RESUMO
Enteric glial cells (EGCs) constitute the majority of the neural population of the enteric nervous system and are found in all layers of the gastrointestinal tract. It is active in enteric functions such as immunomodulation, participating in inflammation and intestinal epithelial barrier (IEB) regulation. Both EGCs and IEB have been described as altered in Parkinson's disease (PD). Using an animal model of PD induced by 6-hydroxydopamine (6-OHDA), we investigated the effect of ongoing neurodegeneration on EGCs and inflammatory response during short periods after model induction. C57Bl/6 male mice were unilaterally injected with 6-OHDA in the striatum. Compared to the control group, 6-OHDA animals showed decreased relative water content in their feces from 1 w after model induction. Moreover, at 1 and 2 w post-induction, groups showed histopathological changes indicative of intestinal inflammation. We identified an increase in IBA1 and GFAP levels in the intestinal mucosa. At an earlier survival of 48 h, we detected an increase in GFAP in the neuromuscular layer, suggesting that it was a primary event for the upregulation of GDNF, TNF-α, and occludin in the intestinal mucosa observed after 1 w. Within 2 w, we identified a decrease in the expression of occludin barrier proteins. Thus, EGCs modulation may be an early enteric signal induced by parkinsonian neurodegeneration, followed by inflammatory and dysmotility signs besides IEB modification.
Assuntos
Sistema Nervoso Entérico , Doença de Parkinson , Animais , Modelos Animais de Doenças , Sistema Nervoso Entérico/metabolismo , Inflamação/metabolismo , Masculino , Camundongos , Neuroglia/metabolismo , Ocludina/metabolismo , Oxidopamina/metabolismo , Oxidopamina/toxicidade , Doença de Parkinson/metabolismoRESUMO
The development, at the experimental level, of therapeutic strategies based on natural products to attenuate neurological alterations in degenerative disorders has gained attention. Antioxidant molecules exhibit both anti-inflammatory and neuroprotective properties. Alpha-mangostin (α-Man) is a natural xanthonoid isolated from the mangosteen tree with demonstrated antioxidant and cytoprotective properties. In this study, we investigated the antioxidant and protective properties of α-Man, both ex vivo and in vivo. We assessed the mitochondrial reductant capacity and oxidative damage to lipids in rat cortical slices, and several endpoints characteristic of physiological stress in the nematode, Caenorhabditis elegans (C. elegans), upon exposure to the parkinsonian neurotoxin, 6-hydroxydopamine (6-OHDA). In rat cortical slices, α-Man (25 and 50 µM) reduced the 6-OHDA (100 µM)-induced oxidative damage to lipid levels, but failed to reverse loss in cell viability. In wild-type (N2) C. elegans, α-Man (5-100 µM) protected against 6-OHDA (25 mM)-induced decrease in survival when administered either as pre- or post-treatment. Protective effects of α-Man were also observed on survival in the VC1772 strain (skn-1 KO-) exposed to 6-OHDA, though the extent of the protection was lesser than in the wild-type N2 strain. However, α-Man (5-50 µM) failed to attenuate the 6-OHDA-induced motor alterations in the N2 strain. The loss of lifespan induced by 6-OHDA in the N2 strain was fully reversed by high concentrations of α-Man. In addition, while 6-OHDA decreased the expression of glutathione S-transferase in the CL2166 C. elegans strain, α-Man preserved and stimulated the expression of this protein. α-Man (25 µM) also prevented 6-OHDA-induced dopaminergic neurodegeneration in the BZ555 C. elegans strain. Altogether, our novel results suggest that α-Man affords partial protection against several, but not all, short-term toxic effects induced by 6-OHDA in cortical slices and in a skn-1-dependent manner in C. elegans.
