(C) The percent response method. Unfortunately, many introductory . Address: 2200 Smithtown Avenue This sample - and the results - are biased, as most workers are at their jobs during these hours. Exp. J. Neurosci. Despite the development of electronic Von Frey tests, manual Von Frey remains the gold standard for determining mechanical thresholds in mice. Use of dynamic weight bearing as a novel end-point for the assessment of Freunds Complete Adjuvant induced hypersensitivity in mice. Behav. The up-down Von Frey method is used to determine the mechanical force required to elicit a paw withdrawal response in 50% of animals, based on the statistical formula used to determine LD50s (Dixon, 1980; Chaplan et al., 1994). The three Rs are a set of principles that scientists are encouraged to follow in order to reduce the impact of research on animals. The clinically translatability of the tail flick test is therefore unclear. 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). Facial expressions of mice can be used to score the subjective intensity of pain. Rodents are allowed to freely move between a reference plate (neutral temperature) and test plate. 15, 6172. Alternatively, voluntary response bias occurs when only a small number of non-representative subjects have the opportunity to participate in the survey, usually because they are the only ones who know about it. doi: 10.1093/gerona/glr210, OBrien, D. E., Brenner, D. S., Gutmann, D. H., and Gereau, R. W. IV (2013). (D) Thermal probe test. 2023 Leaf Group Ltd. / Leaf Group Media, All Rights Reserved. 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. Mol. doi: 10.1016/S1474-4422(10)70143-5, Bautista, D. M., Siemens, J., Glazer, J. M., Tsuruda, P. R., Basbaum, A. I., Stucky, C. L., et al. Figure 4.Methods used to assess cold-evoked pain like behaviors and temperature preference in rodents. A Biol. Pain 47, 211220. Ther. J. Pharmacol. Osteoarthr. Prior to the development of automated digitized platforms, this test was performed by coloring the animals paws with ink; the animal was then allowed to walk freely on a paper, which could be scanned for analysis (Ishikawa et al., 2014). For instance, if you are conducting a survey on whether a certain kitchen cleaner is preferred over another brand, then you should survey a large number of people who use kitchen cleaners. Similarities in pain descriptions of four different ethnic-culture groups. 4:165. doi: 10.3389/fnbeh.2010.00165, Kayser, V., and Christensen, D. (2000). A survey posted only on its website limits the number of people who will participate to those who already had an interest in their products, which causes a voluntary response bias. 372, 301312. The behavioral methods used to measure nociception in rodents can be divided into stimulus-evoked (and further subdivided by the stimulus modalitymechanical, heat, cold) and non-stimulus evoked, with the most commonly used methods discussed in this review article. Pain 154, 17491757. Methods Mol. Osteoarthr. Rat models are therefore still widely used. 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 Rat Grimace Scale is also scored 02 depending on observed changes in facial features, and evaluates the extent of orbital tightening, nose/cheek flattening, ear change and whisker change (Sotocinal et al., 2011). In this model, the lateral plantar skin of the hind paw, which is the area of innervation of the sural nerve, has the greatest reduction in mechanical thresholds compared to other innervation areas of the plantar skin (Decosterd and Woolf, 2000). 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). Lancet Neurol. Typically, the experimental setup consists of a test plate at a fixed temperature (usually between 5C and 55C) that is placed adjacent to a reference plate at neutral temperature (usually between 25C and 30C; Figure 5A). The force ramp and paw withdrawal force are displayed by the software post-test. Eur. doi: 10.1016/0024-3205(85)90227-9. Mechanical hyperalgesia and allodynia can be further subdivided into dynamic (triggered by brushing), punctate (triggered by touch) and static (triggered by pressure). (A) The up-down method. The Kantian view denies moral value to animals because they lack reason. 25, 99111. A., Possani, L. D., Cabot, P. J., Lewis, R. J., et al. doi: 10.1007/bf00230429, Petrus, M., Peier, A. M., Bandell, M., Hwang, S. W., Huynh, T., Olney, N., et al. Toxicol. This raises a moral issue in animal experimentation. Weight bearing as an objective measure of arthritic pain in the rat. Figure 2.Visual representation of the different methodological approaches used to determine mechanical sensitivity using manual Von Frey. 10 Major Disadvantages of Technology [2022 Technology Disadvantages So far, no single behavioral assay can capture the full spectrum of nociception in non-communicating subjects. The outcomes of most behavioral methods used to study nociception are somewhat subjective. J. doi: 10.1016/s1474-4422(14)70102-4, Jensen, T. S., Gottrup, H., Sindrup, S. H., and Bach, F. W. (2001). J. Pharmacol. 