RESUMO
BACKGROUND: Chronic constriction injury (CCI) is a model of neuropathic pain induced by four loose ligatures around the sciatic nerve. This work aimed to investigate the sensory, affective, cognitive, and motor changes induced by an adaptation of the CCI model by applying a single ligature around the sciatic nerve. METHODS: Mechanical allodynia was measured from day 1 to day 28 postsurgery by the von Frey test. The beam walking test (BWT) was conducted weekly until 28 days after surgery. Anxiety- and depression-like behaviors, and cognitive performance were assessed through the open field (OF), forced swimming (FS), and novel object recognition (NOR) tests, respectively, 21 days after surgery. RESULTS: The two CCI models, both Bennett and Xie's model (four ligatures of the sciatic nerve) and a modification of it (one ligature), induced mechanical allodynia, increased immobility in the FS, and reduced recognition index in the NOR. The exploratory behavior and time spent in the central part of the arena decreased, while the defensive behavior increased in the OF. The animals subjected to the two CCI models showed motor alterations in the BWT; however, autotomy was observed only in the group with four ligatures and not in the group with a single ligature. CONCLUSIONS: Overall these results demonstrate that our adapted CCI model, using a single ligature around the sciatic nerve, induces sensory, affective, cognitive, and motor alterations comparable to the CCI model with four ligatures without generating autotomy. This adaptation to the CCI model may therefore represent an appropriate and more easily performed model for inducing neuropathic pain and study underlying mechanisms and effective treatments.
Assuntos
Disfunção Cognitiva , Mononeuropatias , Neuralgia , Animais , Constrição , Modelos Animais de Doenças , Hiperalgesia/epidemiologia , Neuralgia/epidemiologia , Neuralgia/etiologia , Ratos , Nervo IsquiáticoRESUMO
The mechanisms underlying chronic and neuropathic pain pathology involve peripheral and central sensitisation. The medial prefrontal cortex (mPFC) seems to participate in pain chronification, and glutamatergic neurotransmission may be involved in this process. Thus, the aim of the present work was to investigate the participation of the prelimbic (PrL) area of the mPFC in neuropathic pain as well as the role of N-methyl D-aspartate (NMDA) glutamate receptors in neuropathic pain induced by a modified sciatic nerve chronic constriction injury (CCI) protocol in Wistar rats. Neural inputs to the PrL cortex were inactivated by intracortical treatment with the synapse blocker cobalt chloride (CoCl2, 1.0 mM/200 nL) 7, 14, 21, or 28 days after the CCI or sham procedure. The glutamatergic agonist NMDA (0.25, 1 or 4 nmol) or the selective NMDA receptor antagonist LY235959 (2, 4 or 8 nmol) was microinjected into the PrL cortex 21 days after surgery. CoCl2 administration in the PrL cortex decreased allodynia 21 and 28 days after CCI. NMDA at 1 and 4 nmol increased allodynia, whereas LY235959 decreased mechanical allodynia at the highest dose (8 nmol) microinjected into the PrL cortex. These findings suggest that NMDA receptors in the PrL cortex participate in enhancing the late phase of mechanical allodynia after NMDA-induced increases and LY235959-induced decreases in allodynia 21 days after CCI. The glutamatergic system potentiates chronic neuropathic pain by NMDA receptor activation in the PrL cortex. Mechanism of neuropathic pain. The infusion of CoCl2, a synapse activity blocker, into the prelimbic (PrL) division of the medial prefrontal cortex (mPFC) decreased the severity of mechanical allodynia, showing the late participation of the limbic cortex. The glutamatergic system potentiates chronic neuropathic pain via NMDA receptor activation in the PrL cortex.
Assuntos
Neuralgia/metabolismo , Nervos Periféricos/metabolismo , Córtex Pré-Frontal/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Animais , Cobalto/farmacologia , Hiperalgesia/tratamento farmacológico , Isoquinolinas/farmacologia , Masculino , N-Metilaspartato/farmacologia , Neuralgia/tratamento farmacológico , Traumatismos dos Nervos Periféricos/tratamento farmacológico , Córtex Pré-Frontal/efeitos dos fármacos , Ratos Wistar , Transmissão Sináptica/efeitos dos fármacosRESUMO
It is well established that dorsal root ganglion (DRG) cells synthesize prostaglandin. However, the role that prostaglandin plays in the inflammatory hyperalgesia of peripheral tissue has not been established. Recently, we have successfully established a technique to inject drugs (3 µL) directly into the L5-DRG of rats, allowing in vivo identification of the role that DRG cell-derived COX-1 and COX-2 play in the development of inflammatory hyperalgesia of peripheral tissue. IL-1ß (0.5 pg) or carrageenan (100 ng) was administered in the L5-peripheral field of rat hindpaw and mechanical hyperalgesia was evaluated after 3 h. Administration of a nonselective COX inhibitor (indomethacin), selective COX-1 (valeryl salicylate), or selective COX-2 (SC-236) inhibitors into the L5-DRG prevented the hyperalgesia induced by IL-1ß. Similarly, oligodeoxynucleotide-antisense against COX-1 or COX-2, but not oligodeoxynucleotide-mismatch, decreased their respective expressions in the L5-DRG and prevented the hyperalgesia induced by IL-1ß in the hindpaw. Immunofluorescence analysis demonstrated that the amount of COX-1 and COX-2, constitutively expressed in TRPV-1(+) cells of the DRG, significantly increased after carrageenan or IL-1ß administration. In addition, indomethacin administered into the L5-DRG prevented the increase of PKCε expression in DRG membrane cells induced by carrageenan. Finally, the administration of EP1/EP2 (7.5 ng) or EP4 (10 µg) receptor antagonists into L5-DRG prevented the hyperalgesia induced by IL-1ß in the hindpaw. In conclusion, the results of this study suggest that the inflammatory hyperalgesia in peripheral tissue depends on activation of COX-1 and COX-2 in C-fibers, which contribute to the induction and maintenance of sensitization of primary sensory neurons.
