Laser photobiostimulation of wound healing: defining a dose response for splinted wounds in diabetic mice.
OBJECTIVE
We have used a 660 nm, 80 mW laser diode in genetic diabetic mice to stimulate the healing of wounds covered with a Tegaderm HP dressing that causes a retardation of contraction (splinted wounds). The purpose of our study was to examine the effects of irradiating the wounds for different time intervals in order to determine a dose response relationship.


METHODS
A circular excisional wound was made on the left flank of diabetic mice using a 5-mm skin punch, and covered with a Tegaderm HP dressing. Mice were allocated to four groups in which wounds were irradiated 660 nm, 80 mW for 0, 10, 20, or 40 seconds each day for 7 days. In total, 51 mice were used. Wounds were harvested on day 14 and the healing assessed from hematoxylin-eosin stained sections examined by light microscopy.


RESULTS
The wounds were splinted in 40 of the mice, and splinting caused a retardation of healing. The findings for the four treatments showed that irradiation for 20 second/day for 7 days brought about the greatest extent of healing. The wounds healed mainly by re-epithelization and granulation tissue formation. This duration of irradiation represents an energy dose of 1.6 J per irradiation and, for an estimated area of irradiation of 32-43 mm², corresponds to an energy density of 3.7-5.0 J/cm².


CONCLUSIONS
Irradiation with 660 nm, 80 mW at an energy density of 3.7-5.0 J/cm² each day for 7 days caused the maximal stimulation of healing in splinted wounds of diabetic mice.
Chung
Tzu-Yun
TY
Department of Anatomy & Structural Biology, University of Otago, Dunedin, New Zealand.
Peplow
Philip V
PV
Baxter
G David
GD
D000818:Animals; D001458:Bandages; D004195:Disease Models, Animal; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006097:Granulation Tissue / Q000473:pathology / Q000528:radiation effects; D028022:Low-Level Light Therapy / Q000379:methods*; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D013165:Splints; D014945:Wound Healing / Q000528:radiation effects*; D014950:Wounds, Penetrating / Q000209:etiology / Q000473:pathology / Q000628:therapy*