What is Photobiomodulation?

Photobiomodulation (PBM) is a non-thermal light therapy that uses specific wavelengths of light, primarily in the red (600–700 nm) and near-infrared (NIR) (750–1100 nm) spectrum, to modulate biological processes at the cellular level. PBM is also referred to as low-level laser therapy (LLLT) or cold laser therapy. The mechanism of action is primarily linked to the absorption of photons by mitochondrial chromophores, such as cytochrome c oxidase (CCO) in the electron transport chain, leading to increased adenosine triphosphate (ATP) production, modulation of reactive oxygen species (ROS), and the release of nitric oxide (NO), which collectively enhance cellular metabolism and function.

Mechanisms of Action:

1. Mitochondrial Stimulation: PBM promotes ATP production by affecting CCO activity, enhancing cellular energy metabolism (Hamblin, 2017).
2. Anti-inflammatory Effects: It modulates inflammatory pathways by decreasing pro-inflammatory cytokines (TNF-α, IL-6) and increasing anti-inflammatory markers (IL-10) (Gutiérrez-Meca et al., 2022).
3. Neuroprotective Effects: PBM has been shown to enhance neurogenesis, synaptogenesis, and neuroplasticity by activating brain-derived neurotrophic factor (BDNF) pathways (Salehpour et al., 2021).
4. Pain Reduction: PBM affects nociceptive pathways by modulating ion channels, neurotransmitter release, and reducing oxidative stress in neurons (Cotler et al., 2015).
5. Wound Healing & Tissue Repair: It promotes fibroblast proliferation, collagen synthesis, and angiogenesis, contributing to improved healing in soft tissue injuries (de Freitas & Hamblin, 2016).

Clinical Applications:

• Neurological disorders: PBM has been studied for Parkinson’s disease, Alzheimer’s disease, stroke recovery, and traumatic brain injury (Hennessy & Hamblin, 2017).
• Pain management: Effective in musculoskeletal conditions such as arthritis, myofascial pain, and neuropathy (Cotler et al., 2015).
• Wound healing & regeneration: Used in chronic wounds, burns, and post-surgical recovery (Posten et al., 2005).
• Sports medicine & performance: Enhances muscle recovery and reduces fatigue (Leal et al., 2018).

References:

1. Cotler, H. B., Chow, R. T., Hamblin, M. R., & Carroll, J. (2015). The use of low-level laser therapy (LLLT) for musculoskeletal pain. MOJ Orthopedics & Rheumatology, 2(5), 00068. DOI: 10.15406/mojor.2015.02.00068
2. de Freitas, L. F., & Hamblin, M. R. (2016). Proposed mechanisms of photobiomodulation or low-level light therapy. IEEE Journal of Selected Topics in Quantum Electronics, 22(3), 7000417. DOI: 10.1109/JSTQE.2016.2561201
3. Gutiérrez-Meca, A., Celdrán-Bonafonte, D., & Álvarez-Marcos, C. (2022). Photobiomodulation therapy in the modulation of inflammatory biomarkers in humans: A systematic review. Photodiagnosis and Photodynamic Therapy, 39, 102981. DOI: 10.1016/j.pdpdt.2022.102981
4. Hamblin, M. R. (2017). Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS Biophysics, 4(3), 337–361. DOI: 10.3934/biophy.2017.3.337
5. Hennessy, M., & Hamblin, M. R. (2017). Photobiomodulation and the brain: A new paradigm. Journal of Optics, 19(1), 013003. DOI: 10.1088/2040-8986/19/1/013003
6. Leal, E. C. P., Lopes-Martins, R. A. B., Frigo, L., et al. (2018). Effects of photobiomodulation therapy on delayed onset muscle soreness (DOMS): A systematic review and meta-analysis. Lasers in Medical Science, 33(7), 1463–1477. DOI: 10.1007/s10103-018-2535-7
7. Posten, W., Wrone, D. A., Dover, J. S., et al. (2005). Low-level laser therapy for wound healing: Mechanism and efficacy. Dermatologic Surgery, 31(3), 334–340. DOI: 10.1111/j.1524-4725.2005.31096
8. Salehpour, F., Khademi, M., Bragin, D. E., et al. (2021). Transcranial photobiomodulation therapy for traumatic brain injury and neurodegenerative diseases. Neurochemical Research, 46(2), 218–234. DOI: 10.1007/s11064-020-03164-x