The mineral content of thermal spring waters (TSW) applied at the surface of the skin can directly influence the skin barrier. Indeed, our previous study showed that low-mineralized AVENE TSW protects the stratum corneum from dehydration as compared to a mineral-rich TSW (MR TSW) and maintains skin surface ultrastructure. While many TSW have been recognized to have beneficial effects on skin; little is known about their localized and their specific effects on skin barrier biomechanics at the nanometric scale. For that purpose, the aim of this study was to compare the effects of Avène TSW with MR TSW on biomechanical barrier properties of the skin under homeostasis condition using atomic force microscopy (AFM). In this study, AFM was used to obtain a precise nanomechanical mapping of the skin surface, giving specific information on skin topographical profile and elasticity after three applications of both TSW. First, analysis of the topographical profile of skin samples showed a specific compaction of the skin layers after application of the positive reference characterized by an increase of the total number of external skin layers, compared to NT samples. MR-TSW applications also induced a compaction of corneocytes. Interestingly, AVENE TSW did not modify skin topographic profile. Then, using high resolution force/volume acquisitions, we measured the elastic modulus, directly corelated to skin rigidity. Data showed that the elastic modulus strongly and significantly increased after MR-TSW applications, as compared to NT skin. In contrast, applications of AVENE TSW did not increase elastic modulus. In conclusion, all these data demonstrate that applications of a MR-TSW significantly modify skin barrier properties by inducing skin surface layers compaction and skin rigidity. Interestingly, AVENE TSW did not modify topographical profile of skin explants and did not induced mechanical stress at the level of the SC, by maintaining the skin surface integrity.

ESDR153 - Effect of AVENE thermal spring water on skin barrier mechanical properties by atomic force microscopy

50th Annual Meeting of the European Society for Dermatological Research. VIRTUAL MEETING