Assuntos
Proteínas de Caenorhabditis elegans , Fármacos Neuroprotetores , Síndromes Neurotóxicas , Animais , Animais Geneticamente Modificados , Antioxidantes/farmacologia , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/metabolismo , Humanos , Fármacos Neuroprotetores/metabolismo , Fármacos Neuroprotetores/farmacologia , Síndromes Neurotóxicas/metabolismo , Estresse Oxidativo , Oxidopamina/metabolismo , Oxidopamina/toxicidade , Ratos , XantonasRESUMO
BACKGROUND: Parkinson's Disease (PD) is a common neurodegenerative disorder affecting the dopaminergic (DAergic) system. Replacement therapy is a promising alternative aimed at reconstructing the cytoarchitecture of affected brain regions in PD. Experimental approaches, such as the replacement of DAergic neurons with cells obtained from the Enteric Nervous System (ENS) has yet to be explored. OBJECTIVE: To establish and characterize a cell replacement strategy with ENS Cells (ENSCs) in a PD model in rats. METHODS: Since ENSCs can develop mature DAergic phenotypes, here we cultured undifferentiated cells from the myenteric plexus of newborn rats, establishing that they exhibit multipotential characteristics. These cells were characterized and further implanted in the Substantia nigra pars compacta (SNpc) of adult rats previously lesioned by a retrograde degenerative model produced by intrastriatal injection of 6-Hydroxydopamine (6-OHDA). DAergic markers were assessed in implants to validate their viability and possible differentiation once implanted. RESULTS: Cell cultures were viable, exhibited stem cell features and remained partially undifferentiated until the time of implant. The retrograde lesion induced by 6-OHDA produced DAergic denervation, reducing the number of fibers and cells in the SNpc. Implantation of ENSCs in the SNpc of 6-OHDAlesioned rats was tracked after 5 and 10 days post-implant. During that time, the implant increased selective neuronal and DAergic markers, Including Microtubule-Associated Protein 2 (MAP-2), Dopamine Transporter (DAT), and Tyrosine Hydroxylase (TH). CONCLUSION: Our novel results suggest that ENSCs possess a differentiating, proliferative and restorative potential that may offer therapeutic modalities to attenuate neurodegenerative events with the inherent demise of DAergic neurons.
Assuntos
Neurônios Dopaminérgicos/metabolismo , Células-Tronco Neurais/transplante , Doença de Parkinson/terapia , Transplante de Células-Tronco/métodos , Animais , Modelos Animais de Doenças , Dopamina/metabolismo , Sistema Nervoso Entérico , Masculino , Oxidopamina/metabolismo , Ratos , Ratos Sprague-Dawley , Tirosina 3-Mono-Oxigenase/metabolismoRESUMO
Extensive damage to nigrostriatal dopaminergic neurons leads to Parkinson's disease (PD). To date, the most effective treatment has been administration of levodopa (L-DOPA) to increase dopaminergic tone. This treatment leads to responses that vary widely among patients, from predominantly beneficial effects to the induction of disabling, abnormal movements (L-DOPA induced dyskinesia (LID)). Similarly, experimental studies have shown animals with widely different degrees of LID severity. In this study, unilateral injections of 6-hydroxydopamine (6-OHDA) in the medial forebrain bundle (MFB) produced more than 90% depletion of dopamine in both the striatum and the substantia nigra reticulata (SNr) of rats. Population analysis showed that dopamine depletion levels were clustered in a single population. In contrast, analysis of abnormal involuntary movements (AIMs) induced by L-DOPA treatment of 6-OHDA-lesioned animals yielded two populations: one with mild LID, and the other with severe LID, which are also related to different therapeutic responses. We examined whether the severity of LID correlated with changes in dopamine 3 receptor (D3R) signaling because of the following: (a) D3R expression and the induction of LID are strongly correlated; and (b) dopaminergic denervation induces a qualitative change in D3R signaling in the SNr. We found that the effects of D3R activation on cAMP accumulation and depolarization-induced [3H]-gamma-aminobutyric acid ([3H]-GABA) release were switched. L-DOPA treatment normalized the denervation-induced changes in animals with mild LID. The D3R activation caused depression of both dopamine 1 receptor (D1R)-induced increases in cAMP production and depolarization-induced [3H]-GABA release, which were reversed to their pre-denervation state. In animals with severe LID, none of the denervation-induced changes were reversed. The finding that in the absence of identifiable differences in 6-OHDA and L-DOPA treatment, two populations of animals with different D3R signaling and LIDs severity implies that mechanisms intrinsic to the treated subject determine the segregation.
