RESUMO
The present study investigated the effects of interleukin (IL)-4 on striatal neurons in lipopolysaccharide (LPS)-injected rat striatum in vivo. Either LPS or PBS as a control was unilaterally injected into the striatum, and brain tissues were processed for immunohistochemical and Nissl staining or for hydroethidine histochemistry at the indicated time points after LPS injection. Analysis by NeuN and Nissl immunohistochemical staining showed a significant loss of striatal neurons at 1, 3, and 7 days post LPS. In parallel, IL-4 immunoreactivity was upregulated as early as 1 day, reached a peak at 3 days, and was sustained up to 7 days post LPS. Increased levels of IL-4 immunoreactivity were exclusively detected in microglia/macrophages, but not in neurons nor astrocytes. The neutralizing antibody (NA) for IL-4 significantly protects striatal neurons against LPS-induced neurotoxicity in vivo. Accompanying neuroprotection, IL-4NA inhibited activation of microglia/macrophages, production of reactive oxygen species (ROS), ROS-derived oxidative damage and nitrosative stress, and produced polarization of microglia/macrophages shifted from M1 to M2. These results suggest that endogenous IL-4 expressed in LPS-activated microglia/macrophages contributes to striatal neurodegeneration in which oxidative/nitrosative stress and M1/M2 polarization are implicated.
Assuntos
Interleucina-4/metabolismo , Lipopolissacarídeos/efeitos adversos , Microglia/imunologia , Microglia/metabolismo , Estresse Oxidativo , Degeneração Estriatonigral/etiologia , Degeneração Estriatonigral/metabolismo , Animais , Biomarcadores , Corpo Estriado/metabolismo , Corpo Estriado/patologia , Modelos Animais de Doenças , Suscetibilidade a Doenças , Feminino , Imuno-Histoquímica , Lipopolissacarídeos/imunologia , Ativação de Macrófagos/imunologia , Macrófagos/imunologia , Macrófagos/metabolismo , Microglia/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ratos , Degeneração Estriatonigral/patologiaRESUMO
INTRODUCTION: Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the loss of dopaminergic neurons as well as the presence of proteinaceous inclusions named Lewy bodies. α-synuclein (α-syn) is a major constituent of Lewy bodies, and the first disease-causing protein characterized in PD. Several α-syn-based animal models of PD have been developed to investigate the pathophysiology of PD, but none of them recapitulate the full picture of the disease. Ageing is the most compelling and major risk factor for developing PD but its impact on α-syn toxicity remains however unexplored. In this study, we developed and exploited a recombinant adeno-associated viral (AAV) vector of serotype 9 overexpressing mutated α-syn to elucidate the influence of ageing on the dynamics of PD-related neurodegeneration associated with α-syn pathology in different mammalian species. RESULTS: Identical AAV pseudotype 2/9 vectors carrying the DNA for human mutant p.A53T α-syn were injected into the substantia nigra to induce neurodegeneration and synucleinopathy in mice, rats and monkeys. Rats were used first to validate the ability of this serotype to replicate α-syn pathology and second to investigate the relationship between the kinetics of α-syn-induced nigrostriatal degeneration and the progressive onset of motor dysfunctions, strikingly reminiscent of the impairments observed in PD patients. In mice, AAV2/9-hα-syn injection into the substantia nigra was associated with accumulation of α-syn and phosphorylated hα-syn, regardless of mouse strain. However, phenotypic mutants with either accelerated senescence or resistance to senescence did not display differential susceptibility to hα-syn overexpression. Of note, p-α-syn levels correlated with nigrostriatal degeneration in mice. In monkeys, hα-syn-induced degeneration of the nigrostriatal pathway was not affected by the age of the animals. Unlike mice, monkeys did not exhibit correlations between levels of phosphorylated α-syn and neurodegeneration. CONCLUSIONS: In conclusion, AAV2/9-mediated hα-syn induces robust nigrostriatal neurodegeneration in mice, rats and monkeys, allowing translational comparisons among species. Ageing, however, neither exacerbated nigrostriatal neurodegeneration nor α-syn pathology per se. Our unprecedented multi-species investigation thus favours the multiple-hit hypothesis for PD wherein ageing would merely be an aggravating, additive, factor superimposed upon an independent disease process.
