13840110d2d515487e83b87 disadvantages of using rats in research 13840110d2d515487e83b87 disadvantages of using rats in research

Quantification of more subtle behaviors, such as walking backwards or grooming of the front paws has thus been proposed as alternatives to quantify cold pain behaviors, although the validity of this approach has not been systematically assessed. Allowing rodents to have several trial runs prior to the actual experiment can increase burrowing behaviors and reduce variability (Deacon, 2006b). Methods 113, 9197. Heat thresholds in humans can be determined by applying a metal probe to the skin that increases in temperature (starting at 32C) until a warm-sensation threshold and heat-pain threshold is reached. Rodents are placed individually in small cages with a mesh or barred floor. doi: 10.1172/jci42843, Dubner, R. (1983). An additional confounding factor in the hot plate test is the tendency for learned behavioral responses, which lead to diminished reaction times during subsequent exposures to the hot plate (Gamble and Milne, 1989; Plone et al., 1996). doi: 10.1016/j.jpain.2013.06.008, Griffioen, M. A., Dernetz, V. H., Yang, G. S., Griffith, K. A., Dorsey, S. G., and Renn, C. L. (2015). The rat had historically been the preferred animal model for biomedical research due to genetic and physiological similarities to humans. Test-dependent variations in the antinociceptive effect of p-chloroamphetamine-induced release of 5-hydroxytryptamine. Pain research in animals. The first (1880-1950) was when mice and rats became common research animals. People who are at work and unable to answer the phone may have a different answer to the survey than people who are able to answer the phone in the afternoon. (2014). A simple and inexpensive method for determining cold sensitivity and adaptation in mice. Automated analysis of postoperative behaviour: assessment of HomeCageScan as a novel method to rapidly identify pain and analgesic effects in mice. doi: 10.1016/s0304-3959(96)03176-4, Yeomans, D. C., and Proudfit, H. K. (1994). (2000). The MouseMet or RatMet electronic Von Frey systems deliver a mechanical stimulus via a hand-held probe (Figure 1B). Lett. 13, 587599. Mice are cost effective because they are cheap and easy to look after. Also, after advances in gene targeting and gene editing, it is possible to specifically modify the rat genome to produce knockouts and knockins, further enhancing our understanding of human disease through the development of powerful customized CRISPR rat models. *Correspondence: Irina Vetter, i.vetter@uq.edu.au, View all In recent years mice have been used with increasing frequency, to take advantage of genetically modified lines as well as the relatively lower costs compared with rats. In addition, as for manual Von Frey tests, animals still need to be habituated to the cages until exploratory behaviors have ceased. Optimization of the mechanical nociceptive threshold testing with the Randall-Selitto assay. Painful and painless channelopathies. doi: 10.1111/j.1476-5381.2010.00873.x, Medhurst, S. J., Walker, K., Bowes, M., Kidd, B. L., Glatt, M., Muller, M., et al. Depending on the species and strain of rodent used, at least 12 different behaviors have been noted in the hot plate test, including sniffing, grooming, stamping of the legs, freezing, licking, leaning and jumping (Espejo and Mir, 1993). is defined as the deposition of in renal tissue, although a variety of additional terms are sometimes employed to reflect the localization of the mineral in the cortex, medulla, and so on. The assay is also capable of detecting side effects of analgesics, such as drowsiness, although it may be difficult to distinguish whether decreased burrowing arises from lack of efficacy or adverse effects unless additional behavioral tests or full dose-response curves are performed (Andrews et al., 2012). Cartil. As for the static hot plate test, cut off times should be carefully designed and strictly adhered to in order to avoid unnecessary nociceptive stimulation and tissue damage. Hyperalgesia and allodynia: peripheral mechanisms. (2016). The RatMet or MouseMet von Frey filament (0.3 and 0.5 mm tip diameter, delivering forces of 180 g and 0.17 g, respectively) is placed against the plantar surface of the paw and the force is linearly increased via rotation of the device handle (Deuis and Vetter, 2016). Some of the disadvantages of choosing a different animal model for these fields could be difficulty in collecting accurate data, comparing data from previous studies that used rat models, and drawing definitive conclusions that could apply to future studies. Pain 96, 129140. 