Assuntos
Discinesias/etiologia , Discinesias/metabolismo , Levodopa/efeitos adversos , Levodopa/uso terapêutico , Doença de Parkinson/tratamento farmacológico , Animais , AMP Cíclico/metabolismo , Dopamina/metabolismo , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/metabolismo , Masculino , Feixe Prosencefálico Mediano/efeitos dos fármacos , Feixe Prosencefálico Mediano/metabolismo , Oxidopamina/metabolismo , Ratos , Ratos Wistar , Transdução de Sinais/efeitos dos fármacosRESUMO
Parkinson disease (PD) is characterized by the loss of dopaminergic (DAergic) neurons linked to environmental toxicants that cause oxidative stress (OS). The aim of this investigation was to establish the molecular response of human mesenchymal stroma cells (MSCs) depleted of glutathione (GSH) by the specific inhibitor L-buthionine-sulfoximine (BSO) to 6-hydroxydopamine (6-OHDA) and/or N-acetylcysteine (NAC) co-treatment. We found that treatment with BSO (10 mM) plus 6-OHDA (200 µM) induced apoptosis in MSCs through an oxidative stress (OS) mechanism involving H2O2, reflected by the detection of dichlorofluorescein-positive (DCF+) cells and oxidation of DJ-1 Cys106-SH into DJ-1 Cys106-SO3; an almost complete reduction in glutathione peroxidase 1 (GPX1) expression; activation of the transcription factor c-JUN, the pro-apoptotic protein BAX and BH-3-only protein PUMA; loss of mitochondrial membrane potential (∆Ψm); activation of the protease caspase-3 (CASP3) and apoptosis-inducing factor (AIF); chromatin condensation; and DNA fragmentation. Strikingly, co-treatment of MSCs with NAC (5 mM) and BSO + 6-OHDA significantly reduced the expression of OS and cell death markers but were unable to restore the expression of GPX1 compared to the expression in untreated or treated cells with NAC only. These findings highlighted the importance of the maintenance of the GSH-dependent (e.g., GPX1, GSH synthesis) and -independent (e.g., ROS scavenger molecules and thiol reducing activity) antioxidant systems (e.g., NAC) in the protection of MSCs from detrimental stress stimuli, thereby increasing the survival of stromal cells.
Assuntos
Acetilcisteína/farmacologia , Apoptose/efeitos dos fármacos , Células-Tronco Mesenquimais/efeitos dos fármacos , Antioxidantes/metabolismo , Butionina Sulfoximina/metabolismo , Morte Celular/efeitos dos fármacos , Glutationa/metabolismo , Glutationa Peroxidase , Humanos , Peróxido de Hidrogênio/farmacologia , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Oxidopamina/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Glutationa Peroxidase GPX1RESUMO
OBJECTIVES: Aspidosperma species are used for several diseases, especially for malaria in Brazil. Although the genus is object of pharmacological studies, almost none are found on Aspidosperma pyrifolium. We investigate neuroprotective, antioxidant and anti-inflammatory properties of the APSE-Aq fraction (benzoic acid glycosylated derivative) on Parkinson's disease model. METHODS: Male Wistar rats were subjected to a 6-hydroxydopamine injection into the right striatum and treated or not with APSE-Aq (100 or 200 mg/kg, p.o.). The sham-operated group was injected with saline. Two weeks later, animals were subjected to behavioural, neurochemical and immunohistochemical evaluation. The data were analysed by ANOVA and Tukey test. KEY FINDINGS: The APSE-Aq-treated group shows a partial recovery of behavioural changes as compared with the untreated-6-hydroxydopamine group. A partial recovery was also observed in nitrite contents and lipid peroxidation. APSE-Aq treatments significantly reversed decreases in striatal dopamine and metabolites in the untreated 6-hydroxydopamine group. Immunostainings for markers as tyrosine hydroxylase and dopamine transporter decreased in the untreated 6-hydroxydopamine group and values recovered after APSE-Aq treatments. Similar data were seen for TNF-alpha. CONCLUSION: APSE-Aq presents neuroprotective, antioxidant and anti-inflammatory activities. Considering that APSE-Aq is chemically related to salicylic acid, it may act on similar targets.
