Low-Intensity Laser Irradiation at 636 nm Induces Increased Viability and Proliferation in Isolated Lung Cancer Stem Cells.

OBJECTIVE

The purpose of this in vitro study was to evaluate the effects of low-intensity laser irradiation (LILI) on isolated lung cancer stem cells (CSCs) after several time intervals, using a wavelength of 636 nm and fluences between 5 and 20 J/cm.

BACKGROUND DATA

LILI has been proven to have a biomodulatory effect on various diseased conditions. A number of studies have been conducted on CSCs.

METHODS

Lung CSCs were isolated from lung cancer cells (A549), using cell surface marker CD 133. Isolated lung CSCs were divided into four groups: group 1 consisted of control cells receiving no irradiation; groups 2, 3, and 4 were exposed to laser irradiation at fluences of 5, 10, and 20 J/cm, respectively. LILI was performed using a 636 nm diode laser with a power output of ±85 mW. Cellular responses were evaluated after 24, 48, or 72 h, and included cell morphology, viability, and proliferation.

RESULTS

Cellular morphology indicated an increase in cell density caused by cell proliferation over time. Biostimulatory effects were achieved in lung CSCs when examining viability and proliferation.

CONCLUSIONS

It should, therefore, be noted that a low wavelength of 636 nm at various fluences induces biostimulation, which may have detrimental effects when using LILI as a form of regeneration.