香椿子多酚对6-OHDA所致帕金森病大鼠模型的抗炎和神经保护作用

目的:观察香椿子多酚(polyphenols from toona sinensis seeds,PTSS)抑制神经炎症反应,对黑质多巴胺能神经元的保护作用。方法:脑立体定向注射6-羟多巴胺(6-OHDA)至右侧纹状体,制备帕金森病(Parkinson’s disease,PD)大鼠模型。将成模大鼠随机分为模型组和PTSS组,另10只正常大鼠设为对照组,PTSS组每日PTSS灌胃2 ml,另外两组大鼠等体积量生理盐水灌胃,1/d次,连续30 d。免疫组织化学法观测大鼠黑质多巴胺能(酪氨酸羟化酶TH阳性)神经元、星形胶质细胞(GFAP阳性)、小胶质细胞(CD11b阳性)形态和数量变化。RT-PCR和Western Blot分别检测黑质肿瘤坏死因子(TNF-α)和环氧化酶-2(COX-2)在mRNA和蛋白水平上的变化。结果:免疫组织化学结果显示,与对照组比较,模型组和PTSS组大鼠黑质TH阳性细胞数量显著下降、黑质CD11b和GFAP免疫反应阳性细胞数量明显增多(P0.05)。中脑黑质TNF-α和COX-2蛋白含量显著升高;RT-PCR检测TNF-αmRNA和COX-2 mRNA表达量的结果与Western Blot一致。与模型组比较,PTSS组大鼠旋转圈数明显减少(P0.05)、黑质TH阳性细胞数量显著增多,CD11b、GFAP阳性细胞数量明显下降,TNF-α和COX-2阳性表达光密度值降低;黑质中TNF-α和COX-2蛋白含量及其mRNA表达量显著下降。结论:PTSS能够抑制胶质细胞活化,减轻神经炎症,有效保护黑质DA能神经元。     

雌激素和帕金森病

流行病学调查发现，帕金森病的发病率男性多于女性，动物实验和临床试验的结果也提示，雌激素对帕金森病的发生具有一定的保护作用。本文就雌激素舆雌激素受体的特性、雌激素对黑质-纹状体系统多巴胺通路的影响、雌激素在帕金森病模型中可能的神经保护作用的研究进展作一综述。     

脑源性神经营养因子与帕金森病

帕金森病 (PD)的最主要病理特征是中脑黑质致密部(substantia nigra pars com pacta,SNpc)多巴胺 (DA)能神经元的进行性退化变性 ,由于其机制还不清楚 ,因而限制了此病的临床治疗。脑源性神经营养因子 (brain- derived neu-rotrophic factor,BDNF)由 Barde等于 1982年在猪脑中首次发现 ,其氨基酸序列有 5 5 %～ 6 0 %与神经生长因子 (nervegrowth factor,NGF)完全相同 ,也属神经营养素 (neu-rotrophin)家族的成员 ,BDNF可通过其高亲和力受体 trk B和低亲和力受体 p75 NTR发挥生物活性 ,能够促进多种神经元的存活 ,尤其对 DA能神经…     

帕金森病内科治疗新策略

目前左旋多巴仍是治疗帕金森病的最有效药物,但所有的治疗措施仍停留在对症治疗阶段,并且长期应用左旋多巴会产生难以纠正的症状波动及异动症。针对帕金森病发病机制的研究热点,多种抗氧化应激、延缓细胞凋亡、改善线粒体功能及持续性多巴胺受体刺激的药物逐渐被应用于对帕金森病的治疗,这些药物有望延缓疾病进程,更好的改善临床症状。     

他汀类药物的免疫调节及神经保护作用机制

他汀类药物是羟甲基戊二酸单酰辅酶A还原酶的抑制剂,临床上主要用于高胆固醇血症的治疗.近年研究发现,他汀类药物具有抑制促炎性细胞因子(Th1和Th17细胞冈子)的分泌、增加调节性T细胞(Treg)数量和功能、抑制树突状细胞(DC)成熟等作用.通过这些免疫调节和抗炎作用,他汀类药物在神经系统疾病如脑卒中、阿尔茨海默病(AD...     

