Episkin

Description

In vitro Skin Corrosion assay (under OECD TG 431 guidelines)




Models


Reconstructed Human Epidermis

Protocol principle


Skin corrosion refers to the production of irreversible tissue damage in the skin following the application of a test material.
The purpose of this study (validated by ECVAM) is to determine the in vitro corrosion potential of the test product after topical application on the SkinEthic in vitro reconstituted human epidermis model.


Detailed assay procedure


Test method (RHE model)


40 µl of each test product (20 mg if solid), and 40 µl of positive control (8N KOH) are deposited onto the surface of the stratum corneum of six reconstituted human epidermal tissues. All cultures (including six untreated tissues) are consequently incubated at 37°C, 5% CO2 for 3 minutes and 1 hour (3 tissues per time point). At the end of the treatment period, the tissues are washed with PBS, blotted and assessed for tissue viability (MTT assay).

Evaluation of cell viability


Cultures are placed on 300 µl of 1 mg/ml MTT and incubated 3 hours at 37°C, 5% CO˛.
Extraction is performed in 1.5 ml of isopropanol at room temperature, for a minimum of 2 hours. Optical density is measured at 570 nm. Results will be expressed as percentage of viability compared to negative control: % Viability = [OD (570nm) test compound / OD (570nm ) negative control)] x 100


Prediction model


The test substance is considered to be corrosive to skin:
  • if the viability after 3 minutes exposure is less than 50%, or
  • if the viability after 3 minutes exposure is greater than or equal to 50 % and the viability after 1 hour exposure is less than 15%.
The test substance is considered to be non-corrosive to skin:
  • if the viability after 3 minutes exposure is greater than or equal to 50% and the viability after 1 hour exposure is greater  than or equal to 15%.

References


Assessment of the human epidermis model SkinEthicTM RHE for in vitro skin corrosion testing of chemicals according to new OECD TG 431.  H. Kandárová, M. Liebsch, H. Spielmann, E. Genschow, E. Schmidt, D. Traue, R. Guest, A. Whittingham, N. Warren, A.O.Gamer, M. Remmele, T. Kaufmann, E. Wittmer, B. De Wever, M. Rosdy.  Toxicology In Vitro, 20, 547-559, 2006.