Low intensity infrared laser affects expression of oxidative DNA repair genes in mitochondria and nucleus

Abstract

Practical properties and physical characteristics of low intensity lasers have made possible their application to treat soft tissue diseases. Excitation of intracellular chromophores by red and infrared radiation at low energy fluences with increase of mitochondrial metabolism is the basis of the biostimulation effect but free radicals can be produced. DNA lesions induced by free radicals are repaired by the base excision repair pathway. In this work, we evaluate the expression of POLγ and APEX2 genes related to repair of mitochondrial and nuclear DNA, respectively. Skin and muscle tissue of Wistar rats were exposed to low intensity infrared laser at different fluences. One hour and 24 hours after laser exposure, tissue samples were withdrawn for total RNA extraction, cDNA synthesis, and evaluation of POLγ and APEX2 mRNA expression by real time quantitative polymerase chain reaction. Skin and muscle tissue of Wistar rats exposed to laser radiation show different expression of POLγ and APEX2 mRNA depending of the fluence and time after exposure. Our study suggests that a low intensity infrared laser affects expression of genes involved in repair of oxidative lesions in mitochondrial and nuclear DNA.

Low-intensity red and infrared lasers affect mRNA expression of DNA nucleotide excision repair in skin and muscle tissue

“…4). In this tissue, XPA and XPC mRNA expression is decreased after exposure to red and infrared lasers [20], emphasizing that these lasers differently affect the mRNA expression from genes related to DNA repair, at least those involved in NER pathway. Also, red laser has no effect on XPA mRNA expression in burned skin [18].…”

“…However, ERCC2 mRNA expression is decreased in skin tissue exposed to red laser at the lowest fluences used (25 and 50 J/cm 2 ). Previous data demonstrated that the expression of other mRNAs from genes related to NER, XPA (xeroderma pigmentosum A protein), and XPC (xeroderma pigmentosum C protein) is increased in skin 1 h after exposure to red and infrared lasers [18,20,39]. This could suggest that laser exposure differently alters the expression of mRNA from genes related to DNA lesion repair.…”

“…Also, red laser has no effect on XPA mRNA expression in burned skin [18]. In addition, laser-induced alteration on gene expression has been reported to alter the expression of other genes, as type 1 collagen [40], actin [19], myogenin and VEGF [41], Cox-2 [42], as well as mRNA from genes related to BER pathway of DNA repair [19,20].…”

“…Base excision repair acts on single strand breaks, oxidized bases, and few bulky adducts [15,16], induced by endogenous free radicals or from exogenous exposure to genotoxic agents [17]. Previous data demonstrated that the expression of messenger RNA (mRNA) related to base excision repair is altered in biological tissues exposed to low-intensity red [18] and infrared [19,20] lasers. Also, exposure to low-intensity lasers alters the expression of mRNA related to nucleotide excision repair [18,20].…”

“…Previous data demonstrated that the expression of messenger RNA (mRNA) related to base excision repair is altered in biological tissues exposed to low-intensity red [18] and infrared [19,20] lasers. Also, exposure to low-intensity lasers alters the expression of mRNA related to nucleotide excision repair [18,20]. Nucleotide excision repair (NER) is a DNA repair pathway initially described in the repair of pyrimidine dimers induced by ultraviolet radiation [15].…”