神经干细胞移植对帕金森病样模型大鼠的治疗作用

目的 观察大鼠神经干细胞(NSC)植入帕金森病(PD)模型大鼠的脑纹状体后的存活、分化及功能状态.方法 体外分离培养NSC,单克隆培养,免疫细胞化学检测多向分化潜能和特异性标记nestin.建立PD大鼠模型,纹状体内植入DAPI标记的NSC,检测6-羟基多巴胺(6-HHDA)诱发的旋转行为,荧光检测标记细胞的分布情况,免疫细胞化学和高效液相色谱检测细胞分化和神经递质含量.结果 培养的NSC表达nestin,具有自我更新和多向分化能力;NSC植入PD模型大鼠纹状体后大鼠诱导旋转行为显著改善(P＜0.05);NSC在脑内迁移,并在纹状体内形成少量酪胺酸羟化酶(TH)阳性细胞、纤维;植入后纹状体内多巴胺(DA)及其代谢产物含量上升,2个月时分别增加3.6倍和2.8倍,4个月时增加3.4倍和2.4倍(P＜0.01).结论 神经干细胞在体外大量扩增后植入PD脑内能长期存活并分化、分泌神经递质,从而部分改善PD症状.     

肌酸对帕金森病模型大鼠黑质多巴胺能神经元保护作用的研究

目的:观察肌酸对帕金森病模型大鼠黑质多巴胺能神经元的保护作用及其机制。方法:30只雄性SD大鼠随机分成3组:对照组(A组),6-羟多巴胺(6-OHDA)组(B组),肌酸+6-OHDA组(C组),每组各10只。A组不注射6-OHDA,B组进行6-OHDA造模,C组在造模前5天每天给予肌酸(100 mg/kg)灌胃,连续两周,B组给予生理盐水4 ml灌胃。分别观察各组动物行为学、黑质多巴胺能神经元数量及氧化应激指标谷胱甘肽(GSH)和丙二醛(MDA)水平变化。结果:6-OHDA立体定向注射后,实验大鼠出现阿朴吗啡诱导的旋转行为,黑质致密部多巴胺能神经元显著减少,GSH含量降低、MDA水平升高;肌酸能够减轻动物行为学异常(P0.01)、显著增加黑质致密部多巴胺神经元数量(P0.01),拮抗6-OHDA诱导的氧化应激水平升高(P0.01)。结论:肌酸对6-OHDA诱导的多巴胺神经元损伤具有明显保护作用,其机制与抑制氧化应激损伤有关。     

神经干细胞与帕金森病

背景：帕金森病已经成为中老年人常见的运动障碍性疾病之一,目前对其治疗的主要方式仍然是在药物和手术等领域,而神经干细胞作用于帕金森病的功能康复已经受到国内外学者的广泛关注。目的：在分析神经干细胞的生物特性及其帕金森病的病理特征的基础上,探讨了神经干细胞对帕金森病的作用,旨在为神经干细胞移植促进帕金森病康复的应用提供科学依据。方法：应用计算机检索Medline数据库、CNKI数据库和维普数据库(1994-01/2010-08)以“Parkinson disease,Neural Stem Cell,Rehabilitation”为英文检索词,以“帕金森病;神经干细胞;康复”为中文检索词,通过对与帕金森病、神经干细胞等的相关文献,以权威期刊、近年来发表的文献作为纳入标准,以重复性研究、陈旧性研究为排除标准等,对所得文献进性整理分析。结果与结论：神经干细胞作用于帕金森病患者的康复具有取材方便、低免疫原性、多向分化潜能、可定向诱导分化等优势,被作为治疗包括帕金森病在内的神经损伤类疾病的新的手段,但如果要将神经干细胞真正应用于临床治疗仍需要不断的开展研究,主要体现在对于神经干细胞得分化和功能修复机制还不清楚,移植后的细胞能否与体内损伤细胞相整合,建立起正常得神经系统突触联系还需要进一步研究。     

Potential neuroprotective effect of low dose whole-body gamma-irradiation against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopaminergic toxicity in C57 mice

Low dose whole-body γ-irradiation is recently reported to confer neuroprotection against optic nerve crush and contusive spinal cord injury. Here, we extended the study and investigated whether the pretreatment of a single low dose whole-body γ-irradiation may have a preventive effect in MPTP-induced model of PD. One week after the last MPTP treatment, HPLC determination of striatal dopamine and immunostaining for tyrosine hydroxylase (TH), CD11b and GFAP to detect dopamine neurons and associated glial reaction in the substantia nigra pars compacta (SNpc) were performed. MPTP treatment reduced striatal DA levels significantly; nigral TH immunoreactivity was reduced to a lower extent; robust gliosis was also observed in SNpc. We found that 3.5 Gy irradiation but not 5.5 Gy restores the level of DA and its metabolites decreased by MPTP. However, there was no difference in the number of TH positive neurons between 3.5 Gy irradiated and saline treated mice after MPTP treatment. Irradiation also did not have obvious influence on microgliosis and astroglial reaction induced by MPTP treatment. In conclusion, the results presented here demonstrated that low dose whole-body γ-irradiation renders neuroprotection against MPTP-mediated damage of striatal dopaminergic nerve fibers, though it does not seem to influence the MPTP-induced reduction of SNpc dopaminergic neurons and associated glial responses.     

