RESUMO
OBJECTIVE: The aim of this study was to evaluate the GSH effect on functional and histological recovery after experimental spinal cord injury in rats. METHODS: Forty Wistar rats were subjected to spinal cord injury through the Multicenter Animal Spinal Cord Injury Study (MASCIS) Impactor system. The rats were sorted and divided into four groups, as follows: Group 1 â Laminectomy and spinal cord injury; Group 2 â Laminectomy, spinal cord injury and Saline Solution (SS) 0.9%; Group 3 â Laminectomy, spinal cord injury, and GSH; and Group 4 â lLaminectomy without spinal cord injury. GSH and SS were administered intraperitoneally. Groups 1 and 4 received no intervention. RESULTS: The rats were evaluated for locomotor function recovery at seven different times by the Basso, Beattie, and Bresnahan (BBB) scale on days 2, 7, 14, 21, 28, 35, and 42 after the spinal cord injury. On day 42, the rats were sacrificed to analyze the histological findings of the injured spinal cord. In the group submitted to GSH, our experimental study revealed better functional scores on the BBB scale, horizontal ladder scale, and cranial and caudal axon count. The differences found were statistically significant in BBB scores and axonal count analysis. CONCLUSION: This study demonstrated that using glutathione in experimental spinal trauma can lead to better functional recovery and improved axonal regeneration rate in Wistar rats submitted to experimental spinal cord injury.
Assuntos
Modelos Animais de Doenças , Glutationa , Ratos Wistar , Recuperação de Função Fisiológica , Traumatismos da Medula Espinal , Animais , Traumatismos da Medula Espinal/fisiopatologia , Traumatismos da Medula Espinal/patologia , Fatores de Tempo , Laminectomia , Masculino , Medula Espinal/patologia , Medula Espinal/fisiopatologia , Distribuição Aleatória , Ratos , Axônios/patologia , Locomoção/fisiologia , Reprodutibilidade dos Testes , Atividade Motora/fisiologia , Resultado do TratamentoRESUMO
Chronic pain is an incapacitating condition that affects a large population worldwide. Until now, there is no drug treatment to relieve it. The impairment of GABAergic inhibition mediated by GABAA receptors (GABAA R) is considered a relevant factor in mediating chronic pain. Even though both synaptic and extrasynaptic GABAA inhibition are present in neurons that process nociceptive information, the latter is not considered relevant as a target for the development of pain treatments. In particular, the extrasynaptic α5 GABAA Rs are expressed in laminae I-II of the spinal cord neurons, sensory neurons, and motoneurons. In this review, we discuss evidence showing that blockade of the extrasynaptic α5 GABAA Rs reduces mechanical allodynia in various models of chronic pain and restores the associated loss of rate-dependent depression of the Hoffmann reflex. Furthermore, in healthy animals, extrasynaptic α5 GABAA R blockade induces both allodynia and hyperalgesia. These results indicate that this receptor may have an antinociceptive and pronociceptive role in healthy and chronic pain-affected animals, respectively. We propose a hypothesis to explain the relevant role of the extrasynaptic α5 GABAA Rs in the processing of nociceptive information. The data discussed here strongly suggest that this receptor could be a valid pharmacological target to treat chronic pain states.
Assuntos
Dor Crônica/metabolismo , Receptores de GABA-A/metabolismo , Medula Espinal/metabolismo , Analgésicos/farmacologia , Analgésicos/uso terapêutico , Animais , Dor Crônica/tratamento farmacológico , Dor Crônica/fisiopatologia , Antagonistas de Receptores de GABA-A/farmacologia , Antagonistas de Receptores de GABA-A/uso terapêutico , Humanos , Nociceptividade , Medula Espinal/efeitos dos fármacos , Medula Espinal/fisiopatologiaRESUMO
Neonatal anoxia is a well-known world health problem that results in neurodevelopmental deficits, such as sensory alterations that are observed in patients with cerebral palsy and autism disorder, for which oxygen deprivation is a risk factor. Nociceptive response, as part of the sensory system, has been reported as altered in these patients. To determine whether neonatal oxygen deprivation alters nociceptive sensitivity and promotes medium- and long-term inflammatory feedback in the central nervous system, Wistar rats of around 30 h old were submitted to anoxia (100% nitrogen flux for 25 min) and evaluated on PND23 (postpartum day) and PND90. The nociceptive response was assessed by mechanical, thermal, and tactile tests in the early postnatal and adulthood periods. The lumbar spinal cord (SC, L4-L6) motor neurons (MNs) and the posterior insular cortex neurons were counted and compared with their respective controls after anoxia. In addition, we evaluated the possible effect of anoxia on the expression of astrocytes in the SC at adulthood. The results showed increased nociceptive responses in both males and females submitted to anoxia, although these responses were different according to the nociceptive stimulus. A decrease in MNs in adult anoxiated females and an upregulation of GFAP expression in the SC were observed. In the insular cortex, a decrease in the number of cells of anoxiated males was observed in the neonatal period. Our findings suggest that oxygen-deprived nervous systems in rats may affect their response at the sensorimotor pathways and respective controlling centers with sex differences, which were related to the used stimulus.
