REPRODUCIBILITY AND CORRELATION OF EPIOCULAR, A THREE-DIMENSIONAL TISSUE CULTURE MODEL OF HUMAN CORNEAL EPITHELIUM.

The EpiOcular™ tissue model (OCL-200) is an organotypic model of the human corneal epithelium (HCE) cultured from normal human keratinocytes using serum free medium. Paraffin embedded, H&E stained histological cross-sections show the structure of EpiOcular closely parallels that of the HCE; large nucleated basal cells lie beneath 5-6 stratified cell layers which progressively flatten out, ending with a highly squamous, non-keratinized layer at the culture’s apical sur-face. During 1996, 35 lots of the OCL-200 model have been produced and moni-tored using the MTT assay. Exposure of a common surfactant, 0.3% Triton X-100, gave Effective Time-50 values (time of exposure after which viability is reduced to 50%, or ET-50) which had an average of 25.5 ± 6.4 minutes (± 1 standard deviation). Stability of the EpiOcular model for international shipment was probed using these standard quality control tests following packaging and storage of the tissue for 3 days; both positive and negative controls and histology of the tissue remained constant over this time period. ET-50 values for 28 common chemicals from the ECETOC data base were correlated to Draize rabbit eye scores (r = 0.90) and a prediction model was constructed. Next, a set of 41 materials including final formulation shampoos, off-the-shelf personal care products and cosmetics, and surfactants for which Draize data were available were tested and their respective ET-50’s were determined. Based on the correlation for the ECETOC materials (i.e., the “prediction model”), the predicted Draize and the actual Draize scores were compared; a correlation coefficient, r = 0.87, was obtained. Thus, the EpiOcular tissue model appears to be a facile, durable, in vitro means to reduce and/or replace in vivo, animal-based ocular irritancy testing.

Basal cells, Chemicals, Corneal epithelium, Correlation coefficient, Cosmetics, Draize prediction model, Draize scores, Draize tests, ET-50 Value, Endpoints, MTT, EpiOcular, Eye irritation, MTT, MTT ET-50 tissue viability assay, MTT assay, Models, Ocular irritancy testing, Ocular irritation, Ocular irritation testing, Personal care products, Pre-validation, Prediction model, Prevalidation, Quality control tests, Reproducibility, Reproducible, Shampoo(s), Surfactants, Triton X-100, Validation, Viability