Laboratory Animals最新文献

A retrospective comparison of welfare indicators in male rats undergoing thoracotomy for intrapleural dosing is presented. The initial cohort (n = 7) breathed room air after recovery from anaesthesia, while later cohorts (n = 12) had oxygen supplementation for up to 48 h post-surgery. Rats breathing room air sustained a statistically significant average body-weight loss of -1.62% (±1.7%) 2 days after surgery, compared with rats given oxygen supplementation, which maintained a mean weight gain of 0.87% (±1.75%) (p = 0.009). Oxygen-supplemented rats also had lower pain scores on the evening after surgery (median 0.075 [range 0-1.75] vs. median 1.5 [range 0.5-2]). This difference was not statistically significant (p = 0.063) but may be of clinical significance. All rats displayed transient sedation after post-operative opioid administration on the day of surgery, and hypoxaemia (SpO₂ <90%) was observed in rats maintained on room air. Use of an oxygen concentrator to provide post-operative extended oxygen supplementation was easy to implement and may improve animal welfare post-thoracotomy.

Animal care and use personnel in research laboratory facilities are inherently exposed to a variety of workplace hazards. The health and safety of the workforce working directly with or around research animals is of paramount importance, and as such, an occupational health and safety program for at-risk staff is essential. In order to maximize participation in and the effectiveness of health and safety training and occupational health program enrollment for animal care and use personnel at an academic health sciences university, an innovative annual "health fair" was developed and implemented at The University of Texas Health Science Center at Houston. This event allows personnel working in positions that present exposure risk to research animals to be able to obtain hazard-specific health and safety training, re-enroll in the occupational health oversight program and update their medical history, and participate in the institution's other safety programs as required by job title or assigned job tasks. By providing a comprehensive health fair that offers convenient access to the necessary safety training and occupational health services in one location during a designated period of time, management and staff are incentivized to participate and have reported satisfaction with and appreciation of the convenient access. Summarized here is how we plan, organize, and effectively execute the annual health fair so that other institutions who might wish to use this strategy can learn from our approach.

For over a decade, the non-publication of negative results from preclinical studies has been identified as a significant concern in biomedical research. Such underreporting is considered a contributor to the reproducibility crisis in the field and has been recognized by significant journals such as Science and Nature. In response to the consistently high non-publication rates of preclinical animal research in Europe, a survey was conducted among the biomedical research community to gather their views on publishing negative results. Using the EUSurvey platform, over 200 researchers directly working with animals were surveyed. The study aimed to understand the frequency of negative results, the reasons behind their non-publication, and the perceived pros and cons of making such results public. Insights from the survey could guide steps toward promoting transparency in science, refining research methodologies, reducing animal usage in experiments and minimizing research waste.

Three seven-year-old African clawed frogs (Xenopus laevis) from an animal research facility showed weight loss, coelomic distention and an abnormal swimming gait were euthanised on welfare grounds. A complete necropsy of each animal showed a focal, firm, dark brown to green mass with multifocal haemorrhages in the left liver lobe in two animals and a transmural, firm, beige, multilobulated gastric mass in another animal. Additionally, one of the frogs with the hepatic mass had haemocoeloma. Histologically, the hepatic masses were diagnosed as hepatocellular adenomas and the gastric mass as a gastric carcinoma with trans-coelomic metastases. The three tumours were immunophenotyped using the following antibodies: cytokeratin AE1/AE3, vimentin, E-cadherin, P53 and Ki67 and, additionally, for the hepatic tumours only, synaptophysin, Prox-1, S100 and Sox-9. Masson's trichrome, Periodic acid Schiff and Gram stains was also performed in selected cases. One of the hepatocellular adenomas was weakly positively labelled with E-cadherin whereas the other showed variable positivity for Sox-9 only. Vimentin labelled the stroma and sinusoidal endothelia. Interestingly in the liver, the cytokeratin AE1/AE3 labelling was restricted to the biliary epithelium and sinusoidal endothelia. The gastric carcinoma labelled positively with cytokeratin AE1/AE3 only. This report aims to guide laboratory animal veterinarians to accurately diagnose multi-organ masses in amphibians. To the authors' knowledge, this is the first comprehensive morphological study on a case series of hepatocellular and gastric neoplasia in X. laevis.

Inbred mouse strains have long proved useful as tools for biomedical research. They remove the effects of genetic background as an experimental variable. Within all mouse colonies, genetic drift is a recognised phenomenon and monitoring and documenting changes is important for experimental design and consistency. This communication documents the initial characterisation through SNP analysis of the inbred mouse strains bred and used at the time at the Medical Research Council National Institute for Medical Research (MRC-NIMR), Mill Hill, now The Crick Institute. These inbred strains were part of the foundation colonies for the many genetically modified mouse strains made at Mill Hill. We found small genetic changes in four of the nine inbred strains. Although phenotypic differences have not yet been found between the NIMR and the correspondent parental strains, I cannot discard that these may arise or have already arisen. This work has also authenticated the 129/SvJEvNimr-Gpi1^c strain that was widely used at MRC-NIMR for gene targeting. All these inbred strains have been renamed according to The International Committee on Standardized Genetic Nomenclature for Mice.

