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BACKGROUND AND PURPOSE: Fibromyalgia is a complex clinical disorder with an unknown aetiology, characterized by generalized pain and co-morbid symptoms such as anxiety and depression. An imbalance of oxidants and antioxidants is proposed to play a pivotal role in the pathogenesis of fibromyalgia symptoms. However, the precise mechanisms by which oxidative stress contributes to fibromyalgia-induced pain remain unclear. The transient receptor potential ankyrin 1 (TRPA1) channel, known as both a pain sensor and an oxidative stress sensor, has been implicated in various painful conditions. EXPERIMENTAL APPROACH: The feed-forward mechanism that implicates reactive oxygen species (ROS) driven by TRPA1 was investigated in a reserpine-induced fibromyalgia model in C57BL/6J mice employing pharmacological interventions and genetic approaches. KEY RESULTS: Reserpine-treated mice developed pain-like behaviours (mechanical/cold hypersensitivity) and early anxiety-depressive-like disorders, accompanied by increased levels of oxidative stress markers in the sciatic nerve tissues. These effects were not observed upon pharmacological blockade or global genetic deletion of the TRPA1 channel and macrophage depletion. Furthermore, we demonstrated that selective silencing of TRPA1 in Schwann cells reduced reserpine-induced neuroinflammation (NADPH oxidase 1-dependent ROS generation and macrophage increase in the sciatic nerve) and attenuated fibromyalgia-like behaviours. CONCLUSION AND IMPLICATIONS: Activated Schwann cells expressing TRPA1 promote an intracellular pathway culminating in the release of ROS and recruitment of macrophages in the mouse sciatic nerve. These cellular and molecular events sustain mechanical and cold hypersensitivity in the reserpine-evoked fibromyalgia model. Targeting TRPA1 channels on Schwann cells could offer a novel therapeutic approach for managing fibromyalgia-related behaviours.
Assuntos
Fibromialgia , Camundongos Endogâmicos C57BL , Estresse Oxidativo , Espécies Reativas de Oxigênio , Reserpina , Células de Schwann , Canal de Cátion TRPA1 , Animais , Reserpina/farmacologia , Fibromialgia/induzido quimicamente , Fibromialgia/metabolismo , Canal de Cátion TRPA1/metabolismo , Canal de Cátion TRPA1/antagonistas & inibidores , Canal de Cátion TRPA1/genética , Estresse Oxidativo/efeitos dos fármacos , Células de Schwann/metabolismo , Células de Schwann/efeitos dos fármacos , Masculino , Camundongos , Espécies Reativas de Oxigênio/metabolismo , Dor/metabolismo , Dor/induzido quimicamente , Nervo Isquiático/metabolismo , Modelos Animais de Doenças , Camundongos Knockout , Canais de Potencial de Receptor Transitório/metabolismo , Canais de Potencial de Receptor Transitório/antagonistas & inibidores , Canais de Potencial de Receptor Transitório/genéticaRESUMO
Postoperative pain causes discomfort and disability, besides high medical costs. The search for better treatments for this pain is essential to improve recovery and reduce morbidity and risk of chronic postoperative pain. Kinins and their receptors contribute to different painful conditions and are among the main painful inflammatory mediators. We investigated the kinin's role in a postoperative pain model in mice and reviewed data associating kinins with this painful condition. The postoperative pain model was induced by an incision in the mice's paw's skin and fascia with the underlying muscle's elevation. Kinin levels were evaluated by enzyme immunoassays in sham or operated animals. Kinin's role in surgical procedure-associated mechanical allodynia was investigated using systemic or local administration of antagonists of the kinin B1 receptor (DALBk or SSR240612) or B2 receptor (Icatibant or FR173657) and a kallikrein inhibitor (aprotinin). Kinin levels increased in mice's serum and plantar tissue after the surgical procedure. All kinin B1 or B2 receptor antagonists and aprotinin reduced incision-induced mechanical allodynia. Although controversial, kinins contribute mainly to the initial phase of postoperative pain. The kallikrein-kinin system can be targeted to relieve this pain, but more investigations are necessary, especially associations with other pharmacologic targets.
