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Hairless mice (Skh:HR-1) exposed to single doses (0.5, 1.0 and 3. OMED) of UV-B radiation were displayed remarkable changes of barrier function and surface morphology. Trans- epidermal water loss (TEWL) as an index of barrier function was measured by evaporimeter, and wrinkle density (WD) as an index of morphological alteration was measured by image analyzer. Significant changes of TEWL were not observed in the control and 0. SMED group, but 1.OMED and 3. OMED groups noted significant difference. TEWL of 3. OMED group was rapidly increased to the 3rd day and decreased until the 14th day when it reached nearly to normal level, Time-courses of TBWL for 1. OMEB and 3. OMED groups displayed similar pattern, but different only in the magnitude. WD were significantly decreased during the 3rd-5th day in all of the irradiated groups and then increased during the last period to the 14th day, but did not recover the normal level at the 14th day. Time-courses of WD for all groups exhibited similarity, and were entirely dependent on the exposed doses. We also observed histological changes which included hyperplasia, sunburn cell (SBC) formation, accumulation of polymorphonuclear leukocyte (PMNs), and loss of collagen of UVB- exposed hairless mouse skin. Changes of TEWL and WD are helpful in understanding of epidermal and dermal damages by single exposure of UVB
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