RESUMO
OBJECTIVE: The present study aimed to elucidate the mechanisms involved in MSU-induced IL-1ß release in a rodent animal model of acute gout arthritis. METHODS: Painful (mechanical and thermal hypersensitivity, ongoing pain and arthritis score) and inflammatory (oedema, plasma extravasation, cell infiltration and IL-1ß release) parameters were assessed several hours after intra-articular injection of MSU (100 µg/articulation) in wild-type or knockout mice for Toll-like receptor 4 (TLR4), inducible nitric oxide synthase (iNOS), transient receptor potential (TRP) V1 and the IL-1 receptor (IL-1R). Also, wild-type animals were treated with clodronate, lipopolysaccharide from Rhodobacter sphaeroides (LPS-RS) (TLR4 antagonist), spleen tyrosine kinase (SYK) inhibitor (iSYK), aminoguanidine (AMG, an iNOS inhibitor) or SB366791 (TRPV1 antagonist). Nitrite/nitrate and IL-1ß levels were measured on the synovial fluid of wild-type mice, 2 h after intra-articular MSU injections, or medium from macrophages stimulated for MSU (1000 µg) for 2 h. RESULTS: Intra-articular MSU injection caused robust nociception and severe inflammation from 2 up to 6 h after injection, which were prevented by the pre-treatment with clodronate, LPS-RS, iSYK, AMG and SB366791, or the genetic ablation of TLR4, iNOS, TRPV1 or IL-1R. MSU also increased nitrite/nitrate and IL-1ß levels in the synovial fluid, which was prevented by clodronate, LPS-RS, iSYK and AMG, but not by SB366791. Similarly, MSU-stimulated peritoneal macrophages released nitric oxide, which was prevented by LPS-RS, iSYK and AMG, but not by SB366791, and released IL-1ß, which was prevented by LPS-RS, iSYK, AMG and SB366791. CONCLUSION: Our data indicate that MSU may activate TLR4, SYK, iNOS and TRPV1 to induce the release of IL-1ß by macrophages, triggering nociception and inflammation during acute gout attack.
Assuntos
Artrite Gotosa/metabolismo , Interleucina-18/metabolismo , Macrófagos/metabolismo , Receptores de Vasopressinas/metabolismo , Canais de Cátion TRPV/metabolismo , Receptor 4 Toll-Like/metabolismo , Ácido Úrico/farmacologia , Animais , Artrite Gotosa/patologia , Células Cultivadas , Modelos Animais de Doenças , Feminino , Macrófagos/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Líquido Sinovial/metabolismoRESUMO
OBJECTIVE: Verify the role of the kinin B1 receptors (B1R) and the effect of ACE inhibitors (ACEi) on acute gout induced by monosodium urate (MSU) crystals in rodents. METHODS: Painful (overt pain and allodynia) and inflammatory parameters (joint oedema, leukocyte trafficking, interleukin-1ß levels) of acute gout attacks were assessed several hours after an intra-articular injection of MSU (1.25 or 0.5 mg/articulation) into the ankle of rats or mice, respectively. The role of B1R was investigated using pharmacological antagonism or gene deletion. Additionally, B1R immunoreactivity in ankle tissue and sensory neurons, kininase I activity and des-Arg(9)-bradykinin synovial levels were also measured. Similar tools were used to investigate the effects of ACEi on a low dose of MSU (0.0125 mg/articulation)-induced inflammation. RESULTS: Kinin B1R antagonism or gene deletion largely reduced all painful and inflammatory signs of gout. Furthermore, MSU increased B1R expression in articular tissues, the content of the B1 agonist des-Arg(9)-bradykinin and the activity of the B1 agonist-forming enzyme kininase I. A low dose of MSU crystals, which did not induce inflammation in control animals, caused signs of acute gout attacks in ACEi-treated animals that were B1R-dependent. CONCLUSIONS: Kinin B1R contributes to acute gouty attacks, including the ones facilitated by ACEi. Therefore, B1R is a potential therapeutic target for the treatment and prophylaxis of gout, especially in patients taking ACEi.
