DIABETES TECHNOLOGY & THERAPEUTICS Volume 9, Number 5, 2007 © Mary Ann Liebert, Inc. DOI: 10.1089/dia.2007.0203 Irradiation with a 632.8 nm Helium-Neon Laser with 5 J/cm 2 Stimulates Proliferation and Expression of Interleukin-6 in Diabetic Wounded Fibroblast Cells NICOLETTE HOURELD, D.Tech. and HEIDI ABRAHAMSE, Ph.D. ABSTRACT 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 expres- sion. 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/cm 2 or 16 J/cm 2 . IL-6 level, cellular proliferation (neutral red assay), and morphology were then determined. Results: Diabetic cells irradiated with 5 J/cm 2 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/cm 2 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 ex- pression, proliferation, and cellular migration in diabetic wounded cells. A fluence of 5 J/cm 2 stimulates diabetic wound healing in vitro, while 16 J/cm 2 is inhibitive. 451 INTRODUCTION A WOUND IS A PATHOLOGICAL STATE in which tissues become separated or destroyed, while wound healing is the complex sequence of events directed toward closure of the defect, usually by replacement with scar-forming con- nective tissue. Wound healing is aimed at re- versing the loss of structural integrity caused by injury to the tissue. 1 Normal wound heal- ing requires both destructive and reparative processes in controlled balance. Proteases and growth factors play an important role in regu- lating this balance, and if it is disrupted in fa- vor of degradation then delayed healing en- sues, which is a trait of chronic wounds. 2 Cytokines are involved in all phases of wound healing and regulate migration, proliferation, differentiation, and metabolism of mammalian cells. It appears that it is the balance of these cytokines and other mediators rather than the mere presence or absence of one or more cyto- Laser Research Group, Faculty of Health Sciences, University of Johannesburg, Doornfontein, South Africa.