Testing on animals versus alternative methods

 

Previous research projects, including projects funded through the European Union’s Fourth and Fifth Framework Programmes for Research and Technological Development (FP4 and FP5), have shown that combinations of in-vitro tests are capable of determining the acute toxicity quite well. A 70% correlation has been demonstrated between in-vitro tests on the one hand and in-vivo animal tests and data from human poisoning accidents on the other hand. In-vitro tests are carried out on cell cultures of human and animal origin. Following exposure to a chemical, cell growth or cell death is monitored as a measure of toxicity. However, while previous work has yielded promising results, the in-vitro / in-vivo correlation needs to be significantly improved for in-vitro testing to have a chance of becoming widely accepted. Among the areas that need to be addressed are determination of the validity and accuracy of the present in-vitro tests, means to determine when a test result may not be valid because it is out of the predictive range of the test, as well as tests to assess specific organ toxicity. There is also a need to determine kinetic data for absorption, distribution, elimination and metabolism of foreign chemicals in the body. Moreover, a comprehensive strategy for what combinations of in-vitro tests that need to be employed to ascertain the acute toxicity well enough to replace the LD50 tests has yet to be developed.

 

Despite the aforementioned disadvantages of the conventional in-vivo LD50 tests, tradition and standardisation are mighty enemies to any change in test methodology, meaning that considerable efforts will be required to engage both industry and authorities in a creative dialogue to achieve regulatory approval and wide-spread acceptance of in-vitro testing of acute toxicity.