Assuntos
Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Gota/metabolismo , Receptor B1 da Bradicinina/fisiologia , Doença Aguda , Animais , Antagonistas de Receptor B1 da Bradicinina/uso terapêutico , Dioxóis/uso terapêutico , Edema/induzido quimicamente , Edema/metabolismo , Gota/induzido quimicamente , Gota/tratamento farmacológico , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Dor/induzido quimicamente , Dor/metabolismo , Ratos Wistar , Sulfonamidas/uso terapêutico , Ácido ÚricoRESUMO
Acute gout attacks produce severe joint pain and inflammation associated with monosodium urate (MSU) crystals leading to oxidative stress production. The transient potential receptor ankyrin 1 (TRPA1) is expressed by a subpopulation of peptidergic nociceptors and, via its activation by endogenous reactive oxygen species, including hydrogen peroxide (H2O2), contributes to pain and neurogenic inflammation. The aim of this study was to investigate the role of TRPA1 in hyperalgesia and inflammation in a model of acute gout attack in rodents. Inflammatory parameters and mechanical hyperalgesia were measured in male Wistar rats and in wild-type (Trpa1(+/+)) or TRPA1-deficient (Trpa1(-/-)) male mice. Animals received intra-articular (ia, ankle) injection of MSU. The role of TRPA1 was assessed by receptor antagonism, gene deletion or expression, sensory fiber defunctionalization, and calcitonin gene-related peptide (CGRP) release. We found that nociceptor defunctionalization, TRPA1 antagonist treatment (via ia or oral administration), and Trpa1 gene ablation abated hyperalgesia and inflammatory responses (edema, H2O2 generation, interleukin-1ß release, and neutrophil infiltration) induced by ia MSU injection. In addition, we showed that MSU evoked generation of H2O2 in synovial tissue, which stimulated TRPA1 producing CGRP release and plasma protein extravasation. The MSU-elicited responses were also reduced by the H2O2-detoxifying enzyme catalase and the reducing agent dithiothreitol. TRPA1 activation by MSU challenge-generated H2O2 mediates the entire inflammatory response in an acute gout attack rodent model, thus strengthening the role of the TRPA1 receptor and H2O2 production as potential targets for treatment of acute gout attacks.
Assuntos
Gota/metabolismo , Peróxido de Hidrogênio/metabolismo , Hiperalgesia/metabolismo , Inflamação/metabolismo , Canais de Cátion TRPC/metabolismo , Animais , Antioxidantes/farmacologia , Western Blotting , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Knockout , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Ultraviolet B (UVB) irradiation mainly affects biological tissues by inducing an increase in reactive oxygen species (ROS) production which leads to deleterious outcomes for the skin, including pain and inflammation. As a protective strategy, many studies have focused on the use of natural products. The aim of this study was to investigate the effects of Aloe saponaria on nociceptive, inflammatory, and oxidative parameters in a model of UVB-induced sunburn in adult male Wistar rats. Sunburned animals were topically treated with vehicle (base cream), 1% silver sulfadiazine (positive control) or A. saponaria (10%) once a day for 6days. UVB-induced nociception (allodynia and hyperalgesia), inflammation (edema and leukocyte infiltration) and oxidative stress (increases in H2O2, protein carbonyl levels and lipid peroxidation and a decrease in non protein thiol content) were reduced by both A. saponaria and sulfadiazine topical treatment. Furthermore, A. saponaria or its constituents aloin and rutin reduced the oxidative stress induced by H2O2 in skin homogenates in vitro. Our results demonstrate that topical A. saponaria treatment displayed anti-nociceptive and anti-inflammatory effects in a UVB-induced sunburn model, and these effects seem to be related to its antioxidant components.
