Healing Effects

It is well understood that light affects the body and hence the cells. Ultra Violet (UV) radiation (wavelength range 290–400 nm) from sunlight can create damage to the skin.

We also know that visible light (400–760 nm) and Infra-Red (IR) radiation (760–3000 nm) influences the body and in particular the metabolism of mammalian cells (Karu 2010).

The light enters through the skin as waves (photons)

Certain wavelengths of light pass into the cells.

In human beings mitochondria (the chromophores) within the cells are affected by these wavelengths (they act as photoacceptors).

The specific part of the mitochondria affected by the light waves (photons) is called cytochrome c oxidase (CCO) which is part of the respiratory chain.

A CCO is a photoacceptor and photosignal transducer in the region of visible and IR‐A (400 to 3000 nm) wave lengths.

CCO’s are located in the inner mitochondrial membrane. Light creates photodissociation of inhibitory nitric oxide from the CCO leading to enhancement of enzyme activity, and mediating the transfer of electrons from cytochrome c to molecular oxygen (responsible for more than 90% of molecular O2 respired by mammalian cells and tissues).

This reactivity is due to four redox active metal centers:

  • binuclear CuA,
  • CuB,
  • heme a,
  • heme a3,

all of which have absorbency in the red to IR‐A range (Karu 2003).

Lasers/diodes are generally 400-1000 nm

When laser is applied the photons are absorbed which results in a cascade of reactions, known as cellular signalling pathways leading to:

Increased ATP synthesis (Huang et al. 2011).

ROS production,

Increased respiration leads to ROS formation in turn this activates the redox-sensitive NFkB signaling. NF-kappaB regulates immune and inflammatory responses in macrophages as well as production of inflammatory cytokines like TNF-alpha and NO through iNOS expression.

Nitrous oxide (NO) dissociation,

Nitric oxide dilates blood vessels this is induced by several factors.

  • NO results in phosphorylation of several proteins that cause smooth muscle relaxation.
  • It also acts as a neurotransmitter, which in turn raises blood supply.

Conversely, it also helps protect tissues from damage due to low blood supply. NO inhibits vascular smooth muscle contraction and growth, platelet aggregation, and leukocyte adhesion to the endothelium mediating the healing process. 

Transcription in Nucleus

The altered chemistry within the cell (particularly due to the alteration of the cellular Redox state) induces the activation of several signaling pathways which in turn alter the affinity of transcription factors concerned with cell proliferation, survival, tissue repair and regeneration.

The main pathway to increased healing is the increased metabolism and ATP production the full pathway is below.