Effects of IL-6 secreted from astrocytes on the survival of dopaminergic neurons in lipopolysaccharide-induced inflammation

The role of astrocytes in microglia-induced neuronal death remains controversial. In this study, astrocytes and astrocyte-derived conditioned media (ACM) supported the survival of dopaminergic neurons, and the former was more effective than the latter. In the presence of astrocytes, low concentrations of LPS enhanced the survival of dopaminergic neurons, while high concentrations attenuated survival. LPS dramatically induced astrocytes to secrete IL-6 in a dose-dependent manner with no effect on secretion of GDNF. Neuron–astrocyte cultures had highest secretion of GDNF, followed by ACM-treated neuron-enriched cultures. After neuron–astrocyte cultures treated with IL-6-neutralizing antibody, both effects of the enhanced and attenuated survival of dopaminergic neurons were abolished. Our results indicate that astrocytes play a protective role in the LPS-induced damage of dopaminergic neurons in certain circumstances, and the interaction between astrocytes and dopaminergic neurons may enhance the protective effect of astrocytes. Suitable activation of astrocytes increases the protective effect while excessive activation attenuates it, and IL-6 might medicate this dual action. The underlying mechanisms related to the secretion of GDNF and proinflammatory factors warrant further investigation.     

Hypersensitivity of aquaporin 4-deficient mice to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyrindine and astrocytic modulation

Aquaporin 4 (AQP4) is a predominant water channel protein in mammalian brains, which is localized in the astrocyte plasma membrane. AQP4 has gained much attraction due to its involvement in the physiopathology of cerebral disorders including stroke, tumor, infection, hydrocephalus, epilepsy, and traumatic brain injury. But there is almost no evidence whether abnormal AQP4 levels are associated with degenerative diseases, such as Parkinson's disease (PD). In our studies, we established PD animal models by administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine to test the hypothesis that abnormal AQP4 expression is involved in the pathophysiology of this disease. We show that mutant mice lacking AQP4 were significantly more prone to MPTP-induced neurotoxicity than their wild-type littermates. Furthermore, after administration of MPTP, astroglial proliferation and GDNF protein synthesis were inhibited by AQP4 deficiency. This study demonstrates that AQP4 is important in the MPTP neurotoxic process and indicates that the therapeutic strategy targeted to astrocytic modulation with AQP4 may offer a great potential for the development of new treatment for PD.     

Progress in Parkinson's disease-Where do we stand?

Parkinson's disease was first described in 1817 by James Parkinson. It is one of the most common neurodegenerative disorders, affecting the nigrostriatal pathways involved in the control of movement. Since the introduction of L-DOPA as a therapy in the mid-1960s, clinical management of the symptoms has progressed, but, at present, it remains impossible to stop the disease progression or to restore lost functions. A better understanding of neurodegeneration and of midbrain neuronal development has allowed the development of new pharmaceutical compounds with neuroprotective properties and has shown the potential of neurone replacement therapies in Parkinson's disease. Even though major obstacles remain before these can be transferred to the clinic, the progress made in the last 10 years brings hope of improved therapies for Parkinson's disease. In this paper we review the current knowledge of Parkinson's disease including its etiology, some of the current symptomatic therapeutic modalities, and recent progress in neuroprotective and cell replacement therapies.     

Overexpression of CB2 cannabinoid receptors results in neuroprotection against behavioral and neurochemical alterations induced by intracaudate administration of 6-hydroxydopamine

