Pierre Fabre Dermo-Cosmétique et Personal Care, Toulouse, France.
Direction médicale AVENE, Lavaur, France.
Exp Dermatol. 2024 Jun;33(6):e15113. doi: 10.1111/exd.15113.
The mineral content of thermal spring water (TSW) applied to the skin surface can directly influence the skin barrier. Indeed, our previous study showed that Avène TSW (ATSW), a low mineral content thermal spring water, protects the stratum corneum from dehydration compared to a mineral-rich TSW (MR-TSW) and maintains skin surface ultrastructure. While many TSWs have been recognized to have beneficial effects on skin, little is known about their localized and specific effects on skin barrier biomechanics at the nanometric scale. The aim of this study was to compare the effects of ATSW with a reference, MR-TSW, on the biomechanical barrier properties of the skin under homeostasis conditions using atomic force microscopy (AFM). AFM was used to obtain a precise nanomechanical mapping of the skin surface after three applications of both TSW. This provides specific information on the skin topographical profile and elasticity. The topographic profile of skin samples showed a specific compaction of the skin layers after application of MR-TSW, characterized by an increase of the total number of external skin layers, compared to non-treated samples. By contrast, ATSW did not modify the skin topographic profile. High-resolution force/volume acquisitions to capture the elastic modulus showed that it was directly correlated with skin rigidity. The elastic modulus strongly and significantly increased after MR-TSW application compared to non-treated skin. By contrast, applications of ATSW did not increase elastic modulus. These data demonstrate that applications of MR-TSW significantly modified skin barrier properties by increasing skin surface layer compaction and skin rigidity. By contrast, ATSW did not modify the topographical profile of skin explants nor induce mechanical stress at the level of the stratum corneum, indicating it does not disrupt the biophysical properties linked to skin surface integrity.
温泉水（TSW）应用于皮肤表面的矿物质含量可直接影响皮肤屏障。事实上，我们之前的研究表明，与富含矿物质的 TSW（MR-TSW）相比，低矿物质含量的雅漾 TSW（ATSW）可保护角质层免受脱水，维持皮肤表面超微结构。虽然许多 TSW 已被证明对皮肤有益，但对于它们在纳米尺度上对皮肤屏障生物力学的局部和特定影响知之甚少。本研究旨在使用原子力显微镜（AFM）比较 ATSW 与参考物质 MR-TSW 对皮肤生物力学屏障特性的影响，以在稳态条件下。AFM 用于在应用两种 TSW 后三次获得皮肤表面的精确纳米力学图谱。这提供了有关皮肤形貌和弹性的具体信息。皮肤样本的形貌图谱显示，与未经处理的样本相比，MR-TSW 应用后皮肤各层出现特定的压缩，表现为外部皮肤层总数增加。相比之下，ATSW 并未改变皮肤形貌。高分辨率力/体积采集以捕获弹性模量表明，弹性模量与皮肤刚性直接相关。与未经处理的皮肤相比，MR-TSW 应用后弹性模量强烈且显著增加。相比之下，ATSW 的应用并未增加弹性模量。这些数据表明，MR-TSW 的应用通过增加皮肤表面层的压实度和皮肤刚性来显著改变皮肤屏障特性。相比之下，ATSW 并未改变皮肤标本的形貌，也不会在角质层水平引起机械应力，表明它不会破坏与皮肤表面完整性相关的生物物理特性。
