Effect of low-intensity laser irradiation (660 nm) on a radiation-impaired wound-healing model in murine skin.
OBJECTIVE
The use of low-intensity laser therapy (LILT) as a therapeutic modality has become popular in a variety of clinical applications including the promotion of wound repair. Although the clinical evidence base for such application remains sparse, recent studies have demonstrated a number of quantifiable photobiological effects associated with such therapy. In the present study, the effect of laser irradiation at various radiant exposures on a radiation-impaired wound-healing model in murine skin was investigated.


METHODS
The study included two phases; in phase one, male Balb/c mice (n = 36; age-matched at 10 weeks) were randomly allocated to three experimental groups (n = 12, each group). In all groups, a well-defined area on the dorsum was exposed to 20 Gy x-rays. Seventy-two hours postirradiation, all mice were anaesthetised and a 7 x 7 mm area wound was made on the dorsum. All wounds were videotaped alongside a marker scale (three times weekly) until closure was complete. In groups 2 and 3, mice were treated with laser irradiation (0.5 and 1.5 J/cm(2), respectively) three times weekly by using a 660-nm GaAlAs laser unit (5 kHz; 15 mW; Omega Laser Systems, London, UK). Wound areas were then calculated by using an image analysis system (Fenestra 2.1), and results were analyzed by using repeated measures and one-factor analysis of variance statistical tests. In phase two, two experimental groups were included (n = 12 each group); the protocol was identical to that described for phase 1; however, mice in group 2 were treated with a radiant exposure of 4 J/cm(2).


RESULTS
Results from this investigation demonstrated that treatment with 0.5, 1.5. and 4 J/cm(2) had no beneficial effect on the rate of wound closure (P > 0.05).


CONCLUSIONS
These findings provide little evidence of the putative stimulatory effects of LILT in vivo at the parameters investigated.
Walker
M D
MD
Radiation Sciences Research Group, School of Biomedical Sciences, University of Ulster at Jordanstown, Northern Ireland.
Rumpf
S
S
Baxter
G D
GD
Hirst
D G
DG
Lowe
A S
AS
D000818:Animals; D062109:Dermatologic Surgical Procedures; D007834:Lasers; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011829:Radiation Dosage; D012867:Skin / Q000528:radiation effects*; D013997:Time Factors; D014945:Wound Healing / Q000528:radiation effects*