Water-Impermeable Occlusion Effect to Intercorneocyte Lipid Layers in Hairless Mice

ABSTRACT

BACKGROUND: Stratum corneum lipids are arranged as intercellular membrane bilayers presumed to mediate the epidermal permeability barrier. Acute disruption in barrier function will initiate epidermal lipid synthesis, which can be prevented by occlusive membrane. Whereas, occlusion of the skin is known to cause an increased transepidermal water loss(TEWL) and enhanced percutaneous absorption of a variety of compounds. OBJECTIVE: Previous reports with electron microscopy showed varying sizes of lacunae and disorganized intercorneocyte lipids after tape stripping and occlusion with a water impermeable membrane on the murine skin. Hence we studied the effects on stratum corneum lipids and changes in barrier function after occlusion with a water-impermeable membrane. METHODS: Male hairless mice were occluded with one finger of a Latex glove for 24, 48 and 60 hours. After occlusion, TEWL was measured and biopsy specimens were taken from skin. For electron microscopic examination the samples were treated with osmium tetroxide, ruthenitum tetroxide, and tracer (lanthanum) and infrared spectroscopy were also applied. RESULTS: Occlusion with a water-impermeable membrane on the skin induced higher TEWL Values and greater penetration of the tracer than normal. Alterations of the lipid bilayer membrane and lacunae forwation in the stratum corneum interstices were also induced after 24 hours of occlusion. However, the orderness of the lipid alkyl chain in the stratum corneum was not changed until 60 hours of occlusion. CONCLUSION: These studies indicate that the increased epidermal permeability after occlusion may be due to the abnormal lipid membrane structures and volume expansion of existing lacunar domains in the stratum corneum interstices.