Assuntos
Hipóxia/fisiopatologia , Córtex Insular/fisiopatologia , Nociceptividade/fisiologia , Medula Espinal/fisiopatologia , Animais , Feminino , Masculino , Neurônios/fisiologia , Ratos , Ratos Wistar , Fatores SexuaisRESUMO
Spinal cord injury (SCI) is a complex neuropathological condition that represents a major challenge for clinicians and scientists due to patient's functional dysfunction and paralysis. Several treatments have been proposed including biological factors, drugs and cells administered in various ways. Stem cells arise as good candidates to treat SCI since they are known to secrete neurotrophic factors, improving neuroregeneration, but also due to their role in modulating the inflammatory process, favoring a pro-regenerative status. There are several types of cells that have been tested to treat SCI in experimental and clinical studies, but we still face many unanswered questions; one of them is the type of cells that can offer the best benefits and, also the ideal dose and administration routes. This review aimed to summarize recent research on cell treatment, focusing on current delivery strategies for SCI therapy and their effects in tissue repair and regeneration.
Assuntos
Neurogênese , Traumatismos da Medula Espinal/cirurgia , Regeneração da Medula Espinal , Medula Espinal/cirurgia , Transplante de Células-Tronco , Animais , Humanos , Recuperação de Função Fisiológica , Medula Espinal/metabolismo , Medula Espinal/patologia , Medula Espinal/fisiopatologia , Traumatismos da Medula Espinal/metabolismo , Traumatismos da Medula Espinal/patologia , Traumatismos da Medula Espinal/fisiopatologia , Transplante de Células-Tronco/efeitos adversos , Resultado do TratamentoRESUMO
To examine the role of chronic (in)activity on muscle carnosine (MCarn) and how chronic (in)activity affects MCarn responses to ß-alanine supplementation in spinal cord-injured athletes, 16 male athletes with paraplegia were randomized (2:1 ratio) to receive ß-alanine (n = 11) or placebo (PL, n = 5). They consumed 6.4 g/day of ß-alanine or PL for 28 days. Muscle biopsies of the active deltoid and the inactive vastus lateralis (VL) were taken before and after supplementation. MCarn in the VL was also compared with the VL of a group of individuals without paraplegia (n = 15). MCarn was quantified in whole muscle and in pools of individual fibers by high-performance liquid chromatography. MCarn was higher in chronically inactive VL vs. well-trained deltoid (32.0 ± 12.0 vs. 20.5 ± 6.1 mmol/kg DM; P = 0.018). MCarn was higher in inactive vs. active VL (32.0 ± 12.0 vs. 21.2 ± 7.5 mmol/kg DM; P = 0.011). In type-I fibers, MCarn was significantly higher in the inactive VL than in the active deltoid (38.3 ± 4.7 vs. 27.3 ± 11.8 mmol/kg DM, P = 0.014). MCarn increased similarly between inactive VL and active deltoid in the ß-alanine group (VL: 68.9 ± 55.1%, P = 0.0002; deltoid: 90.5 ± 51.4%, P < 0.0001), with no changes in the PL group. MCarn content was higher in the inactive VL than in the active deltoid and the active VL, but this is probably a consequence of fiber type shift (type I to type II) that occurs with chronic inactivity. Chronically inactive muscle showed an increase in MCarn after BA supplementation equally to the active muscle, suggesting that carnosine accretion following ß-alanine supplementation is not influenced by muscle inactivity.
