Electroacupuncture-regulated neurotrophic factor mRNA expression in the substantia nigra of Parkinson's disease rats

Acupuncture for the treatment of Parkinson＇s disease has a precise clinical outcome. This study investigated the effect of electroacupuncture at Fengfu （GV16） and Taichong （LR3） acupoints in rat models of Parkinson＇s disease induced by subcutaneous injection of rotenone into rat neck and back. Reverse transcription-PCR demonstrated that brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor mRNA expression was significantly increased in the substantia nigra of rat models of Parkinson＇s disease, and that abnormal behavior of rats was significantly improved following electroacupuncture treatment. These results indicated that electroacupuncture treatment upregulated brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor mRNA expression in the substantia nigra of rat models of Parkinson＇s disease. Thus, electroacupuncture may be useful in the treatment of Parkinson＇s disease.

Expression of calbindin D28K in substantia nigra of model rats with Parkinson disease

BACKGROUND： Previous researches suggested that expression level of calbindin D28K mRNA decreased in substantia nigra （SN） of model rats with Parkinson disease （PD）, and this might be related to the decrease of anti-degeneration potentials of dopaminergic neurons. OBJECTIVE： To observe expression changes of calbindin D28K in SN dopaminergic neurons during their degeneration and death in midbrain of PD model rats. DESIGN： Completely randomized grouping design SETTING： Department of Neurobiology, Xuzhou Medical College MATERIALS＂ A total of 92 healthy male SD rats, with the age of 3 months, weighing 200-250 g, were selected from Experimental Animal Center of Xuzhou Medical College [certification： SCXK （su） 2003-0003]. Calbindin D28K（CB）, tyroxine hydroxylase （TH）, ABC kit, 6-hydroxydopamine （6-OHDA） and Nissl dyes were provided by Sigma Company, and sheep serum was provided by Beijing Zhongshan Company. METHODS： The experiment was carried out in the Neurobiological Center of Xuzhou Medical College from October 2003 to October 2004. ① With lot method, rats were divided into blank control group （n=28）, experimental control group （n=-28） and experimental group （n=36）. Rats in experimental group were injected with 6-OHDA at right corpus striatum for PD modeling; rats in experimental control group were injected with saline at the same site; rats in blank control group did not give any injections.② On the 7^th, 14^th, 21^st and 28^th days, SN segments on right midbrain from every 5 rats in experimental group were fixed, embedded with paraffin and cut into successively coronary pieces. Rats in other two groups were treated with the same methods and then stained with Nissl to show neuronal form. Meanwhile, CB and TH antibodies staining with immunohistochemistry were used to show CB containing dopaminergic neurons and dopaminergic neurons, and cells were calculated and observed under optic microscope. ③ On the 14^th and 28^th days, every 4 rats in experimental group and every 4 rats in control group were selected to obtain their brains and separate SN on the injured side. Western blot was used to detect expression of calbindin D28K, protein band was scanned with imaging equipment, and data were analyzed with LabWorks software. MAIN OUTCOME MEASURES：① On the 7^th, 14^th, 21^st and 28^th days, Nissl staining results of SN neurons and immunohistochemical staining results of CB and TH antibodies; ② On the 14^th and 28^th days, Western blot results of calbindin D28K in SN neurons, RESULTS; Among 92 rats, 2 rats in experimental group died after 1 day due to 6-OHDA injection and other 90 rats were involved in the final analysis. ①Nissl staining results： On the 7^th day of 6-OHDA injection, most neuronal somas on right SN pars compacta were shown as deep pycnosis or lysis breakage; on the 14^th and 21^st days, amount of neurons was decreased remarkably; on the 28^th day, most neurons in SN pars compacta disappeared. ② Results of immunohistochemical staining： Amount of positive neurons of calbindin D28K in right SN pars compacta was not changed on the 7^th day after 6-OHDA injection; on the 14^th day, the amount was higher in experimental group than that in both control groups （P 〈 0.01） and was decreased till the 21^st day, but it was still higher than that in the two control groups （P 〈 0.05）; on the 28^th day, positive neurons of calbindin D28K nearly disappeared, and the amount was lower than that in the two control groups （P 〈 0.01）. In addition, on the 7^th day after 6-OHDA injection into corpus striatum, positive TH neurons decreased 24% in right SN, and there was significant difference from that in control groups; on the 14^th, 21^st and 28^th days, positive TH neurons decreased 37%, 46% and 64%, respectively. ③ Western blot results： On the 14＇h day after 6-OHDA injection into corpus striatum, expression of calbindin D28K in right SN was higher in experimental group than that in both control groups （P 〈 0.05）; however, on the 28^th day, the expression was lower than that in the two control groups （P 〈 0.01 ）. CONCLUSION ： During degeneration and death of dopaminergic neurons, CB expression in SN pars compacta increases firstly and decreased gradually.