Assuntos
Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Extratos Vegetais/farmacologia , Saponaria/química , Pele/efeitos dos fármacos , Raios Ultravioleta , Analgésicos/química , Analgésicos/farmacologia , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/uso terapêutico , Antioxidantes/química , Antioxidantes/uso terapêutico , Cromatografia Líquida de Alta Pressão , Modelos Animais de Doenças , Emodina/análogos & derivados , Emodina/análise , Emodina/farmacologia , Emodina/uso terapêutico , Inflamação/tratamento farmacológico , Masculino , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/efeitos da radiação , Extratos Vegetais/química , Extratos Vegetais/uso terapêutico , Folhas de Planta/química , Folhas de Planta/metabolismo , Ratos , Ratos Wistar , Saponaria/metabolismo , Sulfadiazina de Prata/química , Pele/efeitos da radiação , Queimadura Solar/tratamento farmacológico , Fatores de TempoRESUMO
OBJECTIVE: The aim of the present study was to investigate the participation of TRPV1 in an acute gout attack model. METHODS: Experiments were conducted to evaluate the participation of TRPV1 in the nociceptive and inflammatory responses (oedema, plasma extravasation, leucocyte infiltration and also IL-1ß production) triggered by IA (ankle) administration of monosodium urate (MSU) in rats using selective antagonist TRPV1 receptor, defunctionalization of sensory fibres and increased immunoreactivity. We have also analysed the inflammatory response. The participation of mast cells in the MSU-induced nociception and inflammation was evaluated using a mast cell stabilizer and a mast cell degranulator compound. RESULTS: We observed that MSU (1.25 mg/site) injected into the rat ankle joint elicited ongoing pain-like behaviour, hyperalgesia, allodynia and articular oedema as well as plasma extravasation, leucocyte infiltration and IL-1ß production in lavage fluid. All of these events were inhibited by the co-administration of the selective TRPV1 receptor antagonist SB366791 (10 nmol/site). MSU crystals also increased the immunoreactivity of the TRPV1 receptor in the articular tissue of injected animals. Furthermore, the defunctionalization of TRPV1-positive sensory neurons also significantly reduced MSU-induced ongoing pain-like behaviour, hyperalgesia and oedema. CONCLUSION: Thus we demonstrate that TRPV1 acts on sensory neurons and plays a relevant role in the nociception and inflammation induced by IA MSU, indicating it as a potential target to treat acute gout attacks.
Assuntos
Gota/induzido quimicamente , Gota/fisiopatologia , Canais de Cátion TRPV/fisiologia , Ácido Úrico/efeitos adversos , Doença Aguda , Anilidas/farmacologia , Animais , Artralgia/fisiopatologia , Cinamatos/farmacologia , Modelos Animais de Doenças , Inflamação/fisiopatologia , Masculino , Ratos , Ratos Wistar , Canais de Cátion TRPV/antagonistas & inibidores , Canais de Cátion TRPV/efeitos dos fármacosRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Viola tricolor, popularly known as heartsease has been empirically used in several skin disorders, including burns. AIM OF THE STUDY: The objective of this study was investigate the antinociceptive and antiinflammatory effect of a gel containing extract of Viola tricolor flowers on thermal burn induced by UVB irradiation and to perform gel stability study. METHODS: The antinociceptive and antiinflammatory effect were evaluated by static and dynamic mechanical allodynia model, paw edema, and neutrophilic cell infiltration. Metabolites compounds were quantified by HPLC. The gel stability study was performed analyzing organoleptical aspects, besides pH, viscosity, and quantification of rutin by HPLC. RESULTS: In the results were evidenced changes in threshold in statical and dynamic mechanical allodynia (I(max)=100 ± 10% and 49 ± 10%, respectively), paw edema (I(max)=61 ± 6%), and myeloperoxidase activity (I(max)=89 ± 5%). Such effects may be attributed, in part, to rutin, salicylic and chlorogenic acids, and others compounds found in this species. No important changes were detected in the stability study, in all aspects analyzed in temperature below 25 °C. CONCLUSION: These findings suggest that Viola tricolor gel has an antinociceptive and antiinflammatory effect in the ultraviolet-B-induced burn, since maintain the temperature below 25 °C.
