Blue-light treatment reduces spontaneous and evoked pain in a human experimental pain model

Abstract

Introduction: Chronic pain is a frequent severe disease and often associated with anxiety, depression, insomnia, disability, and reduced quality of life. This maladaptive condition is further characterized by sensory loss, hyperalgesia, and allodynia. Blue light has been hypothesized to modulate sensory neurons and thereby influence nociception.Objectives: Here, we compared the effects of blue light vs red light and thermal control on pain sensation in a human experimental pain model. Methods: Pain, hyperalgesia, and allodynia were induced in 30 healthy volunteers through high-density transcutaneous electrical stimulation. Subsequently, blue light, red light, or thermal control treatment was applied in a cross-over design. The nonvisual effects of the respective light treatments were examined using a well-established quantitative sensory testing protocol. Somatosensory parameters as well as pain intensity and quality were scored. Results: Blue light substantially reduced spontaneous pain as assessed by numeric rating scale pain scoring. Similarly, pain quality was significantly altered as assessed by the German counterpart of the McGill Pain Questionnaire. Furthermore, blue light showed antihyperalgesic, antiallodynic, and antihypesthesic effects in contrast to red light or thermal control treatment. Conclusion: Blue-light phototherapy ameliorates pain intensity and quality in a human experimental pain model and reveals antihyperalgesic, antiallodynic, and antihypesthesic effects. Therefore, blue-light phototherapy may be a novel approach to treat pain in multiple conditions.

Antimicrobial Blue Light for Prevention and Treatment of Highly Invasive Vibrio vulnificus Burn Infection in Mice

“…Interestingly, TIMP-1, which was found to be upregulated in both male and female mice, has been found to be associated with reduced inflammatory pain (Knight et al, 2019 ). This finding suggests the impact of aBL in reducing pain as a result of inflammation, which has been suggested in another study by Reuss et al ( 2021 ). However, given the preliminary nature of the study, a deeper insight into the effect of aBL on inflammatory pain is warranted.…”

Highlighting nuances of blue light phototherapy: Mechanisms and safety considerations

“…In an attempt to find a "safer" yet effective therapy, the last decade has witnessed a significant increase in the use of the blue light (400-495 nm) within the parameter window (irradiance and exposure time), which induces photobiological effects [8,39,48,49]. Applications include its use as an exogenous photosynthesizer in the treatment of actinic keratosis (AK) during photodynamic therapy (PDT) [19] and on endogenous molecular targets in neonatal jaundice [50], acne [19,49], psoriasis vulgaris [48], eczema [48] alopecia [51], blood pressure reduction [52], stimulation of endorphin release [53], pain relief [54], chronic wounds [55][56][57], and so forth.…”

Feasibility and Safety of Adopting a New Approach in Delivering a 450 nm Blue Laser with a Flattop Beam Profile in Vital Tooth Whitening. A Clinical Case Series with an 8-Month Follow-Up

“…On reflection, the λ 450 nm blue laser provoked antihyperalgesic and antiallodynic effects by blocking the delta A and C fibres, causing the hyperpolarisation of the nervous fibre, preventing transduction, blocking nervous transmission, and promoting pain alleviation [72]. As lasers have unique properties of monochromaticity and coherence, they succeed in being more potent anti-inflammatory and analgesic biomodulators [73][74][75][76] compared to LEDs.…”