The Effect of Low-level Laser Therapy on VEGF, IL-6 Expression and Viability of Oral Squamous Cell Carcinoma Cells

Low-level laser therapy has shown successful results in the prevention and treatment of oral mucositis. One of the concerns about low-level lasers is their effects on remaining malignant cells in the area. Interleukin-6 is a multifunctional cytokine that plays an important role in a wide range of biological activities in increasing tumor functions, decreasing survival and resistance to chemo-radiotherapy. Vascular-endothelial growth factor increases tumor vascularization. It has been shown in the previous studies that LLLT can cause an increase of IL-6 and VEGF in some cells. The present thesis aims to study the effects of LLLT on IL-6 and VEGF expression, as well as cell viability on OSCC cells. Tumorigenic cells of an oral squamous cell carcinoma cell line were irradiated with 3 different diode lasers, and were compared to the control group (660 nm-200 mW-4 J cm^-2 , 810 nm-200 mW-4 J cm^-2 , 940 nm-200 mW-4 J cm^-2 ). MTT assay, ELISA and RT-PCR were used to measure cell viability, IL-6 and VEGF expression. Cell viability of all laser-irradiated groups was significantly lower than the control group. VEGF expression increased in laser-irradiated groups. This was only significant in the 810 nm group. IL-6 protein secretion was significantly higher in all laser-irradiated groups compared to the control group.