The Cytotoxic Effect of 4 Different Wavelengths of Low-Level Laser Therapy on Squamous Cell Carcinoma

Abstract

Introduction: Low-level laser therapy is a noninvasive method with the potential ability to change the balance of cell mediators and gene expressions. It affects cellular function resulting in beneficial clinical effects. This study aims to assess the effect of low-level light therapy (LLLT) using four different laser wavelengths on oral carcinoma cell viability in vitro. Materials and Methods: HN5 human head and neck squamous cell carcinoma cell lines (HNSCC) were cultured and irradiated using four wavelengths of blue (485nm), green (532nm), red (660nm), and near Infra-red (810nm) in a continuous mode with a dose of 1 J/cm2 (0.1W, 10sec) every 24hours for five consecutive days. Cell viability was assessed by evaluating mitochondrial activity by MTT assay. Results: All the wavelengths resulted in reduced viability of these cells compared to the controls. (P<0.05) There were statistically significant differences in cell viability between different wavelengths (P<0.001). The 810nm laser irradiation showed the highest percentage of cell survival (55.92%) while 660nm induced the lowest (36.02%). Conclusion: Different laser wavelengths may result in different effects on irradiated cells and red irradiation showed the lowest cell viability and the infrared laser had the highest cell viability results. Keywords: Low-level laser therapy; LLLT; Head and neck squamous cell carcinomas; HNSCC.

Keywords

• Low-level laser therapy; LLLT; Head and neck squamous cell carcinomas; HNSCC.