Anti-apoptotic effect of Shudipingchan granule in the substantia nigra of rat models of Parkinson＇s disease

Levodopa is the gold-standard treatment for Parkinson's disease. However, although it alleviates the clinical symptoms, it cannot delay the progressive apoptosis of dopaminergic neurons or prevent motor complications in the long term. In the present study, we investigated the effect of Shudipingchan granule on neuronal apoptosis in a rat model of Parkinson's disease, established by injecting 6-hydroxydopamine into the substantia nigra pars compacta and ventral tegmental area. We then administered levodopa(20 mg/kg intraperitoneally, twice daily) with or without Shudipingchan granule(7.5 m L/kg intragastrically, twice daily), for 4 weeks. The long-term use of levodopa accelerated apoptosis of nigral cells and worsened behavioral symptoms by activating the extracellular signal-regulated kinase pathway and downstream apoptotic factors. However, administration of Shudipingchan granule with levodopa reduced expression of phosphorylated extracellular signal-regulated kinase 1/2 and Bax, increased tyrosine hydroxylase and Bcl-2, reduced apoptosis in the substantia nigra, and markedly improved dyskinesia. These findings suggest that Shudipingchan granule suppresses neuronal apoptosis by inhibiting the hyperphosphorylation of extracellular signal-regulated kinase and downregulating expression of anti-apoptotic genes. Shudipingchan granule, used in combination with levodopa, can effectively reduce the symptoms of Parkinson's disease.

Experimental Study of Serum Substantia Nigra Neuron Autoantibody and Its Effect in Parkinson Disease Patients

To investigate the serum substantia nigra neuron autoantibody and its effect in the patients with Parkinson disease (PD), substantia nigra slices and a rat model of injection of serum from PD patients in unilateral side substantia nigra were applied. The results showed that the positive rate of substantia nigra neuron autoantibody in PD patients was significantly higher than in the healthy control group (36.67 % vs 6.67 %, P <0.01), but no significant difference was found between PD group and myasthenia gravis (MG) group (26.67 %, P >0.05). The sera from PD patients positive for substantia nigra neuron autoantibody could decrease the number of the dopaminergic neurons more seriously than those from MG and the healthy once respectively (both P <0.01). The results suggested that the immunological mechanism might partly play a role in the development of PD.

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 7th, 14th, 21st and 28th 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 14th and 28th 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 7th, 14th, 21st and 28th days, Nissl staining results of SN neurons and immunohistochemical staining results of CB and TH antibodies; ② On the 14th and 28th 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. ① Nissl staining results: On the 7th day of 6-OHDA injection, most neuronal somas on right SN pars compacta were shown as deep pycnosis or lysis breakage; on the 14th and 21st days, amount of neurons was decreased remarkably; on the 28th 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 7th day after 6-OHDA injection; on the 14th day, the amount was higher in experimental group than that in both control groups (P < 0.01) and was decreased till the 21st day, but it was still higher than that in the two control groups (P < 0.05); on the 28th 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 7th 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 14th, 21st and 28th days, positive TH neurons decreased 37%, 46% and 64%, respectively. ③ Western blot results: On the 14th 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 28th 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.

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 Polygonati could downregulate the expression of caspase-3 and FasL, and increase neural growth factor and brain-derived neurotrophic factor levels. Fructus Ligustri Lucidi could downregulate caspase-3 expression. Rhizoma Polygonati and Fructus Ligustri 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.

Enriched environment elevates expression of growth associated protein-43 in the substantia nigra of SAMP8 mice

An enriched environment protects dopaminergic neurons from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced neuronal injury, but the underlying mechanism for this is not clear. Growth associated protein-43(GAP-43) is closely associated with neurite outgrowth and axon regeneration during neural development. We speculate that an enriched environment can reduce damage to dopaminergic neurons by affecting the expression of GAP-43. This study is designed to test this hypothesis. Three-month-old female senescence-accelerated mouse prone 8(SAMP8) mice were housed for 3 months in an enriched environment or a standard environment. These mice were then subcutaneously injected in the abdomen with 14 mg/kg MPTP four times at 2-hour intervals. Morris water maze testing demonstrated that learning and memory abilities were better in the enriched environment group than in the standard environment group. Reverse-transcription polymerase chain reaction, immunohistochemistry and western blot assays showed that m RNA and protein levels of GAP-43 in the substantia nigra were higher after MPTP application in the enriched environment group compared with the standard environment group. These findings indicate that an enriched environment can increase GAP-43 expression in SAMP8 mice. The upregulation of GAP-43 may be a mechanism by which an enriched environment protects against MPTP-induced neuronal damage.

