Stratum Corneum Structure of Psoriasis Vulgaris Investigated by EPR Spin-Probe Method

Electron paramagnetic resonance (EPR) spin-probe method was used to investigate structural aspects of psoriasis vulgaris SC (pv-SC). EPR spectra of the SC samples were analyzed using order parameter (S ₀) and rotational diffusion rates. A little, broad three-line pattern of 5-doxylstearic acid (spin probe) in pv-SC was observed. The spectral pattern of pv-SC is quite different from those of control SC reported. The S ₀ values obtained for the pv-SC and the control were approximately 0.20 and 0.49, respectively. The statistical analysis suggests that the 0.20 value of pv-SC is significantly smaller than the 0.49 value of the control (p < 0.01). The rotational diffusion rates for the probe motion in the SC were faster than those of the control. Moreover, there was no spectral difference of the glass plate with the SC against the static magnetic field, except for the signal intensity. Therefore, the pv-SC is less rigid of the structure than that of the control SC, indicating irregular architecture of pv-SC. The present results suggest that the EPR assay is of great use for evaluating various SC function and can be extended to other skin diseases with abnormal keratinization.