Estimating mouse and rat use in American laboratories by extrapolation from Animal Welfare Act-regulated species.

Alone among Western nations, the United States has a two-tier system for welfare protections for vertebrate animals in research. Because its Animal Welfare Act (AWA) excludes laboratory rats and mice (RM), government veterinarians do not inspect RM laboratories and RM numbers are only partially reported to government agencies1. Without transparent statistics, it is impossible to track efforts to reduce or replace these sentient animals' use or to project government resources needed if AWA coverage were expanded to include them. I obtained annual RM usage data from 16 large American institutions and compared RM numbers to institutions' legally-required reports of their AWA-covered mammals. RM comprised approximately 99.3% of mammals at these representative institutions. Extrapolating from 780,070 AWA-covered mammals in 2017-18, I estimate that 111.5 million rats and mice were used per year in this period. If the same proportion of RM undergo painful procedures as are publicly reported for AWA-covered animals, then some 44.5 million mice and rats underwent potentially painful experiments. These data inform the questions of whether the AWA needs an update to cover RM, or whether the NIH should increase transparency of funded animal research. These figures can benchmark progress in reducing animal numbers in general and more specifically, in painful experiments. This estimate is higher than any others available, reflecting the challenges of obtaining statistics without consistent and transparent institutional reports.

Open Transparent Communication about Animals in Laboratories: Dialog for Multiple Voices and Multiple Audiences.

In this article, I offer insights and proposals to the current movement for increased openness and transparency about animal use in laboratories. Increased transparency cannot be total transparency-as no story or picture can ever be complete. When research advocates share their stories, they must decide which words and pictures to edit out. I ask here: Who of the listening "public" gets a chance to revisit this editing, and find the information that is important to them? To the extent that (what I call) the "new openness" attempts to speak to a "lay public" and exclude animal activists, I suggest that refinement-focused animal protectionists deserve enhanced avenues of openness and inclusion-which some research advocates might fear giving to more extreme activists and which a less invested "lay public" may not want or need. I conclude with some specific examples and suggestions to not just invite inquiry from animal advocates, but to bring them in as witnesses and participants, to learn from and incorporate their concerns, priorities, expertise, and suggestions. This can bring a diversity of ideas and values that could improve the quality of science, the credibility of animal researchers, and the welfare of the animals in laboratories.

Expertise and advocacy in animal-welfare decision making: considerations for a veterinary curriculum in animal welfare.

An animal-welfare curriculum for veterinary students should provide learning opportunities in the application of veterinary expertise to patient management and animal-welfare policy. Real-life and hypothetical cases are presented that can allow students to develop their personal-values statement about animal welfare, explore the interaction of facts and values in deciding on a course of action, and understand the unique obligations and authority they will have as veterinarians.

Ethical and IACUC Considerations Regarding Analgesia and Pain Management in Laboratory Rodents.

Scientists have ethical and regulatory commitments to minimize pain and distress during their use of sentient laboratory animals. Here I discuss pain as a special form of distress and the long history of ethical and regulatory standards calling on scientists to prevent, minimize, treat or terminate animal pain. Scientists, veterinarians, and IACUC face 2 challenges: knowledge of effective analgesic doses and regimens for all sexes, ages and genotypes of rodent is incomplete, and concerns regarding the effects of analgesic drugs on research outcomes push scientists to request approval to withhold analgesics and leave animal pain unalleviated. IACUC thus conduct what I call an 'ethics of uncertainty,' in which they factor in the limits of available ethically relevant information on the amount of expected animal suffering, the usefulness of analgesics to mitigate this suffering, and the eventual benefits that come from the research. IACUC must factor in current limitations in severity assessments of various experimental manipulations in various strains, inaccurate pain diagnosis, in known effective analgesic and other refinements, and on effects of pain medications and untreated pain on data outcomes, when deciding to allow potentially painful experiments and animal care practices. This article focuses on 3 areas of concern: the limits of veterinary "professional judgment" when the animal model's degree of pain and the efficacy of pain medications are not yet known; the review of proposals with known, unalleviated significant pain and distress (that is, Category E experiments); and the attempt to review the balance between animal welfare harms and scientific objectives. I propose no new regulations, standards, or ethical norms herein but rather explore some of the implications when existing ethical principles are applied to evolving scientific knowledge (and vice versa). I conclude that applying current animal pain management knowledge to prevailing ethical principles will shift IACUC toward greater caution in allowing potentially painful animal experiments, with heightened caution regarding the ability of analgesics to mitigate the animals' pain.

Considerations for determining optimal mouse caging density.

At the 2006 National Meeting of the American Association of Laboratory Animal Science, a panel discussed the question of what constitutes optimal or acceptable housing density for mice. Though there is a consensus that present guidelines are somewhat arbitrarily defined, scientific research has not yet been able to provide clear recommendations for amending them. Speakers explored the many factors that influence decisions on mouse housing, including regulatory requirements, scientific data and their interpretation, financial considerations and ethical concerns. The panel largely agreed that animal well-being should be the measure of interest in evaluating housing density and that well-being includes not only physical health, but also animals' behavior, productivity and preference.

