On 25 October 2021, Humane Research Australia (HRA) will release a report detailing current animal-based inhalation research in Australia; the limitations of such research, and the potential offered by new human-relevant approaches. HRA commissioned the report following several years of monitoring the use of forced inhalation studies in Australian institutions as documented in related HRA case studies (1). Titled Optimising inhalation research: Transitioning to human-relevant science (2), the report encourages Australian research institutes and universities to transition to scientifically valid and ethical research methods, and is complemented by a HRA advocacy campaign, ‘Forced to Smoke’ (3).
Inhalation research is currently being conducted at institutions across Australia, with mice exposed via nose-only or whole-body exposure to cigarettes or other hazardous inhalants. In a whole-body exposure chamber, the animals are immersed in the test atmosphere, whereas in nose-only or head-only exposure systems, exposures are localised primarily to the head and/or nasal regions. ‘Animal models’ of diseases for which cigarette smoking has a correlation, such as chronic obstructive pulmonary disease, are created to study disease pathogenesis. This requires subjecting mice to smoke inhalation experiments for up to 18 weeks in duration. This is in addition to other invasive procedures that may be carried out during the experiment, such as injections; impacts such as weight loss and hypothermia; the ongoing suffering likely to be incurred from the disease induced; and ultimately death at the end of the experiment.
Released documents, obtained by the Animal Justice Party through a NSW Parliament order for papers, reveal shocking unexpected deaths and adverse outcomes arising from the nose-only exposure method specifically, with over 100 mice having died (commonly from suffocation) during or immediately after ‘being smoked’ at one unnamed Australian research institution between April 2018-June 2020. Besides the cruelty caused, HRA questions the validity of results obtained via animal inhalation models. There are severe limitations to the translation of findings due to biological differences between humans and mice and differing responses to interventions between species. It is impossible for a mouse to accurately mimic human inhalation, and time that new approach methods, such as the lung-on-a-chip or advanced computer modelling and simulation be utilised (4), especially in the field of basic research by academia, where most forced inhalation studies are conducted, and could be replaced without regulatory obstacles.
HRA urges those supportive of an end of forced inhalation studies to take action via the campaign website (3). The initial ask is for the University of Newcastle to cease forced inhalation studies and make a public statement to this effect. Being an early adopter of the nose-only exposure method, the university is identified as a significant user of this inhumane method in the report. However, with fewer students reported to be encouraged to pursue this method as part of their postgraduate research, this presents an apt opportunity for the University of Newcastle to take a progressive stance and lead the way for other universities and institutes to follow.
HRA CEO Rachel Smith states: ‘The report demonstrates that the potential gains to universities and research institutes – and ultimately human patients – of adopting these new approaches, warrants a timely divestment from animal-models used currently in inhalation research. It is the hope that this report can provide a resource and guidance to assist researchers in overcoming some of the institutional and economic barriers to transitioning by showcasing the accessibility of new technologies in the respiratory research field. HRA would welcome the opportunity to work alongside the University of Newcastle to achieve this.’