RESUMEN
BACKGROUND: Peripheral nerve injury results in retrograde cell body-related changes in the spinal motoneurons that will contribute to the regenerative response of their axons. Successful functional recovery also depends on molecular events mediated by innate immune response during Wallerian degeneration in the nerve microenvironment. A previous study in our lab demonstrated that TLR 2 and 4 develop opposite effects on synaptic stability in the spinal cord after peripheral nerve injury. Therefore, we suggested that the better preservation of spinal cord microenvironment would positively influence distal axonal regrowth. In this context, the present work aimed to investigate the influence of TLR2 and TLR4 on regeneration and functional recovery after peripheral nerve injury. METHODS: Eighty-eight mice were anesthetized and subjected to unilateral sciatic nerve crush (C3H/HeJ, n = 22, C3H/HePas, n = 22; C57Bl6/J, n = 22 and TLR2(-/-), n = 22). After the appropriate survival times (3, 7, 14 days, and 5 weeks), all mice were killed and the sciatic nerves and tibialis cranialis muscles were processed for immunohistochemistry and transmission electron microscopy (TEM). Gait analysis, after sciatic nerve crushing, was performed in another set of mice (minimum of n = 8 per group), by using the walking track test (CatWalk system). RESULTS: TLR4 mutant mice presented greater functional recovery as well as an enhanced p75(NTR) and neurofilament protein expression as compared to the wild-type strain. Moreover, the better functional recovery in mutant mice was correlated to a greater number of nerve terminal sprouts. Knockout mice for TLR2 exhibited 30 % greater number of degenerated axons in the distal stump of the sciatic nerve and a decreased p75(NTR) and neurofilament protein expression compared to the wild type. However, the absence of TLR2 receptor did not influence the overall functional recovery. End-point equivalent functional recovery in transgenic mice may be a result of enhanced axonal diameter found at 2 weeks after lesion. CONCLUSIONS: Altogether, the present results indicate that the lack of TLR2 or the absence of functional TLR4 does affect the nerve regeneration process; however, such changes are minimized through different compensatory mechanisms, resulting in similar motor function recovery, as compared to wild-type mice. These findings contribute to the concept that innate immune-related molecules influence peripheral nerve regeneration by concurrently participating in processes taking place both at the CNS and PNS.
Asunto(s)
Neuropatía Ciática/metabolismo , Receptor Toll-Like 2/metabolismo , Receptor Toll-Like 4/metabolismo , Animales , Axotomía/efectos adversos , Regulación de la Expresión Génica/genética , Filamentos Intermedios/metabolismo , Filamentos Intermedios/ultraestructura , Cojera Animal/etiología , Locomoción/fisiología , Macrófagos/patología , Macrófagos/ultraestructura , Ratones , Ratones Endogámicos C3H , Ratones Endogámicos C57BL , Ratones Transgénicos , Mutación/genética , Unión Neuromuscular/patología , Unión Neuromuscular/ultraestructura , Receptor de Factor de Crecimiento Nervioso/metabolismo , Nervio Ciático/metabolismo , Nervio Ciático/patología , Nervio Ciático/ultraestructura , Neuropatía Ciática/complicaciones , Neuropatía Ciática/etiología , Especificidad de la Especie , Factores de Tiempo , Receptor Toll-Like 2/genética , Receptor Toll-Like 4/genéticaRESUMEN
The present study was designed to investigate the ameliorative role of ethanolic extract from leaves of Butea monosperma in chronic constriction injury (CCI) of sciatic nerve induced neuropathic pain in rats. Hot plate, acetone drop, paw pressure, Von Frey hair and tail immersion tests were performed to assess the degree of thermal hyperalgesia, cold chemical allodynia, mechanical hyperalgesia & allodynia in the left hind paw and tail thermal hyperalgesia. Further on, thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH) and total calcium levels were estimated to assess the biochemical changes in the sciatic nerve tissue. Histopathological changes were also observed in the sciatic nerve tissue. Ethanolic extract of Butea monosperma leaves and pregabalin (serving as positive control) were administered for 14 consecutive days starting from the day of surgery. CCI resulted in significant changes in behavioural and biochemical parameters. Pretreatment of Butea monosperma attenuated CCI induced development of behavioural, biochemical and histopathological alterations in a dose dependent manner, which is comparable to that of pregabalin pretreated group. These findings may be attributed to its potential anti-oxidative, neuroprotective and calcium channel modulatory actions of Butea monosperma.
