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  • 4-July-2023

    English

    Test No. 460: Fluorescein Leakage Test Method for Identifying Ocular Corrosives and Severe Irritants

    This Test Guideline describes an in vitro assay that may be used for identifying water soluble ocular corrosives and severe irritants as defined by the UN Globally Harmonized System of Classification and Labelling, Category 1. The assay is performed in a well where a confluent monolayer of Madin-Darby Canine Kidney (MDCK) is used as a separation between two chambers. It uses a fluorescein dye as marqueur. The test substance has the potential to impair the junctions of the MDCK cells and thus to increase the monolayer¡¯s permeability. Consequently the fluorescein passes through the monolayer and the fluorescein leakage (FL) increases. The FL is calculated as a percentage of leakage relative to both a blank control and a maximum leakage control. The concentration of test substance that causes 20% FL (FL20, in mg/mL) is calculated and used in the prediction model for identification of ocular corrosive and severe irritants. The cut-off value of FL20 to identify water soluble chemicals as ocular corrosives/severe irritants is ¡Ü 100mg/mL. The FL test method should be part of a tiered testing strategy.
  • 4-July-2023

    English

    Test No. 442E: In Vitro Skin Sensitisation - In Vitro Skin Sensitisation assays addressing the Key Event on activation of dendritic cells on the Adverse Outcome Pathway for Skin Sensitisation

    The present Key Event based Test Guideline (TG) addresses the human health hazard endpoint skin sensitisation, following exposure to a test chemical. More specifically, it addresses the activation of dendritic cells, which is one Key Event on the Adverse Outcome Pathway (AOP) for Skin Sensitisation. Skin sensitisation refers to an allergic response following skin contact with the tested chemical, as defined by the United Nations Globally Harmonized System of Classification and Labelling of Chemicals (UN GHS). This TG provides three in vitro test methods addressing the same Key Event on the AOP: (i) the human cell Line Activation Test or h-CLAT method, (ii) the U937 Cell Line Activation Test or U-SENS and (iii) the Interleukin-8 Reporter Gene Assay or IL-8 Luc assay. All of them are used for supporting the discrimination between skin sensitisers and non-sensitisers in accordance with the UN GHS. Test methods described in this TG either quantify the change in the expression of cell surface marker(s) associated with the process of activation of monocytes and DC following exposure to sensitisers (e.g. CD54, CD86) or the changes in IL-8 expression, a cytokine associated with the activation of DC. In the h-CLAT and U-SENS assays, the changes of surface marker expression are measured by flow cytometry following cell staining with fluorochrome-tagged antibodies. In the IL-8 Luc assay, the changes in IL-8 expression are measured indirectly via the activity of a luciferase gene under the control of the IL-8 promoter. The relative fluorescence or luminescence intensity of the treated cells compared to solvent/vehicle control are calculated and used in the prediction model, to support the discrimination between sensitisers and non-sensitisers.
  • 4-July-2023

    English

    Test No. 491: Short Time Exposure In Vitro Test Method for Identifying i) Chemicals Inducing Serious Eye Damage and ii) Chemicals Not Requiring Classification for Eye Irritation or Serious Eye Damage

    This Test Guideline describes a cytotoxicity-based in vitro assay that is performed on a confluent monolayer of Statens Seruminstitut Rabbit Cornea (SIRC) cells, cultured on a 96-well polycarbonate microplate. After five-minute exposure to a test chemical, the cytotoxicity is quantitatively measured as the relative viability of SIRC cells using the MTT assay. Decreased cell viability is used to predict potential adverse effects leading to ocular damage. Cell viability is assessed by the quantitative measurement, after extraction from the cells, of blue formazan salt produced by the living cells by enzymatic conversion of the vital dye MTT, also known as Thiazolyl Blue Tetrazolium Bromide. The obtained cell viability is compared to the solvent control (relative viability) and used to estimate the potential eye hazard of the test chemical. A test chemical is classified as UN GHS Category 1 when both the 5% and 0.05% concentrations result in a cell viability smaller than or equal to (≤) 70%. Conversely, a chemical is predicted as UN GHS No Category when both 5% and 0.05% concentrations result in a cell viability higher than (>) 70%.
  • 4-July-2023

    English

    Test No. 240: Medaka Extended One Generation Reproduction Test (MEOGRT)

    This Test Guideline describes the Medaka Extended One Generation Test (MEOGRT), which exposes fish over multiple generations to give data relevant to ecological hazard and risk assessment of chemicals, including suspected endocrine disrupting chemicals (EDCs).  Exposure in the MEOGRT starts with spawning fish (P or F0 generation) and continues until hatching (until two weeks post fertilization, wpf) in the second (F2) generation. This Test Guideline measures several biological endpoints.  Primary emphasis is given to potential adverse effects on population relevant parameters including survival, gross development, growth and reproduction (fecundity).  Secondarily, in order to provide mechanistic information and provide linkage between results from other kinds of field and laboratory studies, where there is a posteriori evidence for a chemical having potential endocrine disrupter activity (e.g. androgenic or oestrogenic activity in other tests and assays) then other useful information is obtained by measuring vitellogenin (vtg) mRNA (or vitellogenin protein, VTG), phenotypic secondary sex characteristics (SSC) as related to genetic sex, and evaluating histopathology.
  • 4-July-2023

