UVB IRRADIATION OF AN ORGANOTYPIC SKIN MODEL, EPIDERM™, RESULTS IN SIGNIFICANT RELEASE OF CYTOKINES.

• TR Number: 3480
• Keywords: Cancer, Cytokines, Cytotoxicity, Endpoints, MTT, EpiDerm, Inflammation, Inflammatory, Inflammatory reactions, MTT, MTT ET-50 tissue viability assay, MTT assay, Phototoxicity, Sun screens, UVA, UVB, Ultra-violet radiation (UV), Viability

Ultraviolet light, especially UVB (290-320 nm), is believed to be responsible for most of the immediate and long term effects of excessive exposure to sunlight. In many cases, the initial stages of these UV induced changes are the release of cytokines. Although cytokine release from human keratinocytes in monolayer cultures following UV exposure has been studied, the results of UVB exposure to keratinocytes in fully differentiated epidermal models have not been adequately delineated. UVB irradiation of EpiDerm™, a commercially available, highly differentiated model of the human epidermis, resulted in significant increases in PGE2 and IL-1α, even at UV fluxes which were not cytotoxic, as determined using the MTT viability assay. At UVB does of up to 100 mj/cm2, MTT viability remained at or above 100% whereas PGE2 and IL-1α release increased to 3.4 and 2.7 fold of baseline cytokine levels, respectively. Hence, EpiDerm may prove to be a useful tool in understanding the immunological and inflammatory reactions associated with UV irradiation and other related skin pathologies.