Estudio morfométrico in vivo con microscopía confocal en tiempo real de las alteraciones epidérmicas de la piel tras dosis bajas y repetitivas de radiación ultravioleta A (UVA)

Abstract

Introductionrepetitive exposure of skin to erythematogenic doses of UVA and UVB is known to produce epidermal changes in human skin. The aim of the present study is the use of high resolution in vivo confocal imaging to assess the effects of repetitive low-dose UVA irradiation on human epidermis. Methods and results1cm2 area on the inner aspect of the arm of 4 volunteers was exposed to a suberythemal dose (0.5 minimal erythema dose [MED]) of UVA once daily, 5 days a week, for 15 cummulative doses. In vivo epidermal changes were analyzed and quantified with a confocal microscope. In each imaging the thickness of the stratum corneum as well as the suprapapillary page (SPP) and rete page were evaluated. Both the stratum corneum and the suprapapillary epidermis showed a progressive increase in their thickness since the second (9 doses) and first (4 doses) evaluation, respectively. The increase was statistically significant since the third evaluation. On the other hand, the thickness of the rete page did not show significant changes. Conclusionreal-time reflectance confocal microscopy is a novel imaging tool that allows to assess in vivo optical sectioning of skin with high resolution and contrast. Hence, confocal microscopy can be very useful for the study of dynamic processes as photodamage.The results of this study demonstrate that low and repetitive doses of UVA include epidermal changes, mainly in the epidermal thickness, that probably represent a protective reaction of the skin against UVA radiation, and must be considered early changes of skin photodamage.