Tag: Ethics

How you handle mice

affects response to rewards.

Science improves too!

There is an increasing body of research to suggest that handling laboratory mice by the tail is both bad for their welfare and the science that the mice are studied for. Tail handling has negative impacts on mouse behaviour and physiology, with tunnel and cupping handling techniques resulting in behavioural improvements across various common behavioural bioassays, including the elevated plus maze, the open field test and the habituation-dishabituation paradigm.

Now new research suggests that handling is also important for reward-based behavioural assays. A study by Clarkson et al (2018) examined mouse response to sucrose solution (a common reward). They found that tail handled mice showed a reduced response to the sucrose than the tunnel handling method, a finding indicative of the tail handled mice having a ‘decreased responsiveness to reward and potentially a more depressive-like state’.

Across eight years and five research papers, from three distinct research groups in two countries, the field of laboratory mouse research has been irrevocably changed. Combined, the research suggests that tail handling results in poor animal welfare and potentially erroneous scientific results. The National Centre for the Replacement, Refinement & Reduction of Animals in Research now has extensive information on mouse handling techniques, example videos, tips and testimonials for researchers and animal carers to find out more about changing their current mouse handling methods to the tunnel or cupping techniques.

Original research: http://dx.doi.org/10.1038/s41598-018-20716-3

Tunnels and cupping

beat tail handling mice for

behavioural tests.

Laboratory mouse handling method can affect mouse behaviour and physiology, and new research suggests that it can also impinge on mouse performance in behavioural tests. Research by Gouveia and Hurst (2017) found that tail handled mice performed poorly in a habituation-dishabituation paradigm test in comparison to cupped or tunnel handled mice. The tail handled mice ‘showed little willingness to explore and investigate test stimuli’ and even prior familiarisation with the test arena didn’t improve their performance much.

Combined with the previous research findings on mouse handling this research continues to expand on the long-reaching impacts of mouse handling technique on both mouse welfare and scientific experimental rigour and asks the question – just how valid are behavioural tests using laboratory mice that have been tail handled? Yet the story of mouse handling is not yet done, click here for the final instalment of this tale/tail!

Original research: http://dx.doi.org/10.1038/srep44999

Further reducing

mouse anxiety using

familiar tunnels.

Building on the finding that handling laboratory mice using a tunnel resulted in lower anxiety than picking them up by the tail, Gouveia and Hurst (2013) next investigated whether familiarity with the tunnel might be an important factor. Once again they found that tunnel handling resulted in lower anxiety than tail handling during an elevated plus maze (a common behavioural test for laboratory mice).

This time they found differences between mouse strains, with C57BL/6 mice being most interactive towards tunnels from their home cage and ICR mice showing no difference in interaction between familiar home cage tunnels and novel tunnels previously used for handling mice from other cages. The researchers suggest that ‘as home cage tunnels can further improve response to handling in some mice, we recommend that mice are handled with a tunnel provided in their home cage where possible as a simple, practical method to minimise handling stress’. The tunnel would also act as a form of environmental enrichment for the home cage.

In science it’s rare to tell a complete story through the findings of two research papers, click here for the next chapter of this tale/tail!

Original research: https://doi.org/10.1371/journal.pone.0066401

The little changes

can make a big difference:

Handle mice with care.

Traditionally laboratory mice are handled by picking them up by the tail, yet increasing evidence suggests that this is bad, both for the mice themselves and the quality of the science they are being used for. The evidence for this started building from Hurst and West’s 2010 study which demonstrated that handling by the tail resulted in increased aversion and anxiety.

The researchers proposed two alternative methods for handling laboratory mice: holding the mice cupped in the hands or using tunnels that the mice can crawl into and be transported by carrying the tunnels. These novel methods of handling led to the mice approaching the handler voluntarily, being more accepting of physical restraint and showing lower levels of anxiety.

In science it’s rare to tell a complete story through the findings of a single research paper, click here for the next chapter of this tale/tail!

Original research: http://dx.doi.org/10.1038/nmeth.1500