OECD 439 - In Vitro Skin Irritation: Reconstructed Human Epidermis (RHE) Test

Skin Irritation Tests (SIT)- In Vitro Toxicity Testing Alternatives

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To predict dermal irritation potential of test articles in the context of identification and classification of skin irritation hazard according to the European Union (EU) classification (R38 or no label), United Nations Globally Harmonized System of Classification and Labeling of Chemicals (GHS) classification system (Category 2 and non-irritants), and OECD Guideline for the Testing of Chemicals No. 439 -- In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method. This study is designed based on MatTek protocol in vitro EpiDermTM Skin Irritation Test.


Since the EU and GHS systems were harmonized in 2008, the procedure described in this protocol also allows for hazard identification of irritant substances in accordance with United Nations Globally Harmonized System of Classification and Labeling of Chemicals (GHS). The Modified EpiDerm SIT allows discrimination between irritants of Category 2 and non-irritants. The test does not discriminate between non-mandatory subcategories of the UN GHS, i.e., it does not distinguish between GHS Category 2 and Category 3 irritants.

Notice: This method is not designed to test highly volatile test substances, gases and aerosols.

Assay Principle

A Test substance is dosed topically to a 3D Reconstructed Human Tissue model, comprised of nontransformed, human-derived epidermal keratinocytes, which have been cultured to form a multi-layered, highly differentiated model of the human epidermis. The 3D tissue consists of organized basal, spinous and granular layers, and a multi-layered stratum corneum analogous to those found in vivo.

This reconstructed 3D tissue model is based on the premise that irritating and corrosive chemicals are able to penetrate the stratum corneum by diffusion or erosion, and are cytotoxic to the cells in the underlying layers. Enzymatic conversion of the vital dye MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, Thiazolyl blue tetrazolium bromide; CAS number 298-93-1], into a blue formazan salt that is quantitatively measured after extraction from tissues is used to determine cell viability.

3D Reconstructed Human Tissue Model

Skin irritation tests are performed using in vitro 3D human skin tissue models that closely mimic the human epidermis. in vitro 3D human skin tissue models were developed to create an in vitro (non-animal) alternative to the animal-based Draize Skin irritation and corrosivity testing utilized by by many industries including: personal care, household products, chemical, pharmaceutical, and biotech industries.

MB Research offers skin irritation test models that have been endorsed by the ECVAM Scientific Advisory Committee (ESAC) as validated in vitro replacements for the Draize Skin Irritation Test - OECD Test guidelines 439.


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Solving the In Vitro Toxicology Puzzle

MB Research Labs works closely with other leaders in the field of in vitro toxicology and is dedicated to advancing techniques that reduce the use of live animals in Toxicological Research. Below are several related sources that are helpful in developing and validating novel in vitro toxicology testing methods.