Genetically modified laboratory animals in the name of the 3Rs?

Although the introduction of GM animal models at first was viewed as a potent way to enhance experimental biology in the name of the 3Rs by its proponents, over the years, the number of animals used has greatly increased and concerns about the suffering of these animals have emerged in the debate. The purpose of this contribution is to show the need and the urgency for a systematic evaluation of genetically modified laboratory animals (GM animals) according to the 3Rs principle. This evaluation presents various difficulties due to the special features of the genetic modifications of animals, the variety of scientific purposes connected with the use of these animals, the lack of coherent statistical data about this use and the difficulties related to the welfare assessment of these animals. In this article I discuss the significance of the procedures involving GM animals for each of the 3R principles. On this basis, I offer an answer to the question of whether these procedures are compatible with the spirit of the 3Rs.