The water-holding capacity of the stratum corneum measured by 1H-NMR.
The amount of bound water in the stratum corneum of the hairless rat was measured by using proton nuclear magnetic resonance (1H-NMR) spectrometry in the temperature range of -5 degrees C to -30 degrees C. A decrease in the bound water content was observed when the stratum corneum was extracted using water, a mixed solvent of chloroform:methanol (2:1), or a 1% sodium dodecyl sulfate (SDS) aqueous solution. However, extraction using a mixed solvent of acetone:ether (1:1) did not change the bound water content at temperatures above -20 degrees C. The lipids extracted by acetone:ether-extraction method consisted of sebaceous gland lipids, cholesterol, free fatty acids, and ceramides. In contrast, the lipids extracted by chloroform:methanol-extraction method contained more polar lipids such as sphingomyelin, which had the same amount of bound water in itself as that of the water-extracted stratum corneum. These results suggest that the polar lipids soluble in the chloroform and methanol mixture may contribute to enhance the bound water content. Therefore, it is hypothesized that the water-holding capacity of the stratum corneum is dependent on both the hygroscopic components such as the natural moisturizing factor (NMF) and the polar lipids, such as sphingolipids, existing in the intercellular spaces of the stratum corneum.
Yamamura
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Shiga Central Research Laboratories, Noevir Co. Ltd., Osaka, Japan.
Tezuka
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D000818:Animals; D001834:Body Water / Q000032:analysis / Q000378:metabolism*; D002725:Chloroform; D009682:Magnetic Resonance Spectroscopy; D000432:Methanol; D051381:Rats; D011923:Rats, Nude; D012867:Skin / Q000032:analysis / Q000378:metabolism*; D012967:Sodium Dodecyl Sulfate; D012996:Solutions; D012997:Solvents
D012996:Solutions; D012997:Solvents; D012967:Sodium Dodecyl Sulfate; D002725:Chloroform; D000432:Methanol