How Does Lasers Work?
Light energy from a cold laser is is absorbed by either chromophores or photoacceptors on the mitochondrial membrane ( cytochrome c oxidase and nitric oxide synthase are particularly reactive to laser stimulation). In animals and humans the most affective wavelength are in the red and near infrared light range. Stimulation increases ATP (cellular energy source) as well as nitric oxide. The results of this stimulation is the increase of cellular metabolism, circulation, and nerve function.
Low level laser therapy helps in the treatment of neuromusculoskeletal conditions in three ways: (From Richard Martin in Practical Pain Management, Nov/Dec 2003)
1. Anti-Inflammation
Stabilization of cellular membrane Ca, Na, K, concentrations
Production and synthesis of ATP is enhanced
Vasodilation reduces ischemia and increases perfusion
Acceleration of leuckocytic activity
Increased prostaglandin production
Reduction in Interleukin 1
Enhanced lymphocyte response
Increased angiogenesis for both blood and lymphatic capillaries
Temperature modulation
Enhanced Superoxide Dismutase levels
Decreased C reactive protein levels
2. Pain Reduction
Increase in b-Endorphins
Suppression of C fibre afferent excitation
Increase in Nitric oxide production
Restoration of nerve cell action potential
Axonal sprouting and nerve cell regeneration
Decreased bradykinin levels
Increased release of acetylcholine
Normalization of Ca, Na, and K ions concentrations
3. Tissue Healing
Enhanced leukocyte infiltration
Increased macrophage activity
Increased neovascularization
Increased fibroblast proliferation
Keratinocyte proliferation
Early epithelialization
Growth factor increases
Enhanced cell proliferation and differentiation
Greater healed wound tensile strength
Cells and tissue that are damaged because of ischemia, inflammation and swelling appear to be more receptive to the photons compared with normal healthy cells. Therefore, laser seems to target damaged cells vs healthy cells.
