iron regulatory protein 1 (IRP-1) control of ferritin mRNA translation in PD. Thus, a dysregulation of the labile iron pool may participate in the degenerative process affecting dopaminergic neurons in PD.     

生酮饮食对MPTP 小鼠帕金森病模型黑质TH、Bcl-2和caspase-3基因表达的影响

目的 研究生酮饮食对PD小鼠黑质多巴胺能神经元的抗凋亡作用. 方法 1-甲基-4-苯基-1、2、3、6-四氢吡啶(MPTP)腹腔注射方法 制备PD模型小鼠.实验分为正常饮食模型组(正常饮食喂养后造模)、实验组(生酮饮食喂养后造模)、正常饮食组(不造模,正常饮食喂养)和生酮饮食组(不造模,生酮饮食喂养).初次MPTP给药前及末次给药后的次日进行滚轴实验并采集血清样本检测血清酮体和血糖浓度.荧光定量PCR技术检测黑质酪氨酸羟化酶(TH)、Bcl-2及caspase-3基因水平的表达情况. 结果 经过生酮饮食喂养后的小鼠经MPTP给药后,死亡率较正常饮食模型组降低;滚轴实验中实验组在转盘上停留时间较正常饮食模型组延长,差异均有统计学意义(P＜0.05).实验组和生酮饮食组的血清酮体浓度较其他2组明显升高,差异有统计学意义(P＜0.05).荧光定量PCR检测发现,与正常饮食模型组相比,实验组黑质中TH基因的表达明显升高,抗凋亡作用的Bcl-2基因也明显升高,促凋亡作用的caspase-3基因的表达明显减少,差异均有统计学意义(P＜0.05). 结论 生酮饮食逆转了MPTP给药后的黑质中Bcl-2基因表达的下调和caspase-3基因表达的上调,进而抑制了多巴胺能神经元的凋亡,起到了保护黑质多巴胺能神经元的作用.     

Pathogenesis of nigral cell death in Parkinson's disease

Parkinson's disease (PD) is primarily a sporadic condition which results mainly from the death of dopaminergic neurons in the substantia nigra. Its etiology remains enigmatic while its pathogenesis begins to be understood as a multifactorial cascade of deleterious factors. As of yet, most insights into PD pathogenesis are derived from toxic models of PD and show that the earlier cellular perturbations arising in dopaminergic neurons include oxidative stress and energy crisis. These alterations, rather than killing neurons, trigger subsequent death-related molecular pathways including elements of apoptosis. The fate of dopaminergic neurons in PD may also be influenced by additional factors such as excitotoxicity, emanating from the increased glutamatergic input from the subthalamic nucleus to the substantia nigra, and the glial response that arises in the striatum and the substantia nigra. In rare instances, PD can be familial, and those genetic forms have also provided clues to the pathogenesis of nigrostriatal dopaminergic neuron death including abnormalities in the mechanisms of protein folding and degradation as well as mitochondrial function. Although more remains to be elucidated about the pathogenic cascade in PD, the compilation of all of the aforementioned alterations starts to shed light on why and how nigral dopaminergic neurons may degenerate in this prominent disease, that is PD.     

“抗帕颗粒”对帕金森病模型鼠的神经保护作用

目的探讨"抗帕颗粒"对1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)帕金森病(PD)模型小鼠黑质纹状体区TH阳性神经元及多巴胺(DA)的影响。方法 90只健康雄性C57BL/6小鼠,鼠龄8~12w,随机分为3组:正常对照组30只、PD模型对照组30只、PD模型干预组30只;MPTP腹腔注射(40mg·kg~(-1)·d~(-1)×7)制备小鼠PD模型;正常对照组及PD模型对照组予生理盐水1m L·d~(-1)灌胃,PD模型干预组给予"抗帕颗粒"40mg·kg~(-1)·d~(-1)灌胃,连续喂养4个月。比较分析各组4月时黑质纹状体区TH阳性神经元及DA情况。结果 1正常对照组30只(30/30只)最终均存活,PD模型对照组4个月时存活27只(27/30只),PD模型干预组4个月时存活28只(28/30只);2PD模型对照组、PD模型干预组小鼠每次注射MPTP后,先有短暂兴奋(持续7.61±2.17min),表现为四处窜跳;随即出现全身中重度震颤,皮毛及尾巴时有竖立,活动减少,持续24.23±3.89min后震颤消失;随后出现活动减少;3经Imagepro~Plus 5.1系统分析,正常对照组TH阳性细胞面积为64145μm~2,高倍镜下可见大量胞质为褐色颗粒的TH阳性细胞;PD模型对照组TH阳性细胞染色面积为40012μm~2,高倍镜下见TH细胞数量明显减少;PD模型干预组TH阳性细胞染色面积为60952μm~2,高倍镜下见TH阳性细胞数量较PD模型对照组增加;4正常对照组DA含量为2.18±0.31μg·m L~(-1),与PD模型对照组1.57±0.22μg·m L~(-1)比较,P0.01;正常对照组与PD模型干预组2.04±0.18μg·m L~(-1)比较。P0.05;PD模型对照组与PD模型干预组比较,P0.01。结论 "抗帕颗粒"可使PD小鼠黑质纹状体中多巴胺能神经元一定程度地减少丢失,并改善DA含量的下降,对多巴胺能神经元的数量、形态及功能具有一定的保护作用,有望改善PD治疗现状并在临床进一步推广应用。     

