ADME-Tox screening in rat models using TRAC

TRAC offers multiplex gene expression analysis with high sample throughput, making it ideal for screening applications in pre-clinical drug testing. As TRAC can be used for any gene where the DNA sequences are known, it can be used across a wide range of model systems. As rat is a popular model for pre-clinical ADME-Tox studies, we have developed a panel of pre-validated probes for analyzing cytochrome P450 gene expression in rat tissue, as these are the major enzymes involved in drug metabolism.

Screening of cytochrome P450 gene induction in rat liver samples using TRAC

The liver is the major target for ADME-Tox research in mammals, as it is the primary organ involved in xenobiotic metabolism. However, there are currently no reliable protein markers available to assess liver toxicity, meaning researchers frequently turn to gene expression analysis.

In one example study, TRAC was used to identify the genes reacting to treatment with the cytochrome P450-inducers phenobarbital (PB), beta-naphthoflavone (BNF) and dexamethasone (DEX) in rat liver tissue. Many of the genes analyzed are involved in hepatoxicity, drug metabolism and drug transport.

The results were compared to those produced using Illumina RatRef-12 BeadChip assays. The findings for four of these genes are shown below.

rat data

Conclusions

The study showed that TRAC is a simple, flexible and effective method to analyze the expression of multiple target and reference genes in rat liver samples. The results show that TRAC data is similar to that produced by the Illumina RatRef-12 BeadChip analysis, and in some cases was a better choice due to the higher dynamic range offered by TRAC technology. Furthermore, TRAC assays can be performed directly using liver tissue lysates without the need for purification etc, thereby simplifying and speeding up analysis.