Assuntos
Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Aspidosperma/química , Fármacos Neuroprotetores/farmacologia , Doença de Parkinson/tratamento farmacológico , Extratos Vegetais/farmacologia , Animais , Comportamento Animal/efeitos dos fármacos , Corpo Estriado/metabolismo , Modelos Animais de Doenças , Dopamina/metabolismo , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Nitritos/metabolismo , Oxidopamina/metabolismo , Extratos Vegetais/química , Ratos , Sementes/química , Fator de Necrose Tumoral alfa/metabolismo , Tirosina 3-Mono-Oxigenase/metabolismoRESUMO
Moderate traumatic brain injury (TBI) might increase the vulnerability to neuronal neurodegeneration, but the basis of such selective neuronal susceptibility has remained elusive. In keeping with the disruption of the blood-brain barrier (BBB) caused by TBI, changes in BBB permeability following brain injury could facilitate the access of xenobiotics into the brain. To test this hypothesis, here we evaluated whether TBI would increase the susceptibility of nigrostriatal dopaminergic fibers to the systemic administration of 6-hydroxydopamine (6-OHDA), a classic neurotoxin used to trigger a PD-like phenotype in mice, but that in normal conditions is unable to cross the BBB. Adult Swiss mice were submitted to a moderate TBI using a free weight-drop device and, 5h later, they were injected intraperitoneally with a single dose of 6-OHDA (100mg/kg). Afterwards, during a period of 4weeks, the mice were submitted to a battery of behavioral tests, including the neurological severity score (NSS), the open field and the rotarod. Animals from the TBI plus 6-OHDA group displayed significant motor and neurological impairments that were improved by acute l-DOPA administration (25mg/kg, i.p.). Moreover, the observation of the motor deficits correlates with (i) a significant decrease in the tyrosine hydroxylase levels mainly in the rostral striatum and (ii) a significant increase in the levels of striatal glial fibrillary acidic protein (GFAP) levels. On the whole, the present findings demonstrate that a previous moderate TBI event increases the susceptibility to motor, neurological and neurochemical alterations induced by systemic administration of the dopaminergic neurotoxin 6-OHDA in mice.
Assuntos
Lesões Encefálicas Traumáticas/metabolismo , Oxidopamina/toxicidade , Animais , Comportamento Animal , Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Lesões Encefálicas/metabolismo , Lesões Encefálicas Traumáticas/complicações , Lesões Encefálicas Traumáticas/patologia , Corpo Estriado/metabolismo , Modelos Animais de Doenças , Dopamina/metabolismo , Neurônios Dopaminérgicos/efeitos dos fármacos , Proteína Glial Fibrilar Ácida/metabolismo , Levodopa/metabolismo , Camundongos , Doenças Neurodegenerativas , Síndromes Neurotóxicas/metabolismo , Oxidopamina/metabolismo , Tirosina 3-Mono-Oxigenase/metabolismoRESUMO
The receptor for advanced glycation end products (RAGE) is commonly involved in different neurodegenerative and inflammatory disorders. The cellular signaling associated to RAGE activation may occur upon binding to different ligands. In this study we investigated whether the toxic model produced by 6-hydroxydopamine (6-OHDA) in rats comprises early noxious responses related to RAGE-mediated signaling cascades. In order to explore a possible interaction between 6-OHDA and RAGE, affinity parameters of RAGE with 6-OHDA were estimated by different means. The possible binding sites of 6-OHDA with the VC1 homodimer for both rat and human RAGE were also modeled. Our results show that the striatal infusion of 6-OHDA recruits RAGE upregulation, as evidenced by an early expression of the receptor. 6-OHDA was also found to bind the VC1 homodimer, although its affinity was moderate when compared to other ligands. This work contributes to the understanding of the role of RAGE activation for 6-OHDA-induced neurotoxicity.
