DNA damage in blood cells exposed to low-level lasers

Lasers Surg Med. 2015 Apr;47(4):361-8. doi: 10.1002/lsm.22344. Epub 2015 Mar 5.


Background and objective: In regenerative medicine, there are increasing applications of low-level lasers in therapeutic protocols for treatment of diseases in soft and in bone tissues. However, there are doubts about effects on DNA, and an adequate dosimetry could improve the safety of clinical applications of these lasers. This work aimed to evaluate DNA damage in peripheral blood cells of Wistar rats induced by low-level red and infrared lasers at different fluences, powers, and emission modes according to therapeutic protocols.

Material and methods: Peripheral blood samples were exposed to lasers and DNA damage was accessed by comet assay. In other experiments, DNA damage was accessed in blood cells by modified comet assay using formamidopyrimidine DNA glycosylase (Fpg) and endonuclease III enzymes.

Results: Data show that exposure to low-level red and infrared lasers induce DNA damage depending on fluence, power and emission mode, which are targeted by Fpg and endonuclease III.

Conclusion: Oxidative DNA damage should be considered for therapeutic efficacy and patient safety in clinical applications based on low-level red and infrared lasers.

Keywords: Wistar rats; comet assay; oxidative lesion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood Cells / radiation effects*
  • Comet Assay
  • DNA Damage / radiation effects*
  • DNA-Formamidopyrimidine Glycosylase / pharmacology
  • Endodeoxyribonucleases / pharmacology
  • Lasers*
  • Rats, Wistar


  • Endodeoxyribonucleases
  • Nthl1 protein, rat
  • DNA-Formamidopyrimidine Glycosylase