Use of human pseudo-epidermis to evaluate the toxicity of bis-(2-chloroethyl)sulfide (BCES) on water permeation barrier formation and function.

Human pseudo-epidermis was used to investigate the effects of bis-(2-chloroethyl)sulfide (BCES) on the formation and function of the water permeation barrier. To generate the culture, 2 million viable basal cells derived from human skin were placed on a Puropore nylon microporous membrane pre-coated with calf skin collagen. Addition of bovine pituitary extract and epidermal growth factor to the medium favored the formation of homogeneous cultures and better barrier function. The water permeation constant (Kp) was shown to decrease significantly and reached 25 +/- 6 x 10(-3) when it was calculated from 71% of the cultures prepared. The effects of topically applied BCES on the incorporation of [14C]linoleic acid, as a marker for lipid synthesis, and Kp, as a measure of water permeation, were studied. Compared with untreated cultures, there was no difference in the Kp immediately after exposure to 1-10 nmol BCES/cm2 for 30 min. On the other hand, [14C]linoleic acid incorporation was dose-dependently decreased immediately after exposure and then returned to normal by 48 h later. These data suggest that BCES produces no direct damage to the water permeation barrier but may affect barrier formation by inhibiting lipid synthesis.