Animal welfare experts and advocates have questioned whether an Australian-led study that non-fatally strangled rats as part of research into the impact of intimate partner violence in humans should have been approved.
They argue that, despite gaining necessary ethical approvals, the study’s use of animals lacked justification given the potentially severe impacts on the animals, the limited translatability of the science and the availability of alternative, non-animal methods, and are calling for it not to be repeated.
In recently published research, dozens of adolescent female rats were non-fatally strangled for 90 seconds using a silicon band weighed down by 680g, applying a force about three times the rat’s body weight. Other rats in the study were given a traumatic brain injury, inflicted by a 50mg weight propelled using pneumatic force into the rat’s head. Some rats received both injuries. A dose of anaesthetic was given prior to these procedures.
Some rats required resuscitation after their injuries, but the paper did not say if any of the rats died as a result of the procedures. It said they were all ultimately euthanised humanely.
Ten minutes after their injuries, all rats were required to undertake walking tests to assess their coordination and balance. Rats were then subjected to various tests designed to assess their memory, coordination and anxiety, at time points ranging from one hour to six days after their injuries, some repeated many times.
The study, led by Monash University in consultation with Alfred Health and other institutions, also included a human clinical element. The aim was to improve the detection of brain injury resulting from intimate partner violence, including the development of a blood test.
In Australia, the use of animals in science is governed by a national code adopted under state and territory animal welfare laws.
Under the code, animal ethics committees (AECs) based at research institutions (made up of researchers, veterinarians, animal welfare and community members) may only approve a project if they are satisfied that it is ethically acceptable.
That judgement is based on whether the effects on animal wellbeing are justified by potential benefits, and whether the study is scientifically valid. The code requires that animals can only be used when there is no scientifically valid, non-animal alternative available.
The study, published in Brain, Behavior and Immunity, was approved by the Alfred Research Alliance ethics committees on behalf of the other institutions. In the paper, the authors say their experiments were conducted in accordance with the code as well as the [US] National Research Council’s Guide for the Care and Use of Laboratory Animals.
An Alfred Research Alliance spokesperson said its committees undertook a “rigorous process” to ensure compliance with the code and to “protect the wellbeing and quality of life of all animals used, and that the use of animals for scientific purposes is ethically acceptable and justifiable.”
A Monash University spokesperson said that intimate partner violence was a complex, serious and widespread public health issue and that “physical attacks during intimate partner violence often include strangulation resulting in brain injury which can frequently go unreported and therefore untreated”. They said the animal model was used due to “the inability to analyse brain tissue in living human patients”.
“Monash University adheres to the rigorous regulations and relevant codes of practice, and ethical considerations in all research involving animals.”
An October press release about the study announced “For the first time, researchers have used blood tests to identify concussion caused by intimate partner violence (IPV) in patients, including some that also experienced non-fatal strangulation.” A senior author said “it is critical to identify IPV-related brain injuries early so that proper support and interventions can occur, and more severe consequences, such as death, are avoided.” One of the study authors said the researchers created an animal model of non-fatal strangulation to investigate the effects of strangulation and concussion separately and together.
“When animal models experienced both injuries at the same time, they had more significant motor and cognitive issues, increased inflammation and injury in the brain, and higher levels of certain brain injury markers in their blood than when they experienced just one of the injuries,”. She said that collectively the study findings provide “important insights that could inform the clinical care and management of IPV patients, and provides a foundation for future research.”
The Australian government’s funding agency, the National Health and Medical Research Council, provided a $1.9m grant for the research.
“NHMRC requires that any method used in animal research must be scientifically valid and ethically justified but does not assess the validity of each animal model proposed itself,” a spokesperson said.
“NHMRC has no comment on the appropriateness of the specific animal model identified.”
Dr Kathrin Herrmann, a veterinary expert in animal welfare science, ethics and law based at Johns Hopkins University in the US, accused the study of “severe and needless” animal suffering – including oxygen deprivation, brain trauma and distress – due to traumatic brain injury and strangulation.
She said this was difficult to justify given key biomarkers of traumatic brain injury were “already established in humans, making their reproduction in animals redundant” and superior human-based alternatives existed for studying traumatic brain injury.
“As a former regulator responsible for assessing animal research proposals and granting licenses in Germany, I can say that I would not have approved this study.” She said she did not believe the suffering inflicted on the animals was justified by the potential benefits for humans.
“The use of a 680g weight on the trachea for 90 seconds is particularly troubling, as it induces severe oxygen deprivation and potential long-term harm, yet the study does not sufficiently describe efforts to refine the model or mitigate suffering,” she said.
Herrmann said brain injury due to intimate partner violence was a complex and cumulative issue, which involved psychosocial trauma that could not be replicated in rats.
“Rather than funding more rat-based or other animal studies, resources should be redirected toward human-relevant research, such as clinical trials, neuroimaging, computational models, and organoid studies,” she said.
Dr Andrew Knight, veterinary professor of animal welfare at Murdoch University, accused the study of “egregious animal cruelty” and described the pain-killing regime outlined in the paper as inadequate.
“Instead of being administered in advance – which is recommended as it’s more effective, pain killers were given after the traumatic brain injuries were inflicted,” he said.
He said he believed that tangible benefits for human beings were unlikely to result given interspecies differences as well as inconsistencies between the rat and human aspects of the study (for example, the recovery times for rats did not align with the human study).
The chief executive of Animal Free Science Advocacy, Rachel Smith, said she was concerned the research paper presented non-fatal strangulation and traumatic brain injury as something that could be built on and expanded in further research.
“Obviously, we would like this method of research not to be repeated, not to be presented as a model that needs further validation.”
Most institutions do not publish AEC minutes or annual reports. Documents relating to the study’s ethics approval were not provided in response to the Guardian’s request. The Guardian contacted senior authors involved with the study, but did not receive a reply.
Bella Lear, chief executive at Understanding Animal Research Oceania, expressed confidence that the institutions involved had good ethical protocols in place, adding that more information would help reassure the public.
“Trauma studies always sound horrible, but when you put them into the clinical context of what this is trying to treat, then they do make sense,” she said.
AECs made ethical judgements weighing up harms versus benefits. Lear said community members were included to offer an independent view, ensuring decisions reflected those that a member of the broader public might have taken.
“The public want to know that the animals are treated with respect and do not suffer cruelty. They also need to know that the science is relevant and will prevent human suffering,” she said, adding that the research was clearly intended to benefit vulnerable people.
More than 850,000 mice and 30,000 rats are used in research annually in states that publicly report statistics (Victoria, New South Wales and Tasmania).