25, 99111. Spared nerve injury: an animal model of persistent peripheral neuropathic pain. doi: 10.1016/s0304-3959(00)00307-9, Kim, S. H., and Chung, J. M. (1992). Influence of skin temperature on heat pain threshold in humans. 11, 821830. The Dynamic Plantar Aesthesiometer (or Plantar Von Frey), houses rodents in an enclosure with a mesh screen floor, under which a movable touch-stimulator unit is placed. Comparison of the antinociceptive action of and opioid receptor ligands in the periaqueductal gray matter, medial and paramedial ventral medulla in the rat as studied by the microinjection technique. The clinically translatability of the tail flick test is therefore unclear. doi: 10.1016/j.ejphar.2014.05.048, Jacobs, B. Y., Kloefkorn, H. E., and Allen, K. D. (2014). doi: 10.1371/journal.pone.0175839, Han, J. S., Bird, G. C., Li, W., Jones, J., and Neugebauer, V. (2005). Twitter Quantitative sensory testing in the german research network on neuropathic pain (DFNS): standardized protocol and reference values. 43, 244258. An animal model of oxaliplatin-induced cold allodynia reveals a crucial role for Nav1.6 in peripheral pain pathways. An overview of animal models of pain: disease models and outcome measures. Dynamic weight bearing is an efficient and predictable method for evaluation of arthritic nociception and its pathophysiological mechanisms in mice. In terms of the diseases that they are used to study, rats are usually not the model of choice when it comes to disorders related to neoplasms, blood and immune function. doi: 10.1038/nature05910, Bennett, D. L., and Woods, C. G. (2014). Some of the disadvantages of choosing a different animal model for these fields could be difficulty in collecting accurate data, comparing data from previous studies that used rat models, and drawing definitive conclusions that could apply to future studies. doi: 10.1016/j.ejpain.2004.10.006, Wibbenmeyer, L., Sevier, A., Liao, J., Williams, I., Latenser, B., Lewis, R., et al. Lancet 383(9924): 1240-9. 4:165. doi: 10.3389/fnbeh.2010.00165, Kayser, V., and Christensen, D. (2000). Sampling errors can significantly affect the precision and interpretation of the results, which can in turn lead to high costs for businesses or government agencies, or harm to populations of people or living organisms being studied. Thus, pain is an experience that encompasses both sensory and emotional components; therefore the term pain is not interchangeable with nociception. In the Mouse Grimace Scale (Figure 6A), five facial features are scored: orbital tightening, nose bulge, cheek bulge, ear position, and whisker position (Langford et al., 2010). However mice are less likely to survive the hypoxia-ischemia procedure, display a wider variety of brain damage, and have dramatic strain-to-strain differences. While the Randall-Selitto test often results in similar types of outcomes to the Von Frey filament tests (Santos-Nogueira et al., 2012), the mechanical stimulation differs fundamentally from Von Frey filaments, which may also activate low-threshold mechanoreceptors in addition to nociceptors. Researchers choose rats over other species for a number of reasons: Lett. Stimulus-evoked pain is described as either hyperalgesia or allodynia, and is further subdivided on the basis of the evoked stimulus modality (e.g., mechanical, heat, cold, chemical; Woolf and Mannion, 1999). One way to evaluate nociception in non-communicating subjects is through observation of behavior. If the response rate is 40% or more (i.e., withdrawal response is elicited in two or more out of five applications) testing stops and the force of the last von Frey filament is designated as the mechanical withdrawal threshold (in this case 2 grams-force). Stimulus-independent or spontaneous pain may be paroxysmal (sudden and severe) or continuous, and can be described as aching, cramping, crushing, shooting and burning (Jensen et al., 2001). The device automatically records the temperature that paw withdrawal occurred (in this case 50C). Researchers and scientists conducting surveys and performing experiments must adhere to certain procedural guidelines and rules in order to insure accuracy by avoiding sampling errors such as large variability, bias or undercoverage. 