Laser therapy uses a process known as photobiomodulation to change the biochemical environment of damaged tissues by stimulating cellular metabolism thus acccelerating the healing process. As the laser unit emits photons of light into the tissues, these photons can be either scattered, reflected, and/ or absorbed by the cell. Lasers operate in the infrared spectrum of light from 650 nm to 1200 nm in wavelength. The greater the wavelength of light, the greater the depth of penetration into the tissues. The greater the power of the laser unit, the greater the number of photons or packets of light energy that are delivered in a shorter delivery period.
The primary target of laser therapy and photobiomodulation is the cytochrome C complex which is found within the mitochondria. Cytochrome C is a vital component of the electron transport chain that drives cellular metabolism. As light is absorbed, cytochrome C is stimulated leading to increased production of ATP. In addition to ATP, laser therapy or photobiomodulation also produces free nitric oxide and reactive oxygen species.
- ATP is the molecule that facilitates energy transfer within the cell thus leading to cellular healing through increased protein synthesis and cellular proliferation.
- Nitric oxide is a powerful vasodilator and an important cellular signaling molecule involved in many beneficial physiological processes.
- Reactive oxygen species have been shown to affect many important physiological signaling pathways including the inflammatory response.
Together, the production of these signaling molecules has have been shown to induce growth factor production, to increase cellular proliferation and motility, and to promote extracellular matrix deposition and pro-survival pathways. Outside of the cell, nitric oxide signaling drives vasodilation which improves microcirculation in the damaged tissues thus delivering oxygen, vital sugars, proteins, and salts while removing cellular by-products and waste. As a result, increased cellular healing is observed, as well as a reduction in pain.
The recent development of higher power, Class 4 lasers, allows the veterinarian the ability to more efficiently deliver adequate therapeutic doses of photons deep into tissues to reduce pain, reduce inflammation, and accelerate healing (Class 3 and 4 lasers carry FDA approval for these three uses).
The introduction of Class 4 lasers make it possible to not only treat superficial lesions but now to treat a greater range of conditions involving the deeper tissues. Some of these conditions include:
- Post surgical wound/ inflammation/ fracture healing and pain relief
- Infected/ traumatic/ or non healing wounds
- Osteoarthritis or degenerative joint disease, such as hip, stifle, and elbow arthritis
- Tendon/ ligament inflammation/ injuries
- Post dental extraction pain and inflammation
- Otitis externa
- Lick granulomas
- Perianal fistulas/ inflammatory bowel disease
- Feline acne/ asthma
- And, the list is ever growing with continued application, discussion among practitioners, and critical assessment of outcome
Photobiomodulation allows the body to harness the benefits of good ole fashion light in order to help heal oneself without the need for pharmacological intervention. Laser therapy may not be fully effective in all conditions; however, it can be used as an adjunct therapy to help lessen conventional therapies which may have negative side effects. Thanks for reading, Dr. Todd Murphy, DVM, DACVS. Feel free to leave a comment or question.