Report of the Working Group on Animal Distress in the Laboratory.

Finding ways to minimize pain and distress in research animals is a continuing goal in the laboratory animal research field. Pain and distress, however, are not synonymous, and measures that alleviate one may not affect the other. Here, the authors provide a summary of a meeting held in February 2004 that focused on distress in laboratory animals. They discuss the difficulties associated with defining 'distress,' propose methods to aid in recognizing and alleviating distressful conditions, and provide recommendations for animal research conduct and oversight that would minimize distress experienced by laboratory animals.

Pain and Laboratory Animals: Publication Practices for Better Data Reproducibility and Better Animal Welfare.

Scientists who perform major survival surgery on laboratory animals face a dual welfare and methodological challenge: how to choose surgical anesthetics and post-operative analgesics that will best control animal suffering, knowing that both pain and the drugs that manage pain can all affect research outcomes. Scientists who publish full descriptions of animal procedures allow critical and systematic reviews of data, demonstrate their adherence to animal welfare norms, and guide other scientists on how to conduct their own studies in the field. We investigated what information on animal pain management a reasonably diligent scientist might find in planning for a successful experiment. To explore how scientists in a range of fields describe their management of this ethical and methodological concern, we scored 400 scientific articles that included major animal survival surgeries as part of their experimental methods, for the completeness of information on anesthesia and analgesia. The 400 articles (250 accepted for publication pre-2011, and 150 in 2014-15, along with 174 articles they reference) included thoracotomies, craniotomies, gonadectomies, organ transplants, peripheral nerve injuries, spinal laminectomies and orthopedic procedures in dogs, primates, swine, mice, rats and other rodents. We scored articles for Publication Completeness (PC), which was any mention of use of anesthetics or analgesics; Analgesia Use (AU) which was any use of post-surgical analgesics, and Analgesia Completeness (a composite score comprising intra-operative analgesia, extended post-surgical analgesia, and use of multimodal analgesia). 338 of 400 articles were PC. 98 of these 338 were AU, with some mention of analgesia, while 240 of 338 mentioned anesthesia only but not post-surgical analgesia. Journals' caliber, as measured by their 2013 Impact Factor, had no effect on PC or AU. We found no effect of whether a journal instructs authors to consult the ARRIVE publishing guidelines published in 2010 on PC or AC for the 150 mouse and rat articles in our 2014-15 dataset. None of the 302 articles that were silent about analgesic use included an explicit statement that analgesics were withheld, or a discussion of how pain management or untreated pain might affect results. We conclude that current scientific literature cannot be trusted to present full detail on use of animal anesthetics and analgesics. We report that publication guidelines focus more on other potential sources of bias in experimental results, under-appreciate the potential for pain and pain drugs to skew data, and thus mostly treat pain management as solely an animal welfare concern, in the jurisdiction of animal care and use committees. At the same time, animal welfare regulations do not include guidance on publishing animal data, even though publication is an integral part of the cycle of research and can affect the welfare of animals in studies building on published work, leaving it to journals and authors to voluntarily decide what details of animal use to publish. We suggest that journals, scientists and animal welfare regulators should revise current guidelines and regulations, on treatment of pain and on transparent reporting of treatment of pain, to improve this dual welfare and data-quality deficiency.

A Good Death? Report of the Second Newcastle Meeting on Laboratory Animal Euthanasia.

Millions of laboratory animals are killed each year worldwide. There is an ethical, and in many countries also a legal, imperative to ensure those deaths cause minimal suffering. However, there is a lack of consensus regarding what methods of killing are humane for many species and stages of development. In 2013, an international group of researchers and stakeholders met at Newcastle University, United Kingdom to discuss the latest research and which methods could currently be considered most humane for the most commonly used laboratory species (mice, rats and zebrafish). They also discussed factors to consider when making decisions about appropriate techniques for particular species and projects, and priorities for further research. This report summarises the research findings and discussions, with recommendations to help inform good practice for humane killing.

Report of the workshop on euthanasia guidelines and practices.

Determining ethical standards for laboratory animal euthanasia requires an assessment of the relative amounts of pain and distress caused by different methods. Animal behaviour data are an important indicator of pain and distress, but their interpretation can be controversial; moreover, behaviour is more easily assessed with some euthanasia methods than with others. While every euthanasia method requires careful study, CO2 inhalation has come under close scrutiny both because it is so widely used for rodent euthanasia, and because it has, until recently, long been considered relatively non-aversive.

Adoption options for laboratory animals.

Adoption programs can be enormously satisfying for all involved-not least the animals themselves-and constitute an important refinement in humane animal care and use. Most of the potential problems associated with adoption can be minimized with careful thought and planning. The authors describe adoption programs at two large academic campuses, noting differences between direct and indirect programs.

Institutional animal care and use committee considerations for animal models of peripheral neuropathy.

