Physical characterization of the stratum corneum of an in vitro psoriatic skin model by ATR-FTIR and Raman spectroscopies.

The stratum corneum is an important permeability barrier for the skin. The disorganization of the skin protective barrier characterizes some skin diseases such as psoriasis. Indeed, psoriatic skin is known to be more permeable than normal human skin. An in vitro human skin substitute may be obtained by the auto-assembly method. This method was adapted to produce psoriatic substitutes. FTIR spectroscopy is a well-established method to evaluate the order of hydrocarbon chains in terms of population of trans and gauche conformers. Using ATR-FTIR, we have compared the physicochemical properties of the stratum corneum in skin models derived from uninvolved and involved psoriatic cells with those derived from normal cells. Our results suggest that the stratum corneum of involved psoriatic skin substitutes is less organized than that of normal skin substitutes. Also, it seems that the properties of uninvolved psoriatic skin may vary with seriousness of the disease. The development of a new psoriatic skin model would be helpful in the design of new treatments and to increase the understanding of the mechanisms of this pathology.