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Toll-like receptors (TLRs) are a well-characterized family of cell-bound pattern recognition receptors able to identify and respond to conserved structures of external microorganisms or Pathogen Molecular-Associated Pattern (PAMPs). They can also interact with Damage-Associated Molecular Patterns (DAMPs) involved with any infectious and sterile cell stress of tissue injury. Accumulated knowledge about TLRs has revealed that these receptors and intracellular signaling pathways triggered through TLR activation contribute to the physiopathology of different inflammatory diseases, including arthritic conditions. Mostly, the literature focuses on exploring TLRs in rheumatoid and osteoarthritis. However, TLRs also seem to be an essential mediator for monosodium urate (MSU) crystals-induced gouty arthritis, both in animal models and humans. Accordingly, naked MSU crystals have a highly negatively charged surface recognized by TLRs; intracellular adapter protein MyD88 are significant mediators of MSU crystals-induced IL1ß production in mice, and gouty patients demonstrate a robust positive correlation between TLR4 mRNA level and serum IL1ß. Here, we revised the literature evidence regarding the involvement of TLRs in gout arthritis pathogenesis, with particular reference to TLR2 and TLR4, by analyzing the actual literature data.
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Artrite Gotosa , Gota , Humanos , Animais , Camundongos , Artrite Gotosa/induzido quimicamente , Artrite Gotosa/genética , Artrite Gotosa/metabolismo , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/metabolismo , Ácido Úrico/metabolismo , Gota/metabolismo , Receptores Toll-Like , Proteínas Adaptadoras de Transdução de SinalRESUMO
BACKGROUND: There is a growing search for therapeutic targets in the treatment of gout. The present study aimed to evaluate the analgesic and anti-inflammatory potential of angiotensin type 2 receptor (AT2R) antagonism in an acute gout attack mouse model. METHODS: Male wild-type (WT) C57BL/6 mice either with the AT2R antagonist, PD123319 (10 pmol/joint), or with vehicle injections, or AT2R KO mice, received intra-articular (IA) injection of monosodium urate (MSU) crystals (100 µg/joint), that induce the acute gout attack, and were tested for mechanical allodynia, thermal hyperalgesia, spontaneous nociception and ankle edema development at several times after the injections. To test an involvement of AT2R in joint pain, mice received an IA administration of angiotensin II (0.05-5 nmol/joint) with or without PD123319, and were also evaluated for pain and edema development. Ankle joint tissue samples from mice undergoing the above treatments were assessed for myeloperoxidase activity, IL-1ß release, mRNA expression analyses and nitrite/nitrate levels, 4 h after injections. RESULTS: AT2R antagonism has robust antinociceptive effects on mechanical allodynia (44% reduction) and spontaneous nociception (56%), as well as anti-inflammatory effects preventing edema formation (45%), reducing myeloperoxidase activity (54%) and IL-1ß levels (32%). Additionally, Agtr2tm1a mutant mice have largely reduced painful signs of gout. Angiotensin II administration causes pain and inflammation, which was prevented by AT2R antagonism, as observed in mechanical allodynia 4 h (100%), spontaneous nociception (46%), cold nociceptive response (54%), edema formation (83%), myeloperoxidase activity (48%), and IL-1ß levels (89%). PD123319 treatment also reduces NO concentrations (74%) and AT2R mRNA levels in comparison with MSU untreated mice. CONCLUSION: Our findings show that AT2R activation contributes to acute pain in experimental mouse models of gout. Therefore, the antagonism of AT2R may be a potential therapeutic option to manage gout arthritis.