Assuntos
Envelhecimento , Intoxicação por MPTP/patologia , Degeneração Estriatonigral/patologia , Substância Negra/metabolismo , alfa-Sinucleína/metabolismo , Animais , Fenômenos Biomecânicos , Callithrix , Modelos Animais de Doenças , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Humanos , Intoxicação por MPTP/induzido quimicamente , Camundongos , Atividade Motora , Análise de Componente Principal , Desempenho Psicomotor/fisiologia , Ratos , Degeneração Estriatonigral/etiologia , Fatores de Tempo , Transdução Genética , Tirosina 3-Mono-Oxigenase/metabolismoRESUMO
Magnetic resonance imaging (MRI) can be useful not only for the diagnosis of multiple system atrophy (MSA) itself, but also to distinguish between different clinical subtypes. This study aimed to investigate whether there are differences in the progression of subcortical atrophy and iron deposition between two variants of MSA. Two serial MRIs at baseline and follow-up were analyzed in eight patients with the parkinsonian variant MSA (MSA-P), nine patients with cerebellar variant MSA (MSA-C), and fifteen patients with Parkinson's disease (PD). The R2* values and volumes were calculated for the selected subcortical structures (caudate nucleus, putamen, globus pallidus, and thalamus) using an automated region-based analysis. In both volume and R2*, a higher rate of progression was identified in MSA-P patients. Volumetric analysis showed significantly more rapid progression of putamen and caudate nucleus in MSA-P than in MSA-C. With regard to R2* changes, a significant increase at follow-up and a higher rate of progression were identified in the putamen of MSA-P group compared to MSA-C and PD groups. This longitudinal study revealed different progression rates of MRI markers between MSA-P and MSA-C. Iron-related degeneration in the putamen may be more specific for MSA-P.
Assuntos
Corpo Estriado/patologia , Progressão da Doença , Ferro/metabolismo , Atrofia de Múltiplos Sistemas/patologia , Doença de Parkinson/patologia , Tálamo/patologia , Idoso , Corpo Estriado/metabolismo , Feminino , Seguimentos , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Atrofia de Múltiplos Sistemas/metabolismo , Atrofias Olivopontocerebelares/metabolismo , Atrofias Olivopontocerebelares/patologia , Doença de Parkinson/metabolismo , Degeneração Estriatonigral/metabolismo , Degeneração Estriatonigral/patologia , Tálamo/metabolismoRESUMO
A double toxin-double lesion strategy is well-known to generate a rat model of striatonigral degeneration (SND) such as multiple system atrophy-parkinsonian type. However, with this model it is difficult to distinguish SND from Parkinson's disease (PD). In this study, we propose a new rat model of SND, which is generated by simultaneous injection of 6-hydroxydopamine into the medial forebrain bundle and quinolinic acid into the striatum. Stepping tests performed 30 min after intraperitoneal L-dopa administration at 6 weeks post-surgery revealed an L-dopa response in the PD group but not the SND group. Apomorphine-induced rotation tests revealed no rotational bias in the SND group, which persisted for 2 months, but contralateral rotations in the PD group. MicroPET scans revealed glucose hypometabolism and dopamine transporter impairment on the lesioned striatum in the SND group. Tyrosine hydroxylase immunostaining in the SND group revealed that 74.7% of nigral cells on the lesioned side were lost after lesion surgery. These results suggest that the proposed simultaneous double toxin-double lesion method successfully created a rat model of SND that had behavioral outcomes, multitracer microPET evaluation, and histological aspects consistent with SND pathology. This model will be useful for future study of SND.
