Effect of intense pulsed-light exposure on lipid peroxides and thymine dimers in human skin in vivo.
BACKGROUND
Intense pulsed light (IPL) generates high-intensity short flashes of visible light and has been used for about 10 years to improve dermatological conditions such as telangiectasia, pigmented lesions, and skin aging. Although these systems deliver a moderate dose (10-30 J/cm(2)) of visible light, this dose is delivered during a short pulse (2-5 milliseconds), which implies a very high fluence rate (approximately 4000 W/cm(2)). For this reason, we speculated whether the Bunsen-Roscoe law of reciprocity could still be valid in these conditions.


METHODS
Nine healthy volunteers were exposed to IPL or UV-A or simulated solar UV radiation, and then thymine dimer and lipid peroxide concentrations were determined in skin biopsy specimens of the exposed sites. Only exposure to solar UV radiation (7-J/cm(2) UV-A + 80-mJ/cm(2) UV-B) produced measurable amounts of thymine dimers in DNA from skin biopsy specimens, whereas UV-A radiation (40 J/cm(2)) and IPL (9 J/cm(2)) induced 3-fold and 6-fold increases of cutaneous lipid peroxides, respectively.


CONCLUSIONS
These preliminary results indicate that IPL, although filtered for wavelengths shorter than 500 nm, can generate oxidative stress, a typical hallmark of UV-A, but does not induce thymine dimers. This emphasizes the need for long-term studies involving IPL before using this technique in a recurrent manner.
Sorg
Olivier
O
Author Affiliations: Dermatology Department, University Hospital of Geneva, Geneva, Switzerland.
Janer
Victor
V
Antille
Christophe
C
Carraux
Pierre
P
Leemans
Evelyne
E
Masgrau
Elizabeth
E
Saurat
Jean-Hilaire
JH
Salomon
Denis
D
D000293:Adolescent; D000328:Adult; D006801:Humans; D008054:Lipid Peroxides / Q000032:analysis / Q000528:radiation effects*; D008875:Middle Aged; D011740:Pyrimidine Dimers / Q000032:analysis / Q000528:radiation effects*; D012867:Skin / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects*
D008054:Lipid Peroxides; D011740:Pyrimidine Dimers