R&D - Development Research, Kao Corporation, 2-1-3, Bunka, Sumida-ku, Tokyo, 131-8501, Japan.
Int J Cosmet Sci. 2021 Apr;43(2):254-262. doi: 10.1111/ics.12691. Epub 2021 Mar 28.
It was previously reported that a highly resistant structure, which functions as a barrier against the penetration of dyes, is present at the interface between the cuticle and the cortex of human hair. That structure was named CARB, cuticle anchored resistant base. The goal of this study was to clarify the formation and composition of the structure CARB.
Cuticular substructures were observed from the keratinized area of each hair to its root end. The positions where the CARB structure appeared were isolated, and the barrier ability before and after that structure was evaluated. The distributions of glycolipid and cystine were measured using a nano-IR and a transmission electron microscope (TEM).
Cuticular substructures were fully constructed several mm from the hair bulb of the hairs observed. The results show that keratinization at the distal side of the cuticle cell precedes that of the proximal side, and CARB is fully constructed last among the substructures. Glycolipid was preferentially distributed at CARB in the keratinized area. The cystine content of CARB is lower than that of the A-layer; however, it is slightly higher than that of the exocuticle and the inner layer.
These results demonstrate that CARB is produced in the final stage of keratinization of the cuticle layers. The rich contents of glycolipid and cystine might contribute to its resistant property.
先前有报道称，在人类头发的角质层和皮质之间的界面存在一种高度抵抗结构，该结构作为染料渗透的屏障，被命名为 CARB，即角质层锚定抵抗基底。本研究的目的是阐明 CARB 结构的形成和组成。
从每个头发的角化区域到其发根观察角质层亚结构。分离出现 CARB 结构的位置，并评估该结构前后的阻挡能力。使用纳米红外（nano-IR）和透射电子显微镜（TEM）测量糖脂和胱氨酸的分布。
在观察到的头发的毛球几毫米处完全构建了角质层亚结构。结果表明，角质层细胞的远端侧比近端侧更早进行角化，而 CARB 是在亚结构中最后完全构建的。糖脂在角化区优先分布在 CARB 上。CARB 的胱氨酸含量低于 A 层，但略高于外角质层和内层。
这些结果表明，CARB 是在角质层层状角化的最后阶段产生的。丰富的糖脂和胱氨酸含量可能有助于其抵抗特性。