Assuntos
Ciclo-Oxigenase 1/metabolismo , Ciclo-Oxigenase 2/metabolismo , Gânglios Espinais/enzimologia , Hiperalgesia/enzimologia , Hiperalgesia/patologia , Inflamação/enzimologia , Inflamação/patologia , Proteínas de Membrana/metabolismo , Animais , Carragenina/farmacologia , Inibidores de Ciclo-Oxigenase/administração & dosagem , Inibidores de Ciclo-Oxigenase/farmacologia , Ativação Enzimática/efeitos dos fármacos , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/patologia , Técnicas de Silenciamento de Genes , Hiperalgesia/complicações , Indometacina/administração & dosagem , Indometacina/farmacologia , Inflamação/complicações , Interleucina-1beta/farmacologia , Vértebras Lombares/efeitos dos fármacos , Vértebras Lombares/patologia , Masculino , Proteína Quinase C-épsilon/metabolismo , Transporte Proteico/efeitos dos fármacos , Ratos , Ratos Wistar , Receptores de Prostaglandina E/antagonistas & inibidores , Receptores de Prostaglandina E/metabolismo , Canais de Cátion TRPV/metabolismoRESUMO
Nitric oxide (NO) is involved in many physiological processes and several lines of evidence have indicated that NO plays a complex and diverse role in the modulation of pain. Nitric oxide is an important neurotransmitter involved in the nociceptive process and, in the dorsal horn of the spinal cord, it contributes to the development of central sensitization. On the other hand, experimental data have also demonstrated that NO inhibits nociception in the peripheral and also in the central nervous system. In addition, it has been shown that nitric oxide mediates the analgesic effect of opioids and other analgesic substances. The information included in the present review aims to present and analyze data about the dual effect of NO on pain transmission and control, the molecular mechanisms involved in these effects and also the potential use of nitric oxide in pain therapy.
Assuntos
Analgesia/métodos , Óxido Nítrico/metabolismo , Nociceptores/metabolismo , Dor/metabolismo , Animais , Humanos , Óxido Nítrico/uso terapêutico , Dor/tratamento farmacológico , Dor/fisiopatologia , Medição da DorRESUMO
We previously described an animal model of persistent inflammatory sensitization of nociceptors. In this model the hypernociception persists for more than 30 days after the cessation of 2 weeks of daily intraplantar treatment with prostaglandin E(2) (PGE(2)). The tetrodotoxin-resistant (TTX-R) voltage-gated sodium channel Na(V)1.8 is considered a characteristic of primary afferent nociceptive C fibers and plays an important role in acute hypernociception. In the present study, the relevance of the Na(V)1.8 channel was investigated in this model of persistent mechanical hypernociception in rats. In the PGE(2)-induced persistent hypernociception, but not in the single injection-induced acute hypernociception, the mRNA expression (RT-PCR) of Na(V)1.8 in dorsal root ganglia (DRG) was up-regulated. A similar increase of Na(V)1.8 mRNA was observed when DbcAMP was used to induce persistent hypernociception. Four daily intrathecal administrations of oligodeoxynucleotides (ODN) antisense against Na(V)1.8 decreased the mRNA encoding Na(V)1.8 in DRG. The intrathecal administration of ODN antisense prevented the PGE(2)-induced acute hypernociception and significantly reduced ongoing PGE(2)-induced persistent hypernociception. A parallel restoration of the persistent hypernociception and up-regulation of Na(V)1.8 mRNA was observed after the cessation of ODN antisense treatment. These results suggest the participation of Na(V)1.8 channels in the development and maintenance of chronic inflammatory hyperalgesia, and confirm their involvement in the acute inflammatory hypernociception.
Assuntos
Inflamação/fisiopatologia , Proteínas do Tecido Nervoso/biossíntese , Dor/fisiopatologia , Canais de Sódio/biossíntese , Animais , Doença Crônica , Dinoprostona/toxicidade , Modelos Animais de Doenças , Gânglios Espinais/efeitos dos fármacos , Gânglios Espinais/metabolismo , Inflamação/induzido quimicamente , Masculino , Canal de Sódio Disparado por Voltagem NAV1.8 , Proteínas do Tecido Nervoso/efeitos dos fármacos , Nociceptores/metabolismo , Oligonucleotídeos Antissenso/farmacologia , Medição da Dor , RNA Mensageiro/análise , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Bloqueadores dos Canais de Sódio/farmacologia , Canais de Sódio/efeitos dos fármacos , Regulação para CimaRESUMO
It has been previously described that daily intraplantar (i.pl.) injections of prostaglandin E2 (PGE2) and dopamine in rats for 14 days cause the development of a persistent mechanical nociceptor hypersensitivity state lasting more than 30 days. Considering that during inflammation, the release of these hyperalgesic agents are mediated by cytokines, we investigated in the present study whether interleukin-1beta (IL-1beta), IL-8 and tumour necrosis factor-alpha (TNF-alpha) are able to induce persistent mechanical nociceptor hypersensitivity. Daily i.pl. administration of TNF-alpha, IL-1beta or IL-8 for 18 days led to persistent mechanical nociceptor hypersensitivity, which lasted at least 30 days after the cessation of treatment. The co-treatment of the animals with IL-1beta plus indomethacin, but not with atenolol, prevented the induction of persistent mechanical nociceptor hypersensitivity. The co-treatment of the animals with IL-8 plus atenolol, but not with indomethacin, prevented the induction of persistent mechanical nociceptor hypersensitivity. The daily co-treatment of TNF-alpha with either indomethacin or atenolol partially inhibited (+/-50%) the induction of persistent mechanical nociceptor hypersensitivity. However, the combined treatment with indomethacin plus atenolol abolished the induction of the persistent mechanical nociceptive hypersensitivity by TNF-alpha.A single injection of cytokines in the contralateral paws of the animals with persistent hypersensitivity caused only an acute nociceptive response. This observation, together with the demonstration of undetectable levels of immunoglobulins against TNF-alpha, IL-1beta or IL-8 in the sera of animals after the development of the persistent hypersensitivity induced by those cytokines, indicate that this event is not due to an ongoing immunological response against the cytokines. In conclusion, our results support the suggestion that IL-1beta- and IL-8-induced persistent mechanical nociceptor hypersensitivity results from the endogenous release of eicosanoids and sympathetic amines, respectively. However, TNF-alpha-induced mechanical nociceptor hypersensitivity results from the concomitant endogenous release of eicosanoids and sympathomimetic mediators.
