Effects of laser-exposition on the secretion of Interleukin-1 and Interleukin-8 by arteficial skin

Abstract

Laser are used in several diagnostic and therapeutical applications in modern medicine. Little is known about mechanisms involved in laser induced effects in the skin. In several publications biostimulary effects of laser Iight could be shown. In our experiments we used a commercially available model of the skin (SkinEthic®), representing a fully differentiated epidermis, generated by culturing normal human keratinocytes on inert polycarbonate filters. The cells are cultured at the air-Iiquid phase and are fed from underneath with a special culture medium. Aim of this study was to determine the influence of laser Iight in co-exposition with SDS, as a model for the influence of Iight with chemicals. To investigate the influence of our treatment on the immune system, we tested the cytokine Interleukin-1 (IL-1) as a potent proinflammatory cytokine and the major chemokine lnterleukin-8 (IL-8). In our experiments we exposed the skin samples with laser Iight at different energy levels and different exposition times. For this purpose a wave length of the laser of 632nm was selected and an energy of lxl05J/m2 or lxl04J/m2 was applicated on the skin samples. The energy was administered in 3, 10 and 30 minutes exposure time. The culture medium was removed and after further culture periods of 24 or 48 hours the supernatants were collected. In ELISA-test systems the concentrations of IL-1 and IL-8 were determined. The histology of the skin samples was investigated in hematoxyilineosin- stainings. Depending on time and energy of exposition, we could show a significant increase of the IL-1-secretion. The most pronounced difference could be shown in coexposition with SDS, whereas an incubation with SDS alone did not show a significant actvation of the lnterleukin-1 -secretion. The histology ot these samples showed a degradation of the structure of the skin and a great number of necrotic and dead cells. The other samples showed in dependence of time and energy of exposure a slightly increased secretion of IL-1. The secretion of IL-8 in these samples occured after 48 hours whereas the IL-1-secretion peaked at 24 hours of culture. SkinEthic® skin samples were a usefiil model to show laser induced effects alone or in coincubation with chemicals. In this model, we were able to demonstrate a synergistic effect of coexposition with laser Iight and chemicals on the secretion of immunomodulary molecules.