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.

Differential protein expression in substantia nigra induced by 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine in a mouse model of chronic Parkinson’s disease

BACKGROUND: To date, a complete protein expression profile of the midbrain substantia nigra in a mouse model of chronic Parkinson’s disease, induced by 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP), does not exist. In addition, there are no reports of analysis of differential protein expression. OBJECTIVE: To separate and evaluate MPTP-induced differential protein expression through the use of proteomics in the substantia nigra of a mouse model of chronic Parkinson’s disease. DESIGN: Randomized controlled animal study. SETTING: Department of Neurology, the First Affiliated Hospital, Chongqing Medical University. MATERIALS: Sixteen 8–10-week old, healthy, male, C57BL mice, weighing 20–25 g, and of clean grade, were provided by the Experimental Animal Center of Chongqing Medical University. The experimental animals were disposed according to ethical criteria. MPTP was provided by Sigma Company, USA; Pdquest 2D image analysis software and gelatum/irradiance image analysis system (ChemiDoc XRS) by Bio-Rad, USA; and Voyager DE-PROMALDI-TOF-MS mass spectroscopy analyzer by ABI Company, USA. METHODS: This study was performed in Chongqing Neurological Laboratory between November 2006 and July 2007. Mice were randomly divided into model and control groups, with 8 mice in each group. Mice in the model group were received a subcutaneous injection of MPTP (25 mg/kg), twice a week, for five successive weeks, to establish a chronic Parkinson’s disease model. Mice in the control group received the same volume of a subcutaneous saline injection at the same time points. Mice were sacrificed by anesthesia to rapidly obtain the midbrain for protein separation of the substantia nigra. MAIN OUTCOME MEASURES: (1) 2-ED handbook (Bio-Rad Company) was referenced for two-dimensional electrophoresis. (2) PDQUEST8.0 analytical electrophoresis pattern was adopted to evaluate differential protein expression. (3) Peptide mass finger print map and data were retrieved on http://www.prospector.ucsf.edu to compare differential substantia nigral protein expression in the two groups. RESULTS: Two-dimensional gel electrophoresis of substantia nigra tissue indicated that there were 33 differential protein expressions between the two groups. Three new proteins were evaluated, including α-enolase, which exhibited regulated expression, tumor necrosis factor ligand superfamily member 4, and cyclin-dependent kinase inhibitor 1B. CONCLUSION: There are three proteins that exhibit differential expression in the substantia nigra- α-enolase, tumor necrosis factor ligand superfamily member 4, and cyclin-dependent kinase inhibitor 1B.

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 ventroposterior 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 Dawley 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.

Effects of Zhichan powder on signal transduction and apoptosis-associated gene expression in the substantia nigra of Parkinson's disease rats

Previous studies have shown that Zhichan powder elevated immunity and suppressed oxidation in mice. Rat models of Parkinson's disease were induced by stereotaxically injecting 6-hydroxydopamine into the substantia nigra. The rat models were intragastrically treated with Zhichan powder, which is composed of milkvetch root, ginseng, bunge swallowwort root, himalayan teasel root, Magnolia officinalis, Ligustrum lucidum Ait. and szechwan lovage rhizome. Immunohistochemistry and reverse transcription-PCR results demonstrated that mRNA and protein expression of tumor necrosis factor receptor 1, Fas, caspase-8, cytochrome C, Bax, caspase-3, and p53 significantly increased, but Bcl-2 expression significantly decreased in the substantia nigra of rats with Parkinson's disease. Following Zhichan powder administration, mRNA and protein expression of tumor necrosis factor receptor 1, Fas, caspase-8, cytochrome C, Bax, caspase-3, and p53 diminished, but Bcl-2 expression increased in the rat substantia nigra. These results indicate that Zhichan powder regulates signal transduction protein expression, inhibits apoptosis, and exerts therapeutic effects on Parkinson's disease.