Assuntos
Antineoplásicos/farmacologia , Hiperalgesia/induzido quimicamente , Interleucina-1/farmacologia , Interleucina-8/farmacologia , Nociceptores/fisiologia , Fator de Necrose Tumoral alfa/farmacologia , Antagonistas Adrenérgicos beta/farmacologia , Animais , Anti-Inflamatórios não Esteroides/farmacologia , Anticorpos/sangue , Atenolol/farmacologia , Quimioterapia Combinada , Hiperalgesia/tratamento farmacológico , Hiperalgesia/fisiopatologia , Indometacina/farmacologia , Masculino , Nociceptores/efeitos dos fármacos , Ratos , Ratos Wistar , Fator de Necrose Tumoral alfa/imunologiaRESUMO
1. We investigated the mediators responsible for mechanical hypersensitivity induced by antigen challenge in rats immunised with ovalbumin (OVA). 2. Challenge with OVA (12.5-100 micro g, intraplantar) caused a dose- and time-dependent mechanical hypersensitivity, which peaked 3 h after, decreased thereafter and reached control levels 24 h later. 3. Levels of TNFalpha, IL-1beta and cytokine-induced neutrophil chemoattractant 1 (CINC-1) were increased in paw skin after antigen challenge. 4. OVA-evoked hypersensitivity was partially inhibited (about 51%) by pretreatment with anti-TNFalpha, IL-1beta and IL-8 sera or with IL-1 receptor antagonist (IL-1ra), but not anti-NGF serum. Pretreatment with thalidomide (45 mg kg(-1)) or pentoxifylline (100 mg kg(-1)) also partially inhibited the hypersensitivity at 1-3 h after challenge. 5. Pretreatment with indomethacin (5 mg kg(-1)) or atenolol (1 mg kg(-1)) reduced the OVA-induced hypersensitivity at 1 and 3 h, but not at 5 h after challenge, while the combination of B(1) and B(2) bradykinin receptor antagonists was ineffective over the same times. 6. Pretreatment with MK886 (5-lipoxygenase-activating protein inhibitor, 3 mg kg(-1)), CP 105696 (LTB(4) receptor antagonist; 3 mg kg(-1)) or dexamethasone (0.5 mg kg(-1)) inhibited the hypersensitivity from 1 to 5 h. Furthermore, LTB(4) levels were increased in the paw skin of challenged rats. 7. In conclusion, our results suggest that the TNFalpha-, IL-1beta- and CINC-1-driven release of prostaglandins, sympathetic amines and LTB(4) mediates the first 3 h of mechanical hypersensitivity induced by antigen challenge in rats. At 5 h after OVA administration, although TNFalpha has some role, LTB(4) is the critical nociceptive mediator.
Assuntos
Antígenos/administração & dosagem , Antígenos/imunologia , Hiperalgesia/imunologia , Hiperalgesia/metabolismo , Leucotrieno B4/fisiologia , Animais , Relação Dose-Resposta a Droga , Relação Dose-Resposta Imunológica , Hipersensibilidade/imunologia , Hipersensibilidade/metabolismo , Injeções Subcutâneas , Leucotrieno B4/biossíntese , Masculino , Ovalbumina/administração & dosagem , Ovalbumina/imunologia , Medição da Dor/métodos , Estimulação Física/métodos , Ratos , Ratos Wistar , Pele/imunologia , Pele/metabolismo , Regulação para Cima/imunologiaRESUMO
Neutrophil migration to an infectious focus is essential for control and resolution of infection. Early studies demonstrated that the failure of such migration is observed in lethal sepsis induced by cecal ligation and puncture (L-CLP), whereas intense neutrophil migration is seen in sublethal CLP (SL-CLP). In this study, we found that inhibition of synthesis of prostaglandins or leukotriene B4 (LTB4) did not modify the failure of neutrophil migration or the survival rate of L-CLP mice. In addition, pretreatment of L-CLP mice with a platelet activating factor (PAF) receptor antagonist (UK74505), despite not interfering with the failure process, significantly increased (33%) the survival rate of the animals. Inhibitors of prostaglandin synthesis (indomethacin and meloxican) and UK74505 did not modify the neutrophil migration observed in SL-CLP. On the other hand, the blockade of LTB4 synthesis (MK886, a 5-lipoxygenase-activating protein inhibitor) or of its receptors (CP-105,696) resulted in reduced neutrophil migration to the peritoneal cavity in SL-CLP mice (62% and 60%, respectively), a consequent increase in the number of bacteria in the inflammatory focus, and a reduced survival rate of the animals (43% and 38%, respectively). Both SL-CLP and L-CLP animals presented significant levels of LTB4 in the peritoneal exudate (3- and 8-fold higher than sham group, respectively) and these were reduced by the pretreatment of mice with LTB4 inhibitors. In conclusion, our results suggest that LTB4, but not prostaglandins or PAF, is an important chemoattractant involved in neutrophil recruitment to infection sites in SL-CLP, a crucial event in confining the invading pathogens to a restricted area. However, in circumstances in which the infection turns to a lethal sepsis, LTB4 is not involved in the observed failure of neutrophil migration to the infectious focus.
