How does RLT help?
Wound healing is a dynamic process that coordinates cellular events essential for tissue repair and the re-establishment of the epithelial barrier function. The healing process consists of three main overlapping phases: the inflammatory phase, followed by cellular proliferation and the tissue remodeling phases.
Red light therapy (RLT) plays a positive role in increasing cellular proliferation and viability of mesenchymal stem cells, endothelial cells, osteoblasts, lymphocytes, epithelial cells and fibroblasts.
RLT provides more effective and efficient healing of soft tissue wounds by enhancing the rate and extent of epithelization. These results also show that RLT plays an important role in normalized wound healing by affecting keratin expression and that illumination provides a safe, easily applicable and cost-effective treatment of surface wounds.
Tell me more...
Skin wounds are amongst the most common health problems worldwide. In the event of injury to the skin, wound healing is initiated for the reconstruction and restoration of the stability and function of damaged tissue. Typical progression of wound repair is divided into overlying stages: inflammation, cellular proliferation (re-epithelialization) & tissue remodeling.
A disrupted wound repair process often leads to the development of chronic wounds. In chronic wounds, extreme hypoxia (lack of oxygen) - mostly critical towards the center of the wound - affects appropriate healing and often leads to reduced cellular survival. Along with hypoxia, chronic inflammation and edema impedes the wound healing process.
Red light therapy is unique in that it can effectively address these two main issues facing wound healing and, especially, chronic wounds. The four major biologic responses evoked by red light therapy are alleviation of pain and inflammation, a modulated immune response and tissue healing & regeneration (secondary to improved circulation and, thus, enhanced oxygenation to the tissues).
Research shows that red light therapy can benefit the healing process in burns, diabetic foot ulcers, venous ulcers, pressure ulcers and everyday wounds from paper cuts to scrapes.
Chronic wounds are a common complication seen in diabetes mellitus (DM), and often the severity necessitates amputation of the lower limbs. DM is a metabolic disorder characterised by various complications that affect virtually every system of the body. Chronic wounds of the foot, also known as diabetic foot ulcers, are debilitating. DM affects almost 20% of the population worldwide, and by 2030, it is projected that the incidence will increase to around 400 million cases. Diabetic foot ulcers are chronic, difficult-to-heal wounds and are a major health problem worldwide. Chronicity of wounds in DM is characterized by resistance to conventional therapy.
Combining effective treatment therapies can be a powerful way to accelerate the healing process and ensure that the wound healing progression is effective and efficient:
Hyaluronic acid has the ability to simulate fibrin development, phagocytic activity, neutrophil and macrophage mobility, and release of chemotaxic factors (migration) to fibroblasts, which contribute during the granulation phase of wound healing.
The use of gold nanoparticles in the treatment of wounds is due to their anti-inflammatory & antioxidant properties, capable of assisting in the tissue repair process by reducing the levels of pro-inflammatory cytokines & their capacity of cell inhibition & cell proliferation; which prevents the exacerbation of the inflammatory process & acceleration of wound healing.
What does the research show?
