Biological effects of helium-neon laser irradiation on normal and wounded human skin fibroblasts

Objective: This study aimed to investigate a number of structural, cellular, and molecular responses to helium-neon (632.8 nm) laser irradiation following a single dose of 0.5, 2.5, 5, or 10 J/cm² on normal and wounded human skin fibroblasts. Background Data: Low-level laser therapy (LLLT) is a form of phototherapy, involving the application of low-power monochromatic and coherent light to injuries and lesions to stimulate healing. This therapy has been successfully used for pain attenuation and to induce wound healing in nonhealing defects. Methods: Changes in normal and wounded fibroblast cell morphology were evaluated by light microscopy. Cellular parameters evaluated cell proliferation, cell viability, and cytotoxicity while molecular parameters assessed the extent of DNA damage. Results: The results clearly demonstrate that LLLT has an effect on normal and wounded human skin fibroblasts. The parameters showed that doses of 0.5, 2.5, 5, and 10 J/cm² were sufficient to produce measurable changes in fibroblast cells. Conclusion: A dose of 10 J/cm² appeared to produce a significant amount of cellular and molecular damage, which could be an important consideration for other therapies, such as photodynamic therapy.