N-cadherin expression in the midbrain substantia nigra of perinatal rats

BACKGROUND: Cellular adhesion molecule mediates the effects of glial cell line-derived neurotrophic factor in dopaminergic neurons during nervous system development. It is assumed that cellular adhesion molecule plays an important role in dopaminergic neuron development. OBJECTIVE: To investigate N-cadherin expression in the midbrain substantia nigra during rat development. DESIGN, TIME AND SETTING: The developmental biology, controlled study was performed at the Laboratory of Research Center of Neurobiology, Xuzhou Medical College, China from April to October 2007. MATERIALS: Sprague Dawley rats (embryonic days 16, 18, and 20, as well as postnatal days 1, 3, 7, 14, and 21) were selected for this study. N-cadherin antibody was purchased from Santa Cruz, USA. METHODS: N-cadherin expression in the midbrain substantia nigra of perinatal rats was detected using reverse transcription polymerase chain reaction, Western blot, and immunohistochemistry methods. N-cadherin-positive cells were counted. MAIN OUTCOME MEASURES: N-cadherin mRNA, protein, and positive cells in the rat midbrain substantia nigra were quantified. RESULTS: The results of reverse transcription polymerase chain reaction and Western blot demonstrated that altered N-cadherin mRNA levels were similar to protein levels in the midbrain substantia nigra. N-cadherin mRNA and protein expression was low in the midbrain substantia nigra of embryonic day 16 rats, but gradually increased, and reached a peak at postnatal day 1. N-cadherin mRNA and protein levels were still high at postnatal days 3 and 7, but significantly decreased at postnatal day 14. There was no significant difference in N-cadherin mRNA and protein expression between postnatal days 14 and 21 (P > 0.05). The immunohistochemistry results demonstrated that there was no significant difference in the quantity of N-cadherin-positive cells per area in rats from embryonic day 16 to postnatal day 7 (P > 0.05). The quantity of N-cadherin-positive cells per area was significantly decreased in rats at postnatal day 14. There was no significant difference in the number of N-cadherin-positive cells per area between postnatal days 14 and 21 (P > 0.05). CONCLUSION: N-cadherin expression was reduced during embryonic stages, but reached a peak at postnatal days 1-7, and then gradually decreased in the rat midbrain substantia nigra.

Directional induction of dopaminergic neurons from neural stem cells using substantia nigra homogenates and basic fibroblast growth factor

To date, complex components of available reagents have been used for directional induction of neural stem cells into dopaminergic neurons, resulting in a poor ability to repeat experiments. This study sought to investigate whether a homogenate of the substantia nigra of adult rats and/or basic fibroblast growth factor could directionally induce neural stem cells derived from the subventricular zone of embryonic rats to differentiate into dopaminergic neurons. Tyrosine hydroxylase-positive cells were observed exclusively after induction with the homogenate supernatant of the substantia nigra from adult rats and basic fibroblast growth factor for 48 hours in vitro. However, in the groups treated with homogenate supernatant or basic fibroblast growth factor alone, tyrosine hydroxylase expression was not observed. Moreover, the content of dopamine in the culture medium of subventricular zone neurons was significantly increased at 48 hours after induction with the homogenate supernatant of the substantia nigra from adult rats and basic fibroblast growth factor. Experimental findings indicate that the homogenate supernatant of the substantia nigra from adult rats and basic fibroblast growth factor could directionally induce neural stem cells derived from the subventricular zone of embryonic rats to differentiate into dopaminergic neurons in the substantia nigra with the ability to secrete dopamine.

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.

The role of substantia nigra sonography in the differentiation of Parkinson’s disease and multiple system atrophy

Background:The differential diagnosis of Parkinson’s disease(PD)and multiple system atrophy(MSA)remains a challenge,especially in the early stage.Here,we assessed the value of transcranial sonography(TCS)to discriminate non-tremor dominant(non-TD)PD from MSA with predominant parkinsonism(MSA-P).Methods:Eighty-six MSA-P patients and 147 age and gender-matched non-TD PD patients who had appropriate temporal acoustic bone windows were included in this study.All the patients were followed up for at least 2 years to confirm the initial diagnosis.Patients with at least one substantia nigra(SN)echogenic size≥18 mm^(2) were classified as hyperechogenic,those with at least one SN echogenic size≥25 mm^(2) was defined as markedly hyperechogenic.Results:The frequency of SN hyperechogenicity in non-TD PD patients was significantly higher than that in MSA-P patients(74.1%vs.38.4%,p<0.001).SN hyperechogenicity discriminated non-TD PD from MSA-P with sensitivity of 74.1%,specificity of 61.6%,and positive predictive value of 76.8%.If marked SN hyperechogenicity was used as the cutoff value(≥25 mm^(2)),the sensitivity decreased to 46.3%,but the specificity and positive predictive value increased to 80.2 and 80.0%.Additionally,in those patients with SN hyperechogenicity,positive correlation between SN hyperechogenicity area and disease duration was found in non-TD PD rather than in MSA-P patients.In this context,among early-stage patients with disease duration≤3 years,the sensitivity,specificity and positive predictive value of SN hyperechogenicity further declined to 69.8%,52.2%,and 66.7%,respectively.Conclusions:TCS could help discriminate non-TD PD from MSA-P in a certain extent,but the limitation was also obvious with relatively low specificity,especially in the early stage.