Assuntos
Corpo Estriado/metabolismo , Oxidopamina/metabolismo , Receptor para Produtos Finais de Glicação Avançada/metabolismo , Animais , Sítios de Ligação/fisiologia , Ligantes , Masculino , Ligação Proteica/fisiologia , Ratos , Ratos WistarRESUMO
Studies have sought to assess various potential neuroprotective therapeutics in Parkinson's disease. The aim of this study was to evaluate the effects of static magnetic field stimulation 14 days after a 6-Hydroxydopamine (6-OHDA) substantia nigra compacta (SNc) lesion on motor behavior, as assessed by the rotarod (RR) test and brain tissue morphology. Forty male Wistar rats were used and were divided into five groups: control group, sham group (SG), lesion group (LG), lesion north pole group (LNPG) and lesion south pole group (LSPG). In groups with magnetic stimulation, a 3200-gauss magnet was fixed to the skull. After the experiments, the animals were anesthetized for brain perfusion. Coronal sections of the SNc were stained with Nissl. The RR test showed a decrease in the time spent on the apparatus in the LG compared with all groups. The LNPG and LSPG had significant increases in the time spent when compared to the LG. A morphometric analysis revealed a significant reduction in the number of neurons in the LG, LNPG and LSPG in relation to the SG. There were a higher number of neurons in the LNPG and LSPG than the LG, and a higher number of neurons in the LSPG than the LNPG. We observed that the LG, LNPG and LSPG showed a higher number of glial cells than the SG, and the LNPG and LSPG showed a lower number of glial cells than the LG. Our results demonstrate a potential therapeutic use of static magnetic fields for the preservation of motor behavior and brain morphology in the SNc after 14 days with 6-OHDA lesion.
Assuntos
Comportamento Animal/efeitos dos fármacos , Campos Magnéticos , Neurotoxinas/toxicidade , Oxidopamina/metabolismo , Oxidopamina/toxicidade , Substância Negra/efeitos dos fármacos , Animais , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Magnetoterapia , Masculino , Atividade Motora/efeitos dos fármacos , Neurônios/citologia , Neurônios/efeitos dos fármacos , Ratos , Ratos Wistar , Substância Negra/citologia , Substância Negra/fisiologiaRESUMO
The work shows the effects of caffeine after the intrastriatal injection of 6-OHDA in rats, considered as a model of Parkinson disease (PD). Two weeks after the 6-OHDA lesion, rats exhibit a characteristic rotation behavior as a response to the apomorphine challenge. Our results showed significant increases in the number of apomorphine-induced rotations in 6-OHDA-lesioned rats, as compared to sham-operated animals. A partial recovery was observed in 6-OHDA-lesioned rats, after caffeine (10 and 20 mg/kg, i.p., daily for 14 days) treatment. The stereotaxic injection of 6-OHDA produced loss of striatal neurons, as indicated by the decrease in monoamines levels, in the ipsilateral side (75-85%) when compared to the contralateral side. Significant decreases in noradrenaline levels were seen in the ipsilateral side of 6-OHDA group (62%), and this effect was not significantly reversed in caffeine-treated groups. While significant decreases in dopamine levels were seen in the ipsilateral side of 6-OHDA group (78%), in the caffeine-treated group (10 and 20 mg/kg, i.p.) the decreases were only 53 and 18%, indicating significant recoveries. In conclusion, our data demonstrated beneficial effects of caffeine in this model of PD, suggesting the potential use of A2A antagonists as a novel treatment for this neurodegenerative disease.