Peripheral neuropathy and neuropathic pain are debilitating, life-altering conditions that affect a significant proportion of the human population. Animal models, used to study basic disease mechanisms and treatment modalities, are diverse and provide many challenges for institutional animal care and use committee (IACUC) review and postapproval monitoring. Items to consider include regulatory and ethical imperatives in animal models that may be designed to study pain, the basic mechanism of neurodegeneration, and different disease processes for which neuropathic pain is a side effect. Neuropathic pain can be difficult to detect or quantify in many models, and pain management is often unsuccessful in both humans and animals, inspiring the need for more research. Design of humane endpoints requires clear communication of potential adverse outcomes and solutions. Communication with the IACUC, researchers, and veterinary staff is also key for successful postapproval monitoring of these challenging models.

Platelet aggregation in rhesus macaques (Macaca mulatta) in response to short-term meloxicam administration.

NSAID administration is often chosen as a method of minimizing pain and discomfort for nonhuman primates. Of concern when using NSAID is the potential for decreased platelet aggregation due to the inhibition of cyclooxygenases 1 and 2. In both dogs and humans, the use of NSAID that are selective for cyclooxygenase 2, like meloxicam, minimizes the inhibition of platelet aggregation in comparison to nonselective NSAID, like aspirin, that inhibit both isoforms of cyclooxygenase. In this study, we measured platelet aggregation in rhesus macaques (n = 6) by using the impedance method on a multiple-electrode aggregometer at baseline, at 1 and 4 d after initiating treatment with aspirin or meloxicam, and after a washout period. There was no statistical difference between aggregation at baseline and after 1 or 4 d of meloxicam treatment, but platelet aggregation decreased after both 1 and 4 d of aspirin therapy. Our data suggest that clinically significant postoperative hemorrhage is unlikely in rhesus macaques briefly treated with meloxicam.

Pain management standards in the eighth edition of the Guide for the Care and Use of Laboratory Animals.

The eighth edition Guide for the Care and Use of Laboratory Animals sets standards for diverse laboratory animal care and use practices. It frames its standards as performance, engineering, and practice standards, with a strong emphasis on performance standards, allowing for multiple routes to clearly defined outcomes. Standards intended to be upheld rigorously are indicated through the use of must in the description, and those accommodating more flexibility are indicated through may and should statements. With respect to pain management standards, a fourth type of standard-the jurisdictional standard-has been prevalent through all 8 editions of the Guide. Under jurisdictional standards, specific methods and outcomes for measuring, preventing, or alleviating pain are not detailed, but the various jurisdictions of veterinarian, investigator, and IACUC are elaborated. Although data on pain management in laboratory animals has expanded greatly since the 1996 Guide, the eighth (2011) edition does not contain major new standards or guidance regarding animal pain management. Requirements for veterinary and IACUC involvement remain as in prior editions, and the duty of veterinarians and scientists to stay abreast of new developments is expected to drive refinement of animal pain management institution by institution. The current article details selected specific pain management standards in the 2011 Guide, lists topics in pain management for which the Guide does not set clear standards, and suggests possible standards for those topics.

Duration of action of sustained-release buprenorphine in 2 strains of mice.

Buprenorphine HCl is a common analgesic for laboratory mice undergoing surgical procedures. The documented duration of action of buprenorphine HCl is as short as 3 to 5 h in mice, potentially necessitating readministration for continued analgesia. A long-acting buprenorphine formulation would reduce handling-associated stress and provide uninterrupted analgesia. This study used the hot-plate assay to assess the antinociceptive effects of a single injection of sustained-release buprenorphine (bup-SR), buprenorphine-HCl (bup-HCl), and saline over 72 h in young adult male BALB/cJ and SWR/J mice. SWR/J mice had shorter baseline latencies than did BALB/cJ mice, possibly reflecting greater sensitivity to thermal nociception. Relative increase from baseline latency (% maximal possible effect) was significant for buprenorphine-SR at 2, 6, and 12 h compared with saline. According to results from a hot-plate assay, the analgesic efficacy of buprenorphine-SR appears to last at least 12 h in male BALB/cJ and SWR/J mice.

Assessing cervical dislocation as a humane euthanasia method in mice.

Research investigators often choose to euthanize mice by cervical dislocation (CD) when other methods would interfere with the aims of a research project. Others choose CD to assure death in mice treated with injected or inhaled euthanasia agents. CD was first approved for mouse euthanasia in 1972 by the AVMA Panel on Euthanasia, although scientific assessment of its humaneness has been sparse. Here we compared 4 methods of spinal dislocation--3 targeting the cervical area (CD) and one the thoracic region--in regard to time to respiratory arrest in anesthetized mice. Of the 81 mice that underwent CD by 1 of the 3 methods tested, 17 (21%) continued to breathe, and euthanasia was scored as unsuccessful. Postmortem radiography revealed cervical spinal lesions in 5 of the 17 cases of unsuccessful CD euthanasia. In addition, 63 of the 64 successfully euthanized mice had radiographically visible lesions in the high cervical or atlantooccipital region. In addition, 50 of 64 (78%) mice euthanized successfully had radiographically visible thoracic or lumbar lesions or both. Intentionally creating a midthoracic dislocation in anesthetized mice failed to induce respiratory arrest and death in any of the 18 mice subjected to that procedure. We conclude that CD of mice holds the potential for unsuccessful euthanasia, that anesthesia could be valuable for CD skills training and assessment, and that postmortem radiography has minimal promise in quality-control assessments.