Class 3B LASER PBM Produces a Joule-Response Dependent Analgesic Effect in Complete Freund Adjuvant-Induced Inflammation in a Mouse Model: Analysis of Action Mechanism
Francisco José Cidral-Filho, Neito Antonio Bonotto, Bruna Hoffman de Oliveira, Aline Raulino Dutra, Juliana Nazário, Daniel Fernandes Martins
Experimental Neuroscience Laboratory (LaNEx), Postgraduate Program in Health Sciences, University of Southern Santa Catarina, Palhoça, SC, Brazil.
Abstract
Objective: This study investigated the roles of opioid, cannabinoid (CBR), and adenosine receptors (ARs) in the antihyperalgesic effects of Class 3B laser photobiomodulation (PBM) in mice with peripheral inflammation.
Methods: Peripheral inflammation was induced by intraplantar (i.pl.) injection of Complete Freund’s Adjuvant (CFA) in male Swiss mice. Experiment 1 assessed the involvement of opioid receptors by i.pl. injection of naloxone 15 minutes prior to PBM. Experiment 2 explored the roles of CBR subtypes by i.pl. injection of selective antagonists AM281 (CB1R) and AM630 (CB2R) 15 minutes before PBM. Experiment 3 evaluated the contribution of ARs using caffeine or DPCPX, an A1 receptor antagonist, 15 minutes before PBM. Mechanical hyperalgesia was measured with the von Frey test 30 minutes after PBM with an energy density of 8 J/cm², delivered using a high-power Class 3B laser system (Avant Wellness LZ30 Pro Z, 1,400 mW at 808 nm and up to 1,000 mW at 637 nm).
Results: CFA induced mechanical hyperalgesia, which was mitigated by PBM. Naloxone, AM281, AM630, caffeine, and DPCPX pretreatments blocked the antihyperalgesic effect of PBM, suggesting the involvement of opioid, cannabinoid, and adenosine receptors in the pain relief mechanism.
Conclusion: Class 3B LASER PBM reduces mechanical hyperalgesia via peripheral opioid, cannabinoid, and adenosine receptors, supporting its use in treating inflammatory pain. These findings highlight the importance of receptor-mediated mechanisms in PBM-induced pain relief and reinforce the potential benefits of high-power Class 3B lasers, such as the LZ30 Pro Z, in pain management applications.
Keywords: Light Therapy, Pain, Photobiomodulation, Inflammation, Receptor Antagonists.
Laser details: Avant Wellness LZ30 Pro Z
