Change of Skin Barrier Function According to Stratum Corneum Removal by Tape Stripping / 대한피부과학회지

BACKGROUND: The major function of the skin is to prevent loss of water and electrolytes and transepidermal penetration of harmful materials. The stratum corneum is known to play a major role in the skin barrier function. Tape stripping (TS) with adhesive cellophane tape is one of the best method of removing the stratum corneum on the skin surface, and has been used in studies of the skin barrier function when investigating material distribution in the stratum corneum and transepidermal absorption of drugs. OBJECTIVE: This study was performed to evaluate the skin barrier function according to removal of the stratum corneum by TS. METHOD: Six vitiligo patients who had undergone autologous suction blister grafting were tested. Transepidermal water loss (TEWL) was measured on the normal skin of the buttocks in each patient after every fifth TS, plus on the skin where the entire epidermis had been removed by autologous suction blister grafting. We compared these two values and also examined morphological change of the stratum corneum after TS, by both light and electron microscope. RESULTS: The TEWL value slightly increased when TS was carried out up to 30 times, but greatly increased to 20g/m2h of TEWL when TS was done 30-40 times. Thereafter, no increase in TEWL was observed when TS was carried out up to 100 times. The pattern of TEWL according to numbers of TS approximately plotted a sigmoid curve. On average, there was about 88% impairment to the skin permeability barrier function after TS. When the TEWL increased to more than 70g/m2h over baseline TEWL, the stratum corneum was almost removed, as revealed by light and transmission electron microscope. CONCLUSION: The stratum corneum acts as a major skin barrier, and the mid to lower portion of the entire stratum corneum appears to play a significant role in the skin permeability barrier function.

The Changes in the Skin Permeability Barrier and Epidermais of Hairless Mouse on Oleic Acid Treatment / 대한피부과학회지

BACKGROUND: The stratum corneum(SC) inhibits t,ransepidermal water loss and makes a permeability barrier against foreign materials, so strategies to overcome relative impermeability of the SC is very important in transdermal drug delivery. This includes occlusion, hydration, chemical permeation enhancers, iontophoresis and sonophoresis, Oleic acid, which is one of the cis-unsaturated fatty acid and chemical permeation enhancers, increases the permeability of the lipophilic molecules and polar miolecules through the SC. By spectrometry, calorimetry and the flux technique, the hypothesis that oleic acid does exist as a liquid within the SC lipids and enhances the transport of polar molecules across the SC by the formation of permeable interfacial defects within the SC lipid bilayers was suggested. Also, repeated application of oleic acid induces epidermal proliferation, hyperkeratosis and sebaceous gland hyperplasia', However the exact pathomechanism was not reported. OBJECTIVE: We carried out some research to observe the mechanism by which oleic acid in creases transdermal drug delivery and the effect to the skin permeability barrier and epidermis by repeated application. METHODS: In the repeated treatment group, hairless mice(6 to 8 weeks) were treated with oleic acid once a day for 7 days unilaterally, and in the single treatment group, only one time, Transepidermal water loss(TEWL) was checked at 24hour after 1, 3 and 7 days of treatment and at, 1 hour, 6 hours, 24 hours, 72 hours after single treatment. Biopsies were taken from treated and controlateral(control) sides immediately after the TEWL checks at each time for light microscopic(H & E stain) and electron microscopic studies. RESULTS: In the repeated treatment group, TEWL was increased by day and epidermal proliferation and hyperkeratosis were also increased. In the single treatment group, TEWL was highly increased in the treated site at 1 hour after treatment and decreased with time. By electronmicroscope, we observed dilated lacunae, intrcellular lipid structural abnormalities and loss of normal calcium gradient. CONCLUSION: The possible domains of the epidermis interacting with oleic acid as a penetration enhancer are the lacunae and liipid bilayer by EM. The suggested pathomechanism of the epidermal changes, epidermal proliferation and hyperkeratosis was increased DNA synthesis of epidermal cells by the loss of epidermal calcium gradient in chronic barrier impairment.