Two-photon fluorescence lifetime imaging of the skin stratum corneum pH gradient
Two-photon fluorescence lifetime imaging of the skin stratum corneum pH gradient
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DOI：
10.1016/s0006-3495(02)73936-2
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发表时间：
2002-09-01
影响因子：
3.4
通讯作者：
Clegg, RM
中科院分区：
文献类型：
--
作者：
Hanson, KM;Behne, MJ;Clegg, RM
双光子荧光寿命成像用于识别表皮最上层（角质层）内两种不同pH值的微域（1-25 μ m）。所使用的荧光团是2',7'-双-（2-羧基乙基）-5-（和6）-羧基荧光素（BCECF），其寿命tau （pH 4.5, tau = 2.75 ns; pH 8.5, tau = 3.90 ns）随角质层pH范围（pH 4.5至pH 7.2）的pH值而变化。以无毛小鼠（SKH1-hrBR）为人体皮肤模型。从角质层表面到第一个可活层（颗粒层），每隔1.7 μ m采集图像（50 μ m x 50 μ m）。在角质层的细胞外基质中检测到不同大小的酸性微域（平均pH值6.0）（直径类似于1微米，长度不同），而角质层中层角质层（直径25微米）的角质层细胞内空间接近中性（平均pH值7.0）。表面呈酸性。角质层的平均pH值随着深度的增加而增加，因为角质层内酸性区域与中性区域的比例减少。这些数据明确地表明角质层酸性地幔是由富含脂质的细胞外基质中存在的水酸性口袋造成的。
Two-photon fluorescence lifetime imaging is used to identify microdomains (1-25 mum) of two distinct pH values within the uppermost layer of the epidermis (stratum corneum). The fluorophore used is 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF), whose lifetime tau (pH 4.5, tau = 2.75 ns; pH 8.5, tau = 3.90 ns) is pH dependent over the pH range of the stratum corneum (pH 4.5 to pH 7.2). Hairless mice (SKH1-hrBR) are used as a model for human skin. Images (: 50 mum x 50 mum) are acquired every 1.7 mum from the stratum corneum surface to the first viable layer (stratum granulosum). Acidic microdomains (average pH 6.0) of variable size (similar to1 mum in diameter with variable length) are detected within the extracellular matrix of the stratum corneum, whereas the intracellular space of the corneocytes in mid-stratum corneum (25 mum diameter) approaches neutrality (average pH 7.0). The surface is acidic. The average pH of the stratum corneum increases with depth because of a decrease in the ratio of acidic to neutral regions within the stratum corneum. The data definitively show that the stratum corneum acid mantle results from the presence of aqueous acidic pockets within the lipid-rich extracellular matrix.