Purpose Narrow band-ultraviolet B (NB-UVB) is efficacious for atopic dermatitis (AD). However, its detailed mechanism remains to be elucidated. The purpose of this study is to explore an in vivo-effect of NB-UVB on AD, utilizing MC903-induced AD model mice. Method To induce AD-like dermatitis, MC903, a vitamin D3 analogue, was applied on the shaved dorsal skin of C57BL/6 mice once a day for twelve days. Mice were irradiated with a 308-nm excimer lamp at 100 mJ/cm2 once every other day from days 0 to 10. Clinical severity was evaluated on days 0-12. Epidermal thickness and infiltrating cells were assessed on day 12, respectively. Real time polymerase chain reaction was performed to assess the mRNA levels of cytokines in skin lesions on days 4,7 and 12. Furthermore, the skin moisture level and pH were assessed on day 12. Results Irradiation of excimer lamp alleviated MC903-induced AD-like dermatitis clinically on days 4 to 12, and pathologically reduced epidermal thickness and the number of epidermal layers on day 12. The number of Foxp3-positive cells infiltrating into the skin was increased on day 12 in MC903-applied mice irradiated with excimer lamp compared with those without irradiation, although a significant increase in the IL-10 mRNA level was not observed on days 4,7 and 12. In addition, irradiation of excimer lamp reduced mRNA expression of thymic stromal lymphopoietin (TSLP) in the skin on day 4. The moisture level and pH in the skin of MC903-applied mice irradiated with excimer lamp were almost the same as those in the skin of MC903-applied mice without irradiation. Conclusions Irradiation of excimer lamp ameliorated MC903-induced AD-like dermatitis with a reduction of TSLP mRNA levels.

ESDR400 - 308-nm excimer lamp ameliorates MC-903 induced atopic dermatitis with a reduction of thymic stromal lymphopoietin mRNA levels.

The scientific meeting of the European Society for Dermatological Research (ESDR) is held yearly, usually in September. With an international attendance of more than 1000 skin scientists from around the globe, the four-day event includes short oral presentations from peer-reviewed abstracts, keynote lectures from international experts, sponsored symposia, satellite programs, educational events as well as an important focus on posters, networking and building collaborations amongst scientists. For more information about this year’s meeting visit our website.