The effect of 630 nm light emitting diode (LED) irradiation on dermal wound healing

Abstract

Background: Recently, light emitting diode (LED) array devices are commercially introduced as an alternative for low level laser therapy for wound healing. Purpose: To determined the effects of 630 nm LED array irradiation on full-thickness wound healing. Methods: Twelve male Sprague-Dawley rats (230–250 g) were randomly divided into LED (n= 6) and control group (n= 6). Two 19.63mm2 circular full-thickness dermal wounds including the panniculus carnosus were created on both side of the back. The LED group received a 630 nmLED array irradiationwith 3.6mW/cm2 for 30minutes (6.6 J/cm2) for 7 days, while the control group received sham LED irradiation. Wound surface area was measured using digital planimeter. Epithelial gap and fibroblast number were measured on hematoxylin–eosin staining, collagen density was measured onMasson trichrome staining and proliferating cell nuclear antigen (PCNA) positive cell number was measured on immunohistochemical staining using image analysis system. An independent t-test was conducted to compare the difference between the LED and the control groups. Results: The wound closure rate, epithelial gap, PCNA positive cell number, fibroblast number and collagen density has shown no significant difference between the LED and the control group at day 3 after the treatment. At day 7 after the treatment, the wound closure rate in the LED group was increased when compared with control group (p< 0.05). The epithelial gap in theLEDgroupwas significantly shorten than the control group at day 7 (p< 0.01), The PCNA positive cell number in the LEDgroupwas higher than the control group at day 7 (p< 0.01), The fibroblast number and the collagen density were increased (p< 0.05) when compared with control group at day 7. Conclusion(s): 630 nm LED appeared to enhance dermal wound healing by accelerated keratinocyte proliferation in the epidermis and collagen deposition in the dermis during the proliferative stage of wound healing. Implications: These findings suggest that LED light might be use for wound management as an inexpensive phototherapy modality.