Asunto(s)
Butea/química , Neuralgia/tratamiento farmacológico , Extractos Vegetales/uso terapéutico , Neuropatía Ciática/complicaciones , Animales , Enfermedad Crónica , Constricción , Modelos Animales de Enfermedad , Femenino , Masculino , Neuralgia/etiología , Ratas , Ratas WistarRESUMEN
Preventing the harm caused by nerve degeneration is a major challenge in neurodegenerative diseases and in various forms of trauma to the nervous system. The aim of the current work was to investigate the effects of systemic administration of 2,4-dinitrophenol (DNP), a compound with newly recognized neuroprotective properties, on sciatic-nerve degeneration following a crush injury. Sciatic-nerve injury was induced by unilateral application of an aneurysm clip. Four groups of mice were used: uninjured, injured treated with vehicle (PBS), injured treated with two intraperitoneal doses of DNP (0.06 mg DNP/kg every 24 h), and injured treated with four doses of DNP (every 12 h). Animals were sacrificed 48 h post injury and both injured and uninjured (contralateral) sciatic nerves were processed for light and electron microscopy. Morphometric, ultrastructural, and immunohistochemical analysis of injured nerves established that DNP prevented axonal degeneration, blocked cytoskeletal disintegration, and preserved the immunoreactivity of amyloid precursor protein (APP) and Neuregulin 1 (Nrg1), proteins implicated in neuronal survival and myelination. Functional tests revealed preservation of limb function following injury in DNP-treated animals. Results indicate that DNP prevents nerve degeneration and suggest that it may be a useful small-molecule adjuvant in the development of novel therapeutic approaches in nerve injury.
Asunto(s)
2,4-Dinitrofenol/farmacología , Fármacos Neuroprotectores/farmacología , Recuperación de la Función/efectos de los fármacos , Neuropatía Ciática/tratamiento farmacológico , Degeneración Walleriana/tratamiento farmacológico , 2,4-Dinitrofenol/uso terapéutico , Precursor de Proteína beta-Amiloide/efectos de los fármacos , Precursor de Proteína beta-Amiloide/metabolismo , Animales , Axones/efectos de los fármacos , Axones/metabolismo , Axones/patología , Citoesqueleto/efectos de los fármacos , Citoesqueleto/metabolismo , Citoesqueleto/patología , Modelos Animales de Enfermedad , Esquema de Medicación , Femenino , Ratones , Neurregulina-1/efectos de los fármacos , Neurregulina-1/metabolismo , Fármacos Neuroprotectores/uso terapéutico , Recuperación de la Función/fisiología , Nervio Ciático/efectos de los fármacos , Nervio Ciático/patología , Nervio Ciático/fisiopatología , Neuropatía Ciática/complicaciones , Neuropatía Ciática/fisiopatología , Degeneración Walleriana/fisiopatología , Degeneración Walleriana/prevención & controlRESUMEN
The main purpose of the present study was to evaluate whether REM sleep deprivation (RSD) influences the development of anhedonia in rats in a peripheral neuropathy model induced by sciatic nerve constriction injury (CCI). Anhedonia was measured by assessing daily water/sucrose intake. Four groups were assessed: control (CTRL), CCI, RSD, and CCI+RSD (n=8/group). Intake data were collected at baseline (mean of 3 days), on the 1st and 2nd days after a CCI or SHAM procedure, during 4 days of RSD, and during an additional 10 days (rebound period or equivalent in home-cage rats). Control rats spontaneously and progressively increased sucrose intake, reaching final daily volumes significantly greater than respective initial baseline amounts. RSD promoted an additional and immediate significant increase in sucrose intake during sleep deprivation days. The CCI group did not display a spontaneous, progressive increase in sucrose intake. When CCI was combined with RSD, the increase in sucrose intake induced by RSD was significantly lower than in animals submitted to RSD alone; the (CCI+RSD) group also failed to show a spontaneous and progressive increase in sucrose intake. The present findings indicate that animal model of chronic neuropathy exhibits reduced sucrose ingestion. Accordingly, this anhedonic condition that constitutes to the core manifestation of depressive states did not occur in response to a single episode of total RSD.