漆黄素对帕金森病小鼠模型的保护作用及机制研究

目的 探讨漆黄素对帕金森病的神经保护作用及具体机制。方法 采用MPTP腹腔注射复制亚急性PD小鼠模型,漆黄素灌胃给药,实验分为3组：control组、MPTP组、漆黄素+MPTP组。通过旷场实验、爬杆实验、悬挂实验等行为学指标评估小鼠的运动行为。采用Western blotting和免疫荧光技术检测纹状体中TH水平和黑质中TH阳性神经元数量。采用尼氏染色检测黑质区神经元的损伤状况。通过检测纹状体区GSH、SOD、T-AOC、MDA含量,评估脑组织中氧化应激水平。结果 与MPTP组相比,漆黄素+MPTP组,小鼠的运动总距离及运动速度提高（P<0.05）;爬杆总时间及转头时间缩短（P<0.05）。悬挂实验评分提高（P<0.05）。尼氏染色结果发现,漆黄素可缓解MPTP小鼠黑质区神经元损伤（P<0.05）。TH免疫印迹及免疫荧光实验发现漆黄素可改善MPTP诱导的小鼠TH表达量水平下降及阳性神经元丢失（P<0.05）。同时,漆黄素处理后,提高了MPTP小鼠GSH、SOD、T-AOC水平,降低了MPTP小鼠MDA的含量（P<0.05）。结论 漆黄素能有效改善帕金森病模型小鼠的运动功能,缓解黑质－纹状体多巴胺能神经元损伤,其机制可能与漆黄素的抗氧化作用有关。     

Transcranial alternating current stimulation rescues motor deficits in a mouse model of Parkinson's disease via the production of glial cell line-derived neurotrophic factor

BackgroundTherapeutic effects of transcranial alternating current stimulation (tACS) for treating Parkinson's disease (PD) are limited to modulating abnormally synchronized oscillations; however, long-lasting tACS effects may involve non-neuronal mechanisms like the regulation of neurotrophic factors.Objectives/HypothesisWe investigated whether tACS exerts neuroprotective effects on dopaminergic neurons in a mouse model of PD by regulating endogenous glial cell line-derived neurotrophic factor (GDNF).MethodsRepeated high-definition tACS (HD-tACS, 20 min, 89.1 μA/mm²) was administered over the primary motor cortex of C57BL/6J 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice. Behavioral tests assessing motor function, immunohistochemistry, western blots, enzyme-linked immunosorbent assays, and flow cytometric analyses were performed to examine suitable tACS conditions and its underlying mechanisms.ResultsStimulation at representative frequencies (theta to gamma; 20-Hz beta frequency, in particular) attenuated motor dysfunction and protected the dopaminergic neurons with increased GDNF production. Beta-frequency (20 Hz) tACS application significantly attenuated motor deficits to levels comparable with those of levodopa treatment. Moreover, beta-frequency tACS induced the survival of dopaminergic neurons in the substantia nigra with upregulated production of endogenous GDNF in striatal parvalbumin-positive interneurons. An inhibitor of the GDNF receptor-associated rearranged during transfection (RET) kinase suppressed most aspects of the tACS-induced behavioral recovery, dopaminergic cell survival, and GDNF production. Beta-frequency tACS activated RET-related survival signaling for dopaminergic neurons in the substantia nigra.ConclusionsApplication of tACS over the primary motor cortex may exert protective effects on dopaminergic neurons in the substantia nigra via activation of endogenous GDNF production by striatal parvalbumin-positive interneurons and its survival signaling.     

Expression of c-Jun in dopaminergic neurons of the substantia nigra in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice

The expression of c-Jun in the brains of young (8-week-old) and older (52-week-old) mice following administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was investigated immunocytochemically. Both age groups exhibited reduction in the number of dopaminergic neurons in the substantia nigra after administration of MPTP. There was a significant difference in the magnitude of decrease in the number of dopaminergic neurons between the two groups, as has previously been reported, and the older mice exhibited more extensive loss of dopaminergic neurons in the substantia nigra after MPTP administration than did the young mice. Prolonged c-Jun expression was induced in the substantia nigra following administration of MPTP, and this induction was more prominent in the older mice than in the young mice. Maximum expression of c-Jun occurred on day 7 after the administration of MPTP in both groups. Double staining for tyrosine hydroxylase (TH; a dopaminergic neuron marker) and c-Jun revealed their co-localization indicating that the cells expressing c-Jun were dopaminergic neurons. Cytoplasmic volumes of strongly c-Jun positive cells were reduced, suggesting that they may have been degenerating. In situ end labeling revealed no apoptotic neurons after MPTP administration. These results suggest the existence of some cascade mechanism of nonapoptotic death of dopaminergic neurons following administration of MPTP.