Characters and Age-associated Changes on Lip Surface

The characteristic differences between skin and lip surface and the age associated alterations on lip surface were studied in this experiment.Transepidermal water loss (TWL) value of lip surface was significantly higher than that of skin surface, And parakeratotic cells of corneocytes obtained by tape-strip method were also significantly more numerous in lip than in skin. These results indicated that the barrier function of lip surface is lower than that of skin, The characteristics between inside and outside of lip corneocytes were remarkably difference on the number of melanin granules and the intensity of DACM (N-(7-dimethylamino-4-methyl-3-coumarinyl) maleimide) fluorescence. The melanin granules stained with Fontana, silver ammonium solution were hardly observed and almost corneocytes were not stained with DACM in inside of lip surface. These phenomena suggested that the lip is more affective regions against environmental stimulation factors; dryness, ultraviolet rays and so on.Age-associated alterations of lip were studied on 101 healthy women (20-58 years old). TWL value of lip was decreased accompany with aging. Parakeratotic cells were observed most numerous in third decade and after that those were decreased with age. The number and depth of sulcus cutis were decreased with age by analyzed with image analyzer from replica of lip surface. These findings were similar to the skin alterations associated with age.