Mojsiewicz-Pieńkowska Krystyna, Stachowska Ewa, Krenczkowska Dominika, Bazar Dagmara, Meijer Frans
Department of Physical Chemistry, Faculty of Pharmacy, Medical University of Gdańsk, al. gen. Józefa Hallera 107, 80-416 Gdańsk, Poland.
Department of Metrology and Measurement Systems, Faculty of Mechanical Engineering and Management, Poznan University of Technology, ul. Piotrowo 3, 60-965 Poznan, Poland.
Int J Mol Sci. 2020 Sep 2;21(17):6375. doi: 10.3390/ijms21176375.
Cyclic siloxanes (D4, D5, D6) are widely used in skin products. They improve skin sensory properties and alleviate dry skin, but there is still one report (published 2019), which regards their effects on the destruction of the skin barrier, by using fluorescence microscopy and attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR). A new skin-imaging technique, digital holographic microscopy (DHM), was used for the first time to investigate the impact of D4, D5, and D6 on the skin barrier. We observed irreversible damage of the stratum corneum due to the interaction with cyclic siloxanes. These substances changed: (a) the first level of the skin barrier through destabilization of the intercellular lipid lamellae and destruction of the corneocyte structure (measured with axial nanometer resolution), (b) the second level by collapse of not only corneocytes but also of a significant part of the clusters, leading to the loss of the stratum corneum integrity and formation of the lacunae, (c) the third level as an effect of the change in the surface geometrical topography of the stratum corneum and disruption of the integrity of this skin layer, measured with lateral micrometer resolution. DHM allowed also to identify an important pathway for substances to penetrate into the skin through canyons surrounding the clusters. Our investigations provide advanced information for understanding the mechanisms by which various substances pass the skin barrier, including uncontrolled diffusion into the skin.
环状硅氧烷（D4、D5、D6）广泛应用于护肤品中。它们能改善皮肤的感官特性并缓解皮肤干燥，但仍有一份报告（2019年发表）通过荧光显微镜和衰减全反射傅里叶变换红外光谱（ATR-FTIR）研究了它们对皮肤屏障破坏的影响。一种新的皮肤成像技术——数字全息显微镜（DHM）首次被用于研究D4、D5和D6对皮肤屏障的影响。我们观察到由于与环状硅氧烷相互作用，角质层出现了不可逆的损伤。这些物质改变了：（a）皮肤屏障的第一层次，通过破坏细胞间脂质片层的稳定性和角质形成细胞结构（以轴向纳米分辨率测量）；（b）第二层次，不仅角质形成细胞而且很大一部分细胞簇塌陷，导致角质层完整性丧失和腔隙形成；（c）第三层次，表现为角质层表面几何形貌的变化以及该皮肤层完整性的破坏（以横向微米分辨率测量）。DHM还能够识别物质通过围绕细胞簇的峡谷渗透到皮肤中的重要途径。我们的研究为理解各种物质穿过皮肤屏障的机制提供了先进信息，包括无控制地扩散到皮肤中。
