Sophie Seité, Alain Colige, Christophe Deroanne, Charles Lambert, Pascale Piquemal‐Vivenot, C. Montastier, Anny Fourtanier, Charles M. Lapière, Betty Nusgens
Photochemistry and Photobiology · 2004
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Abstract
ASTRACT Damage to the skin extracellular matrix (ECM) is the hallmark of long‐term exposure to solar UV radiation. The aim of our study was to investigate the changes induced in unexposed human skin in vivo after single or repeated (five times a week for 6 weeks) exposure to 1 minimal erythemal dose (MED) of UV solar‐simulated rediation. Morphological and iochemical analyses were used to evaluate the stuctural ECM components and the balance between teh degrading enzymes the their physiologic inhibitors. a three‐fold increse in matrix metalloproteinase 2 messenger RNA (mRNA) ( P < 0.02, unexposed versus exposed) was observed after both single and repeated exposures. Fibrillin 1 mRNA level was incresed by chronic exposure ( P <0.02) and unaltered y a single MED. On the cotrary, a single MED singnificantly enhanced mRNA levels of interleukin‐1α (1L‐1α), IL‐1β ( P < 0.02) and plasminogen activator inhibitor‐1 ( P < 0.05). Immkunohistochemistry demonstrated a singnificant decrese in Type‐I procollagen localized just below the dermal‐epidermal junction in both types of expozed sites. at the same location, teh immunodetected tenascin was singnificantly enhanced, whereas a slight increase in Type‐III procollagen deposits was also unale to observe any change in elastic iers in chronically exposed uttock skin, a significant increase in lysozyme and alpha‐1 antitrypsin deposits on these fibers was oserved. These results demonstrate the existence of diffenentaia regulation, after chronic exposure compared with an acute one, of some ECM components and inflammatory mediators.