Low Level Light Therapy Treatment
What is Photobiomodulation?
Since the introduction of low-level laser (light) therapy in 1967, over two hundred randomized, double-blinded, and placebo-controlled phase III clinical trials have been published from over a dozen countries, and the benefits are undeniable.
Soon after the discovery of lasers in the 1960s it was realized that laser therapy had the potential to improve wound healing and reduce pain, inflammation and swelling. In recent years the field sometimes known as photobiomodulation has broadened to include light-emitting diodes and other light sources, and the range of wavelengths used now includes many in the red and near infrared, with deep tissue penetrating properties.
The term “low level laser therapy” or LLLT has become widely recognized.
LLLT involves exposing cells or tissue to low levels of light (red and near infrared (NIR) light often used due to tissue penetrating power), and is referred to as “low level” because of its use of light at energy densities that are low when compared to other forms of therapy employing lasers that are used for ablation, cutting, and thermally coagulating tissue. LLLT may also be obtained from low power lasers, also known as “cold laser” therapy as the power densities used are lower than those needed to produce heating of tissue.
A light-emitting diode (LED) is a semiconductor light source introduced as a practical electronic component in 1962. Early LEDs emitted low-intensity red light, but modern versions are available across the entire visible spectrum, with very high brightness. When the light strikes the biological tissue, part of it is reflected or scattered and part is further transmitted through the tissue being progressively absorbed into the tissue. The extent or depth to which the light penetrates is very dependent on the specific colour.
There are a host of beneficial effects that occur when our cells are exposed to light, particularly cells deep inside our bodies that may not normally get much light.
If you remember back to your high school biology you may recall that cells contain an organella called the mitochondria, a fibrous network responsible for creating most of the energy we use in our life and most importantly that the cell itself uses to maintain, divide, correctly control, repair itself or shut itself down if something goes wrong. Within the cell, studies have shown that LLLT acts on the mitochondria in a very favourable way, to increase the energy molecule adenosine triphosphate (ATP) production, modulate harmful waste products such as reactive oxygen species (ROS), and even effect the induction of transcription factors suggesting an effect on genetic expression. These transcription factors then cause protein synthesis that triggers further effects down-stream, such as increased cell proliferation and migration, modulation in the levels of cytokines, growth factors and inflammatory mediators, and increased tissue oxygenation. Modern understanding on disease suggest a causal relationship between inflammation and many problems / diseases.
At the most basic level, LLLT acts by inducing a beneficial photochemical reaction in your cells, a process referred to as biostimulation or photobiomodulation. When a photon of light is absorbed by a chromophore in the treated cells, an electron in the chromophore can become excited and jump from a low-energy orbit to a higher-energy orbit. This stored energy can then be used by the system to perform various cellular tasks. There are several sources of evidence that point to a chromophore within mitochondria being the initial target of LLLT. Illumination of tissue with light causes an increase in mitochondrial products such as ATP, NADH, beneficial proteins, and RNA, as well as a reciprocal augmentation in oxygen consumption, and various in vitro experiments have confirmed that cellular respiration is up regulated when mitochondria are exposed to forms of illumination.
LLLT can up-regulate various stimulatory and protective genes. These genes are most likely related to cellular proliferation, migration, and the production of cytokines and growth factors, which have all been shown to be stimulated by low-level light.
Among its many effects, LLLT has been shown to cause vasodilation by triggering the relaxation of smooth muscle associated with endothelium, which is highly relevant to the treatment of joint inflammation. This vasodilation increases the availability of oxygen to treated cells, and also allows for greater traffic of immune cells into tissue. These two effects contribute to accelerate healing.