Asunto(s)
Depresión/etiología , Depresión/fisiopatología , Neuropatía Ciática/complicaciones , Neuropatía Ciática/fisiopatología , Privación de Sueño/complicaciones , Privación de Sueño/fisiopatología , Animales , Depresión/psicología , Susceptibilidad a Enfermedades , Conducta de Ingestión de Líquido/fisiología , Masculino , Motivación , Ratas , Ratas Wistar , Neuropatía Ciática/psicología , Privación de Sueño/psicología , Sueño REM/fisiologíaRESUMEN
Neuropathic pain is an important clinical problem and it is usually resistant to the current therapy. We have recently characterized a novel analgesic peptide, crotalphine, from the venom of the South American rattlesnake Crotalus durissus terrificus. In the present work, the antinociceptive effect of crotalphine was evaluated in an experimental model of neuropathic pain induced in rats by chronic constriction of sciatic nerve. The effect of the peptide was compared to that induced by the crude venom, which confirmed that crotalphine is responsible for the antinociceptive effect of the crotalid venom on neuropathic pain. For characterization of neuropathic pain, the presence of hyperalgesia, allodynia and spontaneous pain was assessed at different times after nerve constriction. These phenomena were detected 24 h after surgery and persisted at least for 14 days. The pharmacological treatments were performed on day 14 after surgery. Crotalphine (0.2-5 microg/kg) and the crude venom (400-1600 microg/kg) administered p.o. inhibited hyperalgesia, allodynia and spontaneous pain induced by nerve constriction. The antinociceptive effect of the peptide and crude venom was long lasting, since it was detected up to 3 days after treatment. Intraplantar injection of naloxone (1 microg/paw) blocked the antinociceptive effect, indicating the involvement of opioid receptors in this phenomenon. Gabapentin (200 mg/kg, p.o.), and morphine (5 mg/kg, s.c.), used as positive controls, blocked hyperalgesia and partially inhibited allodynia induced by nerve constriction. These data indicate that crotalphine induces a potent and long lasting opioid antinociceptive effect in neuropathic pain that surpasses that observed with standard analgesic drugs.
Asunto(s)
Analgésicos , Venenos de Crotálidos/farmacología , Dolor/tratamiento farmacológico , Dolor/etiología , Péptidos/farmacología , Enfermedades del Sistema Nervioso Periférico/complicaciones , Enfermedades del Sistema Nervioso Periférico/tratamiento farmacológico , Receptores Opioides/efectos de los fármacos , Animales , Conducta Animal/efectos de los fármacos , Enfermedad Crónica , Constricción Patológica/complicaciones , Hiperalgesia/tratamiento farmacológico , Masculino , Actividad Motora/efectos de los fármacos , Umbral del Dolor/efectos de los fármacos , Estimulación Física , Ratas , Ratas Wistar , Neuropatía Ciática/complicaciones , Neuropatía Ciática/tratamiento farmacológicoRESUMEN
We have recently shown that the administration of bone marrow stromal cells (MSCs) prevents the development of mechanical and thermal allodynia in animals subjected to a sciatic nerve injury. Furthermore, exogenously administered MSCs have been shown to participate in the repair and regeneration of damaged tissues in a variety of animal models. However, some limitations of this therapeutic approach, basically related to the ex vivo cell manipulation procedure, have arisen. IMT504, the prototype of the PyNTTTTGT class of immunostimulatory oligonucleotides, stimulates MSC expansion both in vitro and in vivo. In this study, we evaluated the effect of IMT504 systemic administration on the development of mechanical and thermal allodynia in rats subjected to a sciatic nerve crush. Animals were treated with IMT504, MSCs or saline either immediately after performing the lesion or 4 days after it, and were evaluated using the von Frey and Choi tests at different times after injury. Control animals developed both mechanical and thermal allodynia. Animals receiving either IMT504 or MSCs immediately after injury did not develop mechanical allodynia and presented a significantly lower number of nociceptive responses to cold stimulation as compared to controls. Moreover, injury-induced allodynia was significantly reduced after IMT504 delayed treatment. Our results show that the administration of IMT504 reduces neuropathic pain-associated behaviors, suggesting that IMT504 could represent a possible therapeutic approach for the treatment of neuropathic pain.
