Abstract:

Objective To investigate the effect of 630-650 nm visible light on inflammatory response and wound healing in diabetic mice. Methods Twenty BKS.Cg-m+/+LeprdbNJU mice were used as animal model, and wounds were made on the left and right back of each mice with round fullthickness skin defects of 8 mm in diameter. The experiment group (wounds on the left, n=20) were treated by 630-650 nm visible light, and the control group (wounds on the right, n=20) were treated with normal LED light irradiation. The conditions of wounds and rates of wound healing were observed and recorded 1, 3, 7, 10, 14 and 21 d after injury, the infiltration of neutrophils and macrophages was assessed by immunohistochemical staining, and the expression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) was determined by ELISA. Results From the third day after injury, the rate of wound healing in experiment group was significantly higher than that in control group. The numbers of infiltrated neutrophils and macrophages in wounds in experiment group were significantly bigger than those in control group 1, 3 and 7 d after injury, and were significantly smaller than those in control group 7, 14 and 21 d after injury. Since the third day after injury, the expression of IL-6 and TNF-α in wounds in experiment group was significantly lower than that in control group (P<0.05). Conclusion For the wounds of diabetic mice, 630-650 nm visible light may accelerate the process of inflammatory response, prevent the persistence of inflammatory response, and promote the wound healing.

Key words: low level laser/light therapy, 630-650 nm visible light, wound healing, inflammatory response, diabetes mellitus