The Science Of Low Level Laser Therapy – How does it work?
How does Low Level Laser Therapy (LLLT) Work?
Laser therapy aims to biostimulate the cells in the body. Because of the low power nature of low level lasers, the effects are photochemical (like photosynthesis in plants) and biochemical, not thermal and do not cause heating. There is no damage to living tissue. Three distinct effects are known to occur when using low level laser therapy:
A) Growth factor response within cells and tissue as a result of increased ATP and protein synthesis;
Improved cell proliferation; Change in cell membrane permeability to calcium up-take.
B) Pain relief as a result of increased endorphin release; increased serotonin; suppression of nociceptor
C) Strengthening the immune system response via increasing levels of lymphocyte activity and through
a newly researched mechanism termed photomodulation of blood.
One of the main mechanisms of action occurs in the mitochondria, the cellular power plant inside every cell. The primary effect occurs when light is absorbed in cytochrome c oxidase, a protein within the mitochondria.
When cells get stressed (e.g. due to disease, injury or ageing) the mitochondria produces nitric oxide (NO). This competitively displaces oxygen from cytochrome c oxidase consequently reducing ATP (an essential intracellular cellular energy and extracellular signalling molecule) and causing an over production of reactive
oxygen species (ROS) and leading to oxidative stress. Oxidative stress is well known to lead to inflammation and cell death via the gene transcription factor NF-Kb.
Lack of Side Effects
Low Level Laser Therapy (LLLT) works of the correct wavelength and density, dissociates NO allowing oxygen back in, so ATP is restored and oxidative stress reduced. Once normal mitochondrial function is restored by LLLT then cell metabolism is improved, and the patient gets better more quickly. This improves cell metabolism and reduce inflammation. The effect on normal tissue is not significant.
Light will only stimulate cell proliferation if the cells are growing poorly at the time of the irradiation. If a cell is fully functional, there is nothing for radiation to stimulate, and no therapeutic benefit will be observed. An analogy is that patients will not show a beneficial effect of vitamin therapy if they already receive an adequate supply of vitamins in their daily diet.