Recently, microneedling as a cosmetic product has attracted attention as one way to improve skin barrier function and moisturizing function to reduce wrinkle formation. However, some cases of erythema and edema have been reported as side effects. In order to develop safer microneedle cosmetics, we investigated whether microneedles can improve skin barrier function and moisturizing function even when applied in a non-invasive manner that does not penetrate the stratum corneum. We established the condition of non-penetrating microneedle application on reconstructed human full-thickness skin models and examined the effect on the skin models when microneedles were applied under this condition. Microneedle application increased the gene expression of serine palmitoyltransferase long chain base subunit (SPTLC) 3, filaggrin, and transglutaminase 1. The amount of ceramide produced by SPTLC was also increased by microneedle application. Gene expression of filaggrin-degrading enzymes and the amount of free amino acids, a product of filaggrin degradation, were also increased by microneedling. These results suggest that non-invasive microneedle application can improve skin barrier function and moisturizing function by increasing the amount of ceramide and natural moisturizing factors.
Keywords: ceramide; filaggrin; microneedle; natural moisturizing factor; reconstructed skin model; skin barrier.