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Proceedings Paper

DNA fragmentation and nuclear phenotype in tendons exposed to low-intensity infrared laser
Author(s): Flavia de Paoli; Larissa Ramos Cerqueira; Mayara Martins Ramos; Vera M. Campos; Samara Cristina Ferreira-Machado; Mauro Geller; Adenilson de Souza da Fonseca
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Paper Abstract

Clinical protocols are recommended in device guidelines outlined for treating many diseases on empirical basis. However, effects of low-intensity infrared lasers at fluences used in clinical protocols on DNA are controversial. Excitation of endogenous chromophores in tissues and free radicals generation could be described as a consequence of laser used. DNA lesions induced by free radicals cause changes in DNA structure, chromatin organization, ploidy degrees and cell death. In this work, we investigated whether low-intensity infrared laser therapy could alter the fibroblasts nuclei characteristics and induce DNA fragmentation. Tendons of Wistar rats were exposed to low-intensity infrared laser (830 nm), at different fluences (1, 5 and 10 J/cm2), in continuous wave (power output of 10mW, power density of 79.6 mW/cm2). Different frequencies were analyzed for the higher fluence (10 J/cm2), at pulsed emission mode (2.5, 250 and 2500 Hz), with the laser source at surface of skin. Geometric, densitometric and textural parameters obtained for Feulgen-stained nuclei by image analysis were used to define nuclear phenotypes. Significant differences were observed on the nuclear phenotype of tendons after exposure to laser, as well as, high cell death percentages was observed for all fluences and frequencies analyzed here, exception 1 J/cm2 fluence. Our results indicate that low-intensity infrared laser can alter geometric, densitometric and textural parameters in tendon fibroblasts nuclei. Laser can also induce DNA fragmentation, chromatin lost and consequently cell death, using fluences, frequencies and emission modes took out from clinical protocols.

Paper Details

Date Published: 5 March 2015
PDF: 12 pages
Proc. SPIE 9321, Optical Interactions with Tissue and Cells XXVI, 93210Y (5 March 2015); doi: 10.1117/12.2075726
Show Author Affiliations
Flavia de Paoli, Univ. Federal de Juiz de Fora (Brazil)
Larissa Ramos Cerqueira, Univ. Federal de Juiz de Fora (Brazil)
Mayara Martins Ramos, Centro Univ. Serra dos Órgão (Brazil)
Vera M. Campos, Univ. do Estado do Rio de Janeiro (Brazil)
Samara Cristina Ferreira-Machado, Univ. Federal Fluminense (Brazil)
Mauro Geller, Centro Univ. Serra dos Órgão (Brazil)
Adenilson de Souza da Fonseca, Centro Univ. Serra dos Órgão (Brazil)
Univ. do Estado do Rio de Janeiro (Brazil)
Univ. Federal do Estado do Rio de Janeiro (Brazil)

Published in SPIE Proceedings Vol. 9321:
Optical Interactions with Tissue and Cells XXVI
E. Duco Jansen, Editor(s)

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