14:14. doi: 10.1186/1471-2474-14-14, Pertovaara, A., Kauppila, T., and Hmlinen, M. M. (1996). Physiol. Simmons is a student in the Kenan-Flagler Business School at the University of North Carolina at Chapel Hill. 406, 128132. Rodents are restrained and a focused beam of light is applied to tail. Although animal research may have ethical concerns, the US has regulated its practice since 1966. (1974). Differentiating thermal allodynia and hyperalgesia using dynamic hot and cold plate in rodents. doi: 10.1016/0304-3959(94)90090-6, Carter, R. B. Arthritis Rheum. In the conventional hot plate test, an unrestrained mouse or rat is placed on a metal surface maintained at a constant temperature, usually between 50C and 55C, and the response latency, which is the time taken to observe a nocifensive behavior, is recorded by the investigator (Figure 3B). Electronic Von Frey systems operate under similar principles as manual von Frey, except that a single, un-bending filament is applied with increasing force until a paw withdrawal response is elicited. The Practical Mouse Despite the advantages rats have over mice as human analogs, mice have dominated the modern genetic and biomedical research landscape. These neurons are pseudo-unipolar, with a peripheral branch that terminates in the skin or viscera and a central branch that terminates in the spinal cord. 101, 132143. J. Neurosci. In line with this, the uptake of grimace scales to study pain in the scientific community has been low, with approximately 30 studies published using the method in rodents since its introduction by Langford et al. Rodents are placed individually in a small cage with a barred floor. doi: 10.1523/JNEUROSCI.1526-05.2005, Schtt, E., Berge, O. G., Angeby-Mller, K., Hammarstrm, G., Dalsgaard, C. J., and Brodin, E. (1994). It should be noted that no test can therefore measure pain in animals directlythe presumably unpleasant emotional experience of pain is inferred from pain-like behaviors which can include the withdrawal of a body part from a stimulus, reduced ambulation, agitation, an increase in grooming of the affected area, and vocalizations upon sensory stimulation. For an overview of commonly used pain models in rodents see Gregory et al. The CatWalk method: assessment of mechanical allodynia in experimental chronic pain. Cartil. (1989). Reaction thresholds to pressure in edematous hindpaws of rats and responses to analgesic drugs. The device automatically records the force at which paw withdrawal occurs and the rate at which the force is applied can be changed. This alleviates the mosaicism common with targeting embryos, allowing for the production of specifically targeted germline rats in as little as 3 months. The advantage of this approach is that each animal receives the same number and type of stimuli, although the number of tests per hind paw could exceed 50 (e.g., five different von Frey filaments each applied 10 times), which is not only time consuming, but potentially exposes animals with mechanical hind paw sensitivity to a disproportionate number of more aversive stimuli. J. Chem. doi: 10.1097/NNR.0000000000000082, Gritsch, S., Bali, K. K., Kuner, R., and Vardeh, D. (2016). J. Neurosci. A monofilament is applied perpendicularly to the plantar surface of the hind paw until it buckles, delivering a constant pre-determined force (typically 0.213.7 mN for mice and 5.998 mN for rats) for 25 s (Figure 1A). Rep. 5:14648. doi: 10.1038/srep14648. doi: 10.1016/0304-3959(88)90026-7, Harvey, V. L., and Dickenson, A. H. (2009). The U.S. Department of Agriculture (USDA) does compile annual statistics on some animals used in . Then there is the Sprague Dawley, an outbred albino preferred for behavioral studies. The increasing-temperature hot-plate test: an improved test of nociception in mice and rats. The thermal probe test (MouseMet Thermal, Topcat Metrology) is a novel method recently described to quantify heat thresholds in mice (Deuis and Vetter, 2016). Woolf, C. J., and Mannion, R. J. Most of the animals needed for medical