“PBM leads to photochemical reactions and the production of ATP activates a cascade of cellular events, which in turn leads to biological changes and downstream effects. These effects include, but are not limited to, the restoration of cellular function, mitigation of inflammation and pain, augmentation of tissue regeneration and wound repair, reduced oxidative stress, immunomodulation, neuronal regulation, accelerated cell proliferation and migration, stimulated release of growth factors, and promotion of extracellular matrix synthesis.” (1)
(Regarding diabetic wounds): “The obtained data from most of the reviewed studies affirmed that the PBM alone or combined with other agents (e.g., stem cells) could moderate the inflammatory response and accelerate the wound healing process in pre-clinical diabetic wound models.” (2)
“Photobiomodulation stands out as one of the most efficient resources in the treatment of epithelial lesions. Some studies have suggested that mitochondria are the primary laser target in epithelial tissue.” (3)
(Diabetic Foot Ulcers): "This research noted a significant improvement in PBM-treated wounds (30 – 50%) in a majority of subjects compared with minimal changes in the control group." (4)
(Diabetic Foot Ulcers): "Results demonstrated significant improvements in wound areas following PBM treatments that correlated with increased pro-healing factors, including vascular endothelial growth factor (angiogenesis) & TGF-β (matrix & epithelial closure), whereas TNF-α (inflammation) levels were reduced." (5)
"(Burn Wounds): "All subjects reported less pain and pruritus after PBM treatments, with reduced inflammatory exudate and fibrin with improved re-epithelialization and granulation tissue organization compared with contralateral control sites." (6)
"It has been shown that the association between photobiomodulation and gold nanoparticles generates a greater wound contraction effect compared to the use of each therapy alone, because the combination of both techniques promotes shortening of the inflammatory phase & promotion of angiogenesis & production of collagen." (7)
"Our study demonstrates for the first time that while PBMT (RLT) accelerates epithelial migration, it promotes chromatin remodeling and mobilizes the population of stem cells." (8)
"The results of this study allow us to observe that gold nanoparticles were effective mainly in controlling the inflammatory process and modulating the cellular redox state. In contrast, the use of photobiomodulation and hyaluronic acid caused greater benefits in view of increased fibroblast activity and collagen production. Together, the combination of all therapies induced a significant increase in the acceleration of the tissue repair process." (9)
**While the current scientific research seems to indicate many positive benefits of RLT in relation to wound healing, there is still an appreciable necessity for more extensive research to be conducted in this area, including double-blind RCT (randomized controlled trials), to provide a more comprehensive, robust overview that will further elucidate the optimal parameters and appropriate uses of RLT, which will ultimately lead the most safe & efficacious uses for those dealing with wound healing.
(1) Leyane, Thobekile S et al. “Cellular Signalling and Photobiomodulation in Chronic Wound Repair.” International journal of molecular sciences vol. 22,20 11223. 18 Oct. 2021, doi:10.3390/ijms222011223
(2) Rahmannia, Maryam et al. “Impact of photobiomodulation on macrophages and their polarization during diabetic wound healing: a systematic review.” Lasers in medical science, 10.1007/s10103-022-03581-5. 30 May. 2022, doi:10.1007/s10103-022-03581-5
(3) Mendes, Carolini et al. “Effects of the Association between Photobiomodulation and Hyaluronic Acid Linked Gold Nanoparticles in Wound Healing.” ACS biomaterials science & engineering vol. 6,9 (2020): 5132-5144. doi:10.1021/acsbiomaterials.0c00294
(4) Mathur, R K et al. “Low-level laser therapy as an adjunct to conventional therapy in the treatment of diabetic foot ulcers.” Lasers in medical science vol. 32,2 (2017): 275-282. doi:10.1007/s10103-016-2109-2
(5) Ruh, Anelice Calixto et al. “Laser photobiomodulation in pressure ulcer healing of human diabetic patients: gene expression analysis of inflammatory biochemical markers.” Lasers in medical science vol. 33,1 (2018): 165-171. doi:10.1007/s10103-017-2384-6
(6) de Oliveira, Rauirys Alencar et al. “Low-intensity LED therapy (658 nm) on burn healing: a series of cases.” Lasers in medical science vol. 33,4 (2018): 729-735. doi:10.1007/s10103-017-2399-z
(7) Mendes, Carolini et al. “Effects of the Association between Photobiomodulation and Hyaluronic Acid Linked Gold Nanoparticles in Wound Healing.” ACS biomaterials science & engineering vol. 6,9 (2020): 5132-5144. doi:10.1021/acsbiomaterials.0c00294
(8) Martins, Manoela D et al. “Photobiomodulation therapy drives massive epigenetic histone modifications, stem cells mobilization and accelerated epithelial healing.” Journal of biophotonics vol. 14,2 (2021): e202000274. doi:10.1002/jbio.202000274
(9) Mendes, Carolini et al. “Effects of the Association between Photobiomodulation and Hyaluronic Acid Linked Gold Nanoparticles in Wound Healing.” ACS biomaterials science & engineering vol. 6,9 (2020): 5132-5144. doi:10.1021/acsbiomaterials.0c00294