Assuntos
Oxidopamina/toxicidade , Ácido Quinolínico/toxicidade , Degeneração Estriatonigral/induzido quimicamente , Animais , Apomorfina/farmacologia , Comportamento Animal/efeitos dos fármacos , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/patologia , Modelos Animais de Doenças , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Glucose/metabolismo , Injeções Intraperitoneais , Levodopa/farmacologia , Masculino , Feixe Prosencefálico Mediano/efeitos dos fármacos , Feixe Prosencefálico Mediano/patologia , Doença de Parkinson/metabolismo , Doença de Parkinson/patologia , Tomografia por Emissão de Pósitrons , Ratos , Ratos Wistar , Degeneração Estriatonigral/metabolismo , Degeneração Estriatonigral/patologia , Tato/efeitos dos fármacosRESUMO
Evidence supports the role of inflammation in the development of neurodegenerative diseases. In this work, we are interested in inflammation as a risk factor by itself and not only as a factor contributing to neurodegeneration. We tested the influence of a mild to moderate peripheral inflammation (injection of carrageenan into the paws of rats) on the degeneration of dopaminergic neurons in an animal model based on the intranigral injection of lipopolysaccharide (LPS), a potent inflammatory agent. Overall, the treatment with carrageenan increased the effect of the intranigral injection of LPS on the loss of dopaminergic neurons in the SN along with all the other parameters studied, including: serum levels of the inflammatory markers TNF-α, IL-1ß, IL-6 and C-reactive protein; activation of microglia, expression of proinflammatory cytokines, the adhesion molecule ICAM and the enzyme iNOS, loss of astrocytes and damage to the blood brain barrier (BBB). The possible implication of BBB rupture in the increased loss of dopaminergic neurons has been studied using another Parkinson's disease animal model based on the intraperitoneal injection of rotenone. In this experiment, loss of dopaminergic neurons was also strengthened by carrageenan, without affecting the BBB. In conclusion, our data show that a mild to moderate peripheral inflammation can exacerbate the degeneration of dopaminergic neurons caused by a harmful stimulus.
Assuntos
Gânglios da Base/metabolismo , Dopamina/metabolismo , Neurônios Dopaminérgicos/metabolismo , Encefalite/complicações , Inflamação/complicações , Degeneração Estriatonigral/etiologia , Substância Negra/metabolismo , Animais , Astrócitos/metabolismo , Astrócitos/patologia , Gânglios da Base/patologia , Barreira Hematoencefálica/metabolismo , Barreira Hematoencefálica/patologia , Proteína C-Reativa/metabolismo , Carragenina , Modelos Animais de Doenças , Neurônios Dopaminérgicos/patologia , Encefalite/induzido quimicamente , Encefalite/metabolismo , Encefalite/patologia , Inflamação/induzido quimicamente , Inflamação/metabolismo , Inflamação/patologia , Mediadores da Inflamação/sangue , Molécula 1 de Adesão Intercelular/metabolismo , Interleucina-1beta/sangue , Interleucina-6/sangue , Lipopolissacarídeos , Masculino , Óxido Nítrico Sintase Tipo II/metabolismo , Ratos , Ratos Wistar , Rotenona , Degeneração Estriatonigral/metabolismo , Degeneração Estriatonigral/patologia , Substância Negra/patologia , Fatores de Tempo , Fator de Necrose Tumoral alfa/sangueRESUMO
Multiple system atrophy (MSA) is a sporadic, neurodegenerative disorder, clinically characterized by parkinsonian, autonomic, cerebellar and pyramidal signs. We describe two patients showing different presentations of the same disease. The patient on case 1 presents features of MSA-C or olivopontocerebellar atrophy with the pontine "cross sign" on brain MRI. The second case reports a patient presenting MSA-P or striatonigral degeneration and the brain MRI shows lenticular nucleus sign alteration. We think that brain MRI might increase the accuracy diagnostic of MSA.
