Refining bone marrow ablation and reconstitution in mice.

This report presents findings from a group of UK-based researchers with expertise in the use of animal models for bone marrow ablation and reconstitution. The primary aim is to facilitate the implementation of the Three Rs (Replacement, Reduction and Refinement), with an emphasis on refinement. Bone marrow ablation and reconstitution procedures are performed for a number of different purposes and conducted predominantly in mice. These procedures can induce significant suffering, classified as "severe", Category E or Category D/E under European, US and Canadian legislation, respectively. Although severity categorization is not mandated in countries such as Australia and New Zealand, legislation still requires that the level of animal suffering must be minimized to the greatest extent possible. This report identifies specific animal welfare issues and proposes practical measures aimed at reducing both animal use and suffering.