Assuntos
Analgésicos/uso terapêutico , Anti-Inflamatórios/uso terapêutico , Extratos Vegetais/uso terapêutico , Queimadura Solar/tratamento farmacológico , Viola , Animais , Modelos Animais de Doenças , Estabilidade de Medicamentos , Edema/tratamento farmacológico , Edema/imunologia , Flores , Géis , Hiperalgesia/tratamento farmacológico , Hiperalgesia/imunologia , Masculino , Neutrófilos/imunologia , Ratos , Ratos Wistar , Queimadura Solar/imunologiaRESUMO
OBJECTIVE: Gout is a common cause of inflammatory arthritis and is provoked by the accumulation of monosodium urate (MSU) crystals. However, the underlying mechanisms of the pain associated with acute attacks of gout are poorly understood. The aim of this study was to evaluate the role of transient receptor potential ankyrin 1 (TRPA-1) and TRPA-1 stimulants, such as H2 O2 , in a rodent model of MSU-induced inflammation. METHODS: MSU or H2 O2 was injected into the hind paws of rodents or applied in cultured sensory neurons, and the intracellular calcium response was measured in vitro. Inflammatory or nociceptive responses in vivo were evaluated using pharmacologic, genetic, or biochemical tools and methods. RESULTS: TRPA-1 antagonism, TRPA-1 gene deletion, or pretreatment of peptidergic TRP-expressing primary sensory neurons with capsaicin markedly decreased MSU-induced nociception and edema. In addition to these neurogenic effects, MSU increased H2 O2 levels in the injected tissue, an effect that was abolished by the H2 O2 -detoxifying enzyme catalase. H2 O2 , but not MSU, directly stimulated sensory neurons through the activation of TRPA-1. The nociceptive responses evoked by MSU or H2 O2 injection were attenuated by the reducing agent dithiothreitol. In addition, MSU injection increased the expression of TRPA-1 and TRP vanilloid channel 1 (TRPV-1) and also enhanced cellular infiltration and interleukin-1ß levels, and these effects were blocked by TRPA-1 antagonism. CONCLUSION: Our results suggest that MSU injection increases tissue H2 O2 , thereby stimulating TRPA-1 on sensory nerve endings to produce inflammation and nociception. TRPV-1, by a previously unknown mechanism, also contributes to these responses.
Assuntos
Dor Aguda/metabolismo , Artrite Gotosa/metabolismo , Peróxido de Hidrogênio/metabolismo , Inflamação/metabolismo , Canais de Cátion TRPC/metabolismo , Ácido Úrico/metabolismo , Acetanilidas/farmacologia , Dor Aguda/induzido quimicamente , Dor Aguda/tratamento farmacológico , Animais , Artrite Gotosa/induzido quimicamente , Artrite Gotosa/tratamento farmacológico , Modelos Animais de Doenças , Peróxido de Hidrogênio/farmacologia , Inflamação/induzido quimicamente , Inflamação/tratamento farmacológico , Masculino , Camundongos , Camundongos Knockout , Oxidantes/metabolismo , Oxidantes/farmacologia , Purinas/farmacologia , Ratos , Ratos Wistar , Células Receptoras Sensoriais/metabolismo , Canal de Cátion TRPA1 , Canais de Cátion TRPC/agonistas , Canais de Cátion TRPC/antagonistas & inibidores , Ácido Úrico/farmacologiaRESUMO
Abdominal pain is a frequent symptom of peritoneal cavity irritation, but little is known about the role of the receptors for irritant substances, transient receptor potential vanilloid 1 (TRPV1) and ankyrin 1 (TRPA1), in this painful condition. Thus, we investigated the abdominal nociception caused by peritoneal stimulation with TRPV1 (capsaicin) and TRPA1 (allyl isothiocyanate, AITC) agonists and their mechanisms in rats. The intraperitoneal (i.p.) injection of either capsaicin or AITC (0.03-10 mg/kg) induced short-term (up to 20 min) and dose-dependent