Effect of a portable light emitting diode device on wound healing in a rat model.

Light-emitting diode (LED) lights produce a variety of wavelengths that have demonstrable efficacy in therapeutic and aesthetic fields. However, a repetitive treatment regimen is required to produce treatment outcomes, which has created a need for portable LED devices. In this study, we aimed to develop a portable therapeutic LED device and investigate its healing effect on excisional wounds in a rat model. The 35 × 35 mm-sized LED device was used on a total of 30 rats with full-thickness wounds that were divided into two groups depending on radiation intensity (11.1 and 22.2 mW/cm 2 group). LED irradiation was performed every 24 h for 30 min, over 14 days, in direct contact with the wound. Percentage wound closure was measured by photographic quantification and was assessed histologically using haematoxylin and eosin (H&E) and Masson's Trichrome staining, and immunohistochemistry for Vascular endothelial growth factor (VEGF) and CD31. Percentage wound closure was significantly higher in 22.2 mW/cm 2 irradiated wounds than that in the control wounds on days 7 and 10. The area of collagen deposition was remarkably larger in 22.2 mW/cm 2 irradiated wounds than that in the control, with more horizontally organized fibres. CD31 immunostaining confirmed a significant increase in the number of microvessels in 22.2 mW/cm 2 irradiated wounds than that in the control wounds, although there was no difference in VEGF immunostaining. Our novel portable LED device accelerates wound healing in a rat model, raising the possibility that portable LED devices can combine convenience with accessibility to play an innovative role in wound dressing.