Functional and structural changes of the epidermal barrier induced by various types of insults in hairless mice

Acute barrier disruption, regardless of the method of induction, depletes t he stratum corneum intercellular lipids and this stimulates a series of lip id/ DNA synthesis activities which lead to barrier recovery. After barrier disruption by tape stripping, occlusion with a water vapor-impermeable memb rane inhibits barrier repair. In this study, we investigated the changes in the murine epidermis after barrier perturbation by tape stripping and thre e different types of surfactants (Emalex NP-12, ENP-12; sodium dodecyl sulf ate, SDS; benzalkonium chloride, BKC), To examine the effect of an artifici al barrier, we covered the animals with a water vapor-impermeable membrane for 3 days following barrier disruption and then exposed them to the air fo r 2 days. The histological findings after occlusion or air exposure were si milar. However, after air exposure for 2 days, the thickness of the epiderm is including the stratum corneum and the stratum granulosum layers decrease d to about half that of the epidermis after occlusion, Ultrastructural exam ination revealed obvious distortion of the lamellar bilayers within the str atum corneum interstices immediately after barrier disruption. After 3 days of occlusion, extensive disorganization was evident in the intercellular d omain of the stratum corneum, whereas 2 days after removal of the occlusion , the normal basic unit structure of the lamellar bilayers had partially re appeared. Our findings provide evidence that the kinetic pattern of barrier repair and the morphological changes are similar after occlusion following barrier disruption regardless of the mechanism of disruption.