Circling back to the 3Rs, if 90% or more of most research studies are already using mice, should we expand the 3Rs and ask the IACUC to interpret the use of mice more judiciously for research?  Reproducibility, repeatability, rigor, relevance and rationalization all start with ‘R’ and in today’s world may potentially be more important factors to consider than replacement, reduction, or refinement.  As an animal resources director, IACUC Chair and research investigator, I fully recognize these questions are ‘hot button topics’ that are both sensitive and often controversial.  This is especially true if the science using mice isn’t peer-reviewed by an external agency and the IACUC is also charged with (in some manner) evaluating the science behind the use of animals.  Smaller institutions, which have fewer resources and scientists conducting large-scale experiments with mice, are probably at an even bigger disadvantage when faced with expanding the 3Rs to determine if the use of animals is justified in an unfunded scientific proposal.  Read more