Dyskinesia is Closely Associated with Synchronization of Theta Oscillatory Activity Between the Substantia Nigra Pars Reticulata and Motor Cortex in the Off L-dopa State in Rats

Excessive theta(θ)frequency oscillation and synchronization in the basal ganglia(BG)has been reported in elderly parkinsonian patients and animal models of levodopa(L-dopa)-induced dyskinesia(LID),particularly theθoscillation recorded during periods when L-dopa is withdrawn(the off L-dopa state).To gain insight into processes underlying this activity,we explored the relationship between primary motor cortex(M1)oscillatory activity and BG output in LID.We recorded local field potentials in the substantia nigra pars reticulata(SNr)and M1 of awake,inattentive resting rats before and after L-dopa priming in Sham control,Parkinson disease model,and LID model groups.We found that chronic L-dopa increasedθsynchronization and information flow between the SNr and M1 in off L-dopa state LID rats,with a SNr-to-M1 flow directionality.Compared with the on state,θoscillational activity(θsynchronization and informationflow)during the off state were more closely associated with abnormal involuntary movements.Our findings indicate thatθoscillation in M1 may be consequent to abnormal synchronous discharges in the BG and support the notion that M1θoscillation may participate in the induction of dyskinesia.

Electrophysiological Characterization of Substantia Nigra Pars Reticulata in Anesthetized Rats

The substantia nigra pars reticulate(SNr),which plays a pivotal role in motor control,is the key structure in integrating information for cortex,basal ganglia and thalamus.Abnormal gait and posture deficits can be reversed by SNr deep brain stimulation(DBS)in certain Parkinson’s disease cases.However,functional characterization of SNr,which is the key for the optimization of DBS effect,remains elusive.In current study,we recorded extracellular single unit in SNr of urethane anesthetized rats.We have found that urethane can induce slow delta and theta oscillations in SNr local field potential.The high gamma oscillation observed is positively correlated with the occurrence of action potential.The putative GABAergic neurons have a mean firing rate of(20.82±2.04)Hz,of which 65.2%display a regular firing pattern and 34.8%show irregular firing.Our results demonstrated the heterogeneous property of SNr and provided possible theoretical basis for promoting the next generation of DBS electrode design and optimization of clinical DBS parameters.

天智颗粒对帕金森病小鼠模型黑质和脊髓多巴胺能神经元的影响

目的 探讨天智颗粒对帕金森病(PD)小鼠模型脑黑质和脊髓多巴胺(DA)能神经元的影响。方法 2022年9月采用1-甲基-4-苯基-1,2,3,6-四氢吡啶25 mg/(kg·d)腹腔注射5 d的方法构建PD小鼠模型,采用随机数字表法分为模型组和天智颗粒5、2、1 g/kg组,每组10只,另取10只小鼠作为正常对照组。灌胃给药2周后比较各组小鼠行为学变化、中脑黑质和脊髓DA能神经元存活数量及形态变化、神经元内酪氨酸羟化酶阳性表达情况等。结果 与正常对照组比较,模型组小鼠悬挂能力下降、游泳时间缩短,经天智颗粒干预后可有效提高小鼠悬挂能力,延长游泳时间,黑质和脊髓灰质前角DA能神经元数量和神经元内酪氨酸羟化酶阳性表达均明显减少,经天智颗粒5、2 g/kg干预后小鼠黑质和脊髓DA能神经元检测指标明显改善,差异均有统计学意义(P<0.05)。结论 天智颗粒可改善PD小鼠行为学,提高中脑黑质和脊髓部位DA能神经元及突起的存活数目,增加中枢神经系统内DA的含量,表明天智颗粒对黑质和脊髓灰质前角多巴能神经元具有保护作用。

