Pharmacotoxicological applications of an equivalent dermis: three measurements of cytotoxicity

Abstract

The legal procedure for evaluating the toxicity of cosmetic, household, chemical and pharmaceutical products is still the irritancy Draize test on rabbits. Various irritation tests are currently being developed as alternatives to in vivo animal testing. Our in vitro model system is composed of 24 equivalent dermis (ED) comprising a chitosan-cross-linked collagen-glycosaminoglycan matrix populated by foreskin fibroblasts. In evaluating this system for irritancy testing, three different measures of toxicity were used: MTT (dimethylthiazol diphenyltetrazolium bromide) reduction, and lactate dehydrogenase and interleukin-6 release. The experiments described herein represent a preliminary evaluation to determine the usefulness and predictive value of our 24 ED kit as an alternative method for the prediction of human dermal reaction, versus three chemical products: cadmium chloride, lauryl sulfate, and benzalkonium chloride. Preliminary results suggest that the ED may be a useful in vitro model for the prediction of cutaneous and ocular toxicity and allow the development of a 24-skin-equivalent kit realized by seeding human normal keratinocytes onto the equivalent dermis.

An in vitro Model System to Study the Damaging Effects of Prolonged Mechanical Loading of the Epidermis

“…24 Keratinocyte damage, without disruption of cell membrane, might also not be detected using this method. 2,24 In spite of these limitations, the obtained viability results give an indication of keratinocyte breakdown (i.e., necrosis) as a result of sustained epidermal loading. Other ''damage markers,'' should always be used in conjunction with the MTT viability assay to get a more complete description of the tissue conditions.…”

Highly hydrophilic cationic gold nanorods stabilized by novel quaternary ammonium surfactant with negligible cytotoxicity

“…Positively charged quaternary ammonium heads interact with negatively charged cellular membranes of both Gram‐positive and Gram‐negative bacterial cells leading to its destruction and leakage of intracellular components . Despite a wide range of applications of QAS, they are associated with irritant and cytotoxic effects against human cells and tissues . With regard to a model of cell membranes as a fluid‐like bilayer arrangement of phospholipids, the cytotoxic effect of QAS is generally attributed to their penetration into phospholipids membrane and formation of membrane lipid/protein‐QAS mixed micelles resulting in disruption of cell membrane integrity and membrane ruptures .…”

Fucoidan Promotes the Reconstruction of Skin Equivalents

“…Therefore, alternative testing models, such as reconstructed skin equivalents (SEs), have been developed to test cosmetic and pharmaceutical ingredients that may cause skin irritation [1]. Current SE models, however, are insufficient and have higher permeability than real human skin; therefore improved SEs need to be developed [2]. …”