Bovine corneal stroma and epithelium reconstructed in vitro: characterisation and response to surfactants

In order to define safety profiles and proper handling procedures for new industrial products, it is essential to determine their potential for ocular irritation. The Draize test is normally employed but it involves using rabbits. There is today a great need for all researchers to limit the use of animals for laboratory experiments and to encourage the development and adoption of alternative in vitro methods to evaluate the potential toxicity of new products. This study proposes a three-dimensional model of bovine corneal stroma and epithelium that is not only easy to reproduce but may also be used in the toxicological field as an alternative to animal experimentation. The data presented here show that this model allows the growth of epithelium similar in features to in vivo epithelium. Basal cells are cube-shaped, whereas superficial areas are horizontally longer; desmosomes and 64 kDa keratin, as a marker for differentiation of corneal epithelial cells, are both expressed; the basal lamina is synthesised also. The 3-[4,5-dimethylthiazol-2-yl]2,5-diphenyltetrazolium bromide (MTT) assay was carried out on the model to evaluate the toxicity of some surfactants: benzalkonium chloride, Triton X-100, sodium dodecylsulphate and Tween 20. Since the in vitro data fit very well the results of the Draize test in vivo as reported in the literature, the three-dimensional culture may be used to predict the potential cytotoxicity of surfactants.