Asunto(s)
Analgésicos/uso terapéutico , Hiperalgesia/terapia , Oligodesoxirribonucleótidos/uso terapéutico , Umbral del Dolor/efectos de los fármacos , Animales , Conducta Animal , Trasplante de Médula Ósea/métodos , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Hiperalgesia/etiología , Masculino , Dimensión del Dolor , Ratas , Ratas Sprague-Dawley , Neuropatía Ciática/complicaciones , Células del Estroma/trasplante , Factores de TiempoRESUMEN
The present study examined the anti-hypernociceptive effects of agmatine (AGM) in acute and chronic models of behavioural pain in mice. Agmatine (30 mg/kg, i.p. 30 min early), produced time-dependent inhibition of mechanical hypernociception induced by Complete Freund's Adjuvant (CFA) injected in the mice paw (inhibition of 52+/-7%) after 4 h. Given chronically (twice a day) during 10 days, AGM significantly reversed the mechanical hypernociception caused by CFA (inhibition of 43+/-6% to 67+/-5%). Moreover, AGM also significantly reduced the mechanical hypernociception caused by partial sciatic nerve ligation (PSNL) during 6 h, with inhibition of 81+/-8%. In thermal hypernociception (cold stimuli) caused by PSNL the antinociceptive effect of AGM was prolonged by 4 h with inhibition of 97+/-3% observed 1 h after the treatment. Nevertheless, AGM failed to inhibit the paw oedema caused by CFA and the myeloperoxidase enzyme activity. Of note, AGM (10-100 mg/kg, i.p., 30 min before) also elicited a pronounced inhibition of the biting response induced by TNF-alpha and IL-1beta in mice, with mean ID(50) values of 61.3 mg/kg (47.7-78.6 mg/kg) and 30.4 mg/kg (18.6-49.8 mg/kg) and inhibitions of 75+/-5% and 66+/-6%, respectively. Together, present and previous findings show that AGM given systemically is effective in inhibiting mechanical and thermal hypernociception present in chronic inflammatory processes caused by CFA and also the neuropathic pain caused by PSNL.
Asunto(s)
Agmatina/uso terapéutico , Analgésicos/uso terapéutico , Inflamación/complicaciones , Dolor/tratamiento farmacológico , Dolor/etiología , Neuropatía Ciática/complicaciones , Análisis de Varianza , Animales , Conducta Animal , Citocinas/metabolismo , Modelos Animales de Enfermedad , Edema/etiología , Edema/patología , Femenino , Adyuvante de Freund , Inflamación/inducido químicamente , Ratones , Neutrófilos/efectos de los fármacos , Neutrófilos/enzimología , Dimensión del Dolor/métodos , Peroxidasa/metabolismoRESUMEN
PURPOSE: This study involved a clinical and histopathologic evaluation of the use of gangliosides in nerve regeneration, using an experimental model with higher vertebrates. MATERIALS AND METHODS: Forty Sprague Dawley rats had their right sciatic nerve crushed for 1 minute in a hemostatic tweezer. The animals were divided into experimental and control groups. The animals in the experimental group received an intramuscular injection of gangliosides in the left thigh for 25 days, whereas those in the control group received infiltrations of distilled water. A clinical evaluation of gait was made 24 hours and then 45 days after the surgical intervention, and a histopathologic evaluation of the sciatic nerves was performed after 45 days. RESULTS: There were no signs that the use of gangliosides significantly altered the animals' gait after 45 days. The animals in the experimental group had a greater frequency and intensity of inflammatory response than seen in the control group. CONCLUSION: The systemic use of gangliosides produced no improvement in gait and led to a more frequent and intense inflammatory response at the site of injury.
