Top medical research body says these two tests on mice and rats should end

Australia’s leading body in health and medical research has determined two invasive methods which place rodents under inescapable stress can no longer be justified due to significant scientific, animal welfare and ethical concerns. 

In a rare step, the National Health and Medical Research Council (NHMRC), which also funds research, has issued two statements clarifying the forced swim test “must not proceed”, and nose-only smoke inhalation procedures “must be phased out as soon as practicable” and not be used in any new projects.

One medical research organisation says it’s “disappointed” by the statement on smoke inhalation and is in discussions to continue using the procedure.

The NHMRC’s position has far-reaching influence given the body also publishes the Australian code for the care and use of animals for scientific purposes, a code of practice adopted into animal welfare laws in every state and territory. 

The two tests have recently been under the spotlight. In 2022, a New South Wales inquiry recommended they be rapidly phased out. In September 2023, the NSW Animal Justice Party introduced a bill into state parliament seeking to prohibit the two tests. 

An NHMRC spokesperson tells Cosmos: “the statements were developed to support the conduct of ethical, humane, responsible and high-quality research involving animals”. 

The lead medical research and funding body states the forced swim test – which involves placing a mouse or rat in a tank of water from which it cannot escape – must not proceed. The NHMRC statement cites significant adverse impacts on animal wellbeing (including the stress and distress from an inescapable situation, isolation, fatigue, hypothermia) and scientific grounds. 

The test was developed in the 1970s as a model for depression. However, the NHMRC spokesperson says “it is clear that the evidence does not support the scientific validity of the procedure”.

The use of smoke inhalation procedures in rodents are also associated with significant ethical, welfare and scientific concerns, particularly nose-only procedures which “must be phased out as soon as practicable”, according to the expert body. 

Both nose-only and whole body methods cause significant harm to the animals such as due to tobacco smoke exposure (to eyes and respiratory systems). 

Nose-only exposure, which involves restraining rodents and forcing them to inhale cigarette smoke or other hazardous substances for extended periods, causes additional harm from pain and distress due to restraint and isolation. “This is the most inhumane method for smoke inhalation,” the NHMRC spokesperson says.

Mouse being placed in a smoking tower supplied copy
Mouse in a smoking tower tube used for nose-only smoke inhalation tests / Credit: Supplied

Dr Suzanne Fowler, Chief Science Officer for RSPCA Australia, says the animal welfare organisation is very supportive of the NHMRC statements. 

She says the RSPCA opposes “procedures that have inherent and unsurmountable welfare risks” and “questionable scientific validity”, of which the forced swim test and smoke inhalation procedures are really clear examples. 

Fowler says around the world, institutions and large pharmaceutical companies have stopped doing these experiments.

“Our hope is that within months, there’s no more of these experiments happening in Australia, because we know that the publication of the results will be brought into question.”

The lack of public reporting makes it hard to assess how widespread the practices are. 

While the NHMRC is not aware of any its actively funded projects using the forced swim test, “a small number of NHMRC-funded projects involve the use of smoke inhalation procedures”, the organisation’s spokesperson says. 

A spokesperson for the Centenary Institute, says the medical research organisation based in Sydney is “disappointed” by the NHMRC statement on smoke inhalation procedures in rodent models.

“We are in discussion with the NHMRC about the impact of this decision on our research program into respiratory diseases and we are providing information to support the continued use of the procedure,” the spokesperson says.

“Our researchers are dedicated to helping solve deadly diseases such as [chronic obstructive pulmonary disease] (emphysema), severe asthma, pulmonary fibrosis and other respiratory disorders. We do not take lightly the issue of smoke inhalation experiments involving animals but we do support its use when there are no viable alternatives.”

The Centenary Institute spokesperson says “the Institute is dedicated to maintaining the highest animal welfare standards and fully complies with all national regulations and animal ethics guidelines”.

All NHMRC-funded researchers currently using the methods must conduct an immediate review to be submitted to their institution’s animal ethics committee by mid-March 2024, and provide detailed information justifying any continued use. 

Rachel Smith is the CEO of Animal-Free Science Advocacy, a not-for-profit organisation which has been campaigning against the use of the two tests for years. She welcomes the NHMRC statements.

Smith says the NHMRC position is significant coming from an expert body, and because the statements include clear recommendations which take immediate effect.

She says Animal-Free Science Advocacy has identified published research from major Australian universities and institutes (including several Group of Eight universities) using these methods.

Meanwhile, others – including the University of Adelaide and the University of South Australia – have already banned researchers from using the forced swim test.

In late 2023, prominent New Zealand (NZ) research institute AgResearch also updated its Code of Ethical Conduct to prohibit the use of the forced swim test, in a decision expected to affect a third of NZ institutes using animals in research.

Smith would like to see specific funding made available to support alternative non-animal methods, to ensure the forced swim test and smoke inhalation methods aren’t simply replaced with other animal procedures.

The NHMRC spokesperson says the organisation is now considering how to include compliance with the statements as part of reporting by institutions who receive research funding.  

Fowler says the RSPCA would like to see greater transparency in all aspects of animal research, particularly “high impact studies” which cause severe suffering.

She says the “RSPCA would call for public notification of how many of these experiments are continuing, and whether the justification and the extra steps have been taken to meet that requirement.”

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