Role of reactive oxygen species in low level light therapy

Aaron Chih Hao Chen, Ying Ying Huang, Praveen R. Arany, Michael R. Hamblin

Research output: Contribution to journalConference articlepeer-review

35 Citations (Scopus)


This review will focus on the role of reactive oxygen species in the cellular and tissue effects of low level light therapy (LLLT). Coincidentally with the increase in electron transport and in ATP, There has also been observed by intracellular fluorescent probes and electron spin resonance an increase in intracellular reactive oxygen species (ROS) such as superoxide, Hydrogen peroxide, Singlet oxygen and hydroxyl radical. ROS scavengers, Antioxidants and ROS quenchers block many LLLT processes. It has been proposed that light between 400-500-nm may produce ROS by a photosensitization process involving flavins, While longer wavelengths may directly produce ROS from the mitochondria. Several redox-sensitive transcription factors are known such as NF-kB and AP1, That are able to initiate transcription of genes involved in protective responses to oxidative stress. It may be the case that LLLT can be pro-oxidant in the short-term, But anti-oxidant in the long-term.

Original languageEnglish
Article number716502
JournalProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Publication statusPublished - 2009
Externally publishedYes
EventMechanisms for Low-Light Therapy IV - San Jose, CA, United States
Duration: 24 Jan 200924 Jan 2009


  • Biostimulation
  • Low level laser therapy
  • Mitochondria
  • Reactive oxygen species
  • Redox-sensitive signal transduction
  • Transcription factor

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Biomaterials
  • Radiology, Nuclear Medicine and Imaging


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