Asunto(s)
Gangliósidos/fisiología , Vaina de Mielina/fisiología , Compresión Nerviosa , Regeneración Nerviosa/fisiología , Neuropatía Ciática/terapia , Animales , Femenino , Gangliósidos/uso terapéutico , Inflamación/complicaciones , Inflamación/patología , Vaina de Mielina/efectos de los fármacos , Vaina de Mielina/patología , Regeneración Nerviosa/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Neuropatía Ciática/complicaciones , Neuropatía Ciática/patologíaRESUMEN
Among the numerous ways of assessing regeneration after peripheral nerve lesions, the analysis of gait is one of the most important, because it shows the recovery of function, which is the ultimate goal of the repair machinery. The sciatic function index was introduced as a method to assess reinnervation after an experimental sciatic nerve lesion, and was adapted to the mouse model. The sciatic static index (SSI), is more simple and practical to perform, and is not so influenced by gait's velocity, but this method has not yet been adapted to the mouse model of sciatic lesion. We used 63 male Swiss mice (Mus musculus) to develop a formula to the sciatic static index in mice (SSIm). The animals were divided on three groups (control, transection and crush). They were evaluated at the preoperative and 7th, 14th, 21st, 28th, 35th and 42nd days postoperative by the ink track method (SFI), and by the acquisition of photographs of the plantar aspects of the injured and uninjured hind paws. The parameters evaluated were the 1-5 toe spread (TS), the 2-4 toe spread (ITS) and the distance between the tip of the third toe and the most posterior aspect of the paw (PL), on both methods. After verifying the temporal pattern of function, correlation and reproducibility of the measurements, we performed a multiple regression analysis using SFI values as dependent variable, and the TS, ITS and PL measured with the photo method as independent variables, and found the formula of the SSI for mice (SSIm). The three groups (control, transection and crush) had a characteristic pattern of dysfunction. The parameters measured in the ink and photo method had variable but significant correlations between them (P<0.000), but photo method of measurement showed a better reproducibility. The correlation between SFI and SSIm showed a high correlation coefficient (r=0.892, P<0.000), and demonstrates that SSIm can be used as an alternative method to assess the functional status relative of sciatic nerve activity in mice.
Asunto(s)
Pie/fisiopatología , Trastornos Neurológicos de la Marcha/clasificación , Trastornos Neurológicos de la Marcha/fisiopatología , Indicadores de Salud , Nervio Ciático/fisiopatología , Neuropatía Ciática/clasificación , Neuropatía Ciática/fisiopatología , Animales , Modelos Animales de Enfermedad , Marcha , Trastornos Neurológicos de la Marcha/diagnóstico , Trastornos Neurológicos de la Marcha/etiología , Masculino , Ratones , Neuropatía Ciática/complicaciones , Neuropatía Ciática/diagnósticoRESUMEN
In this study we analyzed the systemic antiallodynic properties of diacerhein, a drug used to treat osteoarthritis, in inflammatory and neuropathic models of nociception in mice. The effects of diacerhein were compared with those of gabapentin, a drug used clinically for the management of neuropathic pain. Similar to gabapentin, diacerhein was able to significantly reverse the mechanical allodynia induced by carrageenan. A significant inhibition of carrageenan-induced nociception was also observed when diacerhein was administered by the intrathecal but not by the intraplantar route. The treatment with diacerhein or with gabapentin also inhibited the mechanical allodynia induced by complete Freund's adjuvant (CFA) or after the partial ligation of the sciatic nerve (PLSN). In the same range of doses, diacerhein or gabapentin did not affect the locomotor activity, motor coordination, or body temperature of the animals. The present results indicate that diacerhein produces marked antiallodynic effects in carrageenan and CFA nociception models and also inhibits the neuropathic pain after PLSN, with an efficacy similar to that observed for gabapentin. Diacerhein may be a potentially interesting tool for the management of inflammatory and neuropathic pain.