    English

    Test No. 458: Stably Transfected Human Androgen Receptor Transcriptional Activation Assay for Detection of Androgenic Agonist and Antagonist Activity of Chemicals

    This Test Guideline describes in vitro assays, which use Androgen Receptor TransActivation (ARTA) to detect Androgen Receptor Agonists and Antagonists. The ARTA assay methods are mechanistically and functionally similar test methods that provide information on the transcription and translation of a reporter gene following the binding of a chemical to the androgen receptor and subsequent transactivation. The cell lines used in these assays express AR and have been stably transfected with an AR-responsive luciferase reporter gene, and are used to identify chemicals that activate (i.e. act as agonist) or inhibit (i.e. act as antagonists) AR-dependent transcription. Some chemicals may, in a cell type-dependent manner, display both agonist and antagonist activity and are known as selective AR modulators. The AR is activated following ligand binding, after which the receptor-ligand complex binds to specific DNA responsive elements and transactivates the receptor gene, resulting in an increase cellular expression of the luciferase enzyme. The enzyme then transforms the substrate to a bioluminescent product that can be quantitatively measured with a luminometer. This Test Guideline includes ARTA assays using the AR-EcoScreenTM cell line, the AR-CALUX® cell line, and 22Rv1/MMTV_GR-KO cell line.
  • 28-June-2023

    English

    Webinar Series on Emerging Science to Improve Chemical Safety

    Report on the WNT Workshop how to prepare the Test Guidelines Programme for emerging technologies | In December 2022, the OECD held a workshop to explore where and how to adapt the Test Guidelines to emerging technologies, and remain relevant and impactful. A number of projects and activities are emanating from this workshop discussions, including the revision of Guidance Document 34 on validation, and more to come.

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  • 27-June-2023

    English

    OECD work on in vitro assays for developmental neurotoxicity

    Initial Recommendations on Evaluation of Data from the Developmental Neurotoxicity (DNT) In-Vitro Testing Battery | This document includes the lessons learned from the application of this technology in the field of pharmaceuticals and considers a range of issues directly relevant to human exposure arising from the application of externally-applied dsRNA-based pesticides, and discusses possible effects of dsRNA exposure in mammals.

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  • 11-October-2022

    English

    OECD Good Laboratory Practice: Frequently asked questions (FAQ)

    GLP issues raised by testing labs are covered in this comprehensive list of questions and answers, recently updated with questions related to: Test Facility organisation and personnel, Quality Assurance, Equipment and computerized systems, Test items, reference items and samples/specimens (Biologicals, GMOs, etc.), SOPs, Management of the study, Histopathology, Archives and E-Archives and Monitoring Test Facility compliance by GLP CMAs.

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  • 30-June-2022

    English

    Test No. 442D: In Vitro Skin Sensitisation - ARE-Nrf2 Luciferase Test Method

    The present Test Guideline addresses the human health hazard endpoint skin sensitisation, following exposure to a test chemical. Skin sensitisation refers to an allergic response following skin contact with the tested chemical, as defined by the United Nations Globally Harmonized System of Classification and Labelling of Chemicals (UN GHS). This Test Guideline (TG) provides an in vitro procedure (the ARE-Nrf2 luciferase test method) used for supporting the discrimination between skin sensitisers and non-sensitisers in accordance with the UN GHS. The second key event on the adverse outcome pathway leading to skin sensitisation takes place in the keratinocytes and includes inflammatory responses as well as gene expression associated with specific cell signalling pathways such as the antioxidant/electrophile response element (ARE)-dependent pathways. The test method described in this Test Guideline (ARE-Nrf2 luciferase test method) is proposed to address this second key event. The cell line contains the luciferase gene under the transcriptional control of a constitutive promoter fused with an ARE element from a gene that is known to be up-regulated by contact sensitisers. The luciferase signal reflects the activation by sensitisers of endogenous Nrf2 dependent genes. This allows quantitative measurement (by luminescence detection) of luciferase gene induction, using well established light producing luciferase substrates, as an indicator of the activity of the Nrf2 transcription factor in cells following exposure to electrophilic test substances. There are currently two in vitro ARE-Nrf2 luciferase test method covered by this Test Guideline: the KeratinoSensTM test method and the LuSens test method. Performance standards have been developed to enable the validation of similar test methods.
  • 2-March-2021

    English

    Substitution of hazardous chemicals

    As the demand for safer chemicals grows, the field of alternatives assessment is becoming increasingly important in guiding the transition towards safer, less toxic alternatives. A major limitation that can hinder efforts is the lack of consistent criteria for defining “safer" alternatives. This guidance outlines key considerations for the identification and selection of safer alternatives.

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