Effects of intense pulsed light on tissue vascularity and wound healing: a study with mouse island skin flap model.

Intense pulsed light (IPL) has been used extensively in aesthetic and cosmetic dermatology. To test whether IPL could change the tissue vascularity and improve wound healing, mice were separated into 4 groups. Mice in Group I were not treated with IPL, whereas, dorsal skins of mice in Groups II, III, and IV were treated with 35 J/cm(2), 25 J/cm(2), and 15 J/cm(2) IPL, respectively. After 2 weeks, dorsal island skin flaps were raised, based on the left deep circumflex iliac vessels as pedicles; then, survival rate was assessed. Flaps in Group IV (treated with lowest dose of IPL) have a survival rate significantly higher than other groups. Counting blood vessels did not demonstrate any significant differences; however, vessel dilation was found in this group. The results show that IPL at the therapeutic doses which are usually applied to humans is harmful to mouse dorsal skin and did not enhance wound healing, whereas, IPL at much lower dose could improve wound healing. The possible mechanism is the dilation of tissue vasculature thanks to the electromagnetic character of IPL. Another mechanism could be the heat-shock protein production.