Obtaining sufficient blood volume from mice significantly facilitates experimental research. This study explored the inferior vena cava puncture under continuous cardiac perfusion (IVCP-UCCP) technique and evaluated its efficiency in comparison with conventional cardiac puncture (CP). In an initial dose-finding study, 50 mice were randomly assigned to one of 10 groups with escalating perfusion volume from 0.5 to 4.5 ml in 0.5-ml increments. The minimum perfusion volume was determined to be 2 ml in collecting whole circulating blood. In the next comparison using the conventional method, 40 mice were randomly assigned to one of two groups denoting different blood collection methods: Group 1: CP, Group 2: IVCP-UCCP. The results showed 1) that the cells and undiluted blood volume collected via IVCP-UCCP was over twofold higher than that by CP (p < 0.001), confirmed by the cell counts and hematoxylin-eosin staining of different tissues slides (p < 0.001); 2) the new technique did not alter the cellular composition or viability, which was verified by routine blood tests and flow cytometry (p > 0.05); 3) the blood collected via the novel technique was diluted 2.1 times: the hemato-biochemical indicator results multiplied by 2.1 were identical with the test results of blood from CP (p > 0.05). Together, the refined blood collection method of IVCP-UCCP completely extracted the limited blood resources in mice, significantly enhanced the utilization of each mouse, and thus offered scientific and ethical benefits. This technique may be also applicable for other small animal models.

The strategy of centralizing equipment sanitation and processing was developed by a top-tier public university to address the growing physical infrastructure and human resource challenges of its expanding in-vivo research enterprise. Subsequently, a center for automated equipment processing physically separate from all animal research facilities was developed and has operated consistently since 2016. The facility incorporates systems such as process automation to sanitize and sterilize equipment as efficiently as possible. Analysis of the differences between the new centralized and old distributed research enterprise configurations shows a total estimated fiscal benefit of almost US$54 m to date projected out to US$124 m through 2028. Utility consumption of operations over nine years in the new configuration was estimated to be decreased by over 125 million gallons of water, 14 million gallons of chilled water, 121 million pounds of steam, and almost 3.6 million kilowatts of electricity, with consumption savings significantly increased projected out to 2028. Additional operational and organizational benefits as well as direct research benefits were identified. The new configuration has functioned for nine years without detectable cross contamination within the research enterprise thus providing evidence that the location of equipment processing can be less of a "microbial" risk factor than previously attributed.

Facilities involved in laboratory animal research often face ethical challenges such as: what should I do with the animals that are no longer suitable for experimental purposes? One of the common answers to this question is to kill them. And while numerous scientifically justifiable reasons exist for killing laboratory animals, we must not overlook our ethical responsibility towards these sentient beings. Animal facility managers and scientists frequently find themselves in a moral dilemma, torn between furthering their research and addressing the well-being of experimental animals required for their studies. We elaborated a concept consisting of six decision trees and recommendations for making informed decisions about the need to kill laboratory animals in research facilities, considering legal and ethical considerations. The concept is based on the German regulatory perspective. However, the measures and decisions for animal welfare can be implemented in all laboratory animal facilities. These recommendations suggest several courses of action, including implementing consistent breeding plans, exploring alternative uses, reassigning surplus animals and their organs, and establishing appropriate housing capacity limits that ensure species-appropriate care. We encourage scientists and animal facility managers to develop and implement decision-making frameworks and procedures tailored to their specific facilities, in the hope that this work will promote a thoughtful and responsible approach to the complex challenges associated with the killing of laboratory animals, advancing scientific progress and the humane treatment of these animals.

Isoflurane anesthesia prior to carbon dioxide euthanasia is recognized as a refinement by many guidelines. Facilities lacking access to a vaporizer can use the "drop" method, whereby liquid anesthetic is introduced into an induction chamber. Knowing the least aversive concentration of isoflurane is critical. Previous work has demonstrated that isoflurane administered with the drop method at a concentration of 5% is aversive to mice. Other work has shown that lower concentrations (1.7% to 3.7%) of isoflurane can be used to anesthetize mice with the drop method, but aversion to these concentrations has not been tested. We assessed aversion to these lower isoflurane concentrations administered with the drop method, using a conditioned place aversion (CPA) paradigm. Female C57BL/6J (OT-1) mice (n = 28) were randomly allocated to one of three isoflurane concentrations: 1.7%, 2.7%, and 3.7%. Mice were acclimated to a light-dark apparatus. Prior to and following dark (+ isoflurane) and light chamber conditioning sessions, mice underwent an initial and final preference assessment; the change in the duration spent within the dark chamber between the initial and final preference tests was used to calculate a CPA score. Aversion increased with increasing isoflurane concentration: from 1.7% to 2.7% to 3.7% isoflurane, mean ± SE CPA score decreased from 19.6 ± 20.1 s to -25.6 ± 23.2 s, to -116.9 ± 30.6 s (F_1,54 = 15.4, p < 0.001). Our results suggest that, when using the drop method to administer isoflurane, concentrations between 1.7% and 2.7% can be used to minimize female mouse aversion to induction.

Cage effects: some researchers worry about them, some don't, and some aren't even aware of them. When statistical analyses do not account for cage effects, there is real reason to worry. Regardless of researchers' worries or lack thereof, all researchers should be aware of how cage effects can affect the results. The "how" depends, in part, on the experimental design. Here, I (a) define cage effects; (b) illustrate a completely randomized design (CRD) often used in animal experiments; (c) explain how statistical significance is artificially inflated when cage effects are ignored and (d) give guidance on proper analyses and on how to increase statistical power in CRDs.