Assuntos
Carnosina/metabolismo , Homeostase/fisiologia , Músculo Esquelético/fisiopatologia , Traumatismos da Medula Espinal/fisiopatologia , Medula Espinal/fisiopatologia , Atletas , Suplementos Nutricionais , Humanos , Medula Espinal/efeitos dos fármacos , beta-Alanina/administração & dosagem , beta-Alanina/farmacologiaRESUMO
Agents that modulate the activity of high-voltage gated calcium channels (HVCCs) exhibit experimentally and clinically significant effect by relieving visceral pain. Among these agents, the toxins Phα1ß and ω-conotoxin MVIIA effectively reduce chronic pain in rodent models. The molecular mechanisms underlying the chronic pain associated with acute pancreatitis (AP) are poorly understood. Hypercalcemia is a risk factor; the role of cytosolic calcium is considered to be a modulator of pancreatitis. Blockade of Ca2+ signals may be useful as a prophylactic treatment of pancreatitis. We explored the pathophysiological roles of three peptide toxins: Phα1ß and its recombinant form CTK 01512-2-blockers of TRPA1 receptor and HVCCs and ω-conotoxin MVIIA, a specific blocker of N-type calcium channels in cerulein-induced AP. Cerulein injection elicits AP in rats, evidenced by an increase in hyperalgesic pain, inflammatory infiltration, amylase and lipase secretion, and reactive oxygen species, TNF-α, and p65 NF-κB levels. These effects of cerulein-induced AP were abolished by Phα1ß and its recombinant form CTK 01512-2, whereas ω-conotoxin MVIIA had no effect on the induced increase in pancreatic enzyme secretion. Our results demonstrate that Phα1ß and CTK 01512-2 toxins-antagonists of HVCCs and TRPA1 receptor presented an effective response profile, in the control of nociception and inflammatory process in the AP model in rats, without causing changes in spontaneous locomotion of the rats.
Assuntos
Dor Abdominal/prevenção & controle , Analgésicos/farmacologia , Anti-Inflamatórios/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio/efeitos dos fármacos , Hiperalgesia/prevenção & controle , Limiar da Dor/efeitos dos fármacos , Pancreatite/prevenção & controle , Dor Abdominal/etiologia , Dor Abdominal/metabolismo , Dor Abdominal/fisiopatologia , Animais , Comportamento Animal/efeitos dos fármacos , Canais de Cálcio/metabolismo , Sinalização do Cálcio/efeitos dos fármacos , Ceruletídeo , Modelos Animais de Doenças , Comportamento Exploratório/efeitos dos fármacos , Hiperalgesia/etiologia , Hiperalgesia/metabolismo , Hiperalgesia/fisiopatologia , Mediadores da Inflamação/metabolismo , Masculino , Neuropeptídeos/farmacologia , Pâncreas/efeitos dos fármacos , Pâncreas/metabolismo , Pancreatite/induzido quimicamente , Pancreatite/metabolismo , Pancreatite/fisiopatologia , Ratos Wistar , Venenos de Aranha/farmacologia , Medula Espinal/efeitos dos fármacos , Medula Espinal/metabolismo , Medula Espinal/fisiopatologia , ômega-Conotoxinas/farmacologiaRESUMO
BACKGROUND AND PURPOSE: The spinal subarachnoid space (SSAS) is vital for neurologic function. Although SSAS alterations are known to occur after spinal cord injury (SCI), there is a lack of high-resolution imaging studies of the SSAS after SCI in rodents. Therefore, the aim here was to assess changes in the SSAS of rats subjected to graded SCI, using high-resolution micro-CT myelography. METHODS: Long-Evans adult rats were subjected to mild or severe spinal cord contusion at T9. Imaging studies of SSAS features were carried out in injured rats at acute (day 1) and subacute (day 15) stages postinjury, as well as in control rats, using high-resolution micro-CT myelography with a contrast-enhanced digital subtraction protocol. We studied a total of 33 rats randomly allocated into five experimental groups. Micro-CT myelograms were assessed by expert observers using both qualitative and quantitative criteria. RESULTS: Qualitative and quantitative analyses showed that SCI induces changes in the SSAS that vary as a function of both injury severity and time elapsed after injury. SSAS blockage was the main alteration detected. Moreover, the method used here allowed fine details to be observed in small animals, such as variations in the preferential pathways for contrast medium flow, neuroimaging nerve root enhancement, and leakage of contrast medium due to tearing of the dural sac. CONCLUSION: Micro-CT myelography provides high-resolution images of changes in the SSAS after SCI in rats and is a useful tool for further experimental studies involving rat SCI in vivo.
