IACUC Challenges in Invertebrate Research

IACUC Challenges in Invertebrate Research Chris Harvey-Clark Abstract A Passion for Invertebrates? With billions of individuals and possibly hundreds of thousands of genera, invertebrates represent the largest number and greatest diversity of all animals used in research. Although the capacity for nociception is recognized in many invertebrate taxa, researchers and IACUC members are challenged by a lack of clear understanding of invertebrate welfare and by differing standards of moral concern for these taxa. In practice this has led IACUCs to consider invertebrates in two major groups: species worthy of increased moral concern approximating that shown to vertebrate species (this group includes cephalopods and to some extent decapod crustaceans) and all others. This dichotomy has led to differences in how invertebrate research is regulated and documented. This article presents two case studies illustrating specific concerns in invertebrate research protocols and then provides relevant information to address practical IACUC matters related to regulatory and ethical issues, sourcing and record keeping, risk management, assessment of pain and nociception in invertebrates, housing and husbandry, invasive procedures, veterinary care, and humane endpoints. Introduction The sheer number of invertebrate species is what impressed the biologist Haldane. Within one order (Coleoptera) of the phylum Arthropoda there are over 300,000 species, and the total numbers of arthropod taxa—in excess of 750,000 species—outnumber all other animals on the planet threefold. Invertebrate species range from comparatively simple single-cell life forms (e.g., protozoa) to colonial aggregations of cell types (e.g., sponges and coelenterates) to complex animals that share morphological and physiological convergence with vertebrates (e.g., cephalopods and crustaceans). Some of the longest-lived colonial and noncolonial animals on the planet are invertebrates: the common red sea urchin (Strongylocentrotus franciscanus) may live 200 years (Ebert and Southton 2003); it has been estimated that vestimentiferan worms found near deep-sea hydrothermal vents live up to 250 years, and some corals and sponges may be thousands of years old (Bergquist et al. 2000). Invertebrates in Research A fundamental concern of institutional animal care and use committee (IACUC) members is the welfare of all animals used in research regardless of their phylogenetic position. The increase in knowledge of functional and comparative genomics has revealed extensive genetic homology between humans and other species and underscores the fact that although there are great differences, there are also fundamental similarities in all eukaryotes. Yet with invertebrates humans seem to be more aware of the differences than the similarities, notwithstanding the vast numbers of organisms and variety of species that populate every corner of the planet, accounting for over 90% of animal biodiversity. Chris Harvey-Clark, DVM, is Director of the Animal Care Centre at the University of British Columbia in Vancouver, Canada. Address correspondence and reprint requests to Dr. Chris Harvey-Clark, Animal Care Centre, University of British Columbia, 6199 South Campus Road, V6T 1W5 Vancouver BC, Canada or email chclark@interchange. ubc.ca. Volume 52, Number 2 The Creator would appear as endowed with a passion for stars, on the one hand, and for beetles on the other. – JBS Haldane (1949) 2011 Invertebrates are used both in a wide range of field research on biodiversity and conservation and in the laboratory as animal models for a variety of science questions. Uses range from acute toxicity assays in aquatic invertebrates such as Hydra and Daphnia to invasive neurophysiology in the sea hare Aplysia. Wilson-Sanders (2011) describes a large number of well-defined invertebrate models using fruit flies and the nematode C. elegans in diverse research areas such as drug screening, cell death, aging, retrovirus biology, memory, muscular dystrophy, Parkinson’s disease, wound healing, aging, amyloidosis, programmed cell death, diabetes, and immunology. The diversity of invertebrates requires particular IACUC care in dealing with research ethics issues. A central challenge is the lack of scientific consensus on what constitutes pain and suffering in these species and whether they are applicable to even “advanced” invertebrate species. Elwood (2011) discusses efforts and methods to distinguish between pain and nociception in invertebrates, and Crook and Walters (2011) elaborate on the nociceptive behavior and physiology of molluscs; but 213 scientific evidence of pain and suffering in invertebrates remains poorly researched and controversial. This subject is discussed in greater detail in the section below on the Challenge of Assessing Pain and Nociception in Invertebrates. IACUC Invertebrate Protocol Case Studies The following case studies illustrate the challenges that IACUC members confront in their review of protocols for research involving invertebrates. These cases raised questions about proper scientific procedure, animal welfare, containment, handling and human safety, and attitudes toward invertebrates. Both cases underscore the importance of thoughtful and informed IACUC review. Case Study 1 The Protocol An IACUC received a protocol from a newly recruited principal investigator (PI) working with orb-weaving spiders. The PI proposed to conduct single-cell electrode recordings from the giant ganglia in the spider’s leg, which he proposed to pull off without the use of anesthesia. One or two legs would be sufficient for each day’s recording sessions, and each spider would yield a total of eight legs over the course of 1 to 2 weeks. The PI asserted that this was an accepted and widespread practice among neurophysiologists working with this model. He also indicated that stepping on the spiders was the preferred method of physical euthanasia. IACUC Concerns and Resolution The IACUC was sufficiently concerned about issues of both human safety and animal welfare that they requested a meeting with the investigator, a neurophysiologist, to discuss the protocol. As a justification for the technique proposed the PI made the point that this species of spider has a natural detachment line at the base of each leg for separation of limbs by autotomy and does so to avoid predation in the wild. He also stated that a number of investigators worldwide use this technique and that it is accepted practice in his discipline. When asked how many legs could be harvested, he answered “all the legs.” When asked if the spider would be able to selffeed with fewer than three or four legs, he was unsure. When asked if he did indeed step on the spiders to euthanize them he indicated that he had been facetious and that they were generally killed with ether in a bell jar. The committee consulted with the institutional veterinarian who cited evidence in the veterinary lit (...truncated)