RESUMO
UNLABELLED: Due to an increasing number of skin diseases as a result of exposure to ultraviolet (UV) radiation, it is necessary to evaluate the effectiveness of new skin care formulations with broad-spectrum sunscreens. OBJECTIVES: This study aims to assess the status of nerve fibres in healthy human skin, to quantify effects of UV radiation on nerve endings, and to evaluate neuroprotective effects of new skin care formulations against UV exposure damage. METHODS: Samples were obtained from 34 female patients enrolled for plastic surgery and were immediately treated (10 min) with three emulsions: Cream 1, Cream 2 (placebo) and a sunscreen with sun protection factor 15 (SPF15). Control samples and those treated with the cream emulsions were exposed to UVA and UVB for 60 min. Nerve fibres were identified by immunofluorescence using a monoclonal antibody (anti-human CD56/NCAM). Cell damage was assessed by image analysis. RESULTS: Several cellular nervous structures were identified in the skin samples, including free nerve endings. UVA and UVB significantly decreased (40-60%) density of nerve endings in the control samples and those treated with placebo (Cream 2) or SPF15 (all P < 0.001). Cream 1 completely blocked effects of UV radiation on nerve endings (P > 0.05 vs. control). CONCLUSIONS: Quantification of cell damage induced by UV radiation provides useful information for identification of new skin care compounds with neuroprotective properties.
