Animal welfare and the refinement of neuroscience research methods--a case study of Huntington's disease models.

The use of animals in biomedical and other research presents an ethical dilemma: we do not want to lose scientific benefits, nor do we want to cause laboratory animals to suffer. Scientists often refer to the potential human benefits of animal models to justify their use. However, even if this is accepted, it still needs to be argued that the same benefits could not have been achieved with a mitigated impact on animal welfare. Reducing the adverse effects of scientific protocols ('refinement') is therefore crucial in animal-based research. It is especially important that researchers share knowledge on how to avoid causing unnecessary suffering. We have previously demonstrated that even in studies in which animal use leads to spontaneous death, scientists often fail to report measures to minimize animal distress (Olsson et al. 2007). In this paper, we present the full results of a case study examining reports, published in peer-reviewed journals between 2003 and 2004, of experiments employing animal models to study the neurodegenerative disorder Huntington's disease. In 51 references, experiments in which animals were expected to develop motor deficits so severe that they would have difficulty eating and drinking normally were conducted, yet only three references were made to housing adaptation to facilitate food and water intake. Experiments including end-stages of the disease were reported in 14 papers, yet of these only six referred to the euthanasia of moribund animals. If the reference in scientific publications reflects the actual application of refinement, researchers do not follow the 3Rs (replacement, reduction, refinement) principle. While in some cases, it is clear that less-than-optimal techniques were used, we recognize that scientists may apply refinement without referring to it; however, if they do not include such information in publications, it suggests they find it less relevant. Journal publishing policy could play an important role: first, in ensuring that referees seriously consider whether submitted studies were indeed carried out with the smallest achievable negative impact on the animals and, secondly, in encouraging scientists to share refinements through the inclusion of a 3Rs section in papers publishing the results of animal-based research.