黄芪提取物对帕金森病小鼠黑质区白介素-17通路的影响

目的:探究黄芪提取物干预白介素-17(IL-17)信号通路治疗帕金森病(PD)作用机制。方法:将30只雄性C57BL/6小鼠均分为五组。除对照组之外均采用MPTP诱导PD模型,建模成功后,低、中、高浓度黄芪组分别以50、100、200 mg/kg黄芪提取物持续灌胃14 d,模型组和对照组采用等量0.9%氯化钠溶液灌胃。灌胃后结束后采用转棍实验和爬杆实验评估各组小鼠行为表现。免疫组化法测定各组脑黑质致密区(SNpc)酪氨酸羟化酶(TH)和Th17细胞数目;Western blot测定纹状体区IL-17、抗肿瘤坏死因子受体相关因子6(TRAF6)、核因子-κB(NF-κB)、白介素-1β(IL-1β)、白介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、环氧合酶-2(COX-2)蛋白相对表达量。结果:与对照组比较,模型组和各浓度黄芪组小鼠转棍掉落潜伏期明显缩短,爬杆实验头向下时间(T1)、由杆顶爬至杆底所用时间(T-LA)明显延长,SNpc区TH表达水平下降,Th17细胞数目增多,纹状体区IL-17、TRAF-6、NF-κB、IL-1β、IL-6、TNF-α、COX-2蛋白相对表达水平明显升高(均P<0.05)。与模型组比较,各浓度黄芪组小鼠转棍掉落潜伏期明显延长,爬杆实验T1和T-LA明显缩短,SNpc区TH表达水平升高,Th17细胞数目减少,纹状体区IL-17、TRAF-6、NF-κB、IL-1β、IL-6、TNF-α、COX-2蛋白相对表达水平明显下降(均P<0.05),且与黄芪提取物浓度呈正相关。结论:黄芪提取物能有效改善PD模型小鼠转棍和爬杆活动能力,保护SNpc区TH阳性神经元,其机制可能与抑制IL-17/TRAF-6/NF-κB信号通路,减少多巴胺神经元炎症性损伤凋亡有关。

神经黑色素敏感磁共振成像在帕金森病中的应用进展

神经黑色素敏感MRI(neuromelanin-sensitive MRI,NM-MRI)是一种无创可视化脑内神经黑色素(neuromelanin,NM)含量变化的新兴技术,对颅内NM的变化具有敏感性。帕金森病(Parkinson’s disease,PD)是常见的神经退行性疾病,病理表现为黑质中含NM的多巴胺神经元损失,NM减少。NM-MRI能够检测到颅内NM含量变化,间接提示多巴胺神经元活性状态。NM-MRI在PD诊断中的作用不可忽视,因此,本文就近年来NM-MRI在PD诊断中的研究进展进行综述,为后续相关研究提供参考资料,期待随着NM-MRI技术的成熟,早日成为辅助临床PD诊断的影像学工具,同时对PD病理机制研究作出贡献。

Nigral dopaminergic neuron replenishment in adult mice through VE-cadherin-expressing neural progenitor cells

The function of dopaminergic neurons in the substantia nigra is of central importance to the coordination of movement by the brain’s basal ganglia circuitry.This is evidenced by the loss of these neurons,resulting in the cardinal motor deficits associated with Parkinson’s disease.In order to fully understand the physiology of these key neurons and develop potential therapies for their loss,it is essential to determine if and how dopaminergic neurons are replenished in the adult brain.Recent work has presented evidence for adult neurogenesis of these neurons by Nestin^+/Sox2~–neural progenitor cells.We sought to further validate this finding and explore a potential atypical origin for these progenitor cells.Since neural progenitor cells have a proximal association with the vasculature of the brain and subsets of endothelial cells are Nestin^+,we hypothesized that dopaminergic neural progenitors might share a common cell lineage.Therefore,we employed a VE-cadherin promoter-driven CRE^(ERT2):TH^(lox)/TH^(lox) transgenic mouse line to ablate the tyrosine hydroxylase gene from endothelial cells in adult animals.After 26 weeks,but not 13 weeks,following the genetic blockade of tyrosine hydroxylase expression in VE-cadherin^+cells,we observed a significant reduction in tyrosine hydroxylase^+neurons in the substantia nigra.The results from this genetic lineage tracing study suggest that dopaminergic neurons are replenished in adult mice by a VE-cadherin^+progenitor cell population potentially arising from an endothelial lineage.