Assuntos
Ceco/cirurgia , Movimento Celular , Leucotrieno B4/sangue , Leucotrieno B4/fisiologia , Neutrófilos/citologia , Ferimentos Penetrantes , Animais , Di-Hidropiridinas/farmacologia , Eicosanoides/metabolismo , Imidazóis/farmacologia , Indóis/farmacologia , Inflamação , Leucotrienos/metabolismo , Inibidores de Lipoxigenase/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neutrófilos/metabolismo , Peritônio/metabolismo , Fator de Ativação de Plaquetas/metabolismo , Prostaglandinas/metabolismo , Fatores de TempoRESUMO
In recent years, evidence that sensitization of primary afferent nociceptors is an important event associated with chronic pain has been accumulating. The present study aimed to evaluate the participation of the prostaglandin and sympathetic components in the long-lasting sensitization of nociceptors induced by acute inflammation in mice. The intraplantar administration of carrageenan (100 µg) enhanced the nociceptive response to a small dose of PGE(2) (9 ng/paw) or dopamine (3 µg/paw) up to 30 days later. This long-lasting sensitization is dependent on dopaminergic and prostanoid systems, since the pre-treatment with chlorpromazine (3 µg/paw) or indomethacin (100 µg/paw), but not local (6 µg/paw) or systemic (6 mg/kg) treatment with morphine, prevented its development. In agreement with this idea, the previous intraplantar administration of hyperalgesic doses of PGE(2) or dopamine also induced long-lasting sensitization, which was fully prevented by pretreatment with EP(4) and D(1) antagonists, respectively. In summary, the present work described in mice a long-lasting sensitization of nociceptors, initiated by an acute inflammatory stimulation and dependent on dopaminergic and prostanoid systems. The present data represent new insights on the mechanisms of peripheral sensitization that could contribute to establish the basis of new therapeutic strategies for acute and chronic inflammatory pain.
Assuntos
Sensibilização do Sistema Nervoso Central/fisiologia , Dopamina/fisiologia , Inflamação/fisiopatologia , Nociceptores/fisiologia , Prostaglandinas/fisiologia , Animais , Anti-Inflamatórios não Esteroides/farmacologia , Compostos de Bifenilo/farmacologia , Carragenina , Sensibilização do Sistema Nervoso Central/efeitos dos fármacos , Clorpromazina/farmacologia , Dinoprostona/antagonistas & inibidores , Dinoprostona/farmacologia , Modelos Animais de Doenças , Dopamina/farmacologia , Antagonistas de Dopamina/farmacologia , Hiperalgesia/tratamento farmacológico , Hiperalgesia/fisiopatologia , Indometacina/farmacologia , Inflamação/induzido quimicamente , Inflamação/tratamento farmacológico , Masculino , Camundongos , Morfina/farmacologia , Nociceptores/efeitos dos fármacos , Dor/tratamento farmacológico , Medição da Dor/efeitos dos fármacos , Antagonistas de Prostaglandina/farmacologiaRESUMO
Melanocortin is a potent anti-inflammatory molecule. However, little is known about the effect of melanocortin on acute inflammatory processes such as neutrophil migration. In the present study, we investigated the ability of [Nle4, D-Phe7]-melanocyte-stimulating hormone (NDP-MSH), a semisynthetic melanocortin compound, in the inhibition of neutrophil migration in carrageenin-induced peritonitis model. Herein, subcutaneous pretreatment with NDP-MSH decreased neutrophil trafficking in the peritoneal cavity in a dose-dependent manner. NDP-MSH inhibited vascular leakage, leukocyte rolling, and adhesion and reduced peritoneal macrophage inflammatory protein 2, but not TNF-alpha, IL-1beta, IL-10, and keratinocyte-derived chemokine production. In addition, the effect on neutrophil migration was reverted by the pretreatment with both propranolol (a nonselective beta-adrenergic antagonist) and mecamylamine (a nonselective nicotinic antagonist) but not by splenectomy surgery. Moreover, NDP-MSH intracerebroventricular administration inhibited neutrophil migration, indicating participation of the central nervous system. Our results propose that the NDP-MSH effect may be due to a spleen-independent neuro-immune pathway that efficiently regulates excessive neutrophil recruitment to tissues.
