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Effect of laser therapy on DNA damage
Author(s) -
Fonseca Adenilson S.,
Moreira Thiago O.,
Paixão Deise L.,
Farias Fernanda M.,
Guimarães Oscar R.,
de Paoli Severo,
Geller Mauro,
de Paoli Flavia
Publication year - 2010
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/lsm.20921
Subject(s) - hydrogen peroxide , dna damage , plasmid , agarose gel electrophoresis , escherichia coli , dna , exonuclease iii , gel electrophoresis , chemistry , exonuclease , microbiology and biotechnology , biology , biochemistry , gene , dna polymerase
Background and Objective Whereas the biostimulative effect on tissues using low intensity laser therapy for treating many diseases has been described, the photobiological basis and adverse effects are not well understood. The aim of this study, using experimental models, is to observe the combined effect of physical damage (laser) and a chemical agent (hydrogen peroxide) on Escherichia coli cultures and bacterial plasmids. Materials and Methods Survival of E. coli AB1157 (wild type) and BW9091 (xth − ) cultures were used as an experimental model to assess the effect of agents on DNA, also agarose gel electrophoretic profile of bacterial plasmids for studying single and double strand breaks in DNA exposed to laser irradiation and in DNA pre‐exposed to laser and subsequently incubated with hydrogen peroxide. Results Data indicate low intensity laser: (i) did not alter the survival of E. coli cultures, (ii) pre‐exposure had a protective effect against lethal action of hydrogen peroxide on E. coli cultures, and (iii) did not alter the electrophoretic profile and action of hydrogen peroxide on plasmids. This suggests that low intensity therapeutic red laser doses at different emission modes induces sub‐lethal effects on E. coli wild type and exonuclease III mutant cultures inducing protective mechanisms against lethal action of hydrogen peroxide. Laser action on bacterial plasmids is related to lesions other than single or double DNA strands breaks. Conclusions This study shows a protective effect or DNA repair mechanism induction by pre‐exposure to low intensity red laser on the lethal action of oxidant agents and, therefore, laser therapy protocol should consider fluencies, wavelength and tissue conditions before beginning treatment. Lasers Surg. Med. 42:481–488, 2010. © 2010 Wiley–Liss, Inc.