A atrofia de múltiplos sistemas (AMS) é uma doença neurodegenerativa esporádica caracterizada clinicamente por diferentes combinações de sinais parkinsonianos, autonômicos, cerebelares e piramidais. Descrevemos dois pacientes apresentando diferentes formas clínicas da mesma afecção. O caso 1 tem características da AMS-C ou atrofia olivopontocerebelar, apresentando na ressonância magnética (RM) o "sinal da cruz" na ponte. Já o caso 2 tem AMS-P ou degeneração nigro-estriatal, a RM mostra alteração do sinal no núcleo lentiforme entre outras alterações. Acreditamos que a RM cerebral possa contribuir para o melhor diagnóstico da AMS.
Assuntos
Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Encéfalo/patologia , Atrofias Olivopontocerebelares/patologia , Degeneração Estriatonigral/patologia , Imageamento por Ressonância MagnéticaRESUMO
Structural and functional defects in 26/20S proteasomes occur in the substantia nigra pars compacta and may underlie protein accumulation, Lewy body formation and dopaminergic neuronal death in Parkinson's disease. We therefore determined the pathogenicity of proteasomal impairment following stereotaxic unilateral infusion of lactacystin, a selective proteasome inhibitor, into the substantia nigra pars compacta of rats. These animals became progressively bradykinetic, adopted a stooped posture and displayed contralateral head tilting. Administration of apomorphine to lactacystin-treated rats reversed behavioral abnormalities and induced contralateral rotations. Lactacystin caused dose-dependent degeneration of dopaminergic cell bodies and processes with the cytoplasmic accumulation and aggregation of alpha-synuclein to form inclusion bodies. These findings support the notion that failure of the ubiquitin-proteasome system to degrade and clear unwanted proteins is an important etiopathogenic factor in Parkinson's disease.
Assuntos
Acetilcisteína/análogos & derivados , Corpos de Inclusão/patologia , Complexos Multienzimáticos/antagonistas & inibidores , Degeneração Estriatonigral/patologia , Substância Negra/patologia , Acetilcisteína/farmacologia , Animais , Cisteína Endopeptidases/metabolismo , Dopamina/metabolismo , Relação Dose-Resposta a Droga , Corpos de Inclusão/efeitos dos fármacos , Corpos de Inclusão/enzimologia , Complexos Multienzimáticos/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/patologia , Doença de Parkinson/patologia , Doença de Parkinson Secundária/induzido quimicamente , Complexo de Endopeptidases do Proteassoma , Ratos , Ratos Sprague-Dawley , Degeneração Estriatonigral/induzido quimicamente , Degeneração Estriatonigral/enzimologia , Substância Negra/efeitos dos fármacos , Substância Negra/enzimologiaRESUMO
The effects of embryonic neural transplantation in experimental models of neurodegenerative disorders are commonly assessed by behavioral tests and postmortem neurochemical or anatomical analysis. The purpose of the present study was to evaluate embryonic neuronal grafts in a novel rat model of multiple system atrophy (MSA) with the help of in vivo magnetic resonance imaging (MRI) and to correlate imaging with histological parameters. Striatonigral double lesions were created in male Wistar rats by unilateral intrastriatal injection of 3-nitropropionic acid (3-NP). Seven weeks following lesion surgery animals were divided into four transplantation groups receiving either pure mesencephalic, pure striatal, mesencephalic-striatal cografts, or sham grafts. In vivo structural imaging was performed 21 weeks after transplantation using a whole body 1.5 Tesla MR scanner. The imaging protocol comprised T2-weighted TSE and T1-weighted TIR sequences. Immunohistochemistry using DARPP-32 as striatal marker and tyrosinhydroxylase as marker for nigral neurons was performed for correlation analysis of imaging and histological parameters. The sensitivity of graft detection by in vivo MRI was 100%. The graft tissue was clearly demarcated from the remaining striatal tissue in both T2- and T1-weighted sequences. Morphometrically, cross-sectional areas of the grafts and spared intact striatum as defined by immunohistochemistry correlated significantly with measurements obtained by in vivo MRI. In conclusion, we were able to evaluate in vivo both lesion-induced damage and graft size in a 3-NP rat model of MSA using a conventional whole body 1.5 Tesla MRI scanner. Additionally, we obtained an excellent correlation between MRI and histological measurements.