and scientific inquiry in the U.S. are rodents (for example, rats and mice), and they are specifically bred for this purpose. Exp. While the underlying principle of the temperature gradient assay is similar to the two-temperature choice assay, the animal is free to explore along the gradient (usually between 4C and 65C over a length of 120 cm) until they settle within their preferred temperature or comfort zone. Eur. Temperature 3, 7791. [ 120] B., and Hole, K. (1985). Nat. Rep. 7:40883. doi: 10.1038/srep40883, Deuis, J. R., Yin, K., Cooper, M. A., Schroder, K., and Vetter, I. A response is considered positive if the animal exhibits any nocifensive behaviors, including brisk paw withdrawal, licking, or shaking of the paw, either during application of the stimulus or immediately after the filament is removed. 16, 13241332. Front Neurol 7: 57. Toxicol. The temperature at which this occurs is designated as the response temperature (Ogren and Berge, 1984; Tjolsen et al., 1991). PLoS One 10:e0125822. doi: 10.1016/s0304-3959(96)03177-6, Yin, K., Deuis, J. R., Lewis, R. J., and Vetter, I. Sci. doi: 10.1038/nprot.2006.19, Decosterd, I., and Woolf, C. J. The tail flick test, first described in 1941, involves application of a heat stimulus to the tail of mice and rats, and the time taken for the tail to flick or twitch is recorded (DAmour and Smith, 1941; Figure 3A). Both the mouse and rat grimace scale are limited by the need for extensive training of the observer and a degree of subjectivity, which could lead to variability. The dynamic weight-bearing test is able to detect reduced weight bearing behaviors of the affected hind limb in multiple pain models, including CFA-induced inflammation, chronic constriction injury, bone cancer pain and antigen-induced arthritis (Tetreault et al., 2011; Robinson et al., 2012; Quadros et al., 2015). (1988). While several systems are commercially available, the Dynamic Plantar Aesthesiometer (Ugo Basile) and MouseMet or RatMet (TopCat Metrology) are particularly robust and user-friendly systems. Role of the NLRP3 inflammasome in a model of acute burn-induced pain. The Hargreaves test permits measurement of ipsilateral and contralateral heat thresholds, allowing each animal to serve as its own internal control in unilateral pain models. Hyperalgesia is defined as an increased or exaggerated pain response to a normally noxious stimulus, while allodynia is defined as a painful response to a normally non-noxious or innocuous stimulus. Therefore, there is an urgent need to increase our understanding of the underlying mechanisms of pain and to develop new treatments. Rat ES cells are very unstable, with any disturbance leading them to activate, so that they could not be implanted in an embryo and brought to term. The three Rs are: Reduction, Refinement, Replacement.. Neurosci. doi: 10.1016/j.jbspin.2004.01.010, Cox, J. J., Reimann, F., Nicholas, A. K., Thornton, G., Roberts, E., Springell, K., et al. It is a low-cost, single-use product made from sterilized quarry sand and treated with a hydrophobic coating. Scientists often cite the similarities between animals and humans as the rationale for animal experimentation. doi: 10.1021/je00019a016, Viscardi, A. V., Hunniford, M., Lawlis, P., Leach, M., and Turner, P. V. (2017). The time spent on the test plate relative to the reference plate is measured over a set period of time. Ultrasonic sound as an indicator of acute pain in laboratory mice. Attenuated cold sensitivity in TRPM8 null mice. As each researcher cultivates a slightly different cut off point in their minds as to what constitutes a behavior on this spectrum, results can vary significantly between laboratories. Rodents are allowed to freely move between a reference plate (neutral temperature) and test plate. doi: 10.1523/JNEUROSCI.2203-07.2007, Yalcin, I., Charlet, A., Freund-Mercier, M. J., Barrot, M., and Poisbeau, P. (2009). Diabetes Res. While rats tend the habituate quickly (<15 min), mice can take up to an hour or more to settle in the cage before testing can begin, which can be time consuming (Chaplan et al., 1994; Minett et al., 2011). This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). Neurosci. 