A possible mechanism for visible light‐induced wound healing
A Lipovsky, Y Nitzan, R Lubart - Lasers in Surgery and …, 2008 - Wiley Online Library
A Lipovsky, Y Nitzan, R Lubart
Lasers in Surgery and Medicine: The Official Journal of the …, 2008•Wiley Online LibraryAbstract Background and Objectives Chronic wounds resistant to conventional therapy have
been treated successfully with low energy lasers and light emitting diodes (LEDs) in the
visible and near IR region. It has been proposed that production of low level reactive oxygen
species (ROS) following illumination is the first step of photobiomodulation. It was also
shown that white light (400–800 nm) has similar stimulatory effects as lasers and LEDs. ROS
at higher levels are toxic to cells and bacteria. Study Design/Materials and Methods In the …
been treated successfully with low energy lasers and light emitting diodes (LEDs) in the
visible and near IR region. It has been proposed that production of low level reactive oxygen
species (ROS) following illumination is the first step of photobiomodulation. It was also
shown that white light (400–800 nm) has similar stimulatory effects as lasers and LEDs. ROS
at higher levels are toxic to cells and bacteria. Study Design/Materials and Methods In the …
Background and Objectives
Chronic wounds resistant to conventional therapy have been treated successfully with low energy lasers and light emitting diodes (LEDs) in the visible and near IR region. It has been proposed that production of low level reactive oxygen species (ROS) following illumination is the first step of photobiomodulation. It was also shown that white light (400–800 nm) has similar stimulatory effects as lasers and LEDs. ROS at higher levels are toxic to cells and bacteria.
Study Design/Materials and Methods
In the present study, we examined the phototoxicity of broadband (400–800 nm, 120 J/cm2) visible light on the survival of several pathogenic bacteria: Staphylococcus aureus 195, Pseudomonas aeruginosa 1316, Escherichia coli 1313, and Serratia marcescens. These bacteria were chosen due to their high prevalence in infected wounds. The survival of bacterial cells following illumination was monitored by counting the number of colony forming units before and after exposure to light.
Results
Illumination with white light, 120 J/cm2, caused a reduction of 62%, 83%, and 56% in the colony count of E. coli 1313, S. aureus 195 and S. marcescens, respectively, though no reduction in the viability of P. aeruginosa 1316 was demonstrated. The phototoxic effect was found to involve induction of ROS production by the bacteria. It was also found that illumination of S. aureus 195 and E. coli 1313 in the presence of pyocyanin, known to be secreted by P. aeruginosa, had a stronger bactericidal effect compared to illumination alone.
Conclusion
Visible light at high intensity can kill bacteria in infected wounds. Thus, illumination of infected wounds with intense visible light, prior to low intensity illumination for stimulating wound closure, may reduce infection and promote healing. Lesers Surg. Med. 40:509–514, 2008. © 2008 Wiley‐Liss, Inc.
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