Baicalin and deferoxamine alleviate iron accumulation in different brain regions of Parkinson's disease rats

Previous studies found that iron accumulates in the substantia nigra of Parkinson＇s disease patients However, it is still unclear whether other brain regions have iron accumulation as well. In this experiment, rats with rotenone-induced Parkinson＇s disease were treated by gastric perfusion of baicalin or intraperitoneal injection of deferoxamine. Immunohistochemical staining demonstrated that iron accumulated not only in the substantia nigra pars compacta, but also significantly in the striatum globus pallidus, the dentate gyrus granular layer of the hippocampus, the dentate-interpositus and the facial nucleus of the cerebellum. Both baicalin and deferoxamine, which are iron chelating agents, significantly inhibited iron deposition in these brain areas, and substantially reduced the loss of tyrosine hydroxylase-positive cells. These chelators also reduced iron content in the substantia nigra. In addition to the substantia nigra, iron deposition was observed in other brain regions as well. Both baicalin and deferoxamine significantly inhibited iron accumulation in different brain regions, and had a protective effect on dopaminergic neurons.

Copper (Cu^(2+)) induces degeneration of dopaminergic neurons in the nigrostriatal system of rats

Objective To study the effects of intranigral injection of different doses of CuSO45H2O on dopaminergic neuron in the nigrostriatal system of rats. Methods Wistar rats were divided into four groups, including control group, 10 nmol, 50 nmol and 200 nmol copper injected into left substantia nigra （SN） groups. Seven days after the intranigral injection of copper, dopamine （DA） contents in the striatum （Str） were measured by high performance lipid chromotophotography （HPLC）; the density of tyrosine hydroxylase （TH） positive axons in the Str was measured by TH staining method; TH and Caspase-3 mRNA expression in the SN were measured by semi-quantitative RT-PCR. We detected the activity of superoxide dismutase （SOD） in the lesioned midbrain of rats using biochemical methods. Results DA and its metabolites contents had no significant difference between control group and low dose （10 nmol） copper group. But from 50 nmol copper group, DA contents in the lesioned sides were reduced with the increase in the copper doses injected, showing a significant linear correlation （F = 34.16, P 〈 0.01）. In the 50 nmol copper group, TH positive axons in the Str decreased compared with those of the control and unlesioned sides （F = 121.9, P 〈 0.01）. In the 50 nmol copper group, TH mRNA expression decreased （t =3.12, P 〈 0.01） while Caspase-3 mRNA expression increased （t =8.96, P 〈 0.01） in the SN compared with the control. SOD activity decreased in the midbmin of rots treated with 50 nmol copper compared with that of the control （t = 2.33, P〈0.01）. Conclusion Copper could induce damage of dopaminergic neurons in the SN of rats through destroying antioxidant defenses and promoting apoptosis.

Rapid transport of insulin to the brain following intranasal administration in rats

