Electroperturbation of human stratum corneum fine structure by high voltage pulses: a freeze-fracture electron microscopy and differential thermal analysis study.
Jadoul A, Tanojo H, Preat V, Bouwstra JA, Spies F, Bodde HE
Unite de Pharmacie Galenique, Ecole de Pharmacie, Universite Catholique de Louvain, Brussels, Belgium.
Application of high voltage pulses (HVP) to the skin has been shown
to promote the transdermal drug delivery by a mechanism involving skin
electroporation. The aim of this study was to detect potential changes
in lipid phase and ultrastructure induced in human stratum corneum by various
HVP protocols, using differential thermal analysis and freeze-fracture
electron microscopy. Due to the time involved between the moment the electric
field is switched off and the analysis, only "secondary" phenomena rather
than primary events could be observed. A decrease in enthalpies for the
phase transitions observed at 70 degrees C and 85 degrees C was detected
by differential thermal analysis after HVP treatment. No changes in transition
temperature could be seen. The freeze-fracture electron microscopy study
revealed a dramatic perturbation of the lamellar ordering of the intercellular
lipid after application of HVP. Most of the planes displayed rough surfaces.
The lipid lamellae exhibited rounded off steps or a vanished stepwise order.
There was no evidence for perturbation of the corneocytes content. In conclusion,
the freeze-fracture electron microscopy and differential thermal analysis
studies suggest that HVP application induces a general perturbation of
the stratum corneum lipid ultrastructure.
PMID: 9734831, UI: 98403900