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. Rodents are placed individually in small enclosures with a glass floor. Anim. The principles that apply to mice generally apply to rats and other laboratory rodents, but species-specific differences in behaviour and size alter the specifics of handling procedures that work well in each species. Abstract The laboratory rat was the first mammal domesticated for research purposes. An extinct rat shows CRISPR's limits for resurrecting species However, rodents do not vocalize in the audible range unless the pain is severe, making use vocalization as an endpoint ethically limited (Mogil, 2009). The same methods that allow this to be so in mice have failed in rats. If an individual is on a company's website, then it is likely that he supports the company; he may, for example, be looking for coupons or promotions from that manufacturer. Third, aversive response to a cooling ramp can be used to determine the cold response threshold (Yalcin et al., 2009). doi: 10.1016/0166-4328(93)90035-o, Festing, M. F., and Altman, D. G. (2002). Pain 12:1744806916665366. doi: 10.1177/1744806916665366, Yoburn, B. C., Morales, R., Kelly, D. D., and Inturrisi, C. E. (1984). It is an estimate, as the force applied by manual von Frey filaments can only be applied in discrete steps, and not continuously like electronic von Frey (see below). A wide variety of other species make up the remaining 4%, from . Nose bulge refers to the bulge noticeable on the bridge of the nose, whereas cheek bulge refers to the rounded projection of the cheek muscle compared to its typical appearance. In this experiment, a previously unafraid baby was conditioned to become afraid of a rat. If there is no response, the next filament with a higher force is tested; if there is a response, the next lower force filament is tested. doi: 10.1097/NNR.0000000000000082, Gritsch, S., Bali, K. K., Kuner, R., and Vardeh, D. (2016). This work was supported by an Australian Research Council Future Fellowship (IV). However, with the use of animal models come challenges relating to the appropriate quantification of behavioral responses that could be considered equivalent to pain in humans. With the sequencing of the Brown Norway rat in 2004 by the Rat Genome Sequencing Project Consortium, led by the Baylor College of Medicine, it is now known that almost all disease-linked human genes have counterparts in the rat. doi: 10.1016/j.pain.2013.05.032, Dixon, W. J. Response latencies in the tail-flick test depend on tail skin temperature. Assoc. The sheep grimace scale as an indicator of post-operative distress and pain in laboratory sheep. 6, 17511758. As altered weight bearing can be a major symptom of human pain conditions, these tests were developed to improve translation of rodent nociception models to the clinic. Pain 7:55. doi: 10.1186/1744-8069-7-55, Tappe-Theodor, A., and Kuner, R. (2014). This problem can be overcome by restraining the rodent and only placing the plantar surface of a one hind paw on the metal surface and recording the time to withdrawal, however this method requires significant handling and associated stress (Menndez et al., 2002). 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). Ther. The software records the duration of different behavior types, including movement, grooming and rearing behaviors. doi: 10.1213/01.ane.0000158471.41575.f0, Vriens, J., Owsianik, G., Hofmann, T., Philipp, S. E., Stab, J., Chen, X., et al. This therefore provides measure of paw withdrawal threshold on a continual scale, as the force is applied continuously and not in steps. The ascending stimulus method provides an estimate of the mechanical withdrawal threshold. Animal Testing | Pros & Cons | ProCon.org (2005). 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. Rodents are placed in an enclosed box with a camera, accelerometer and wall-mounted photobeams for a set period of time. But the missing genes signal a problem for using gene editing to de-extinct species. Ann. Mouse Biol. doi: 10.1080/23328940.2015.1135689, Vazquez, G., Alvarez, E., and Navaza, J. M. (1995). Eur. Research scientists worldwide agree that the use of rat models for disease research and experimentation has become more relevant in the past few years. There are protections in place for the animals. 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. 429, 111. The biggest challenge of temperature preference tests is choosing the optimal temperature pairs, so that preference for one side is either exaggerated or overcome in experimental animals compared with control animals. Similarly, the terms nociception and pain are often used interchangeably, although the term pain is rarely appropriate to use in reference to animal studies. J. doi: 10.1016/j.pain.2013.06.015, Keywords: pain, rodent, hyperalgesia, allodynia, spontaneous pain, mechanical, heat, cold, Citation: Deuis JR, Dvorakova LS and Vetter I (2017) Methods Used to Evaluate Pain Behaviors in Rodents. Methods 255, 92103. The clinical picture of neuropathic pain. 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. Appreciation that the human pain experience encompasses multiple stimulus modalities, distinct molecular mechanisms and sensory, motor, vegetative, emotional, motivational components should highlight the need for carefully designed experiments that take this complexity into consideration. A disadvantage of systems that only use video recordings (e.g., DigiGait, GaitScan/TreadScan) is that they cannot measure paw print intensity or pressure (weight bearing parameters), which is relevant for pain models. ACS Chem. Nature 444, 894898. Electrophysiological, behavioral and histological characterization of paclitaxel, cisplatin, vincristine and bortezomib-induced neuropathy in C57Bl/6 mice. Clin. However, concerns over the clinical translatability of stimulus-evoked nociception in recent years has led to the development and increasing implementation of non-stimulus evoked methods, such as grimace scales, burrowing, weight bearing and gait analysis. It should be noted that rather than flinching or licking, some rat strains tend to simply avoid weight bearing on the affected paw or reposition their stance to minimize contact with the cool surface, so all observation should be adapted to the specific model animal. 1. In the past, housing of rodents used for research was designed primarily to prevent Development of the Rodent Face Finder, which captures stills of rodent faces that a researcher then scores according to the relevant scale, has automated some of the experimental process (Sotocinal et al., 2011) albeit development of automatic facial expression scoring will make this approach even more widely useful.