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Updated: Jun 9, 2026
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An In Vitro Skin Irritation Test (SIT) using the EpiDerm Reconstructed Human Epidermal (RHE) Model
Published on: July 13, 2009
In vitro skin irritation testing with human skin cell cultures.
1Human & Environmental Safety Division, Miami Valley Laboratories, The Procter & Gamble Company, PO Box 398707, Cincinnati, OH 45239-8707, USA.
Summary
Human skin cell cultures effectively model skin irritancy. In vitro tests on keratinocyte and co-cultures showed dose-dependent responses correlating with human patch test results for chemical irritants and surfactants.
Area of Science:
- Toxicology
- Dermatology
- In Vitro Assays
Background:
- Cultured human skin cells offer a promising alternative for skin irritancy testing.
- Traditional methods often involve animal testing, necessitating the development of reliable in vitro models.
Purpose of the Study:
- To evaluate the efficacy of human epidermal keratinocyte (NHEK) and keratinocyte-dermal fibroblast (NHEK/DF) co-cultures for in vitro skin irritancy assessment.
- To correlate in vitro responses with human patch test data for chemical irritants and surfactants.
Main Methods:
- Assessed cell viability using neutral red (NR) uptake in NHEK cultures and MTT incorporation in NHEK/DF co-cultures.
- Measured cytotoxicity via lactate dehydrogenase (LDH) and N-acetyl glucosaminidase (NAG) release in NHEK/DF co-cultures.
- Evaluated inflammatory mediator release (prostaglandin E2) and glucose utilization in NHEK/DF co-cultures.
Main Results:
- NR50 values in NHEK cultures correlated with human patch test irritation scores.
- All tested endpoints in NHEK/DF co-cultures demonstrated dose-dependent responses to surfactants.
- Strong correlations were observed between in vitro results and human patch test scores for surfactants.
Conclusions:
- Human skin cell cultures, including NHEK and NHEK/DF co-cultures, are valuable tools for in vitro skin irritancy testing.
- Cell viability, cytotoxicity, and inflammatory mediator release serve as reliable endpoints for assessing skin irritancy in vitro.