Asunto(s)
Antraquinonas/uso terapéutico , Antiinflamatorios no Esteroideos/uso terapéutico , Inflamación/tratamiento farmacológico , Dolor/tratamiento farmacológico , Neuropatía Ciática/tratamiento farmacológico , Aminas/uso terapéutico , Animales , Ácidos Ciclohexanocarboxílicos/uso terapéutico , Modelos Animales de Enfermedad , Femenino , Gabapentina , Ratones , Neuropatía Ciática/complicaciones , Ácido gamma-Aminobutírico/uso terapéuticoRESUMEN
Injury to peripheral nerves often results in a persistent neuropathic pain condition that is characterized by spontaneous pain, allodynia, and hyperalgesia. Nerve injury is accompanied by a local inflammatory reaction in which nerve-associated and immune cells release several pronociceptive mediators. Kinin B1 receptors are rarely expressed in nontraumatized tissues, but they can be expressed after tissue injury. Because B1 receptors mediate chronic inflammatory painful processes, we studied their participation in neuropathic pain using receptor gene-deleted mice. In the absence of neuropathy, we found no difference in the paw-withdrawal responses to thermal or mechanical stimulation between B1 receptor knock-out mice and 129/J wild-type mice. Partial ligation of the sciatic nerve in the wild-type mouse produced a profound and long-lasting decrease in thermal and mechanical thresholds in the paw ipsilateral to nerve lesion. Threshold changed neither in the sham-operated animals nor in the paw contralateral to lesion. Ablation of the gene for the B1 receptor resulted in a significant reduction in early stages of mechanical allodynia and thermal hyperalgesia. Furthermore, systemic treatment with the B1 selective receptor antagonist des-Arg9-[Leu8]-bradykinin reduced the established mechanical allodynia observed 7-28 d after nerve lesion in wild-type mice. Partial sciatic nerve ligation induced an upregulation in B1 receptor mRNA in ipsilateral paw, sciatic nerve, and spinal cord of wild-type mice. Together, kinin B1 receptor activation seems to be essential to neuropathic pain development, suggesting that an oral-selective B1 receptor antagonist might have therapeutic potential in the management of chronic pain.
Asunto(s)
Neuralgia/etiología , Receptor de Bradiquinina B1/deficiencia , Receptor de Bradiquinina B1/fisiología , Neuropatía Ciática/complicaciones , Animales , Bradiquinina/análogos & derivados , Bradiquinina/farmacología , Bradiquinina/uso terapéutico , Antagonistas del Receptor de Bradiquinina B1 , Femenino , Lateralidad Funcional , Expresión Génica/fisiología , Hiperalgesia/genética , Hiperalgesia/fisiopatología , Masculino , Ratones , Ratones Noqueados/fisiología , Neuralgia/terapia , Dimensión del Dolor/métodos , ARN Mensajero/metabolismo , Receptor de Bradiquinina B1/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Piel/metabolismo , Piel/patología , Temperatura Cutánea/genética , Factores de TiempoRESUMEN
The main purpose of the present study was to examine sleep patterns over 21-day periods of rats in a peripheral neuropathy model induced by sciatic nerve constriction. Evaluation of the recordings showed that chronic constrictive injury (CCI) induced sleep alterations such as reduced sleep efficiency and increased number of arousals, especially during the light period. Among these alterations, sleep patterns were most affected between day 2 and day 10. The rats took longer to get to sleep from day 2 to 7 days after the CCI in the light period. Additionally, latency to the first paradoxical sleep episode was reduced in the second to fourth day after CCI in both light and dark period recordings. In conclusion, sciatic nerve constriction induced poor sleep quality with disrupted sleep in rats, particularly during the first week of that condition.