RESUMO
ABSTRACT BACKGROUND AND OBJECTIVES: Hypnotic suggestions for hypoalgesia or analgesia are efficient for relieving different pain conditions, presenting few or no side effects. However, little is known about its direct effect on the modulation of peripheral nociception. The goal of this study was to evaluate the mechanical and thermal response after specific hypnotic suggestions in healthy volunteers. METHODS: This is a randomized double-blinded controlled trial that aimed to evaluate both mechanical and thermal nociception after specific hypnotic suggestions in healthy volunteers. For this, twenty-seven participants were enrolled, according to the following eligibility criteria: age between 18-65 years and absence of pain complaints or psychological disorders. After signed Free Informed Consent Term (FICT) the participants were divided by a computer-generated randomization in three groups: sham group (no induction of hypnosis), hypnosis-induced pain group and hypnosis-induced analgesia group. Susceptibility to hypnosis was assessed through the Waterloo-Stanford Group C (WSGC) scale of hypnotic susceptibility and outcomes included evaluation of questionnaires (Hospital Anxiety and Depression Scale and Short Form Brief Pain Inventory) as well as the examination of mechanical and thermal nociception through the Quantitative Sensory Testing (QST), a tool widely used to investigate somatosensory sensitivity by assessing functions of small A-δ and C nerve sensory fibers, before and after specific hypnotic suggestion for pain and analgesia made by a qualified hypnotherapist. RESULTS: Data demonstrated that specific hypnotic suggestions induced significant changes in mechanical and thermal sensitivity. The pain group revealed an increase in mechanical hyperalgesia and allodynia, while the analgesia group increased pain thresholds to thermal stimulations, being conditioned to withstand temperature changes after hypnosis, demonstrating a modulatory effect for both pain and analgesia sensations in healthy volunteers. CONCLUSION: The evidence presented in this study supports the use of the hypnosis technique as an auxiliary tool in clinical practice. HIGHLIGHTS Specific hypnotic suggestions can modulate peripheral nociception in healthy subjects. Data show a modulatory effect for both pain and analgesia sensations. Hypnosis can be considered a feasible technique for the clinical pain management.
RESUMO JUSTIFICATIVA E OBJETIVOS: Sugestões hipnóticas de hipoalgesia ou analgesia são eficientes para aliviar diferentes quadros álgicos, apresentando poucos ou nenhum efeito colateral. No entanto, pouco se sabe sobre seu efeito direto na modulação da nocicepção periférica. O objetivo deste estudo foi avaliar a resposta mecânica e térmica após sugestões hipnóticas específicas em voluntários saudáveis. MÉTODOS: Este é um estudo randomizado e duplo-cego que visou avaliar a nocicepção mecânica e térmica após sugestões hipnóticas específicas em voluntários saudáveis. Para isso, vinte e sete participantes foram selecionados, de acordo com os seguintes critérios de elegibilidade: idade entre 18 e 65 anos e ausência de distúrbios psicológicos e de queixas de dor. Após a assinatura do Termo de Consentimento Livre e Esclarecido (TCLE), os participantes foram divididos por randomização gerada por computador em três grupos: grupo sham (sem indução de hipnose), grupo dor induzida por hipnose e grupo analgesia induzida por hipnose. A suscetibilidade à hipnose foi avaliada através da escala Waterloo-Stanford Group C (WSGC) de suscetibilidade hipnótica e os resultados incluíram a avaliação de questionários (Escala Hospitalar de Ansiedade e Depressão e Inventário Breve de Dor), bem como o exame de nocicepção mecânica e térmica através do Teste Sensorial Quantitativo (QST), uma ferramenta amplamente utilizada para investigar a sensibilidade somatossensorial por meio da avaliação das funções das fibras sensoriais finas dos nervos A-δ e C, antes e após sugestão hipnótica específica para dor e analgesia aplicada por um hipnoterapeuta qualificado. RESULTADOS: Os dados mostraram que as sugestões hipnóticas específicas induziram mudanças significativas na sensibilidade mecânica e térmica dos indivíduos. O grupo dor revelou aumento da hiperalgesia mecânica e da alodinia, enquanto o grupo analgesia aumentou os limiares de dor por estímulos térmicos, sendo condicionado a suportar mudanças de temperatura após a hipnose, demonstrando efeito modulador tanto para as sensações de dor quanto de analgesia em voluntários saudáveis. CONCLUSÃO: As evidências apresentadas neste estudo sustentam o uso da técnica de hipnose como ferramenta auxiliar na prática clínica. DESTAQUES Sugestões hipnóticas específicas podem modular a nocicepção periférica em sujeitos saudáveis. Os dados mostram um efeito modulador tanto para as sensações de dor quanto de analgesia. A hipnose pode ser considerada uma técnica viável para o manejo clínico da dor.
RESUMO
BACKGROUND: Envenoming induced by Bothrops snakebites is characterized by drastic local tissue damage that involves an intense inflammatory reaction and local hyperalgesia which are not neutralized by conventional antivenom treatment. Herein, the effectiveness of photobiomodulation to reduce inflammatory hyperalgesia induced by Bothrops moojeni venom (Bmv), as well as the mechanisms involved was investigated. METHODOLOGY/PRINCIPAL FINDINGS: Bmv (1 µg) was injected through the intraplantar route in the right hind paw of mice. Mechanical hyperalgesia and allodynia were evaluated by von Frey filaments at different time points after venom injection. Low level laser therapy (LLLT) was applied at the site of Bmv injection at wavelength of red 685 nm with energy density of 2.2 J/cm2 at 30 min and 3 h after venom inoculation. Neuronal activation in the dorsal horn spinal cord was determined by immunohistochemistry of Fos protein and the mRNA expression of IL-6, TNF-α, IL-10, B1 and B2 kinin receptors were evaluated by Real time-PCR 6 h after venom injection. Photobiomodulation reversed Bmv-induced mechanical hyperalgesia and allodynia and decreased Fos expression, induced by Bmv as well as the mRNA levels of IL-6, TNF-α and B1 and B2 kinin receptors. Finally, an increase on IL-10, was observed following LLLT. CONCLUSION/SIGNIFICANCE: These data demonstrate that LLLT interferes with mechanisms involved in nociception and hyperalgesia and modulates Bmv-induced nociceptive signal. The use of photobiomodulation in reducing local pain induced by Bothropic venoms should be considered as a novel therapeutic tool for the treatment of local symptoms induced after bothropic snakebites.
