Practicing the “3 Rs” – Considerations for Investigators

The Animal Welfare Act legislatively mandates that IACUCs ensure that PIs have considered the use of “animal alternatives”. The concept of alternatives is embodied in what has come to be referred to as the “3 Rs”–Replacement, Reduction, and Refinement.

  1. Replacement –Substitution of other systems for animal use.
    PIs might consider the following questions:
    Can the hypothesis be tested in a protocol that uses cells, tissue, or organ culture?
    Might a chemical system or computer simulation provide a means for testing the hypothesis?
  2. Reduction –Decreasing the number of animals needed to yield statistically accurate and reliable outcomes.
    PIs might consider these questions:
    What is the minimum treatment difference necessary to demonstrate a biologically significant result?
    What might be a reasonable expectation for the range of variability in my animal subjects?
    These and related questions help focus the PI’s thinking on experimental designs aimed at utilizing the most appropriate number of animals. The IACUC encourages PIs to consult with a statistician for help in discerning the appropriate animal sample size. The PI’s protocol must provide the IACUC with a clear and logical statement of the process s/he used in specifying the specific number of animals to be used in their protocol.
  3. Refinement –Efforts used to eliminate or minimize animal pain or distress.
    Some questions the PIs might consider:
    May appropriate analgesics and/or anesthetic agents be used without confounding the experiment?
    Might it be possible to choose an “end-point” other than the death of the animal in order to minimize pain and distress?
    Might the current sampling or surgical technique(s) be modified or replaced in order to minimize pain and distress?
    The IACUC encourages PIs to consult with a veterinarian for help in discerning possible refinements.