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Dor Aguda , Artrite Gotosa , Gota , Camundongos , Masculino , Animais , Ácido Úrico , Hiperalgesia/tratamento farmacológico , Angiotensina II , Receptor Tipo 2 de Angiotensina , Peroxidase , Camundongos Endogâmicos C57BL , Gota/tratamento farmacológico , Gota/metabolismo , Artrite Gotosa/tratamento farmacológico , Bloqueadores do Receptor Tipo 2 de Angiotensina II/farmacologia , Anti-Inflamatórios/uso terapêutico , Edema/tratamento farmacológico , Antioxidantes/uso terapêutico , Dor Aguda/tratamento farmacológico , RNA MensageiroRESUMO
The biological applicability of nanomaterials has been limited due to cytotoxicity. Studies have described the effects of nanomaterials on different tissues and cell types, but their actions on immune cells are less elucidated. This study describes unprecedented in vitro and in vivo antioxidant activities of cadmium selenide magic-sized quantum dots (CdSe MSQDs) with implications on rheumatoid arthritis. While the generation of ROS induced by nanomaterials is linked to cytotoxicity, we found that CdSe MSQDs reduced ROS production by neutrophils and macrophages following opsonized-zymosan stimuli, and we did not find cytotoxic effects. Interestingly, inherent antioxidant properties of CdSe MSQDs were confirmed through DPPH, FRAP, and ORAC assays. Furthermore, CdSe MSQDs reduced ROS levels generated by infiltrating leukocytes into joints in experimental model of rheumatoid arthritis. Briefly, we describe a novel application of CdSe MSQDs in modulating the inflammatory response in experimental rheumatoid arthritis through an unexpected antioxidant activity.
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Artrite Reumatoide , Compostos de Cádmio , Pontos Quânticos , Compostos de Selênio , Antioxidantes/farmacologia , Artrite Reumatoide/tratamento farmacológico , Compostos de Cádmio/química , Compostos de Cádmio/farmacologia , Humanos , Macrófagos , Neutrófilos , Pontos Quânticos/química , Espécies Reativas de Oxigênio , Compostos de Selênio/química , Compostos de Selênio/farmacologiaRESUMO
The use of botulinum neurotoxin-A (BoNT-A) is an alternative for the management of orofacial pain disorders. Although only Botox has labeled, there are other commercial brands available for use, among them: Dysport, Botulift, Prosigne, and Xeomin. The objective of the present study was to evaluate the possible differences in the antinociceptive effect evoked by different commercially available formulations of BoNT-A in an animal model of inflammatory orofacial pain induced by formalin injection. Male C57/BL6 mice (20-25 g) were submitted to the pre-treatment with five different commercial brands of BoNT-A (Botox, Botulift, Xeomin, Dysport, or Prosigne; with doses between 0.02 and 0.2 Units of Botulinum Toxin, in 20 µL of 0.9% saline) three days prior the 2% formalin injection. All injections were made subcutaneously into the right perinasal area. After formalin injections, nociceptive behaviors like rubbing the place of injection were quantified during the neurogenic (0-5 min) and inflammatory (15-30 min) phases. The treatment using Botox, Botulift, and Xeomin were able to induce antinociceptive effects in both phases of the formalin-induced pain animal model, however, Dysport and Prosigne reduced the response in neither of them. Our data suggest that the treatment using different formulations of BoNT-A is not similar in efficacy as analgesics when evaluated in formalin-induced orofacial pain in mice.
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AIMS: Breast cancer-induced chronic pain is usually treated with opioids, but these compounds cause various adverse effects. Transient receptor potential ankyrin 1 (TRPA1) is involved in cancer pain; also, endogenous TRPA1 agonists are associated with cancer pain development. The aim of this study was to observe the antinociceptive effect of a repeated-dose TRPA1 antagonist administration and the production of endogenous TRPA1 agonists and TRPA1 expression in bone tissue in a model of breast cancer pain in mice. Second, we used a sequence reading archive (SRA) strategy to observe the presence of this channel in the mouse bone and in mouse bone cell lines. MAIN METHODS: We used BALB/c mice for experiments. The animals were subjected to the tumor cell inoculation (4 T1 strain). HC-030031 (a TRPA1 antagonist) treatment was done from day 11 to day 20 after tumor inoculation. TRPA1 expression and biochemical tests of oxidative stress were performed in the bone of mice (femur). SRA strategy was used to detect the TRPA1 presence. KEY FINDINGS: Repeated treatment with the TRPA1 antagonist produced an antinociceptive effect. There was an increase in hydrogen peroxide levels, NADPH oxidase and superoxide dismutase activities, but the expression of TRPA1 in the bone tissue was not altered. SRA did not show TRPA1 residual transcription in the osteoblast and osteoclast cell lines, as well as for mice cranial tissue and in mouse osteoclast precursors. SIGNIFICANCE: The TRPA1 receptor is a potential target for the development of new painkillers for the treatment of bone cancer pain.
