Irradiation with a 632.8 nm helium-neon laser with 5 J/cm² stimulates proliferation and expression of interleukin-6 in diabetic wounded fibroblast cells

Background: The use of lasers has been shown to stimulate wound healing in vivo and in vitro. There is an increase in wound closure, cell viability, proliferation, and cytokine expression. If laser parameters can be optimized and standardized, and the underlying mechanisms better understood, this phototherapy can become an alternative safe treatment to slow-to-heal wounds, such as in patients with diabetes. This study aimed to determine the effect on cellular proliferation, migration, and cytokine [interleukin-6 (IL-6)] expression in diabetic and diabetic wounded fibroblast cells (WS1) post-laser irradiation. Methods: Diabetic and diabetic wounded WS1 cells were irradiated at 632.8 nm (23 mW) with 5 J/cm² or 16 J/cm². IL-6 level, cellular proliferation (neutral red assay), and morphology were then determined. Results: Diabetic cells irradiated with 5 J/cm² showed no significant change, while diabetic wounded cells showed an increase in IL-6 level, proliferation, and migration. On the other hand, diabetic and diabetic wounded cells irradiated with 16 J/cm² showed a significant decrease in proliferation and evidence of cellular damage, and wounded cells showed no migration. Conclusion: This study showed that phototherapy at the correct fluence stimulates IL-6 expression, proliferation, and cellular migration in diabetic wounded cells. A fluence of 5 J/cm² stimulates diabetic wound healing in vitro, while 16 J/cm² is inhibitive.