Alternative Methods for Evaluating Skin Irritation Using Three-Dimensional Cultures

Abstract

The Draize test has long been used as a method to evaluate skin irritancy. However, alternative methods have since been developed, in response to pressure from the ever-increasing movement of animal protectionists. Cell culture represents the most promising alternative method, and many trials of various kinds are under way, for example the monolayer culture, skin explant culture and three-dimensional skin equivalent culture. It is quite likely that better-qualified three-dimensional culture systems constitute the final goal in the search for alternative methods to evaluate skin irritancy. However, its effective validation will require not only further large-scale studies, but also the development of superior artificial skin models, with properties more closely resembling those of normal skin. In this review, we focus mainly on the skin equivalent culture method for measuring skin irritancy. Its superiority to other models as well as its problems and limitations are discussed.

Three‐dimensional organization of dermal fibroblasts by macromass culture

“…The use of cell monolayers for in vitro assessment of cytotoxicity has been found not to reflect the actual in vivo picture, since cells in monolayers have properties quite different from those of cells in three‐dimensional tissues [16]. Various three‐dimensional culture models based on keratinocytes and/or dermal fibroblasts have been tried for assessing skin irritation potential of compounds [17]. Therefore it was investigated whether the macromass constructs made from dermal fibroblasts have potential as in vitro models for cytotoxicity testing, in comparison with monolayers.…”

“…Thus these results show that the macromass constructs could have potential for use as in vitro models, in which effects on dermal fibroblasts can be specifically studied, with further validation of this model system including different parameters and chemicals. One advantage of the macromasses as three‐dimensional models over some other three‐dimensional culture models that require longer time and are more technically complex to culture [17], would be the suitability for development and implementation of higher throughput assays, since the simplicity of the culture method for macromasses makes them more easily adaptable to higher throughput. Secondly there is less variability, since macromasses are a less complex model than some other three‐dimensional models [17].…”

“…The medium was DMEM+10% FBS. For exposure to a known irritant [16,17], monolayers and macromasses were incubated in the presence of different concentrations of SDS (Sigma) or vehicle (water) added to the medium. Separate 80 μl volumes of 0, 0.1, 0.2, 0.3, 0.4 and 0.5% (w/v) SDS were added/ml of medium.…”