Alternative handling techniques for improved experimental standardisation, reproducibility and reduced stress in laboratory mice
Despite decades of artificial selection and inbreeding, laboratory mice retain the fight or flight response to restraint which kept enough of their ancestors alive during predation attempts to genetically cement it into their innate behavioural repetoire. Even what might seem like a light form of handling, such as picking up the mouse by its tail, can be a source of great stress to the individual, particularly when the experience is novel.
The handling of mice during experiments is difficult to avoid. They often need to be physically moved into a test arena, maze or new cage where the research will be carried out. The stress response elicited by handling will vary between individuals based on a number of factors, such as previous experiences with being handled, and results in behavioural and physiological changes which can have a significant effect on the results of an experiment.
So, in addition to the reduction of the suffering of the individual, there is a further incentive to explore alternative methods of handling mice. One such suggestion is the use of a small mobile tunnel. Mice are attracted to dark enclosed spaces and will readily enter a tunnel (once they are familiar with it). This tunnel can then be lifted and placed into a new cage as a form of restraint-free transportation throughout which the mouse is in an enclosed dark space and in full control of itself. This technique, in addition to the importance of familiarisation with the test arena are described in the following paper published in Nature in 2017 by Kelly Gouveia and Jane L. Hurst. “Optimising reliability of mouse performance in behavioural testing: the major role of non-aversive handling”.
Above photo: https://www.nc3rs.org.uk/handling-and-restraint