The role of CB2 cannabinoid receptors in the behavioral and neurochemical changes induced by intracaudate administration of 6-hydroxydopamine (6-OHDA) was evaluated. 6-OHDA (12 μg/4 μL) or its vehicle was injected in the caudate-putamen (CPu) of mice overexpressing the CB2 cannabinoid receptor (CB2xP) and wild type (WT) mice. Motor impairment, emotional behavior, and cognitive alterations were evaluated. Tyrosine hydroxylase (TH), glial fibrillary acidic protein (GFAP), and ionized calcium-binding adapter molecule 1 (Iba-1) were measured by immunocytochemistry in the CPu and/or substantia nigra (SN) of CB2xP mice and WT mice. Oxidative/nitrosative and neuroinflammatory parameters were also measured in the CPu and cortex of 6-OHDA-treated and sham-treated mice. 6-OHDA-treated CB2xP mice presented significantly less motor deterioration than 6-OHDA-treated WT mice. Immunocytochemical analysis of tyrosine hydroxylase in the SN and CPu revealed significantly fewer lesions in CB2xP mice than in WT mice. GFAP and Iba-1 immunostaining revealed less astrocyte and microglia recruitment to the treated area of the CPu in CB2xP mice. Malonyldialdehyde (MDA) concentrations were lower in the striatum and cerebral cortex of sham-treated CB2xP mice than in sham-treated WT mice. The administration of 6-OHDA increased MDA levels in both WT mice and CB2xP mice; it increased the oxidized (GSSG)/reduced (GSH) glutathione ratio in the striatum in WT mice alone compared with matched sham-treated controls. The results revealed that overexpression of CB2 cannabinoid receptors decreased the extent of motor impairment and dopaminergic neuronal loss, reduced the recruitment of astrocytes and microglia to the lesion, and decreased the level of various oxidative parameters. These results suggest that CB2 receptors offer neuroprotection against dopaminergic injury.     

Exercise reverses chronic stress-induced Bax oligomer formation in the cerebral cortex

Chronic stress may lead to neuronal atrophy and functional impairments within the CNS, and increasing evidence indicates that exercise can protect the brain from these changes. Bax is a key protein of the B-cell lymphoma (Bcl) family that complexes within the mitochondrial membrane and forms pores to initiate cellular apoptosis. Herein, we measured cortical Bax levels following chronic and acute stress via immunoblotting. We reveal that chronic, but not acute, stress increases cortical levels of Bax oligomer 270, a complex revealed in previous studies to be associated with apoptosis. Several recent studies have revealed that physical exercise can protect rodents from neurochemical and/or behavioral changes occurring with stress. Previous studies have also revealed that voluntary exercise enhances the expression and activation of cellular proteins associated with enhanced neuronal survival. Herein, we reveal that 3 weeks of daily restraint led to increased oligomerization of Bax within the cerebral cortex, and that chronic corticosterone administration had a similar effect. Voluntary wheel running, concurrent with chronic restraint, prevented an increase in Bax oligomer 270. Analysis of subcellular fractions also revealed that the combination of exercise with chronic stress reduced the percent of total Bax localized to the mitochondria. Ours is the first study to investigate dynamic molecule complexes associated with the initiation of apoptosis with stress, and the influence of exercise upon the levels of these complexes, suggesting that exercise is an effective preventative measure that can promote neuronal survival and protect the brain against the damaging effects of chronic stress.     

BMSC and CoQ10 improve behavioural recovery and histological outcome in rat model of Parkinson's disease

Objective: This study assessed the ability of a combination treatment of bone marrow stromal cell (BMSC) graft and oral coenzyme (CoQ10) in a rat model of Parkinson's disease (PD) as an appropriate substitute for current Parkinson treatments. The combination treatment was compared to sole treatments of BMSC and CoQ10. Materials and methods: In this experimental study, there were six groups of male Wistar rats: control, sham, lesion, CoQ10, graft BMSC and graft BMSC plus CoQ10. Oral administration of CoQ10 began 1 week before the PD and continued during the entire treatment period. To simulate PD, we injected 6 hydroxydopamine (6OHDA) in rats. BMSC were labelled by 5-bromo-2′-deoxyuridine (Brdu) before transplantation. We assessed behaviour before PD, 2 weeks after PD and 8 weeks after cell transplantation. At the end of the second month of treatment, immunohistochemistry, histology and molecular studies were performed. Results: Behavioural assessment of the CoQ10 group and BMSC group indicated equal recovery in comparison with the lesion group (P < 0.01), while the combined treatment of BMSC and CoQ10 showed considerably better recovery compared with the lesion group (P < 0.001). There were no signs of gliosis and graft rejection. Immunohistochemistry analysis of Brdu indicated that cells were alive after 2 months of application in host tissue. Cell counts showed significantly greater numbers of neural cells in the combination treatment of BMSC and CoQ10 compared to the other groups. Tyrosine hydroxylase (TH) gene expression levels in the combined therapy group was significantly more than the other experimental groups (P < 0.001). Conclusion: The combined use of two neuroprotective treatments and cell replacement therapy can be effective in the treatment of PD, at least in experimental settings.     