We previously reported that intranasal insulin protects substantia nigra dopaminergic neurons against6-hydroxydopamine neurotoxicity in rats. This study aimed to assess insulin pharmacokinetics in the rat brain following intranasal application. Recombinant human insulin(rh-Ins) or phosphate buffer solution was administered to both nostrils of rats. Animals were sacrificed at 15 minutes, 1, 2, and 6 hours to determine insulin levels in different brain regions by an ultrasensitive, human-specific enzyme-linked immunosorbent assay kit. For fluorescence tracing study, rats were administered with intranasal florescence-tagged insulin(Alex546-Ins), and brains were fixed at 10 and 30 minutes to prepare sagittal sections.rh-Ins was detected in all brain regions examined except the cerebral cortex. The highest levels were detected in the brainstem, followed by the cerebellum, substantia nigra/ventral tegmental area, olfactory bulb,striatum, hippocampus, and thalamus/hypothalamus. Insulin levels reached a peak at 15 minutes and then declined gradually overtime, but remained significantly higher than baseline levels at 6 hours in most regions.Consistently, widespread Alex546-Ins-binding cells were detected in the brain at 10 and 30 minutes, with the olfactory bulb and brainstem showing the highest while the cerebral cortex showing lowest fluorescence signals. Double-immunostaining showed that Alex546-Ins-bindings were primarily co-localized with neuronal nuclei-positive neurons. In the subtantia nigra, phospho-Akt was found to be activated in a subset of Alex546-Ins and tyrosine hydroxylase double-labeled cells, suggesting activation of the Akt/PI3 K pathway in these dopaminergic neurons. Data from this study suggest that intranasal insulin could effectively reach deep brain structures including the nigrostriatal pathways, where it binds to dopaminergic neurons and activates intracellular cell survival signaling. This study was approved by the Institutional Animal Care Committee at the University of Mississippi Medical Center(protocol 1333 A) on June 29, 2015.

Intracerebroventricularly-administered 1-methyl-4-phenylpyridinium ion and brain-derived neurotrophic factor affect catecholaminergic nerve terminals and neurogenesis in the hippocampus,striatum and substantia nigra

Parkinson＇s disease is a progressive neurological disease characterized by the degeneration of dopaminergic neurons in the substantia nigra.A highly similar pattern of neurodegeneration can be induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine（MPTP） or 1-methyl-4-phenylpyridinium ion（MPP＋）,which cause the death of dopaminergic neurons.Administration of MPTP or MPP＋ results in Parkinson＇s disease-like symptoms in rodents.However,it remains unclear whether intracerebroventricular MPP＋ administration affects neurogenesis in the substantia nigra and subgranular zone or whether brain-derived neurotrophic factor alters the effects of MPP＋.In this study,MPP＋（100 nmol） was intracerebroventricularly injected into mice to model Parkinson＇s disease.At 7 days after administration,the number of bromodeoxyuridine（Brd U）-positive cells in the subgranular zone of the hippocampal dentate gyrus increased,indicating enhanced neurogenesis.In contrast,a reduction in Brd U-positive cells was detected in the substantia nigra.Administration of brain-derived neurotrophic factor（100 ng） 1 day after MPP＋ administration attenuated the effect of MPP＋ in the subgranular zone and the substantia nigra.These findings reveal the complex interaction between neurotrophic factors and neurotoxins in the Parkinsonian model that result in distinct effects on the catecholaminergic system and on neurogenesis in different brain regions.

Mechanisms of secondary damage to the thalamic nucleus and substantia nigra in an adult hypertensive rat model following middle cerebral artery occlusion

