Development of an in vitro method for skin corrosion testing

Area of Science:

• Toxicology
• Dermatology
• In Vitro Testing

Background:

• Chemical safety regulations mandate accurate skin corrosion assessments.
• Traditional in vivo rabbit skin tests are ethically and practically challenging.
• Development of reliable in vitro alternatives is crucial for regulatory compliance and animal welfare.

Purpose of the Study:

• To develop and validate an in vitro skin corrosion test using reconstructed human skin cultures.
• To establish a reliable alternative to in vivo rabbit testing for chemical classification.
• To assess the predictive accuracy of the in vitro method for distinguishing corrosive from irritant chemicals.

Main Methods:

• Application of test chemicals to the stratum corneum of reconstructed human skin cultures.
• Measurement of cytotoxicity via 3-[4,5-dimethylthiazol-2-yl] 2,5-diphenyltetrazolium bromide (MTT) vital dye metabolism.
• Calculation of the time to 50% reduction in MTT metabolism (t50) and histological grading of epidermal necrosis.

Main Results:

• The in vitro method accurately distinguished 9 corrosive chemicals from 15 irritants with a t50 cutoff of < 3 minutes.
• Histological examination correlated well with chemical corrosivity and cytotoxicity measurements.
• The assay demonstrated consistent predictivity across skin culture models from different suppliers.

Conclusions:

• The in vitro assay using human skin equivalent cultures is a viable and promising alternative to in vivo rabbit skin corrosion tests.
• This method provides a reliable tool for assessing chemical corrosivity to human skin.
• The utility of the assay is independent of the commercial source of the skin cultures, enhancing its applicability.