Muscle injury Muscle tissue are injured from time to time through various activities. Repair of muscle tissue is very complex, but is de-fined by very specific steps. Macrophages play an important role in the regenerative processes due to their plasticity and multiple functions. In the muscle repair process, while M1 macrophages regulate the inflammatory and proliferative phases, M2 (anti-inflammatory) macrophages direct the dif-ferentiation and remodelling phases, leading to tissue regener-ation. Both PBMt of red and NIR wavelengths positively affect M1 and M2 macrophages. However, only NIR wavelength is able to increase the number of M2 and mRNA, allowing the repair process to rapidly express itself. Treatment with PBMt, using NIR wavelength is able to modulate the inflammation phase, optimize the transition from the inflammatory to the regeneration phase, and improve the final step of regeneration, enhancing tissue repair.(12). Specific exercise protocols can also help to stimulate the regenerative process and assist with tissue repair.(13). Interestingly, exercise for tissue repair can cause low grade fibrous/scar formation. In acute injuries, with early intervention with PBMt, fibrous/scar formation does not occur. However, in my practice we have had cases with fibrous/ scar in the chronic injured area, using PBMt on the area re-duced the fibrous/scar tissue, decreased the pain and increased the range of movement. Treating my low back with the specific protocols for that area, after 12 treatments, my pain was 80% better. Muscle performance Muscles seem to love PBMt because they have a high density of mitochondria and muscles respond significantly to PBMt application. PBMt can increase muscle performance when applied before training, increase the effectiveness of training and decrease the after effects of training. Not to mention that PBMt can also alleviate pain, soreness and heal micro injuries due to training. Because of its efficacy and performance en-hancing effect, researchers have even raised concerns regarding whether it should be allowed at Olympic competition. In a systematic review with meta-analysis the researchers concluded that PBMt with red and NIR wavelengths improves muscular performance and accelerates recovery mainly when applied before exercise.(14) These results were not limited to athletes, because PBMt in combination with strength training was also able to improve muscle performance in elderly people. (15) PBMt using 904 nm wavelength was effective in reducing fatigue levels and increasing muscle performance in young active women.(16) In another systemic review with meta-anal-ysis, PBMt and exercise caused the improvement of muscular 20 Chiropractic and Naturopathic Doctor January/February 2021 performance and reduction of muscular fatigue in healthy people.(17). When red, NIR, and red/NIR mixtures were used, PBMt caused increased muscle mass gained after training, and decreased inflammation and oxidative stress in muscle biopsies. The researchers raised the question of whether PBMt should be permitted in athletic competition by international regula-tory authorities.(18). This is a valid question, because this study showed that PBMt applied for 12 weeks before and after en-durance-training exercise sessions lead to improvement of endurance three times faster than exercise only.(19). Can you imagine the results if they had added nutrition and supple-ments, because these have also been shown to improve muscle health and strength? The future is very promising for PBMt, whether it focuses on treatment/rehab, a therapy for human performance, or a combination of both. Due to its efficacy, its scope of applica-tions continues to expand into neuromuscular skeletal and osteoarthritis(20),(21), traumatic brain injury and stroke(5), Parkinson’s Disease(22) and depression(23), to name a few. New therapeutic approaches are also developing, such as using multiple wavelengths to treat different layers of tissue at the same time for more comprehensive results.(24).What is re-quired to help PBMt reach its’ full potential is an Institute for researching all the parameters and defining specific protocols for each condition. This will assist with standardizing for re-search and treatment purposes, which will help to advance PBMt as an evidence based alternate health care choice. References 1. 2. 3. 4. 5. 6. 7. 8. 9. Zein R, et al. Review of light parameters and photobio-modulation efficacy: dive into complexity. J Biomed Opt. 2018 Dec; 23(12): 1-17. Hamblin M. Mechanisms and applications of the anti-in-flammatory effects of photobiomodulation. AIMS Bio-phys. 2017;4(3):337-361. Dompe C, et al. Photobiomodulation-Underlying Mech-anism and Clinical Applications. J Clin Med. 2020 Jun 3; 9(6): 1724. Holanda V, et al. The mechanistic basis for photobiomod-ulation therapy of neuropathic pain by near infrared laser light. Lasers Surg Med. 2017 Jul; 49(5): 516-524. Hamblin M. Photobiomodulation for traumatic brain injury and stroke. J Neurosci Res. 2018 Apr; 96(4): 731-743. Fekri A, et al. Short-term Effects of Transcranial Near-In-frared Photobiomodulation on Motor Performance in Healthy Human Subjects: An Experimental SingleBlind Randomized Clinical Trial. J Lasers Med Sci. Fall 2019;10(4):317-323. Li K, et al. Attenuation of the inflammatory response and polarization of macrophages by photobiomodulation. Lasers Med Sci. 2020 Sep;35(7):1509-1518. Rochkind S. Photobiomodulation in Neuroscience: A Summary of Personal Experience. Photomed Laser Surg. 2017 Nov;35(11):604-615. Hwang M, et al. Effects of photobiomodulation on annu-lus fibrosus cells derived from degenerative disc disease patients exposed to microvascular endothelial cells condi-tioned medium. Sci Rep. 2020 Jun 15; 10(1): 9655. www.Cndoctor.ca
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