Assuntos
Cafeína/farmacologia , Fármacos Neuroprotetores/farmacologia , Oxidopamina/metabolismo , Animais , Apomorfina/metabolismo , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Encefalopatias/tratamento farmacológico , Cafeína/metabolismo , Modelos Animais de Doenças , Dopaminérgicos/metabolismo , Masculino , Neurônios/efeitos dos fármacos , Doença de Parkinson/tratamento farmacológico , Ratos , Ratos WistarRESUMO
Neuropeptide Y (NPY) and noradrenaline (NA) are co-transmitters at many sympathetic synapses, but it is not yet clear if their release is independently regulated. To address this question, we quantified the electrically evoked release of these co-transmitters from perivascular nerve terminals to the mesenteric circulation in control and drug-treated rats. 6-Hydroxydopamine reduced the tissue content and the electrically evoked release of ir-NPY and NA as well as the rise in perfusion pressure. A 0.001 mg/kg reserpine reduced the content of ir-NPY and NA, but did not modify their release nor altered the rise in perfusion pressure elicited by the electrical stimuli. However, 0.1mg/kg reserpine reduced both the content and release of NA but decreased only the content but not the release of ir-NPY; the rise in perfusion pressure was halved. Clonidine did not affect the release of ir-NPY while it lowered the outflow of NA, not altering the rise in perfusion pressure elicited by the electrical stimuli. Yohimbine, did not modify the release of ir-NPY but increased the NA outflow, it antagonized the clonidine effect. Therefore, presynaptic alpha2-adrenoceptors modulate the release of NA but not NPY, implying separate regulatory mechanisms.
Assuntos
Neurônios/metabolismo , Neuropeptídeo Y/metabolismo , Norepinefrina/metabolismo , Receptores Adrenérgicos alfa 2/fisiologia , Acetilcolinesterase/metabolismo , Animais , Clonidina/farmacologia , Dopamina beta-Hidroxilase/metabolismo , Relação Dose-Resposta a Droga , Imuno-Histoquímica , Microscopia de Fluorescência , Oxidopamina/metabolismo , Ratos , Ratos Sprague-Dawley , Reperfusão , Reserpina/farmacologia , Fatores de Tempo , Distribuição Tecidual , Ioimbina/farmacologiaRESUMO
Oxidation of catecholamines is suggested to contribute to oxidative stress in Parkinson's disease. Nitric oxide (*NO) is able to oxidize cyclic compounds like ubiquinol; moreover, recent lines of evidence proposed a direct role of *NO and its by-product peroxynitrite in the pathophysiology of Parkinson's disease. The aim of this study was to analyze the potential reaction between 6-hydroxydopamine, a classic inducer of Parkinson's disease, and *NO. The results showed that *NO reacts with the deprotonated form of 6-hydroxydopamine at pH 7 and 37 degrees C with a second-order rate constant of 1.5 x 10(3) M(-1) x s(-1) as calculated by the rate of *NO decay measured with an amperometric sensor. Accordingly, the rates of formation of 6-hydroxy-dopamine quinone were dependent on *NO concentration. The coincubation of *NO and 6-hydroxydopamine with either bovine serum albumin or alpha-synuclein led to tyrosine nitration of the protein, in a concentration dependent-manner and sensitive to superoxide dismutase. These findings suggest the formation of peroxynitrite during the redox reactions following the interaction of 6-hydroxydopamine with *NO. The implications of this reaction for in vivo models are discussed in terms of the generation of reactive nitrogen and oxygen species within a propagation process that may play a significant role in neurodegenerative diseases.