Assuntos
Mielografia , Razão Sinal-Ruído , Traumatismos da Medula Espinal/diagnóstico por imagem , Medula Espinal/diagnóstico por imagem , Espaço Subaracnóideo/diagnóstico por imagem , Microtomografia por Raio-X , Animais , Masculino , Ratos , Ratos Long-Evans , Medula Espinal/fisiopatologia , Traumatismos da Medula Espinal/fisiopatologia , Espaço Subaracnóideo/fisiopatologiaRESUMO
Regenerative medicine offers hope for patients with diseases of the central and peripheral nervous system. Urodele amphibians such as axolotl display an exceptional regenerative capacity and are considered as essential preclinical model organisms in neurology and regenerative medicine research. Earlier studies have suggested that the limb regeneration ability of this salamander notably decreases with induction of metamorphosis by thyroid hormones. Metamorphic axolotl requires further validation as a negative control in preclinical regenerative medicine research, not to mention the study of molecular substrates of its regenerative abilities. In this study, we report new observations on the effect of experimentally induced metamorphosis on spinal cord regeneration in axolotl. Surprisingly, we found that metamorphic animals were successful to functionally restore the spinal cord after an experimentally induced injury. To discern the molecular signatures of spinal cord regeneration, we performed transcriptomics analyses at 1- and 7-days postinjury (dpi) for both spinal cord injury (SCI)-induced (experimental) and laminectomy (sham) groups. We observed 119 and 989 differentially expressed genes at 1- and 7-dpi, respectively, while the corresponding mouse orthologous genes were enriched in junction-, immune system-, and extracellular matrix-related pathways. Taken together, our findings challenge the prior notions of limited regenerative ability of metamorphic axolotl which exhibited successful spinal cord regeneration in our experience. Moreover, we report on molecular signatures that can potentially explain the mechanistic substrates of the regenerative capacity of the metamorphic axolotl. To the best of our knowledge, this is the first report on molecular responses to SCI and functional restoration in metamorphic axolotls. These new findings advance our understanding of spinal cord regeneration, and may thus help optimize the future use of axolotl as a preclinical model in regenerative medicine and integrative biology fields.
Assuntos
Perfilação da Expressão Gênica , Regeneração Nervosa , Medicina Regenerativa , Medula Espinal/metabolismo , Medula Espinal/fisiopatologia , Transcriptoma , Ambystoma mexicanum , Animais , Biologia Computacional/métodos , Modelos Animais de Doenças , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Sequenciamento de Nucleotídeos em Larga Escala , Regeneração Nervosa/genética , Transdução de Sinais , Traumatismos da Medula Espinal/etiologia , Traumatismos da Medula Espinal/metabolismo , Traumatismos da Medula Espinal/patologia , Traumatismos da Medula Espinal/reabilitaçãoRESUMO
Central neuropathic pain is a common untreated symptom in progressive multiple sclerosis (PMS) and is associated with poor quality of life and interference with patients' daily activities. The neuroinflammation process and mitochondrial dysfunction in the PMS lesions generate reactive species. The transient potential receptor ankyrin 1 (TRPA1) has been identified as one of the major mechanisms that contribute to neuropathic pain signaling and can be activated by reactive compounds. Thus, the goal of our study was to evaluate the role of spinal TRPA1 in the central neuropathic pain observed in a PMS model in mice. We used C57BL/6 female mice (20-30 g), and the PMS model was induced by the experimental autoimmune encephalomyelitis (EAE) using mouse myelin oligodendrocyte glycoprotein (MOG35-55) antigen and CFA (complete Freund's adjuvant). Mice developed progressive clinical score, with motor impairment observed after 15 days of induction. This model induced mechanical and cold allodynia and heat hyperalgesia which were measured up to 14 days after induction. The hypersensitivity observed was reduced by the administration of selective TRPA1 antagonists (HC-030031 and A-967079, via intrathecal and intragastric), antioxidants (α-lipoic acid and apocynin, via intrathecal and intragastric), and TRPA1 antisense oligonucleotide (via intrathecal). We also observed an increase in TRPA1 mRNA levels, NADPH oxidase activity, and 4-hydroxinonenal (a TRPA1 agonist) levels in spinal cord samples of PMS-EAE induced animals. In conclusion, these results support the hypothesis of the TRPA1 receptor involvement in nociception observed in a PMS-EAE model in mice.