10:284. doi: 10.3389/fnmol.2017.00284. Stimulus-evoked methods, which include manual and electronic von Frey, Randall-Selitto and the Hargreaves test, were the first to be developed and continue to be in widespread use. To address this, a modified Hargreaves test has been reported, that utilizes a feedback-controlled radiant heat source to apply a constant temperature to the hind paw. Burrowing behavior as an indicator of post-laparotomy pain in mice. Mouse Biol. 1. Boehmerle, W., Huehnchen, P., Peruzzaro, S., Balkaya, M., and Endres, M. (2014). doi: 10.1016/0304-3940(88)90497-1. Br. doi: 10.1038/nrn2606, Moqrich, A., Hwang, S. W., Earley, T. J., Petrus, M. J., Murray, A. N., Spencer, K. S., et al. Behav. Its characterized primarily by motor impairment, but there are also a range of accompanying conditions such as seizure disorders and cognitive defects. doi: 10.1111/pme.12230, Dalla Costa, E., Stucke, D., Dai, F., Minero, M., Leach, M. C., and Lebelt, D. (2016). This normally protective response, which is absent in these individuals, leads to frequent injuries and often results in higher mortality rates early in life (Bennett and Woods, 2014). (2005). Under the direction of the researcher, the apparatus applies a von Frey (0.5 mm) filament to the plantar surface, increasing the force incrementally (050 g) until the paw withdrawal threshold is reached. Stimulus-evoked pain can be evaluated in humans using quantitative sensory testing. Assoc. Ann Neurol 9(2): 131-41. It remains to be determined whether pain behavior outcomes obtained using gait and weight-bearing analysis will translate more (or less) readily to the clinic compared to stimulus-evoked methods. Pain 12:1744806916629049. doi: 10.1177/1744806916629049, Guilford, B. L., Ryals, J. M., and Wright, D. E. (2011). A disadvantage of this method is that the number of measurements per animal is variable and that it requires repeated, time-intensive measurements, which may lead to sensitization or learnt responses. Interested in using rats for your next research project? Cooling of the glass leads to unilateral exposure of the hind paws to a cooled surface, the temperature of which can be determined by attaching a thermocouple probe to the glass or skin. 738, 111117. Unlike the hot plate test, the cold plate test is particularly useful for models where only one paw is affected or sensitized by the experimental compound (unilateral pain) as guarding of the affected limb can be easily achieved, and thus can be easily quantified. In addition to burrowing, other spontaneous behaviors can be assessed, including nesting construction and food hoarding (Deacon, 2006a; Rock et al., 2014). 130, 117122. A caveat is, however, that no pain-specific behaviors are captured, leading to potential interference from drug or phenotype effects that could mask nociception, or anti-nociception. doi: 10.1016/j.joca.2015.05.001, Buys, M. J., and Alphonso, C. (2014). J. Neurosci. Monkeys, rabbits, cats, ferrets, pigs, sheep and chimpanzees are just some of the animals used for biomedical experiments, science education, and product and cosmetics testing. Brain Res. Colver A, Fairhurst C, Pharoah PO. Facebook A wide variety of other species make up the remaining 4%, from . 524, 107110. doi: 10.1016/j.jpain.2009.01.325, Yamamoto, K., Tsuboi, M., Kambe, T., Abe, K., Nakatani, Y., Kawakami, K., et al. doi: 10.1590/s0100-879x2006001200013, Gregory, N. S., Harris, A. L., Robinson, C. R., Dougherty, P. M., Fuchs, P. N., and Sluka, K. A. ILAR J. For example, paw licking is diminished by opioids but not other analgesics, while other behaviors can also be affected by other classes of analgesics (Ankier, 1974; Hunskaar et al., 1985). Effects of morphine on thermal sensitivity in adult and aged rats. Ther. (1991). The Randall-Selitto test can be performed using bench-top (e.g., Analgesy-Meter, Ugo Basile; Paw and Tail Pressure Meter; Harvard Apparatus) or hand-held devices (e.g., Paw Pressure Test Apparatus, IITC) with animals either restrained in a hammock that provides access to the hind paws, a towel, or in a plastic cone or cylinder. An experimental model for peripheral neuropathy produced by segmental spinal nerve ligation in the rat. doi: 10.1523/JNEUROSCI.0122-10.2010, Ltsch, J., Dimova, V., Lieb, I., Zimmermann, M., Oertel, B. G., and Ultsch, A. The framework for these standards and guidelines are based on the principles of the 3Rs (replacement, reduction, refinement).