BACKGROUND： Following ischemia, apoptosis is observed at the ipsilateral ventropostenor thalamic nucleus and substantia nigra, which are distant from, but connected to, the ischemic cerebral cortex, in animals with normotension. However, secondary brain damage in hypertension has not been clearly investigated. OBJECTIVE： The present study determined whether neuronal apoptosis is associated with neuronal loss in the ipsilateral ventroposterior thalamic nucleus and substantia nigra following cortical ischemia in adult hypertensive rats. Results should provide options for determining a time window for anti-apoptotic therapy. DESIGN, TIME AND SETTING： All experimental procedures in this randomized, controlled trial were conducted at the Neurological Laboratory of the First Affiliated Hospital of Sun Yat-sen University of China between October 2006 and July 2008. MATERIALS： Monoclonal primary antibodies specific to mouse anti-rat microtubule-associated protein 2 and glial fibrillary acidic protein were respectively purchased from Sigma Chemical, USA and BD Pharmingen, USA. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labeling （TUNEL） detection kits were purchased from Roche Applied Science, Switzerland and Upstate, USA, respectively. METHODS： A total of 64 male, Sprague Dawiey rats, aged 60-90 days, were equally and randomly divided into middle cerebral artery occlusion and sham surgery groups. Renovascular hypertension was established in both groups by renal artery occlusion. Right distal middle cerebral artery occlusion was performed by electrocoagulation in the middle cerebral artery occlusion group. MAIN OUTCOME MEASURES： Microtubule-associated protein 2 and glial fibrillary acidic protein were detected by immunohistochemistry, and apoptotic cells were observed by TUNEL assay. The stainings were separately detected in the ipsilateral ventroposterior thalamic nucleus and substantia nigra. RESULTS： During the 4 weeks following distal middle cerebral artery occlusion in renovascular hypertensive rats, microtubule-associated protein 2 expression gradually, but significantly, decreased （P 〈 0.05）. Expression of glial fibrillary acidic protein increased significantly in the ipsilateral ventroposterior thalamic nucleus and substantia nigra （P 〈 0.05） and reached a peak at 4 weeks. In addition, number of apoptotic cells was significantly increased in both areas compared with the sham controls （P 〈 0.05）, with a peak at 2 weeks. CONCLUSION： Results suggested that neuronal loss in the ipsilateral ventroposterior thalamic nucleus and substantia nigra following distal middle cerebral artery occlusion in hypertensive rats could be a secondary event resulting from apoptosis. The temporal apoptosis profile provides options for determining a time window for anti-apoptotic therapy at 2 weeks after stroke.

Protective effects of kidney-tonifying Chinese herbal preparation on substantia nigra neurons in a mouse model of Parkinson's disease

The Chinese herbs Herba Epimedii, Fructus Ligustri Lucidi and Rhizoma Polygonati were injected into Parkinson＇s disease mice established via intraperitoneal injection of 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine hydrochloride. The selective monoamine oxidase B inhibitor selegiline was used as a positive control drug. After successive administration for 4 weeks, Herba Epimedii could downregulate the expression of caspase-3 and increase the brain-derived neurotrophic factor level, as well as increase tyrosine hydroxylase activity in the substantia nigra of Parkinson＇s disease mouse models. Rhizoma Polygonaticould downregulate the expression of caspase-3 and FasL, and increase neural growth factor and brain-derived neurotrophic factor levels. Fructus Ligustn Lucidi could downregulate caspase-3 expression. Rhizoma Polygonati and Fructus Ligustn Lucidi did not produce obvious effects on tyrosine hydroxylase activity. Herba Epimedii and Fructus Ligustri Lucidi yielded similar effects on apoptosis-promoting factors to those elicited by selegiline. Herba Epimedii and Rhizoma Polygonati significantly increased the levels of neurotrophic factors compared with selegiline. Herba Epimedii significantly increased tyrosine hydroxylase activity compared with selegiline. It is indicated that the kidney-tonifying Chinese herbal preparation can downregulate the expression of apoptosis-promoting factors, increase neurotrophic factors levels in the substantia nigra and striatum, as well as increase tyrosine hydroxylase activity in the substantia nigra of Parkinson＇s disease mouse models, thereby exerting a stronger or similar neuroprotective effects compared with selegiline.

Dopamine and GABA Interaction in Basal Ganglia: GABA-A or GABA-B Receptor Stimulation Attenuates L-DOPA-Induced Striatal and Nigral ERK1/2 Signaling in a Rat Model of Parkinson’s Disease