abdominal nociception, and also produced c-fos expression in spinal afferents of the dorsal horn. TRPV1 antagonism prevented (94 ± 4% inhibition) nociception induced by capsaicin but not by AITC. In contrast, the TRPA1 antagonism almost abolished AITC-induced nociception (95 ± 2% inhibition) without altering the capsaicin response. Moreover, nociception induced by either capsaicin or AITC was reduced by the desensitisation of TRPV1-positive sensory fibres with resiniferatoxin (73 ± 18 and 76 ± 15% inhibitions, respectively) and by the NK1 receptor antagonist aprepitant (56 ± 5 and 53 ± 8% inhibitions, respectively). Likewise, the i.p. injections of capsaicin or AITC increased the content of substance P in the peritoneal fluid. Nevertheless, neither the mast cell membrane stabiliser cromoglycate, nor the H1 antagonist promethazine, nor depletion of peritoneal macrophages affected abdominal nociception induced either by capsaicin or AITC. Accordingly, neither capsaicin nor AITC increased the histamine content in the peritoneal fluid or provoked peritoneal mast cell degranulation in vitro. Collectively, our findings suggest that TRPV1 and TRPA1 stimulation in the peritoneum produces abdominal nociception that is mediated by sensory fibres activation.
Assuntos
Nociceptividade , Peritônio/efeitos dos fármacos , Canais de Cátion TRPC/metabolismo , Canais de Cátion TRPV/metabolismo , Animais , Capsaicina/farmacologia , Trânsito Gastrointestinal/efeitos dos fármacos , Intestinos/efeitos dos fármacos , Intestinos/fisiologia , Isotiocianatos/farmacologia , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Masculino , Mastócitos/citologia , Mastócitos/efeitos dos fármacos , Nociceptividade/efeitos dos fármacos , Peritônio/imunologia , Peritônio/metabolismo , Peritônio/fisiologia , Ratos , Ratos Wistar , Receptores da Neurocinina-1/metabolismo , Substância P/farmacologia , Canal de Cátion TRPA1 , Canais de Cátion TRPC/agonistas , Canais de Cátion TRPV/agonistasRESUMO
OBJECTIVE AND DESIGN: We investigated the effect of glibenclamide on inflammatory parameters in a model of acute gouty attack in rats. TREATMENT: Intra-articular injection of 50 µl of monosodium urate (MSU) crystals (1.25 mg/site) was used to induce gout-related inflammation. The effects of glibenclamide (1-10 mg/kg, s.c.) or dexamethasone (8 mg/kg, s.c., positive control) were assessed on several inflammation parameters. METHODS: Spontaneous nociception assessment, edema measurement, total and differential leucocyte counts, interleukin (IL)-1ß release, prostaglandin E2 production and determination of blood glucose levels were analyzed. Peritoneal macrophages were incubated with MSU and levels of IL-1ß were measured. Statistical significance was assessed by one- or two-way analysis of variance. RESULTS: Glibenclamide (3 mg/kg) or dexamethasone (8 mg/kg) prevented nociception and edema induced by MSU injection in rats. Glibenclamide did not affect leukocyte infiltration, IL-1ß release and PGE2 production, but only reduced IL-1ß production by MSU-stimulated macrophages at very high concentration (200 µM). Dexamethasone significantly reduced leukocyte infiltration, IL-1ß release and PGE2 production. Glibenclamide reduced whereas dexamethasone increased blood glucose levels of MSU-injected rats. CONCLUSIONS: Glibenclamide reduced nociception and edema, but not leukocyte infiltration, IL-1ß release and PGE2 production. However, its substantial effect on nociception and edema suggests that glibenclamide can be an interesting option as an adjuvant treatment for pain induced by acute attacks of gout.