Effects of low-level laser therapy on malignant cells: in vitro study.
The aim of this study was to assess the effect of 635- and 670-nm laser irradiation on H.Ep.2 cells in vitro using MTT. In addition to our previous report on the effects of LLLT on the proliferation of laryngeal carcinoma cells in which it was found that irradiaton H.Ep.2 cells with 670-nm laser results in increased cell proliferation, it was decided to evaluate the effect of increased doses of laser light on these cells. The cells, obtained from SCC of the larynx, were routinely processed from defrost to the experimental condition. The cultures were kept either at 5% or 10% of FBS. Twenty-four hours after transplantation, the cells were irradiated with laser light (5-mW diode lasers; 635 and 670-nm; beam cross section approximately 1 mm) at local light doses between 0.04 and 4.8.10(4) Jm(-2). For 670 nm, significant differences in the proliferation were observed between the two concentrations of FBS (p = 0.002) and between irradiated cultures and controls (p = 0.000). Although the results were not significant, 635-nm irradiated cells also proliferated more than nonirradiated ones. This occurred under both conditions of nutrition. It is concluded, that irradiation with 670-nm laser light applied at doses between 0.04 and 4.810(4) Jm(-2) could significantly increase proliferation of laryngeal cancer cells.
Pinheiro
Antonio Luiz Barbosa
AL
School of Dentistry, Universidade Federal da Bahia, Salvador, BA, Brazil. albp@ufba.br
Carneiro
Nascimento Silene
NS
Vieira
Alessandro Leonardo de Barros
AL
Brugnera
Aldo
A
Zanin
Fatima A
FA
Barros
Rolim Aluizio
RA
Silva
Pedro Soriano da
PS
D002455:Cell Division / Q000502:physiology / Q000528:radiation effects; D006801:Humans; D028022:Low-Level Light Therapy / Q000379:methods*; D010610:Pharyngeal Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D012016:Reference Values; D012680:Sensitivity and Specificity; D014407:Tumor Cells, Cultured / Q000528:radiation effects