ToxTracker AO

The ToxTracker assay is a state-of-the-art stem cell-based reporter assay that provides mechanistic insight into genotoxic properties of compounds. ToxTracker AO (Antioxidant) is an extended version of the ToxTracker assay and includes discrimination between direct DNA reactivity of a compound and indirect genotoxicity caused by high levels of oxidative stress and the production of reactive oxygen species (ROS). ToxTracker AO combines the power of 6 fluorescent reporter cell lines and ROS scavengers NAC and GSH for the detection of DNA damage response, oxidative stress and protein damage. This unique combination gives unparalleled mechanistic insight into the hazardous properties of chemicals and pharmaceuticals in a single assay. The information generated is particularly useful in Mode-of-Action (MoA) and Adverse-Outcome Pathway (AOP) approaches.

crop ao

Key Features

        • assesses production of ROS and oxidative stress inducing properties
        • discriminates between direct and indirect genotoxicity
        • unsurpassed sensitivity and specificity of 95%
        • excellent predictor for regulatory in vitro and in vivo assays
        • low amount of compound required
        • rapid and cost effective
        • metabolic activation using S9 liver extract

ToxTracker AO is an extended version of the ToxTracker assay. In ToxTracker AO, the reporter assay is performed in the absence and presence of two ROS scavengers, n-acetyl cysteine (NAC) and reduced glutathione (GSH). This protocol can be used to assess the contribution of oxidative stress to the genotoxic profile of a compound. The combination of differential activation of these endpoints is a unique and very powerful means to identify the MOA of genotoxicity and the dose response relationship between oxidative stress and genotoxic effects.

Unique combination of endpoints

DNA damage vs. oxidative stress

We compared potassium bromate (KBrO3) and methyl methanesulfate (MMS)  in the absence and presence of a ROS scavenger.

In this example, KBrO3 and MMS were tested in the ToxTracker assay. Both compounds demonstrate DNA damage (genotoxicity) and oxidative stress activity (2-fold induction defines a positive ToxTracker result). Introduction of NAC reduces oxidative stress as determined using ToxTracker for both compounds; however DNA damage for KBrO3 only. Apparently, DNA lesions caused by MMS are ROS-independent while DNA lesions caused by KBrO3 are partially ROS-dependent.

This example illustrates one possible approach to investigate the role of oxidative stress for a given test compound. Evidently, we can and have performed variations on this approach, tailored to customer needs.

Below is a table of compounds tested with ToxTracker AO in the presence and absence of ROS scavengers NAC and GSH.

From sample to report

This visualisation illustrates the sequence of events between receiving your test compound,  performing the ToxTracker AO and providing the final results.


We can perform ToxTracker AO for you at our state-of-the-art laboratory. You can then send your compounds and receive a full report, in most cases within 2 weeks. Most of our customers ask us to perform the assay as a fee-for-service project as we have all tools and equipment in house and are experienced in the data interpretation. We work together on this basis with various of the top 10 pharma, chemical and cosmetics companies

Local lab installation

The assay can also be installed in your laboratory under license. We provide full support for integration of ToxTracker AO in your toxicology laboratory. Please contact us via the contact form below or via email:

ToxTracker via research marketplaces Science Exchange and

Toxys has made its ToxTracker AO assay available through the research service marketplaces Science Exchange and These platforms are used worldwide by large and small companies to source their testing services. Organisations listed as buyers can now make use of the standardised legal agreements of these platforms and efficiently order ToxTracker services.

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More information

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