Takahashi Toshie
R&D - Development Research, Kao Corporation, 2-1-3, Bunka, Sumida-ku, Tokyo, 131-8501, Japan.
Int J Cosmet Sci. 2019 Feb;41(1):28-35. doi: 10.1111/ics.12507. Epub 2019 Feb 22.
We previously reported that a chemically resistant structure is present at the interface between the cuticle and the cortex of human hair. The goal of this study was to identify the position of that structure and to clarify its barrier ability.
Untreated, partially and completely decuticled hair fibres were characterized. The correlation between the number of cuticle layers and the penetration depth of a dye into the cortex was microscopically investigated. In addition, similar measurements were performed using hair with a denatured cell membrane complex.
The penetration depth of the dye into the cortex showed no statistically significant correlation with the number of cuticle layers in the case of partially decuticled hair fibres (the number of cuticle layers ranged from one to four). Penetration of the dye proceeded drastically just when the last cuticle layer was lost, but denaturation of the cell membrane complex did not affect the depth of penetration. That suggested that the penetration barrier at the interface between the cuticle and the cortex is not the cell membrane complex, but rather is the resistant structure previously reported. It was observed that a thin layer structure is located beneath the endocuticle of the innermost cuticle cell layer, only in the range where the cuticle borders the cortex. It is thought that this is the structure in question.
These results demonstrate that a highly resistant structure located at the interface between the cuticle and the cortex of human hair acts as a penetration barrier. We propose that structure be named CARB, cuticle anchored resistant base.
我们之前报道过，在人类头发的角质层和皮质层之间的界面处存在一种抗化学结构。本研究的目的是确定该结构的位置并阐明其屏障能力。
对未处理的、部分和完全去除角质的毛发纤维进行了表征。通过显微镜研究角质层层数与染料进入皮质层的渗透深度之间的相关性。此外，对具有变性细胞膜复合物的头发进行了类似的测量。
对于部分去除角质的毛发纤维（角质层层数从一层到四层不等），染料进入皮质层的渗透深度与角质层层数之间没有统计学上的显著相关性。当最后一层角质层消失时，染料的渗透急剧进行，但细胞膜复合物的变性并不影响渗透深度。这表明角质层和皮质层之间界面处的渗透屏障不是细胞膜复合物，而是之前报道的抗性结构。观察到在最内层角质层细胞的内角质层下方仅在角质层与皮质层接壤的范围内存在一层薄结构。据认为这就是所讨论的结构。
这些结果表明，位于人类头发角质层和皮质层之间界面处的高度抗性结构起到了渗透屏障的作用。我们建议将该结构命名为CARB，即角质层锚定抗性基部。
