New! ECVAM-Validated, Peer-Reviewed, PubMed-Indexed VIDEO Technical Article -
EpiDerm Skin Irritation Test (SIT) VIDEO
EpiDerm™ In Vitro Skin Irritation Measurement
Skip to EpiDerm Skin Irritation Test Overview
The EpiDerm in vitro 3-D human skin tissue model was introduced 15 years ago in response to demand for an in vitro (non-animal) alternative to the animal-based Draize skin irritation test used in the cosmetics, personal care, household products and chemical industries.
The driving forces behind this movement included humane objections to animal testing, as well as the equally important need for a measurement system that produced quantitative, reproducible results. Also, introducing a skin irritation test derived from human skin cells was important because, in many instances, results obtained using animal-based testing do not correlate well with the actual response seen in human tissue.
Key Features: EpiDerm Tissue Model
Human Skin Cell-Derived Model
The responses elicited by test materials using the EpiDerm in vitro 3-D tissue model more closely approximate the skin irritation responses that are seen in human subjects.
Again, responses to test materials more closely mirror real-world skin irritation responses, versus the use of human cadaver skin.
Excellent In Vitro-to-In Vivo Correlation
In a just-completed European study of in vitro alternatives for measuring skin irritation potential, EpiDerm once again performed well in this critical area, posting a study-best coefficient of correlation of 0.94.
Objective, Quantifiable Endpoints
Animal testing skin irritation "end points" are typically comprised of human observation of the condition of the test animal's skin after exposure to test material(s), and the ranking of that observation in an arbitrary, qualitative way. The EpiDerm skin irritation test endpoint is based on the widely accepted, highly quantifiable MTT ET-50 Assay1.
Reproducible - lot-to-lot, year-to-year
EpiDerm has been produced continuously for 15 years, with lot-to-lot QC data dating back that far. No other manufacturer of in vitro tissue models can provide such a solid, well documented foundation on which to base one's skin irritation testing.
Fully Validated by ECVAM
The ECVAM Scientific Advisory Committee (ESAC) endorsed the scientific validity of the EpiDerm SIT (Skin Irritation Test) method at its November 2008 meeting.
ECVAM Scientific Advisory Committee Statement
Link to MatTek Press Release
The EpiDerm SIT (Skin Irritation Test) method is a modification of the previously validated EpiDerm skin irritation method. The main modification is the increased exposure time to test substances from 15 to 60 minutes, while all other essential model parameters remained unchanged.
Any test method submitted to or validated by ECVAM must be reviewed and endorsed by its Scientific Advisory Committee before the test can be used within the European Union regulatory framework.
See the EpiDerm Skin Irritation "Hazard Identification" test method outlined below for a description of this ECVAM-validated method.
EpiDerm Description EpiDerm is a normal (non-transformed), human cell-derived, metabolically active, 3-dimensional organotypic in vitro skin model. Also known generically as reconstructed human epidermis (RhE), EpiDerm closely mimics human epidermis, both structurally and biochemically, and does so in a very reproducible manner. Proven EpiDerm skin irritation protocols, based on the well-documented MTT ET-50 assay, allow researchers to quantitatively measure the dermal irritancy of their experimental materials. Types of materials that have been tested using the EpiDerm system include cosmetics and their constituents, household products, and pharmaceuticals. Major companies on the EpiDerm user list include Clairol, Johnson & Johnson, Procter & Gamble, Revlon and Unilever.
EpiDerm Skin Irritation Testing Overview
MatTek offers 2 Skin Irritation test methods – one for Irritation Potency Assessment (ideal for use in formulation development applications), the other for Hazard Identification (the ECVAM-validated EpiDerm SIT method - ideal for use in the European REACH program). The basic differences between the two and an overview of each test method protocol are given below.
Test Method Overview – Hazard Identification
Test provides an Irritant (R38) / Non-Irritant result – fixed time point assay - detailed training VIDEO now available.
EpiDerm tissues (catalog number EPI-200-SIT) are conditioned by incubation overnight. The next day, the tissues are topically exposed to the test chemicals for 60 minutes. Three tissues each are used per test chemical, positive control and negative control. Tissues are then thoroughly rinsed and blotted to remove the test substances, and transferred to fresh medium. After a 24 hour incubation period, the medium is collected for IL-1 alpha analysis. Tissues are incubated for another 18 hours. After 42 hours total incubation time, the tissues are tested for viability using the MTT viability assay (MTT Kit catalog number MTT-100). Relative cell viability is calculated for each tissue as a percent of the mean of the negative control tissues. Skin irritation potential of the test materials is predicted if the remaining relative cell viability is below 50%.
Test Method Overview – Irritation Potency Assessment
Test provides skin irritation potential of test articles over multiple time points
After equilibration/conditioning (1 hour or overnight), EpiDerm tissues (catalog number EPI-200) are dosed with test materials in duplicate, and exposed for 2, 5, and 18 hours (duplicate negative controls are dosed for 5 hours). At the end of each dosing period, those tissues exposed for that time period are removed from the incubator, test materials are removed from those tissues, and the tissues are tested for viability using the MTT viability assay (MTT Kit catalog number MTT-100). If desired, additional testing for specific cytokines can also be performed.
Detailed test protocols are available--please contact MatTek to receive a copy.
MatTek Skin Irritation Technical References
Clicking on the link below will open a page that contains links to over 60 technical references describing the development, characterization, and use of this innovative human skin irritation measurement system.
Link to ALL MatTek Skin Irritation Technical References
Extensive List of Materials Tested for Skin Irritation
Click on the link below to view representative list of the materials MatTek and others have tested using the EpiDerm tissue model.
Materials Tested using EpiDerm
Contact MatTek today to learn more about the EpiDerm In Vitro Human Skin Irritation Measurement System.
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EpiDerm Reconstructed Human Epidermis (RhE) Data Sheet
EpiDerm Product Specifications
EpiDerm Technical References
1. MTT Tissue Viability Assay - A colorimetric assay system that measures the reduction of a yellow tetrazolium component (MTT) into an insoluble purple formazan product by the mitochondria of viable cells. After incubation of the cells with the MTT reagent for several hours, a solution is added to lyse the cells and solubilize the colored crystals. Samples are read using an ELISA plate reader at a wavelength of 570 nm. The amount of color produced is directly proportional to the number of viable cells.