Does LLLT stimulate laryngeal carcinoma cells? An "in vitro" study

Abstract

Low level laser therapy (LLLT) has been used successfully in biomedicine and some of the results are thought to be related to cell proliferation. The effects of LLLT on cell proliferation is debatable because studies have found both an increase and a decrease in proliferation of cell cultures. Cell culture is an excellent method to assess both effects and dose of treatment. The aim of this study was to assess the effect of 635nm and 670 nm laser irradiation of H.Ep.2 cells in vitro using MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide). The cells were obtained from squamous cell carcinoma (SCC) of the larynx and were routinely processed from defrost to the experimental condition. Twenty-four hours after transplantation the cells were irradiated with doses ranging from 0.04 to 0.48J/cm2 for seven consecutive days (5 mW diode lasers: 635nm or 670 nm, beam cross-section approximately 1 mm) at local light doses between 0.04 and 0.48 J/cm2. The results showed that 635nm laser light did not significantly stimulate the proliferation of H.Ep.2 cells at doses of 0.04 J/cm2 to 0.48 J/cm2, However, 670nm laser irradiation led to an increased cell proliferation when compared to both control and 635nm irradiated cells. The best cell proliferation was found with 670nm laser irradiated cultures exposed to doses of doses of 0.04 to 0.48 J/cm2. We conclude that both dose and wavelength are factors that may affect cell proliferation of H.Ep.2 cells.

Downregulation of Tumorogenicity and Changes in the Actin Cytoskeleton of Murine Hepatoma After Irradiation with Polychromatic Visible and IR Light

“…Studies of the effect of VIS and IR light on the proliferation of various tumor cell lines using different modes of irradiation (wavelengths and doses) indicate that there are still several remaining questions regarding the effect on tumor cell proliferation postirradiation. 10,13,23 Our work demonstrated that irradiation with VIS-IR light did not lead to a change in the MH-22a cell proliferation after 24-72 h, nor did it cause cell death; hence neither cytotoxic nor cytostatic effects were observed. Inhibition of tumor growth rate had no direct correlation with a change in the tumor cell proliferation.…”

“…However, the effect of irradiation of optic diapason on the proliferation of tumor cells under conditions in vitro, and on the growth of malignant tumors in laboratory animals in vivo are far from being resolved. It has been shown that different wavelengths of low-power laser irradiation can stimulate cell proliferation in culture, [6][7][8][9][10][11][12] have no effect on proliferation of transformed cells, 10,12 or even inhibit proliferation. 13 Low-power laser irradiation can stimulate the growth of transplanted malignant tumors in laboratory animals, 14 but many more studies demonstrate either the absence of the stimulating effect of light on this process, or its inhibition.…”

Treatment of Diseased Mice With Carcinoma by Activating the Immune Cells by Soft Laser Without Drugs

“…The number of the immune cells of the lymph nodes of the diseased mice with carcinoma treated with laser in the control group was increased gradually to 16 due to laser stimulation as shown in tab. (3). And so on, there was always a gradual increase in the number of the immune cells of the lymph nodes of the diseased mice with carcinoma treated with laser from the beginning of the experiment until the last day of the experiment 35 which reached to 42 as shown in tab.…”

Effects of He-Ne laser irradiation on chronic atrophic gastritis in rats

“…Moreover, in our experiment we found that three different dosages of He-Ne laser preceding the incitement to the rat in CAG, resulted in different effects. The best effect was the small dosage of He-Ne laser, the inside dose and the large dose were not as well as the small dose of He-Ne laser, which showed the dependence on dosage [20,30,31] . Perhaps it is because the biology effect of He-Ne laser closely related to the action time, power density that organized He-Ne laser.…”