How omics technologies can contribute to the '3R' principles by introducing new strategies in animal testing.

In Europe, in light of ethical, political and commercial pressure, every effort should be made to replace animals with alternatives (e.g. in vitro models), to reduce the number of animals used in experiments to a minimum and to refine current testing strategies in a way that ensures animals undergo minimum pain and distress. Methods currently used in toxicology for mandatory safety tests rely heavily on the dosing of animals, followed by the detection and pathological evaluation of manifested toxic lesions. Through the integration of so-called 'omics' technologies, a global analysis of treatment-related changes on the molecular level becomes feasible and therefore might provide a means for predicting toxicity before classical toxicological endpoints. This Opinion article summarizes the key features of pushing the '3R' principles in animal testing, discusses the possible impact on safety testing in toxicology and describes the potential of using omics technologies for improved toxicity prediction to meet ethical, political and commercial expectations.