Increased carbonyl protein levels in the stratum corneum of the face during winter

Synopsis The stratum corneum (SC) is the interface between the body and the environment, and is continuously exposed to oxidative stress that results in carbonyl modification of proteins. We previously developed a simple and non-invasive method to assess the stratum corneum carbonyl protein (SCCP) levels. In this study, we used this method to examine the seasonal changes in the SCCP levels and the relationship between the SCCP level and the physiological condition of the SC. SC was collected from the face of healthy Japanese volunteers by adhesive tape stripping and its carbonyl groups were determined by reaction with fluorescein-5-thiosemicarbazide. The average fluorescence intensity of the SC was calculated as the SCCP level. The SCCP level in the cheek was higher in winter than summer. The SCCP level was negatively correlated with the water content in the SC measured by the conductance and capacitance, and also negatively correlated with the extensibility of the skin measured by a Cutometer, suggesting that the mechanical properties of the skin can be affected by oxidative modification of the SC. These data suggest the involvement of oxidative modification of SC proteins in the generation of rough skin during winter. Resume Le stratum corneum (SC) est l’interface entre le corps et l’environnement et il est continuellement expose au stress oxydatif provoque par la carbonylation des proteines. Nous avons precedemment developpe une methode simple et non invasive pour mesurer le taux en proteines carbonylees du SC (SCCP). Dans la presente etude, nous utilisons cette methode pour examiner les variations saisonnieres des taux de SCCP et la relation entre le niveau de SCCP et l’etat physiologique du SC. Le SC a ete collecte sur le visage de volontaires japonais en bonne sante par stripping a l’aide d’un ruban adhesif et les groupes carbonyles ont ete determines par reaction avec la fluoresceine-5-thiosemicarbazide. L’intensite de fluorescence moyenne du SC a ete calculee et assimilee a la teneur en SCCP. La teneur en SCCP sur la joue est plus elevee en hiver qu’en ete. La teneur en SCCP est inversement correlee avec la teneur en eau du SC mesuree par conductance et capacitance et egalement inversement correlee a l’extensibilite de la peau mesuree par la technique du Cutometer, ce qui suggere que les proprietes mecaniques de la peau peuvent etre affectees par la modification oxydative du SC. Ces resultats suggerent l’implication de la modification oxydative des proteines du SC dans l’apparition de la peau reche en hiver.