Parkinson’s disease (PD) is characterized by degeneration of nigrostriatal dopamine (DA) neurons. The primary drug used to treat PD symptoms is L-DOPA, but side effects such as dyskinesias limit its use. Previous findings show that L-DOPA treatment induces extracellular signal-regulated kinase (ERK1/2), a MAP-kinase protein. γ-aminobutyric acid (GABA) is intimately involved in basal ganglia function. Our previous study using a unilaterally lesioned rat model of PD indicated that elevating GABA levels by GABA transaminase inhibitor, aminooxyacetic acid significantly attenuated L-DOPA-induced ERK phosphorylation in the striatum and substantia nigra (SN). The aim of the present study was to assess the role of GABA-A and GABA-B receptor by using a selective agonists, muscimol and baclofen respectively, on L-DOPA-induced ERK phosphorylation in the striatum and SN. Unilaterally 6-OHDA-lesioned rats were prescreened by apomorphine induced rotation test for the extent of DA loss. Lesioned rats were treated with L-DOPA alone or after muscimol or baclofen pretreatment. Appropriate control groups were used. Phospho-ERK levels, tyrosine hydroxylase (to ascertain DA loss) and substance P (an indirect marker for DA loss) levels were assessed by immunohistochemistry using coronal slices at the level of striatum and SN. L-DOPA administration induced a robust increase (>300%) in phospho-ERK1/2 levels in the striatum and SN. Muscimol as well as baclofen pretreatment attenuated the L-DOPA-induced increase in phospho-ERK1/2 levels by >60% in the striatum and SN. Muscimol and baclofen pretreatment also greatly reduced the number of L-DOPA induced phospho-ERK1/2 stained cells in the striatum as well as the contralateral rotational behavior. The present data taken together with our previous study indicate that the L-DOPA induced increase in ERK1/2 is attenuated by GABA via a GABA-A and GABA-B receptor linked mechanism. The study provides further insight into a dopamine-GABA-ERK interaction in the therapeutic and/or side effects of L-DOPA in the basal ganglia.

GABA Attenuates L-DOPA-Induced Striatal and Nigral ERK1/2 Signaling in a Rat Model of Parkinson’s Disease

L-DOPA is the primary drug used to treat Parkinson’s disease (PD) symptoms, but motor side effects limit its long term use. Previous experimental studies show that L-DOPA acts on supersensitive D1 receptors in the basal ganglia to induce extracellular signal-regulated kinases 1 and 2 (ERK1/2), a pair of MAP-kinase proteins that may be involved in induction of motor side effects. Since GABA is known to be intimately involved in basal ganglia function, we investigated whether elevating GABA levels via a GABA-transaminase (GABA-T) inhibitor affects the L-DOPA-induced ERK1/2 phosphorylation in the striatum and substantia nigra (SN) using a rat model of PD. Unilateral dopaminergic lesions of median forebrain bundle neurons were done using the neurotoxin 6-hydroxydopamine. Rats were prescreened for the extent of the lesion by apomorphine-induced rotation test. Lesioned rats were treated with aminooxyacetic acid (AOAA, a GABA-T inhibitor), L-DOPA, or in combination. Immunohistochemistry of tyrosine hydroxylase (TH, a direct indicator of dopaminergic lesion), substance P (SP, an indirect marker that decreases after lesion), and phospho-ERK1/2 was done using slices at the level of striatum and SN. Unilateral dopaminergic lesioned rats, as expected, exhibited >90% TH loss and a modest SP loss in the striatum and SN. L-DOPA alone induced a 343% and 330% increase in phospho-ERK1/2 in the striatum and SN, respectively. We report here a novel finding that pretreatment with AOAA attenuated the L-DOPA induced increase in phospho-ERK1/2 by 62% and 68% in the striatum and SN, respectively, suggesting a DA-GABA-ERK1/2 link in the therapeutic and/or side effects of L-DOPA.

不同剂量6-OHDA对小鼠多巴胺能神经元及行为的影响

目的:探讨多巴胺能神经元数量与动物运动行为之间的关系,为基于6-羟基多巴胺(6-OHDA)注射的、不同病程阶段及不同类型运动障碍的帕金森病(PD)小鼠造模提供参考依据。方法:在C57BL/6雄性小鼠单侧黑质致密部(SNc)注射不同剂量(3 g/L、6 g/L和12 g/L)6-OHDA诱导病变,构建不同损伤程度的PD小鼠,从而模拟人类帕金森病的不同进展阶段(早期、中期和晚期)。在术后第14天,通过转棒实验、爬杆测试、平衡木穿越实验、旷场测试、圆筒实验及步态分析评估小鼠模型的行为缺陷。此外,通过免疫荧光染色定量检测SNc中酪氨酸羟化酶(TH)阳性神经元数量,以及纹状体尾壳核(CPu)中TH+的多巴胺能神经元末梢的密度,以评估小鼠脑组织损伤情况。结果:与对照组相比,注射6-OHDA后,高剂量组和中剂量组的SNc多巴胺能神经元数量显著减少(P<0.05),且损伤呈剂量依赖性(Spearman相关,P<0.01)。同时,高剂量组(P<0.01)和中剂量组(P<0.05)的CPu多巴胺能神经末梢也显著减少。行为学测试显示,高剂量组小鼠的运动协调性和后肢平衡能力严重受损,表现为转棒测试时间缩短、步态异常及圆筒测试中前肢使用不对称等。而中剂量组和低剂量组的小鼠肢体协调性轻度下降,但自主运动能力和步态指标未受明显影响。结论:(1)SNc多巴胺能神经元损伤程度呈剂量依赖效应,即剂量越高,损伤程度越严重;同时,运动障碍与多巴胺能神经元损伤程度并不同步,仅高剂量组才出现明显的运动障碍;(2)基于高剂量6-OHDA的小鼠模型可作为研究PD及运动障碍的有效动物模型;(3)基于低剂量和中剂量6-OHDA的小鼠模型可用于研究PD运动症状出现前期的发病机制。