Assuntos
Neutrófilos/efeitos dos fármacos , Peritonite/imunologia , alfa-MSH/análogos & derivados , Animais , Carragenina , Adesão Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Quimiocina CXCL2/imunologia , Citocinas/imunologia , Migração e Rolagem de Leucócitos/efeitos dos fármacos , Masculino , Camundongos , Neutrófilos/fisiologia , Peritonite/induzido quimicamente , Receptores Adrenérgicos/fisiologia , Receptores Nicotínicos/fisiologia , alfa-MSH/farmacologiaRESUMO
Acacia farnesiana lectin-like protein (AFAL) is a chitin-binding protein and has been classified as phytohaemagglutinin from Phaseolus vulgaris (PHA). Legume lectins are examples for structural studies, and this family of proteins shows a remarkable conservation in primary, secondary, and tertiary structures. Lectins have ability to reduce the effects of inflammation caused by phlogistic agents, such as carrageenan (CGN). This paper explains the anti-inflammatory activity of AFAL through structural comparison with anti-inflammatory legume lectins. The AFAL model was obtained by molecular modeling and molecular docking with glycan and carrageenan were performed to explain the AFAL structural behavior and biological activity. Pisum sativum lectin was the best template for molecular modeling. The AFAL structure model is folded as a ß sandwich. The model differs from template in loop regions, number of ß strands and carbohydrate-binding site. Carrageenan and glycan bind to different sites on AFAL. The ability of AFAL binding to carrageenan can be explained by absence of the sixth ß -strand (posterior ß sheets) and two ß strands in frontal region. AFAL can inhibit pathway inflammatory process by carrageenan injection by connecting to it and preventing its entry into the cell and triggers the reaction.
Assuntos
Anti-Inflamatórios/química , Inflamação/tratamento farmacológico , Modelos Moleculares , Lectinas de Plantas/química , Acacia , Animais , Anti-Inflamatórios/metabolismo , Carragenina/toxicidade , Quitina/química , Cristalografia por Raios X , Inflamação/induzido quimicamente , Inflamação/patologia , Camundongos , Simulação de Acoplamento Molecular , Fito-Hemaglutininas/química , Fito-Hemaglutininas/metabolismo , Lectinas de Plantas/administração & dosagem , Lectinas de Plantas/isolamento & purificação , Lectinas de Plantas/metabolismo , Ligação ProteicaRESUMO
A reduction of the neutrophil migration into the site of infection during cecal ligation and puncture-induced sepsis increases host mortality. Inhibition of heme oxygenase (HO) prevents this neutrophil paralysis and improves host survival in the cecal ligation and puncture model. Taking into account that almost 50% of all sepsis cases are a consequence of pneumonia, we designed the present study to determine the role of HO in an experimental model of pneumonia-induced sepsis. The objective of this study was to evaluate whether the inhibition of HO improves the outcome and pathophysiologic changes of sepsis induced by an intratracheal instillation of Klebsiella pneumoniae. The pretreatment of mice subjected to pneumonia-induced sepsis with ZnDPBG (zinc deuteroporphyrin 2,4-bis glycol), a nonspecific HO inhibitor, increased the number of neutrophils in the bronchoalveolar spaces, reduced the bacterial load at the site of infection, and prevented the upregulation of CD11b and the downregulation of CXCR2 on blood neutrophils. Moreover, the pretreatment with ZnDPBG decreased alveolar collapse, attenuating the deleterious changes in pulmonary mechanics and gas exchanges and, as a consequence, improved the survival rate of mice from 0% to â¼20%. These results show that heme oxygenase is involved in the pathophysiology of pneumonia-induced sepsis and suggest that HO inhibitors could be helpful for the management of this disease.
Assuntos
Bacteriemia/enzimologia , Heme Oxigenase (Desciclizante)/antagonistas & inibidores , Doenças do Sistema Imunitário/enzimologia , Infecções por Klebsiella/enzimologia , Transtornos Leucocíticos/enzimologia , Pneumonia Bacteriana/enzimologia , Alvéolos Pulmonares/enzimologia , Lesão Pulmonar Aguda/prevenção & controle , Animais , Bacteriemia/microbiologia , Brônquios/enzimologia , Quimiocinas/metabolismo , Creatina Quinase Forma MB/metabolismo , Citocinas/metabolismo , Deuteroporfirinas/farmacologia , Inibidores Enzimáticos/farmacologia , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae , Camundongos , Pneumonia Bacteriana/microbiologia , Receptores de Interleucina-8B/metabolismoRESUMO
PURPOSE: To assess in vitro the correlation between the number of neurons and the sensitivity to cholinergic drugs and acetylcholinesterase activity in chagasic patients. METHODS: A 3 x 1 cm strip of the muscle layer of the anterior part of the stomach, always close to the angular incisure, was removed from 10 chronic chagasic patients (6 men) submitted to megaesophagus or megacolon surgery and from 10 non-chagasic patients (4 men) submitted to other types of surgery (control group), aged on average 52.3 and 50.1 years, respectively, for histological and pharmacological studies. The action of cholinergic drugs was investigated in isolated preparations according to the superfusion method of Ferreira and Costa, and acetylcholinesterase activity was determined by the method of Ellman. For neuron count, the strips were cut into 8 µm sections according to the method standardized by Alcântara. RESULTS: There was a difference in number of neurons between the chagasic (5,6) and control (7,3) groups. Acetylcholinesterase activity, in moles of hydrolyzed substrate per minute per gram tissue, was reduced in chagasic patients (4,32) compared to the controls (7,30). No hypersensitivity of the gastric musculature to cholinergic drugs was detected, with a reduced maximum response to carbachol and betanechol in the chagasic group. CONCLUSIONS: The reduction of neurons in the myenteric plexus of the stomach of chronic chagasic patients can be demonstrated even in the absence of clinical chagasic gastropathy. The hypersensitivity of the gastric musculature to cholinergic drugs probably depends on intense denervation. The reduced acetylcholinesterase activity demonstrates the involvement of the cholinergic innervation in the stomach of chronic chagasic patients. There was no correlation between number of neurons, sensitivity to cholinergic drugs and acetylcholinesterase activity in the gastric musculature of chagasic and non-chagasic patients.
