Preventive effect of chemical peeling on ultraviolet induced skin tumor formation

Background: Chemical peeling is one of the dermatological treatments available for certain cutaneous diseases and conditions or improvement of cosmetic appearance of photoaged skin. Objectives: We assessed the photochemopreventive effect of several clinically used chemical peeling agents on the ultravoilet (UV)-irradiated skin of hairless mice. Methods: Chemical peeling was done using 35% gycolic acid dissolved in distilled water. 30% salicyclic acid in ethanol, 10% or 35% trichloroacetic acid (TCA) in distilled water at the right back of UV-irradiated hairless mice every 2 weeks in case of glycolic acid, salicylic acid, and 10% TCA and every 4 weeks in case of 35% TCA for totally 18 weeks after the establishment of photoaged mice by irradiation with UVA + B range light three times a week for 10 weeks at a total dose of 420 J/cm(2) at UVA and 9.6J/cm(2) at UVB. Tumor formation was assessed every week. Skin specimens were taken from treated and non-treated area for evaluation under microscopy, evaluation of P53 expression, and mRNA expression of cyclooxygenase (COX)-2. Serum level of prostaglandin E-2 was also evaluated. Results: All types of chemical peeling reduced tumor formation in treated mice, mostly in the treated area but also non-treated area. Peeling suppressed clonal retention of P53 positive abnormal cells and reduced mRNA expression of COX-2 in treated skin. Further, serum prostaglandin E-2 level was decreased in chemical peeling treated mice. Conclusions: These results indicate that chemical peeling with glycolic acid, salicylic acid, and TCA could serve tumor prevention by removing photodamaged cells. (C) 2010 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.