For the past several years, LED Red Light Therapy in clinical studies, application, and basic experimental research, especially in skin disease, arthritis, osteoporosis, wound healing and repair, anti-infection and immunomodulation, etc.
The effects of red light are closely related to the biological functions of the organism, therefore, LED red light has received more and more attention in the application of related diseases and basic research. Next, we will review the biological changes induced by LED red light and its clinical studies.
Contents
- 1 What Is LED?
- 2 What Is LED Light Therapy?
- 3 What Is LED Red Light Therapy?
- 4 How Does Red Light Therapy Work?
- 5 1. LED Red Light Repairs Damaged Skin and Tissue
- 6 2. LED Red Light for Skin Pigmentation
- 7 3. LED Red Light for Bone and Joint Diseases
- 8 4. LED Red Light Promotes The Regeneration of Blood Vessels
- 9 5. LED Red Light Promotes Hair Growth
- 10 Summary
What Is LED?
LED is a light-emitting diode (Light Emitting Diode) abbreviation, it is a semiconductor electronic component that converts electrical energy into light energy, which through the electron and hole complex, will be converted into light energy, the release of energy to emit light, belongs to a kind of artificial light source.
What Is LED Light Therapy?
In agriculture, LED light technology is often used to improve plant productivity, such as LED grow lights. Previous studies have shown that LED light therapy has applications in anti-inflammatory and pain relief, wound healing, modulation of neurological disorders, control of neonatal hyperbilirubinemia, treatment of bone disorders, and treatment of benign and malignant tumors with photodynamic therapy.
What Is LED Red Light Therapy?
Red Light Therapy (RLT) is a treatment that utilizes low-intensity LED red light to promote health and wellness. Red Light Therapy typically uses red light with wavelengths between 620 and 660 nanometers(nm), or near-infrared light between 800 and 850 nanometers.
These wavelengths of red light or near-infrared light penetrate the skin and reach the cellular, stimulating the mitochondria in the cells, promoting intracellular biochemical reactions, enhancing cellular energy production, increasing energy metabolism, and thus accelerating the process of tissue repair and regeneration, decreasing inflammation, and relieving pain, among other things.
How Does Red Light Therapy Work?
Red light irradiation of human skin can increase the activity of catalase in cell mitochondria, and improve cellular metabolism so that ATP decomposition, protein synthesis, and glycogen content are increased to promote cell synthesis.
1. LED Red Light Repairs Damaged Skin and Tissue
Post-surgical wound infection and healing have always been a concern for surgeons. Some studies have shown that the use of LED light treatment can significantly improve the healing of human skin suture incisions. Trelles’ study showed that after 20 min of irradiation with 630nm LED red light at a dose of 80 mW/cm2, the healing of wounds in patients was significantly improved, and the speed of postoperative wound healing was also effectively increased.
In Wang’s experimental study, rat gingival fibroblasts were irradiated with 660nm LED red light at a dose of 3.5 mW/cm2 for a certain period to evaluate cell activity and in vitro wound healing, and the results showed that 660nm LED red light irradiated with an energy of 10-20 J/cm2 reduced reactive oxygen species production, and at the same time, it promoted angiogenesis and the reorganization of temporary matrix, thus accelerating wound healing in rats.
The results showed that 660nm LED red light irradiation energy in the range of 10 ~ 20 J/cm2 reduced reactive oxygen species production and promoted angiogenesis and reorganization of the temporary matrix in vivo, thus accelerating wound healing in rats.
660nm LED red light irradiation promotes an increase in collagen IV in skeletal muscle, leading to more efficient repair of damaged muscle. The combination of LED red and blue light effectively stimulates collagen synthesis and accelerates the conversion of fibroblasts to myofibroblasts, demonstrating a compound regenerative effect.
660nm LED red light is also used in the treatment of keloids and other fibrotic skin diseases. Mamalis and Jagdeo found that 660nm LED red light can inhibit fibroblast proliferation, potentially helping to treat scars and other fibrotic skin diseases.
As research progresses, clinical studies and applications of LED red light in wound healing and other areas will become more widespread.