Protective effect of adenosine in rat model of Parkinson's disease: neurobehavioral and neurochemical evidences

Normal cellular metabolism produces oxidants which are neutralized within the cell by antioxidant enzymes and other antioxidants. An imbalance between oxidant and antioxidant has been postulated to lead the degeneration of dopaminergic neurons in Parkinson's disease. In this study, we examined whether adenosine, an antioxidant, can prevent or slowdown neuronal injury in 6-hydroxydopamine (6-OHDA) model of Parkinsonism. Rats were treated with adenosine (500, 250, 125 mg/kg b.wt.) once before surgery and five times after surgery (1 h interval). 2 microl 6-OHDA (12.5 microg in 0.2% ascorbic acid in normal saline) was infused in the right striatum. Two weeks after 6-OHDA infused rats were tested for neurobehavioral activity and sacrificed after 3 weeks of 6-OHDA infusion, for the estimation of glutathione peroxidase, glutathione-S-transferase, glutathione reductase, glutathione content, lipid peroxidation and dopamine and its metabolites. Adenosine was found to be successful in up-regulating the antioxidant status, lowering the dopamine loss and functional recovery returned close to the baseline dose. This study revealed that adenosine, which is an essential part of our body, might be helpful in slowing down the progression of neurodegeneration in Parkinsonism.     

维生素C对MPP+致帕金森病细胞模型中PC12细胞凋亡的影响

目的　探讨维生素C（Vit C）对MPP+致帕金森病细胞模型中PC12细胞凋亡的影响及作用机制。 方法　培养神经细胞株PC12细胞,将其分为单纯帕金森病组（MPP+组）和Vit C治疗组（Vit C组）,Vit C组加入250 μmol/L Vit C孵育6 h,之后向两组均加入100 μmol/L MPP+,在体外模拟帕金森病的神经损伤,孵育12 h后,利用乳酸脱氢酶（LDH）试剂盒检测LDH变化;TUNEL法检测鼠脑神经元凋亡情况,并利用Western-blot检测神经元中c-Caspase3和Caspase表达情况。 结果　与MPP+组比较,Vit 　C能明显减轻帕金森病PC12细胞凋亡,显著改善细胞生存环境; TUNEL检测结果显示,Vit C能明显减少PC12细胞凋亡。同时,Western-blot结果提示Vit C下调c-Caspase3蛋白的表达,组间差异有统计学意义( P<0.05)。 结论　Vit C可以直接抑制c-Caspase3表达,减少细胞凋亡,可能对帕金森病造成的细胞凋亡具有一定的拮抗作用。     

Role of nuclear transcription factor kappa B (NF-kappaB) for MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahyropyridine)-induced apoptosis in nigral neurons of mice

The biochemical and cellular changes that occur following treatment with MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahyropyridine) are remarkably similar to that seen in idiopathic Parkinson's disease. In this study, we investigated the time course changes of NF-kappaB (Nuclear factor kappa B) p65 protein and apoptosis in the substantia nigra after MPTP treatment in mice. Four administrations of MPTP at 2 h intervals showed a significant and severe decrease of the number of TH (tyrosine hydroxylase) immunopositive neurons in the substantia nigra of mice from 5 h up to 21 days posttreatment. Densities of DAT (dopamine transporter) immunoreactivity were also significantly decreased in nigral neurons of mice from 1 up to 21 days after MPTP treatment. GFAP (glial fibrillary acidic protein) immunopositive cells were increased significantly in the substantia nigra from 5 h up to 21 days after MPTP treatment. In contrast, isolectin B₄ positive microglia were increased markedly in the substantia nigra only 3 and 7 days after MPTP treatment. On the other hand, a significant increase of NF-kappaB p65 immunoreactivity was observed mainly in glial cells of the substantia nigra from 5 h to 3 days after MPTP treatment. A significant increase of ssDNA (single stranded DNA) immunopositive apoptotic neurons was also observed in the substantia nigra from 5 h to 3 days after MPTP treatment. These results demonstrate that dopaminergic neuronal loss may be caused by apoptosis due to increased cytokines and apoptosis-related proteins via the activation of NF-kappaB in reactive astrocytes of the substantia nigra after MPTP treatment in mice. Thus our findings suggest that the inhibition of NF-kappaB activation in astrocytes may be useful intervention in Parkinson's disease and other neurogenerative disorders where apoptosis or inflammation plays a key role in disease pathogenesis.