Homogeneous transport in a heterogeneous membrane: Water diffusion across human stratum corneum in vivo
Homogeneous transport in a heterogeneous membrane: Water diffusion across human stratum corneum in vivo
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DOI：
10.1016/s0006-3495(96)79460-2
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发表时间：
1996-11-01
影响因子：
3.4
通讯作者：
Guy, RH
中科院分区：
文献类型：
--
作者：
Kalia, YN;Pirot, F;Guy, RH
本研究的目的是确定结构不均匀的生物膜——人角质层（SC）是否表现为水运输的均匀屏障。这个问题是相关的，因为SC在体内的主要功能是提供一个屏障，以防止组织水在皮肤上的无意识损失。在人体受试者体内，通过连续应用胶带条逐步去除Sc层，依次记录皮肤的阻抗谱（IS）和经皮失水率（TEWL）的测量结果。胶带剥离对皮肤低频阻抗（小于或等于100 rad s(-1)）的影响要明显大于高频阻抗；去除最外层的SC层效果最大。相比之下，当外层SC层被剥离时，TEWL变化不大，但当6-8 μ m的组织被移除时，TEWL急剧增加。因此，两种非侵入性技术以不同的方式探测SC屏障的完整性。去除SC后，屏障功能的恢复（通过增加低频阻抗值来评估）明显快于TEWL下降到剥离前的控制。TEWL的变化作为SC去除的函数表现为完全一致的均质屏障，从而允许发现水的明显SC扩散率，皮肤阻抗（低频）与SC内水的相对浓度相关，从而为皮肤水合作用提供了体内探针。最后，计算SC对水的渗透系数作为SC厚度的函数，并将其与由IS导出的相应皮肤导纳值进行关联。
The objective of this study was to determine whether a structurally heterogeneous biomembrane, human stratum corneum (SC), behaved as a homogeneous barrier to water transport. The question is relevant because the principal function of the SC in vivo is to provide a barrier to the insensible loss of tissue water across the skin. Impendance spectra (IS) of the skin and measurements of the rate of transepidermal water loss (TEWL) were recorded sequentially in vivo in human subjects as layers of the Sc were progressively removed by the serial application of adhesive tape strips. The low-frequency (less than or equal to 100 rad s(-1)) impedance of skin was much more significantly affected by tape stripping than the higher frequency values; removal of the outermost SC layer had the largest effect. In contrast, TEWL changed little as the outer SC layers were stripped off, but increased dramatically when 6-8 mu m of the tissue had been removed. It follows that the two noninvasive techniques probe SC barrier integrity in somewhat different ways. After SC removal, recovery of barrier function, as assessed by increasing values of the low-frequency impedance, apparently proceeded faster than TEWL decreased to the prestripping control. The variation of TEWL as a function of SC removal behaved in a manner entirely consistent with a homogeneous barrier, thereby permitting the apparent SC diffusivity of water to be found, Skin impedance (low frequency) was correlated with the relative concentration of water within the SC, thus providing an in vivo probe for skin hydration. Finally, the SC permeability coefficient to water, as a function of SC thickness, was calculated and correlated with the corresponding values of skin admittance derived from IS.