Promising drug targets and associated therapeutic interventions in Parkinson's disease

Parkinson's disease(PD) is one of the most debilitating brain diseases. Despite the availability of symptomatic treatments, response towards the health of PD patients remains scarce. To fulfil the medical needs of the PD patients, an efficacious and etiological treatment is required. In this review, we have compiled the information covering limitations of current therapeutic options in PD, novel drug targets for PD, and finally, the role of some critical beneficial natural products to control the progression of PD.

Arbutin effectively ameliorates the symptoms of Parkinson’s disease:the role of adenosine receptors and cyclic adenosine monophosphate

An antagonistic communication exists between adenosinergic and dopaminergic signaling in the basal ganglia,which suggests that the suppression of adenosine A2A receptors-cyclic adenosine monophosphate pathway may be able to restore the disrupted dopamine transmission that results in motor symptoms in Parkinson’s disease(PD).Arbutin is a natural glycoside that possesses antioxidant,antiinflammatory,and neuroprotective properties.The purpose of this study was to investigate whether arbutin could ameliorate the symptoms of PD and to examine the underlying mechanism.In this study,Swiss albino mouse models of PD were established by the intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine for 4 successive days,with the concurrent intraperitoneal administration of arbutin(50 and 100 mg/kg)for 7 days.The results showed that arbutin significantly reduced lipid peroxidation,total nitrite levels,and inflammation in the substantia nigra and striatum of PD mouse models.In addition,arbutin decreased the activity of endogenous antioxidants,reduced the levels of dopamine,3,4-dihydroxyphenylacetic acid,homovanillic acid,andγ-aminobutyric acid,and minimized neurodegeneration in the striatum.Arbutin also reduced the abnormal performance of PD mouse models in the open field test,bar test,pole test,and rotarod test.The therapeutic efficacy of arbutin was similar to that of madopar.The intraperitoneal injection of the A2AR agonist CGS21680(0.5 mg/kg)attenuated the therapeutic effects of arbutin,whereas the intraperitoneal injection of forskolin(3 mg/kg)enhanced arbutin-mediated improvements.These findings suggest that arbutin can improve the performance of PD mouse models by inhibiting the function of the A2AR and enhancing the effects of cyclic adenosine monophosphate.This study was approved by the Institutional Animal Ethics Committee(1616/PO/Re/S/12/CPCSEA)on November 17,2019(approval No.IAEC/2019/010).

表皮生长因子改善老年大鼠自发运动活性衰退伴随黑质多巴胺含量升高

目的:探讨表皮生长因子(EGF)对老年大鼠自发运动活性及黑质-纹状体多巴胺体系(NSDAs)的影响。方法:经皮给予健康24月龄大鼠EGF(0.15 mg/mL)7 d,通过旷场试验检测大鼠的自发运动活性;通过实时定量PCR和免疫印迹检测NSDAs中酪氨酸羟化酶(TH)和多巴胺转运体(DAT)的表达;通过液相色谱-串联质谱分析NSDAs中多巴胺(DA)的含量变化。结果:老年组大鼠自发运动活性、NSDAs中TH和DAT的表达以及DA的含量均较成年大鼠显著下降。EGF处理后,老年大鼠自发运动活性、NSDAs中TH和DAT的表达以及黑质(而非纹状体)DA的含量显著上升,但未达到成年大鼠水平。结论:EGF改善老年大鼠自发运动活性衰退伴随黑质DA含量升高。

