Mechanisms and Mitochondrial Redox Signaling in Photobiomodulation

Photochem Photobiol. 2018 Mar;94(2):199-212. doi: 10.1111/php.12864. Epub 2018 Jan 19.


Photobiomodulation (PBM) involves the use of red or near-infrared light at low power densities to produce a beneficial effect on cells or tissues. PBM therapy is used to reduce pain, inflammation, edema, and to regenerate damaged tissues such as wounds, bones, and tendons. The primary site of light absorption in mammalian cells has been identified as the mitochondria and, more specifically, cytochrome c oxidase (CCO). It is hypothesized that inhibitory nitric oxide can be dissociated from CCO, thus restoring electron transport and increasing mitochondrial membrane potential. Another mechanism involves activation of light or heat-gated ion channels. This review will cover the redox signaling that occurs in PBM and examine the difference between healthy and stressed cells, where PBM can have apparently opposite effects. PBM has a marked effect on stem cells, and this is proposed to operate via mitochondrial redox signaling. PBM can act as a preconditioning regimen and can interact with exercise on muscles.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Animals
  • Disease Models, Animal
  • Electron Transport Complex IV / radiation effects
  • Humans
  • Ion Channels / radiation effects
  • Low-Level Light Therapy*
  • Membrane Potential, Mitochondrial / radiation effects
  • Mitochondria / radiation effects*
  • Oxidation-Reduction / radiation effects
  • Stem Cells / radiation effects
  • Transcription Factors / radiation effects


  • Ion Channels
  • Transcription Factors
  • Electron Transport Complex IV