The dependence of detergent-induced cell dissociation in non-palmo-plantar stratum corneum on endogenous proteolysis.

We have recently shown that cell cohesion in plantar stratum corneum is mediated to a significant extent by protein structures, and that endogenous proteolysis plays an important role in desquamation in this tissue. This paper is a report of our investigations into whether similar mechanisms for cell cohesion and desquamation can be found in non-palmo-plantar stratum corneum. Biopsies of non-palmo-plantar human skin were incubated at 37 degrees C, pH 8, in a buffer with and without additions of detergents (a mixture of N,N-dimethyldodecylamine oxide and sodium dodecyl sulphate), ethylene diamine tetraacetate (EDTA), and the proteinase inhibitor aprotinin. Released cells were examined by phase contrast microscopy and counted. The incubated biopsies were examined by light microscopy. As has been previously shown by others, we found that in the presence of detergents there was a dissociation of stratum corneum cells. This dissociation was stimulated by EDTA and inhibited by aprotinin. After 36 h of incubation the entire stratum corneum and, on some parts of the biopsies, the stratum granulosum had dissociated. There was no evidence of cell dissociation in the spinous or basal epidermal layers. We conclude that the detergent-induced cell dissociation in non-palmo-plantar human stratum corneum is dependent on the action of proteinases present in the tissue on protein structures. These structures may be of significant importance for non-palmo-plantar stratum corneum cell cohesion.