2. LED Red Light for Skin Pigmentation
LED is a low-heat light source, which is less damaging to the skin and safer, and LED red light is effective in skin pigmentation diseases such as melasma, freckles, acne, etc. A researcher has investigated the effect of red light on melanin synthesis and its mechanism by irradiating melanoma cells (B16F10) with 660nm LED red light at a dose of 7.8 J/cm2.
The results showed that 660nm LED red light could inhibit the tyrosinase activity induced by α-melanocyte stimulating hormone in B16F10 cells, thus inhibiting melanin synthesis.
It was also found that 660nm LED red light induced a depigmenting effect by inducing the activation of extracellular regulated protein kinases and decreasing the expression of microphthalmia-associated transcription factors and tyrosinase proteins.
Phototherapy can be used as a safe alternative therapy for the treatment of inflammatory skin diseases such as acne, and it has been demonstrated in the literature that high-dose (>10 J/cm2 ) LED blue and red light irradiation has significant effects on inflammatory acne. Acne lesions were also improved by low-dose (0.2~1.2J/cm2) LED red light irradiation.
3. LED Red Light for Bone and Joint Diseases
LED red light therapy has positive regulation and positive effects on osteoblast differentiation and bone formation, many systemic and regional bone loss diseases, such as osteoporosis and osteochondrosis are mainly caused by the increase and up-regulation of osteoclast activity.
It was found that 635nm LED red light irradiated osteoclasts at a dose of 2mW/cm2 for 72 hours can cause actin disorders and reduce the level of gene expression (such as integrin β3 and c-Src) that affects the formation of actin rings, thus inhibiting bone resorptive osteoclasts, thus we can see that 635nm LED red light plays a key role in the regulation of bone remodeling.
Sohn found that 635 nm, 5 mW/cm2 LED red light irradiation can significantly reduce the activity of nuclear factor-κB (NF-κB) and intracellular ROS production, which can down-regulate osteoclastogenesis.
Another study showed that irradiating mice with 630 nm LED red light at a dose of 5 mW/cm2 promoted the proliferation of embryonic osteoblast precursor cells (MC3T3-E1), and improved osteoblast differentiation after a certain period of cell culture.
Therefore, LED red light irradiation may be an effective tool for the prevention of bone loss in osteoporosis and other bone resorptive diseases.
4. LED Red Light Promotes The Regeneration of Blood Vessels
Local ischemia is a common disease associated with reduced blood supply to certain organs or tissues, and the primary goal of its treatment is to stimulate the neovascularization of blood vessels.
Park explored the regeneration of blood vessels from adipose-derived stem cells (ASCs) by irradiating the ischemic limbs with LED red light. After irradiation with LED red light at 650 nm, 50 mW/cm2, the LED-treated ASCs showed new blood vessel formation and tissue regeneration, suggesting that LED red light can promote the regeneration of blood vessels and enhance the survival of ASCs and stimulate the secretion of growth factors in the ischemic limbs.
5. LED Red Light Promotes Hair Growth
In the late 1960s, a Hungarian doctor conducted a series of conjecture tests on mice that lasers caused cancer, but the test found that lasers improved the proliferation of hair around the mouse shaving, and for the first time proposed photobiological therapy for the development of medicine to open up a new path. LED is a great alternative to the laser light source, for a variety of diseases in a wide range of applications.
Based on the above research, Hong conducted a large number of experiments, proving that human dermal hair papilla cells (hDPCs) proliferated faster after being irradiated by 660nm, 2. 42 mW/cm2 LED for 70 min.
Further studies found that LED red light promotes the proliferation of HD-PCs by stimulating Wnt / β-cyclin signaling and ERK signaling pathway, and in vitro tests on human scalp skin hair follicles showed that LED red light has a positive effect on hair growth.
Summary
LED As a highly promising cold light source, LED red light plays an active role in the positive modulation of skin, wound healing, pain relief, metabolic abnormalities, and immune disorders. As a light source with physical intervention, LED red light can promote the proliferation of primary cells (such as adipose-derived stem cells and nerve cells) and play a certain auxiliary role in the treatment of diseases.
LED-related medical equipment research and development will be the important direction of the future combination of medicine and optics, especially portable, wearable LED light therapy devices is bound to be the direction of future medical progress, LED red light therapy will be more extensive services and human health.
