In Vitro Toxicology: A Challenge for the 21st Century

Foreword — Animal experimentation is an emotional topic, which arouses passionate feelings both in animal protection groups and in the scientific community. For many years, antivivisectionists have fought for the abolition of all animal experimentation, whereas other groups campaign for suppression/reduction of the level of pain animals suffer because of experimentation. Despite all these efforts, the number of animals used in scientific research does not seem to have decreased significantly during the last few years. At best, this number remains constant or shows minor reductions in some countries, whereas in others it is still increasing. In addition to this situation, which certainly does not satisfy the antivivisectionists, the validity of the use of animal models in biomedical research is increasingly being questioned. On the other hand, a number of developments and projects exist which attest to the growing interest of scientists in in vitro models which use few, or even no, animals. Such a change in attitude is particularly evident in practice and research in toxicology, which uses a large number of animals. Taking into account the special status of toxicology among the biomedical sciences, since its practice is required and defined by laws and directives, a semantic problem exists over which adjective should be applied to describe such new methods. For some, it must be alternative — for consistancy to underline the possibility of replacing classical in vivo tests with new in vitro tests, the validity of which is demonstrated by reference to these in vivo tests. For others, it has to be complementary — to characterise the new protocols and the new experimental models which are of interest, because they contribute to the improvement of toxicology by strengthening its scientific nature. For a third group, it must be adjunct — to emphasise the relatively minor role of non-animal tests in relation to the conventional animal tests. It is the second concept that is favoured in this article. The experimental models to which it applies will, according to the Three Rs of Russell & Burch (1), lead either to the replacement of animal models, or to a reduction in the number of animals used or to refinement of test procedures in order to minimise the suffering and stress caused to animals.