Activation and polarization of striatal microglia and astrocytes are involved in bradykinesia and allodynia in early-stage parkinsonian mice

In addition to the cardinal motor symptoms,pain is a major non-motor symptom of Parkinson's disease(PD).Neuroinflammation in the substantia nigra pars compacta and dorsal striatum is involved in neurodegeneration in PD.But the polarization of microglia and astrocytes in the dorsal striatum and their contribution to motor deficits and hyperalgesia in PD have not been characterized.In the present study,we observed that hemiparkinsonian mice established by unilateral 6-OHDA injection in the medial forebrain bundle exhibited motor deficits and mechanical allodynia.In these mice,both microglia and astrocytes in the dorsal striatum were activated and polarized to M1/M2 microglia and A1/A2 astrocytes as genes specific to these cells were upregulated.These effects peaked 7 days after 6-OHDA injection.Meanwhile,striatal astrocytes in parkinsonian mice also displayed hyperpolarized membrane potentials,enhanced voltage-gated potassium currents,and dysfunction in inwardly rectifying potassium channels and glutamate transporters.Systemic administration of minocycline,a microglia inhibitor,attenuated the expression of genes specific to M1 microglia and A1 astrocytes in the dorsal striatum(but not those specific to M2 microglia and A2 astrocytes),attenuated the damage in the nigrostriatal dopaminergic system,and alleviated the motor deficits and mechanical allodynia in parkinsonian mice.By contrast,local administration of minocycline into the dorsal striatum of parkinsonian mice mitigated only hyperalgesia.This study suggests that M1 microglia and A1 astrocytes in the dorsal striatum may play important roles in the development of pathophysiology underlying hyperalgesia in the early stages of PD.

益智仁挥发油对帕金森病模型小鼠脑内纹状体和黑质损伤的影响

目的观察益智仁挥发油(VOA)脑保护作用的机制。方法C57BL小鼠随机分为正常对照组、帕金森病(PD)模型组、司来吉兰10mg·kg-1阳性对照组,VOA0.278,0.833和2.5mL·kg-1组。除正常对照和模型组外,各给药组分别预先ig给予VOA或司来吉兰,每天1次,连续12d。第6天开始,除正常对照组外,各组ip给予1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)30mg·kg-1,每天1次,连续7d,制备PD小鼠模型。末次给药后第2天处死小鼠,荧光分光光度法测定小鼠脑内纹状体高香草酸(HVA)和5-羟色胺(5-HT)含量,比色法检测纹状体内超氧化物岐化酶(SOD)活性、还原型谷胱甘肽(GSH)和丙二醛(MDA)含量,SABC免疫组化法测定黑质致密部神经细胞内Bcl-2和天冬氨酸半胱氨酸蛋白酶3(caspase 3)的表达。结果与正常对照组比较,模型组小鼠脑内纹状体HVA,5-HT和GSH含量显著下降,SOD活性下降,MDA含量明显升高;黑质致密部Bcl-2和caspase 3免疫阳性细胞数增加。预先给予VOA0.833和2.5mL·kg-1可明显抑制MPTP所诱导的HVA和GSH含量及SOD活性的降低,并抑制MDA含量升高,2.5mL·kg-1可明显抑制5-HT含量降低。VOA0.833和2.5mL·kg-1可增加黑质致密部Bcl-2免疫阳性细胞数,减少caspase 3免疫阳性细胞数。VOA2.5mL·kg-1的作用与司来吉兰的作用相近。结论VOA的脑保护作用可能与其增加脑内纹状体单胺类神经递质释放、减轻氧化应激反应以及减少黑质致密部神经元凋亡等因素有关。

