Cell-based evaluation of photosensitization using IL-8 and VEGF as predictive markers

According to the animal welfare awareness and economic and scientific aspects, the use of laboratory animals in cosmetics has been reduced, and the need to develop alternative animal testing methods has increased. Photo-sensitizing potential of locally applied chemicals is a significant threat to skin safety, however, the test methods to evaluate the possibility of photo-sensitization are limited. We recently suggested that the released inflammatory mediators such as vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8) can be used as biomarkers for evaluating skin-sensitization. In this study, we tested whether we could evaluate the photo-sensitizing potential by release of VEGF and/or IL-8 from keratinocytes exposed to chemicals. Through an intensive review on the clinical, in vitro and in vivo reports about chemical-related photo-sensitization, we listed 42 chemicals as reference testing compounds. Cytotoxicity and release of VEGF or IL-8 were assessed using human keratinocyte HaCaT in the absence or presence of UV irradiation after treatment of the testing compounds. Several test conditions were optimized, but the predictive power of the control and photo-sensitizer were observed to be somewhat low for the test method. If we supplement the study with other photo-sensitization markers, however, it is expected to be presented as a suitable test method for evaluating sensitization. Keywords: Alternative animal testing methods, Keratinocytes, Photo-sensitization, VEGF, IL-8Maste