Assuntos
Acetilcolinesterase/metabolismo , Doença de Chagas/tratamento farmacológico , Colinérgicos/farmacologia , Músculo Liso/inervação , Plexo Mientérico/patologia , Estômago/inervação , Acetilcolina/farmacologia , Adulto , Carbacol/farmacologia , Estudos de Casos e Controles , Contagem de Células , Doença de Chagas/enzimologia , Agonistas Colinérgicos/farmacologia , Acalasia Esofágica/patologia , Acalasia Esofágica/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Liso/efeitos dos fármacos , Músculo Liso/enzimologia , Neurônios/citologia , Estômago/efeitos dos fármacos , Estômago/enzimologiaRESUMO
In the present study, the participation of the Na(V)1.8 sodium channel was investigated in the development of the peripheral pro-nociceptive state induced by daily intraplantar injections of PGE(2) in rats and its regulation in vivo by protein kinase A (PKA) and protein kinase C epsilon (PKCvarepsilon) as well. In the prostaglandin E(2) (PGE(2))-induced persistent hypernociception, the Na(V)1.8 mRNA in the dorsal root ganglia (DRG) was up-regulated. The local treatment with dipyrone abolished this persistent hypernociception but did not alter the Na(V)1.8 mRNA level in the DRG. Daily intrathecal administrations of antisense Na(V)1.8 decreased the Na(V)1.8 mRNA in the DRG and reduced ongoing persistent hypernociception. Once the persistent hypernociception had been abolished by dipyrone, but not by Na(V)1.8 antisense treatment, a small dose of PGE(2) restored the hypernociceptive plateau. These data show that, after a period of recurring inflammatory stimuli, an intense and prolonged nociceptive response is elicited by a minimum inflammatory stimulus and that this pro-nociceptive state depends on Na(V)1.8 mRNA up-regulation in the DRG. In addition, during the persistent hypernociceptive state, the PKA and PKCvarepsilon expression and activity in the DRG are up-regulated and the administration of the PKA and PKCvarepsilon inhibitors reduce the hypernociception as well as the Na(V)1.8 mRNA level. In the present study, we demonstrated that the functional regulation of the Na(V)1.8 mRNA by PKA and PKCvarepsilon in the primary sensory neuron is important for the development of the peripheral pro-nociceptive state induced by repetitive inflammatory stimuli and for the maintenance of the behavioral persistent hypernociception.
Assuntos
Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Inflamação/fisiopatologia , Proteínas do Tecido Nervoso/fisiologia , Dor/fisiopatologia , Proteína Quinase C-épsilon/metabolismo , Canais de Sódio/fisiologia , Animais , Sequência de Bases , Primers do DNA , Dinoprostona/administração & dosagem , Ativação Enzimática , Inflamação/induzido quimicamente , Masculino , Canal de Sódio Disparado por Voltagem NAV1.8 , Dor/enzimologia , Reação em Cadeia da Polimerase , Ratos , Ratos WistarRESUMO
PURPOSE: To assess in vitro the correlation between the number of neurons and the sensitivity to cholinergic drugs and acetylcholinesterase activity in chagasic patients. METHODS: A 3x1 cm strip of the muscle layer of the anterior part of the stomach, always close to the angular incisure, was removed from 10 chronic chagasic patients (6 men) submitted to megaesophagus or megacolon surgery and from 10 non-chagasic patients (4 men) submitted to other types of surgery (control group), aged on average 52.3 and 50.1 years, respectively, for histological and pharmacological studies. The action of cholinergic drugs was investigated in isolated preparations according to the superfusion method of Ferreira and Costa, and acetylcholinesterase activity was determined by the method of Ellman. For neuron count, the strips were cut into 8 µm sections according to the method standardized by Alcântara. RESULTS: There was a difference in number of neurons between the chagasic (5,6) and control (7,3) groups. Acetylcholinesterase activity, in moles of hydrolyzed substrate per minute per gram tissue, was reduced in chagasic patients (4,32) compared to the controls (7,30). No hypersensitivity of the gastric musculature to cholinergic drugs was detected, with a reduced maximum response to carbachol and betanechol in the chagasic group. CONCLUSIONS: The reduction of neurons in the myenteric plexus of the stomach of chronic chagasic patients can be demonstrated even in the absence of clinical chagasic gastropathy. The hypersensitivity of the gastric musculature to cholinergic drugs probably depends on intense denervation. The reduced acetylcholinesterase activity demonstrates the involvement of the cholinergic innervation in the stomach of chronic chagasic patients. There was no correlation between number of neurons, sensitivity to cholinergic drugs and acetylcholinesterase activity in the gastric musculature of chagasic and non-chagasic patients.