偏侧帕金森病模型猴脑黑质和纹状体的超微结构变化

目的 :观察偏侧帕金森病 (Parkinson sdisease,PD)模型猴脑黑质和纹状体的超微结构变化 .方法 :对 2只恒河猴经右侧颈内动脉注射 1 甲基 4 苯基 1 ,2 ,3,6 四氢吡啶 (MPTP)制备成偏侧PD模型猴后 ,应用透射电镜观察黑质和纹状体神经元和神经胶质细胞的超微结构变化 .结果 :偏侧PD模型猴MPTP注射侧黑质和纹状体的超微结构均呈病理性改变 :神经元细胞线粒体肿胀和部分空泡化、粗面内质网和高尔基复合体囊腔扩张、脂褐素增多 ,星形胶质细胞呈增生性改变 .MPTP注射侧对侧黑质和纹状体的超微结构未发现异常变化 .结论 :黑质和纹状体的超微结构的病理性变化从而导致黑质 纹状体 黑质环路功能障碍 。

1H-MRS检测早期帕金森病纹状体、黑质的功能代谢

目的探讨1H-MRS检测早期帕金森病(PD)患者纹状体和黑质代谢变化的可能性。材料与方法 44例经临床确诊的双侧肢体症状不伴痴呆的早期PD患者纳入研究,32名年龄、性别等相匹配的健康志愿者作为对照组,两组均进行纹状体单体素1H-MRS及黑质多体素1H-MRS检查。PD患者33例获得纹状体MRS谱线,32例获得黑质MRS谱线;志愿者31名获得双侧纹状体MRS谱线,28名获得双侧黑质谱线。测量豆状核、黑质区域NAA、Cho、Cr及各参数比值,并进行比较分析。结果 PD组及对照组左右侧纹状体、黑质NAA、Cho、Cr各参数比值的差异均无统计学意义(P值均>0.05)。PD组纹状体NAA/Cr较对照组降低(P<0.05),其余各参数比值与对照组无明显差异(P>0.05);黑质各参数值两组间的差异无统计学意义(P值均>0.05)。结论 1H-MRS能检测双侧症状不伴痴呆的早期PD患者纹状体代谢异常,有助于早期PD的诊断。

帕金森病模型大鼠脑内多巴胺与铁含量的关系

实验采用原子吸收分光光度法、快速周期伏安法、高效液相电化学检测等方法 ,研究以 6 羟基多巴( 6 OHDA)制备的帕金森病 (PD)模型大鼠黑质内铁含量的变化 ,铁对多巴胺 (DA)能神经元的直接毒性作用以及铁离子螯合剂甲磺酸去铁胺的神经保护作用。结果发现 :( 1)PD大鼠损毁侧黑质内铁含量为非标准PD大鼠的 3倍左右 ;( 2 )PD大鼠损毁侧纹状体内铁含量无明显改变 ;( 3 )单纯注射 6 OHDA的大鼠其损毁侧纹状体 (CPu)DA的释放量和含量均明显降低 ;( 4 )侧脑室预先注射甲磺酸去铁胺 ,再重复上述实验 ,损毁侧CPuDA释放量和含量均无明显改变 ;( 5 )单侧黑质内注射 4 0 μgFeCl3后 ,大鼠损毁侧CPu内DA释放量和含量显著降低。上述结果提示 ,6 OHDA可导致CPuDA释放量及含量减少 ,此过程有铁的参与。由于铁可导致DA神经元死亡 ,因此铁含量的增加可能是DA含量减少的原因之一 。

人参再造丸联合美多巴对帕金森病模型大鼠黑质纹状体TH阳性神经元的影响

目的 :观察人参再造丸联合美多巴对帕金森病模型大鼠黑质纹状体TH阳性神经元的影响。方法 :PD鼠 80只 ,随机分为 4组 :对照组、美多巴组、人参再造丸组、人参再造丸联合美多巴组。于喂养 4个月后取黑质纹状体组织免疫组化染色 ,检测TH阳性神经元的分布、密度。结果 :美多巴组黑质TH阳性神经细胞及纹状体TH阳性终末较生理盐水组明显减少 ,而人参再造丸组略有增多达5 %～ 8% ,联合组增多较显著达 2 0 %～ 2 5 %。结论 :人参再造丸对PD大鼠黑质纹状体毒性作用较轻 ,人参再造丸联合美多巴可改善TH阳性神经元的病理改变。