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Acetanilidas/farmacologia , Osso e Ossos/efeitos dos fármacos , Dor do Câncer/tratamento farmacológico , Hiperalgesia/tratamento farmacológico , Neoplasias Mamárias Animais/complicações , Nociceptividade/efeitos dos fármacos , Purinas/farmacologia , Canal de Cátion TRPA1/antagonistas & inibidores , Acetanilidas/administração & dosagem , Animais , Osso e Ossos/metabolismo , Dor do Câncer/etiologia , Dor do Câncer/metabolismo , Dor do Câncer/patologia , Feminino , Hiperalgesia/etiologia , Hiperalgesia/metabolismo , Hiperalgesia/patologia , Camundongos , Camundongos Endogâmicos BALB C , Purinas/administração & dosagemRESUMO
Fibromyalgia is a potentially disabling chronic disease, characterized by widespread pain and a range of comorbidities such as hypertension. Among the mechanisms involved in fibromyalgia-like pain symptoms are kinins and their B1 and B2 receptors. Moreover, angiotensin I converting enzyme (ACE) inhibitors, commonly used as antihypertensive drugs, can enhance pain by blocking the degradation of peptides such as substance P and bradykinin, besides enhancing kinin receptors signalling. We investigated the effect of ACE inhibitors on reserpine-induced fibromyalgia-like pain symptoms and the involvement of kinins in this effect in mice. Nociceptive parameters (mechanical and cold allodynia and overt nociception) were evaluated after ACE inhibitors administration in mice previously treated with reserpine. The role of kinin B1 and B2 receptors was investigated using pharmacological antagonism. Additionally, bradykinin levels, as well as the activity of ACE and kininase I, were measured in the sciatic nerve, spinal cord and cerebral cortex of the mice. The ACE inhibitors enalapril and captopril enhanced reserpine-induced mechanical allodynia, and this increase was prevented by kinin B1 and B2 receptor antagonists. Substance P and bradykinin caused overt nociception and increased mechanical allodynia in animals treated with reserpine. Reserpine plus ACE inhibitors increased bradykinin-related peptide levels and inhibited ACE activity in pain modulation structures. Since hypertension is a frequent comorbidity affecting fibromyalgia patients, hypertension treatment with ACE inhibitors in these patients should be reviewed once this could enhance fibromyalgia-like pain symptoms. Thus, the treatment of hypertensive patients with fibromyalgia could include other classes of antihypertensive drugs, different from ACE inhibitors.
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Inibidores da Enzima Conversora de Angiotensina/toxicidade , Fibromialgia/induzido quimicamente , Sistema Nervoso/efeitos dos fármacos , Dor Nociceptiva/induzido quimicamente , Limiar da Dor/efeitos dos fármacos , Peptidil Dipeptidase A/metabolismo , Receptores da Bradicinina/metabolismo , Animais , Comportamento Animal/efeitos dos fármacos , Captopril/toxicidade , Modelos Animais de Doenças , Enalapril/toxicidade , Fibromialgia/enzimologia , Fibromialgia/fisiopatologia , Masculino , Camundongos , Sistema Nervoso/enzimologia , Sistema Nervoso/fisiopatologia , Dor Nociceptiva/enzimologia , Dor Nociceptiva/fisiopatologia , Reserpina , Transdução de SinaisRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Pfaffia glomerata roots are widely used in Brazil to treat various pathological conditions, particularly psychological disorders. 20-hydroxyecdysone, a phytosteroid present in the plant, can promote greater body resistance against exogenous and endogenous stressors. The objective of this study was to evaluate the possible neuroprotective effect of a 20-hydroxyecdysone-enriched fraction (20E-EF), obtained from P. glomerata roots, in an acute murine stress model. MATERIAL AND METHODS: The 20E-EF was obtained by partitioning the methanol extract from P. glomerata roots with dichloromethane. Mice were treated by gavage with three doses of 20E-EF (3, 10, and 30 mg/kg) and parameters of stress, anxiety, and depression were evaluated. Biomarkers of oxidative stress (enzymes, antioxidant profile, and oxidized molecules) were evaluated in the cortex, striatum (basal ganglia), and hippocampus of animals treated with 30 mg/kg of 20E-EF. RESULTS: Mass spectrometry revealed that 20E was the main compound in the dichloromethane fraction. At a dose of 30 mg/kg, 20E-EF reduced stress, anxiety, and depression, while stimulating antioxidant enzymes (catalase, superoxide dismutase, and glutathione peroxidase), promoting antioxidant activity (antioxidant capacity, sulfhydryl groups, and reduced glutathione), and reducing oxidative markers (lipid peroxidation). In addition, 20E increased the concentration of NO in the striatum, possibly improving memory function and antioxidant activity. CONCLUSION: A 30 mg/kg dose of 20E-EF was able to reduce stress, anxiety, and depression, in addition to maintaining antioxidant defenses of the cortex and striatum. These findings open new perspectives for understanding the therapeutic properties of P. glomerata and the underlying mechanism(s).
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Amaranthaceae , Ansiolíticos/farmacologia , Antidepressivos/farmacologia , Ansiedade/prevenção & controle , Comportamento Animal/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Depressão/prevenção & controle , Ecdisterona/farmacologia , Extratos Vegetais/farmacologia , Raízes de Plantas , Estresse Psicológico/prevenção & controle , Amaranthaceae/química , Animais , Ansiolíticos/isolamento & purificação , Antidepressivos/isolamento & purificação , Antioxidantes/farmacologia , Ansiedade/metabolismo , Ansiedade/fisiopatologia , Ansiedade/psicologia , Biomarcadores/metabolismo , Encéfalo/metabolismo , Encéfalo/fisiopatologia , Depressão/metabolismo , Depressão/fisiopatologia , Depressão/psicologia , Modelos Animais de Doenças , Ecdisterona/isolamento & purificação , Comportamento Exploratório/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Memória/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Atividade Motora/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/isolamento & purificação , Raízes de Plantas/química , Estresse Psicológico/metabolismo , Estresse Psicológico/fisiopatologia , Estresse Psicológico/psicologiaRESUMO
Pain relief represents a critical unresolved medical need. Consequently, the search for new analgesic agents is intensively studied. Annona crassiflora, a native species of the Brazilian Savanna, represents a potential source for painful treatment. This study aimed to investigate the antinociceptive potential of A. crassiflora fruit peel, focusing on its major alkaloid, stephalagine, in animal models of pain evoked by the activation of transient receptor potential ankyrin 1 (TRPA1) and vanilloid 1 (TRPV1) channels. Male C57BL/6/J mice were submitted to formalin-, cinnamaldehyde-, and capsaicin-induced nociception tests to assess nociceptive behavior, and to the open-field and rotarod tests for motor performance analyses. Moreover, the stephalagine's effect was tested on capsaicin- and cinnamaldehyde-induced Ca2+ influx in spinal cord synaptosomes. In silico assessments of the absorption, distribution, metabolism and central nervous system permeability of stephalagine were carried out. The ethanol extract and alkaloidal fraction reduced the nociception induced by formalin. When administered by oral route (1 mg/kg), stephalagine reduced the spontaneous nociception and paw edema induced by TRPV1 agonist, capsaicin, and by TRPA1 agonists, cinnamaldehyde- and formalin, without altering the animals' locomotor activity. The prediction of in silico pharmacokinetic properties of stephalagine suggests its capacity to cross the blood-brain barrier. Furthermore, this alkaloid reduces the capsaicin- and cinnamaldehyde-mediated Ca2+ influx, indicating a possible modulation of TRPV1 and TRPA1 channels, respectively. Together, our results support the antinociceptive and anti-edematogenic effects of the A. crassiflora fruit peel and suggest that these effects are triggered, at least in part, by TRPV1 and TRPA1 modulation by stephalagine.