OBJETIVO: Avaliar in vitro a correlação entre o número de neurônios e a sensibilidade a drogas colinérgicas e a atividade da acetilcolinesterase em pacientes chagásicos. MÉTODOS: Em 10 pacientes chagásicos crônicos (6 homens) submetidos à cirurgia de megaesôfago ou de megacólon e em 10 pacientes não chagásicos (4 homens) submetidos a outros tipos de cirurgia (grupo controle), respectivamente com idade média de 52,3 e 50,1 anos, retirou-se uma tira de 3x1 cm da camada muscular da parede anterior do estômago, sempre junto á cisura angular, que serviu para os estudos histológicos e farmacológicos. A ação de drogas colinérgicas foi feita em preparação isolada de acordo com o método de superfusão de Ferreira e Costa, e a determinação da atividade da acetilcolinesterase pelo método de Ellman. Para a contagem de neurônios a tira muscular foi submetida a cortes de 8 micra segundo método padronizado por Alcântara. RESULTADOS: Houve diferença do número de neurônios entre os grupos chagásico (5,6) e controle (7,3). A atividade da acetilcolinesterase mostrou-se diminuída nos chagásicos (4,32) expressa como número de moles do substrato hidrolisado por minuto por grama de tecido, em relação aos controles (7,30). Não se encontrou hipersensibilidade da musculatura gástrica a drogas colinérgicas, encontrando-se inclusive efeito máximo reduzido ao carbacol e betanecol no grupo chagásico. CONCLUSÕES: A redução de neurônios no plexo mioentérico do estômago de pacientes chagásicos crônicos pode ser demonstrada mesmo na ausência de gastropatia chagásica clínica. A hipersensibilidade da musculatura gástrica a drogas colinérgicas provavelmente depende de desnervação intensa. A redução da atividade da acetilcolinesterase demonstra o comprometimento da inervação colinérgica no estômago de pacientes chagásicos crônicos. Não houve correlação entre número de neurônios, sensibilidade a drogas colinérgicas e atividade da acetilcolinesterase na musculatura gástrica de pacientes chagásicos ou não chagásicos.
Assuntos
Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Acetilcolinesterase/metabolismo , Doença de Chagas/tratamento farmacológico , Colinérgicos/farmacologia , Músculo Liso/inervação , Plexo Mientérico/patologia , Estômago/inervação , Acetilcolina/farmacologia , Estudos de Casos e Controles , Contagem de Células , Carbacol/farmacologia , Doença de Chagas/enzimologia , Agonistas Colinérgicos/farmacologia , Acalasia Esofágica/patologia , Acalasia Esofágica/cirurgia , Músculo Liso/efeitos dos fármacos , Músculo Liso/enzimologia , Neurônios/citologia , Estômago/efeitos dos fármacos , Estômago/enzimologiaRESUMO
IL-15 is closely associated with inflammatory diseases. IL-15 targeting is effective in treating experimental and clinical rheumatoid arthritis (RA). Because hyperalgesia accompanies RA, we investigated the ability of IL-15 to induced nociceptor sensitization (hypernociception). We report here that IL-15 induced time- and dose-dependent mechanical hypernociception in mice. IL-15-induced hypernociception was inhibited by treatment with a dual endothelin receptor type A (ET(A))/endothelin receptor type B (ET(B)) antagonist (bosentan), ET(A) receptor antagonist (BQ123), or cyclooxygenase inhibitor (indomethacin). Moreover, IL-15 failed to induce hypernociception in IFN-gamma(-/-) mice, suggesting that IL-15 mediated hypernociception via an IFN-gamma-, endothelin (ET)-, and prostaglandin-dependent pathway. Consistent with this finding, IFN-gamma and ET-1 induced dose- and time-dependent mechanical hypernociception that was inhibited by BQ123 or indomethacin but not BQ788 (an ET(B) receptor antagonist). IFN-gamma induced the production of ET-1 and the expression of its mRNA precursor (preproET-1, PPET-1). Moreover, IL-15 also induced ET-1 production and PPET-1 mRNA expression in an IFN-gamma-dependent manner. Prostaglandin E(2) (PGE(2)) production was induced by IL-15, IFN-gamma, or ET-1. We also found that hypernociception induced by ovalbumin (OVA) in OVA-immunized mice was significantly diminished by treatment with sIL-15Ralpha (soluble IL-15 receptor alpha-chain), bosentan, BQ123, or indomethacin. Furthermore, OVA challenge induced the expression of PPET-1 mRNA in WT mice but not in IFN-gamma(-/-) mice. The PPET-1 mRNA expression was also inhibited by sIL-15Ralpha pretreatment. Therefore, our results demonstrate the sequential mechanical hypernociceptive effect of IL-15 --> IFN-gamma --> ET-1 --> PGE(2) and suggest that these molecules may be targets of therapeutic intervention in antigen-induced hypernociception.
Assuntos
Endotelinas/metabolismo , Interferon gama/metabolismo , Interleucina-15/farmacologia , Prostaglandinas/metabolismo , Animais , Endotelinas/farmacologia , Regulação da Expressão Gênica , Inflamação/induzido quimicamente , Inflamação/imunologia , Inflamação/metabolismo , Interferon gama/deficiência , Interferon gama/genética , Interferon gama/farmacologia , Camundongos , Ovalbumina/farmacologia , Prostaglandinas/genética , RNA Mensageiro/genéticaRESUMO
We developed two models of sepsis with different degrees of severity, sublethal and lethal sepsis, induced by cecal ligation and puncture. Lethal sepsis induced by cecal ligation and puncture (L-CLP) resulted in failure of neutrophil migration to the infection site and high mortality. Treatment of septic animals with aminoguanidine (AG), a nitric oxide (NO) synthase inhibitor, precluded the failure of neutrophil migration and protected the animals from death. However, cytokine-induced NO synthase (iNOS)-deficient (iNOS(-/-)) mice subjected to L-CLP did not present neutrophil migration failure, but 100% lethality occurred. iNOS(-/-) mice subjected to sublethal sepsis induced by cecal ligation and puncture (SL-CLP) also suffered high mortality despite the occurrence of neutrophil migration. This apparent paradox could be explained by the lack of microbicidal activity in neutrophils of iNOS(-/-) mice present at the infection site due to their inability to produce NO. Notably, SL- and L-CLP iNOS(-/-) mice showed high bacterial numbers in exudates. The inhibition of neutrophil migration by NO is due to inhibition of a neutrophil/endothelium adhesion mechanism, since a reduction in leukocyte rolling, adhesion, and emigration was observed in L-CLP wild-type mice. These responses were prevented by AG treatment and were not observed in the iNOS(-/-) L-CLP group. There was no significant change in L-selectin expression in neutrophils from L-CLP mice. Thus, it seems that the decrease in leukocyte rolling is due to a defect in the expression of adhesion molecules on endothelial surfaces mediated by iNOS-derived NO. In conclusion, the results indicate that despite the importance of NO in neutrophil microbicidal activity, its generation in severe sepsis reduces neutrophil migration by inhibiting leukocyte rolling and their firm adhesion to the endothelium, in effect impairing the migration of leukocytes and consequently their fundamental role in host cell defense mechanisms.
