Effects of intense pulsed light on skin carcinogenesis

Abstract

Objective: Intense pulsed light (IPL) is a non-laser high intensity light that has been used to the treatment of several skin conditions. This work intended to evaluate the effects of IPL on a mouse model of two-stage skin carcinogenesis. Methods: Procedures were made in accordance with the Directive 2010/63/EU. Sixteen DBA/2JRccHsd mice were divided into two groups: IPL-exposed and non-exposed. The carcinogen agent DMBA was topically applied once and TPA was applied twice a week during 22 weeks. Animals IPL-exposed received IPL applications twice a week, at an intensity of 2J/cm2 during 22 weeks. Animals were sacrificed and skin samples were histologically evaluated. Results: Animals IPL-exposed developed 44 skin lesions (5.5 lesions per animal) while non-exposed animals developed 63 lesions (7.9 lesions per animal) (p=0.066). The animals IPL-exposed developed 20 skin neoplastic lesions while non-exposed animals developed 38 lesions (p=0.018), however the number of malignant lesions was higher in IPL-exposed animals (3 lesions) than in non-exposed animals (1 lesion) (p>0.05). Conclusion: The animals IPL-exposed developed lower number of skin lesions and neoplastic lesions, but the number of malignant lesions was higher. IPL inhibits the development of skin lesions but may have a promoting effect on the malignant conversion.