Assuntos
Encefalomielite Autoimune Experimental/complicações , Hiperalgesia/fisiopatologia , Proteínas do Tecido Nervoso/fisiologia , Neuralgia/fisiopatologia , Nociceptividade/fisiologia , Medula Espinal/fisiopatologia , Canal de Cátion TRPA1/fisiologia , Acetanilidas/farmacologia , Acetanilidas/uso terapêutico , Acetofenonas/farmacologia , Analgésicos/farmacologia , Analgésicos/uso terapêutico , Animais , Antipirina/análogos & derivados , Antipirina/farmacologia , Antipirina/uso terapêutico , Dipirona/farmacologia , Dipirona/uso terapêutico , Encefalomielite Autoimune Experimental/fisiopatologia , Feminino , Hiperalgesia/tratamento farmacológico , Hiperalgesia/etiologia , Camundongos , Camundongos Endogâmicos C57BL , Glicoproteína Mielina-Oligodendrócito/imunologia , Glicoproteína Mielina-Oligodendrócito/toxicidade , NADPH Oxidases/antagonistas & inibidores , Proteínas do Tecido Nervoso/biossíntese , Proteínas do Tecido Nervoso/genética , Neuralgia/tratamento farmacológico , Neuralgia/etiologia , Nociceptividade/efeitos dos fármacos , Oligonucleotídeos Antissenso/farmacologia , Estresse Oxidativo , Oximas/farmacologia , Oximas/uso terapêutico , Fragmentos de Peptídeos/imunologia , Fragmentos de Peptídeos/toxicidade , Pregabalina/farmacologia , Pregabalina/uso terapêutico , Purinas/farmacologia , Purinas/uso terapêutico , Canal de Cátion TRPA1/antagonistas & inibidores , Canal de Cátion TRPA1/biossíntese , Canal de Cátion TRPA1/genética , Ácido Tióctico/farmacologia , Regulação para Cima/efeitos dos fármacosRESUMO
During the progression of the neurodegenerative process, mitochondria participates in several intercellular signaling pathways. Voltage-dependent anion-selective channel 1 (VDAC1) is a mitochondrial porin involved in the cellular metabolism and apoptosis intrinsic pathway in many neuropathological processes. In spinal cord injury (SCI), after the primary cell death, a secondary response that comprises the release of pro-inflammatory molecules triggers apoptosis, inflammation, and demyelination, often leading to the loss of motor functions. Here, we investigated the functional role of VDAC1 in the neurodegeneration triggered by SCI. We first determined that in vitro targeted ablation of VDAC1 by specific morpholino antisense nucleotides (MOs) clearly promotes neurite retraction, whereas a pharmacological blocker of VDAC1 oligomerization (4, 4'-diisothiocyanatostilbene-2, 2'-disulfonic acid, DIDS), does not cause this effect. We next determined that, after SCI, VDAC1 undergoes conformational changes, including oligomerization and N-terminal exposition, which are important steps in the triggering of apoptotic signaling. Considering this, we investigated the effects of DIDS in vivo application after SCI. Interestingly, blockade of VDAC1 oligomerization decreases the number of apoptotic cells without interfering in the neuroinflammatory response. DIDS attenuates the massive oligodendrocyte cell death, subserving undisputable motor function recovery. Taken together, our results suggest that the prevention of VDAC1 oligomerization might be beneficial for the clinical treatment of SCI.