Assuntos
Leucócitos/imunologia , Ativação de Neutrófilo/imunologia , Infiltração de Neutrófilos/imunologia , Neutrófilos/imunologia , Óxido Nítrico/imunologia , Sepse/imunologia , Animais , Antígenos CD18/biossíntese , Ceco/microbiologia , Quimiotaxia de Leucócito , Modelos Animais de Doenças , Endotélio Vascular/imunologia , Interleucina-1/metabolismo , Interleucina-10/metabolismo , Selectina L/biossíntese , Ligadura , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico/biossíntese , Óxido Nítrico Sintase/genética , Óxido Nítrico Sintase/fisiologia , Óxido Nítrico Sintase Tipo II , Peritônio/citologia , Sepse/mortalidade , Taxa de Sobrevida , Fator de Necrose Tumoral alfa/metabolismoRESUMO
The present study investigated whether activation of presynaptic N-methyl-d-aspartate (NMDA) receptors in the spinal cord produces a retrograde nociceptor sensitization (hypernociception) to mechanical nonnoxious stimulus. By using an electronic version of the von Frey hair test (pressure meter), s.c. intraplantar administration of prostaglandin E(2) (PGE(2)) (50-400 ng per paw) evoked a dose-related ipsilateral paw hypernociception. In contrast, intrathecal (i.t.) administration of NMDA (5-80 ng) and PGE(2) (15-150 ng) evoked dose-related bilateral paw hypernociception. The s.c. intraplantar administration of dipyrone (80-320 microg per paw) or morphine (3 and 9 microg per paw), usually used to antagonize peripheral PGE(2) (100 ng per paw), induced hypernociception and also antagonized the ipsilateral (without affecting the contralateral) paw hypernociception induced by i.t. injections of NMDA (40 ng) or PGE(2) (50 ng). These doses of drugs did not modify the basal mechanical sensitivity of control paws. This result shows that intraspinal NMDA or PGE(2) produces sensitization of the primary sensory neuron in response to mechanical stimulation. In a second series of experiments it was shown that the i.t. treatment with NaV1.8 (SNS/PN3) sodium channel antisense oligodeoxynucleotides, but not mismatch oligodeoxynucleotides, decreased the mRNA expression of sodium tetrodotoxin-resistant channels on the dorsal root ganglia and abolished the mechanical hypernociception induced by i.t. administration of NMDA. Thus, our results support the suggestion that glutamate release in the spinal cord during inflammation causes retrograde hypernociception of nociceptors associated with sodium tetrodotoxin-resistant channels in primary nociceptive sensory neurons.
Assuntos
Neuropeptídeos/genética , Neuropeptídeos/fisiologia , Nociceptores/fisiologia , Receptores de N-Metil-D-Aspartato/metabolismo , Canais de Sódio/genética , Canais de Sódio/fisiologia , Analgésicos Opioides/farmacologia , Animais , Anti-Inflamatórios não Esteroides/farmacologia , Dipirona/farmacologia , Relação Dose-Resposta a Droga , Gânglios Espinais/metabolismo , Glutamatos/metabolismo , Inflamação , Morfina/farmacologia , Canal de Sódio Disparado por Voltagem NAV1.8 , Nociceptores/efeitos dos fármacos , Oligonucleotídeos Antissenso/farmacologia , Medição da Dor , Reação em Cadeia da Polimerase , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Medula Espinal/metabolismo , Fatores de TempoRESUMO
There is controversy in the literature over whether nitric oxide (NO) released during the inflammatory process has a pro- or inhibitory effect on neutrophil migration. The aim of the present investigation was to clarify this situation. Treatment of rats with non-selective, NG-nitro-L-arginine (nitro), or selective inducible NO synthase (iNOS), aminoguanidine (amino) inhibitors enhanced neutrophil migration 6h after the administration of low, but not high, doses of carrageenan (Cg) or Escherichia coli endotoxin (LPS). The neutrophil migration induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP) was also enhanced by nitro or amino treatments. The enhancement of Cg-induced neutrophil migration by NOS inhibitor treatments was reversed by co-treatment with L-arginine, suggesting an involvement of the L-arginine/NOS pathway in the process. The administration of Cg in iNOS deficient (iNOS(-/-)) mice also enhanced the neutrophil migration compared with wild type mice. This enhancement was markedly potentiated by treatment of iNOS(-/-) mice with nitro. Investigating the mechanisms by which NOS inhibitors enhanced the neutrophil migration, it was observed that they promoted an increase in Cg-induced rolling and adhesion of leukocytes to endothelium and blocked the apoptosis of emigrated neutrophils. Similar results were observed in iNOS(-/-) mice, in which these mechanisms were potentiated and reverted by nitro and L-arginine treatments, respectively. In conclusion, these results suggest that during inflammation, NO released by either constitutive NOS (cNOS) or iNOS down-modulates the neutrophil migration. This NO effect seems to be a consequence of decreased rolling and adhesion of the neutrophils on endothelium and also the induction of apoptosis in migrated neutrophils.