Nexus - 0226 - New Times Magazine-pages

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Alternatives to Animal Testing fect...replica of the human disorder under reserved for secondary testing only, has study. Rather, it is usually a highly simpli- dropped from a peak of six million animals fied, theoretically biased, and incompletely annually to 300,000. generalised version." Alternative methods can answer ques- Many animal tests are widely regarded as __ tions that traditional animal studies cannot. outmoded. The Lethal Dose 50 per cent According to the NAS, “major recent (LDS50) test, which estimates the dose of a advances in our knowledge of the immune substance necessary to kill half the test ani- system made possible by cell cultures mals, has been termed “an anachronism" by would have been virtually impossible to the former director of the National achieve in intact vertebrates." Toxicology Program. WHAT ARE SOME SPECIFIC WHAT ARE SOME EXAMPLES OF THE EXAMPLES OF REDUCTION AND ADVANTAGES AND IMPORTANCE REFINEMENT? aa OF REPLACEMENT ALTERNATIVES? In the standard Draize eye-irritancy test, A review of all Nobel Prizes awarded in intended to assess how damaging sub- physiology or medicine through 1985 _ stances might be to human eyes, at least six revealed the strong role of alternatives in rabbits receive a relatively large dose of a research that the National Academy of chemical ion one eye. US regulatory agen- Sciences (NAS) has described as “of the cies are considering modifications that Skintex solution reacts when mixed highest calibre, the most enduring influ- would reduce the amount of suffering with a toxic substance. Such a test ence, and the most importance to biomed- involved. One reduction under considera- could replace the Draize skin test. ical science". Two-thirds of the prizes tion is to use from one to three rabbits, were awarded to research that included instead of the usual six. In many instances, time, these companies should suspend ani- major contributions from alternative tech- the smaller number can provide nearly the mal testing and manufacture products only _ niques. same information as the standard number. from the long list of ingredients already The National Cancer Institute has One refinement under consideration is to known to be safe. replaced the use of mice with a technologi- treat the rabbits’ eyes with an anaesthetic Cosmetic companies that continue to test cally advanced in vitro system to determine before adding the potentially irritating on animals should not hide behind techni- _ the anticancer properties of potential drugs. chemical. cal arguments about the shortcomings of The new system can screen the effects of In the classical LDSO test, researchers existing non-animal test methods. In the about 20,000 compounds on several human attempting to obtain a rough measure of a event that the industry is never completely cancer cell types for approximately the substance's toxicity deliberately poison satisfied with altemative methods and con- same cost as testing the compounds, effects scores of animals to estimate the dose that tinues to rely on animals to a certain extent, on only one cancer type in mice. The num- kills half of the animals. Several reduction the HSUS would continue to object to the _ ber of mice used in the mouse testing, now alternatives using 10 to 20 animals, includ- painful testing of cosmetics on animals on the grounds that it is both unethical and powerless to assure human safety. fect...replica of the human disorder under study. Rather, it is usually a highly simpli- fied, theoretically biased, and incompletely generalised version." Many animal tests are widely regarded as outmoded. The Lethal Dose 50 per cent (LDS50) test, which estimates the dose of a substance necessary to kill half the test ani- mals, has been termed "an anachronism" by the former director of the National Toxicology Program. reserved for secondary testing only, has dropped from a peak of six million animals annually to 300,000. Alternative methods can answer ques- tions that traditional animal studies cannot. According to the NAS, "major recent advances in our knowledge of the immune system made possible by cell cultures would have been virtually impossible to achieve in intact vertebrates." A new, high-tech device measures toxicity using microscopic wells in a silicon chip (left), to which human cells are adhered (right). WHAT ARE SOME SCIENTIFIC DISADVANTAGES OF TRADITIONAL ANIMAL RESEARCH AND TESTING? Animals and humans differ in medically important ways. Therefore effects of drugs and other treatments studied in animals are not necessarily seen in humans, and many effects that do occur in humans have no apparent counterparts or are not readily observable in animals (for example, nausea or headache). Animal 'models' of human diseases involve artificially inducing injury or dis- ease in other species. To what extent do the resulting disorders resemble naturally occurring human disorders? It is difficult to know. According to a researcher at the National Institutes of Health (NIH), him- self an advocate of animal models, "in vir- tually no case is an animal model a per- JUNE - JULY 1995 NEXUS ¢ 21