Laboratory Animals最新文献

Transcranial direct current stimulation (tDCS) for painless, non-invasive brain stimulation is a promising approach to enhance recovery after stroke. However, the precise molecular and cellular mechanisms underlying the effects of tDCS remain unclear, impeding its use in humans and necessitating research in experimental animals. Unlike humans, who receive tDCS fully awake, experimental models of tDCS have so far been conducted under anaesthesia to ensure the immobility required by currently available experimental setups. The use of anaesthesia may, however, confound results, decreasing their translational value. To address this problem, we developed a refined method enabling tDCS in awake and freely moving mice. A tube attached to the skull contains the stimulation electrode, whose position can be adapted flexibly to the target brain region; the reference electrode is implanted subcutaneously at the contralateral chest. Here, we report n = 135 awake mice that underwent tDCS in their home cage for up to 15 minutes per session over 10 consecutive days. None of those animals showed any adverse effects, neither regarding their general wellbeing, body weight, and behavioural activity, nor in ex vivo histology and immunohistochemistry. We suggest using this refined approach in future experimental studies of neuropsychological disorders.

No systematic procedures exist to ensure that differences in animal sensory capacities are accounted for in experimental design and ethical review processes. This oversight can compromise both scientific validity and animal welfare. This review presents three practical methodologies to address this gap: incorporation of specialist expertise through consultation frameworks, voluntary certification schemes modeled on Open Science practices, and mandatory sensory capacity review integrated into existing ethics committee processes. We provide a concrete tool-a sensory modality survey-that can be implemented by institutional review committees to evaluate sensory considerations in research proposals systematically. These approaches align with the 3Rs principles by enhancing experimental refinement and potentially reducing animal use through improved study design.

Antimicrobial resistance (AMR) is a major global threat to human health, animal welfare and sustainable development. Whilst resistance can arise naturally, inappropriate antimicrobial exposure accelerates its emergence. Recognizing this risk, international One Health initiatives emphasize reducing antimicrobial use, especially of drugs considered critical for human medicine. Much of the evidence guiding these efforts comes from food-producing and companion animals, but antimicrobial use in laboratory animals, particularly rodents, remains poorly described. To address this gap, we surveyed all veterinarians certified by the American College of Laboratory Animal Medicine in the United States (921) and Canada (10). A total of 157 veterinarians completed the survey, resulting in a 16.9% overall response rate. The response rate was 16.6% for participants in the United States and 40.0% for those in Canada. Despite a strong response, the small number of eligible veterinarians restricts data extrapolation in the Canadian context. Survey results showed that antimicrobial use is common and routine in rodent vivaria. Overall, 91.7% of respondents reported regular antimicrobial use. Applications included both clinical treatment and research purposes such as induction of microbiome dysbiosis, prophylaxis in immunocompromised rodents and gene induction. Reported drug classes included fluoroquinolones and third-generation cephalosporins, with some use of glycopeptides and carbapenems, all considered critically important to human health. Disposal practices often involved release into sewerage or landfill without inactivation, raising environmental concerns. These findings suggest that antimicrobial use in laboratory rodents may represent an underrecognized contributor to AMR and highlight the importance of targeted stewardship.

A continuing professional development (CPD) process should be implemented in all organisations involved in animal research to ensure professionals stay up to date with scientific advancements, best practices and regulations regarding animal welfare and laboratory animal science. These recommendations advocate for a lean and transparent CPD process to maintain the competence of professionals performing functions, roles and tasks outlined in Directive 2010/63/EU throughout a professional's career. CPD starts after initial training and once individual competence has been achieved. The first step involves creating a CPD portfolio, which the 'Person(s) Responsible for Training and Competence' reviews regularly to ensure it aligns with the professional's personal development plan (PDP). A structured portfolio is proposed for tracking and assessing CPD activities, enabling monitoring. We recommend this monitoring in cycles of up to 5 years.This document discusses the various types and formats of CPD activities, the minimum CPD requirements for professionals and the essential information that CPD certificates should include. This will be pivotal when developing a common framework for assessing CPD activities across institutions. To conclude, a harmonised CPD strategy that incorporates planning and record-keeping will facilitate mutual recognition and mobility of personnel. Moreover, promoting high-quality CPD will help motivate and reward staff while fostering a culture of care.

The thyroid gland's proper function is essential for controlling the metabolism, which varies to some extent between the sexes, thus maintaining the homeostasis. This research aimed to investigate differences in the histological structure and number of mast cells in the thyroid gland of male and female rats, and to establish whether there is a correlation between the levels of thyroid-stimulating hormone (TSH) and the activation index (Ia), which quantifies the functional activity of the gland based on histological parameters. Thyroid glands of 20 Wistar rats were analyzed morphometrically and stereologically to determine follicle size, distribution, and volume density of the epithelium, colloid, and connective tissue. Male thyroid glands had more small and medium follicles and a higher volume density of epithelium, while female thyroid glands had more large follicles and a higher volume density of connective tissue. The volume density of colloid was not significantly different between the sexes. The histological structure of the thyroid glands in both groups was in accordance with the measured TSH levels. The correlation between TSH serum levels and Ia were established in both sexes. Both the TSH serum levels and Ia were lower in females compared to males. A higher number of mast cells was noted in the connective tissue of female thyroid glands, compared to those of males, but this difference was not significant. The results of this study indicate that there are differences in the histological structure of male and female rat thyroid glands and that Ia can be used as a reliable complementary parameter for assessment of thyroid gland function.

The EU Directive 2010/63 on the protection of animals used for scientific purposes, as well as the Swiss Animal Welfare Legislation, demand monitoring and documentation of specific aspects of an animal experiment, including welfare-related issues and the (retrospective) assessment of the severity of the procedures that the animals underwent. A score sheet is an efficient tool for the evaluation of the burden of an animal during an experiment and, if properly designed and used, helps adhere to the 3Rs principle. It must be adapted to the specifics of each experiment and explicitly conceived for it. Several score sheet examples have been published; however, some contain fundamental flaws or are designed for specific settings only, requiring modifications to fit other experimental designs. This paper suggests an eight-step procedure to design a score sheet that can be adapted to any animal species and experimental conditions.

An approximately 7.5-month-old female Sprague Dawley rat (Rattus norvegicus) housed in a research facility presented for skin lesions including multifocal crusting and hypotrichosis. On presentation the research rat was mildly underconditioned with a distended abdomen and later developed small-bowel diarrhea. Abdominal ultrasound demonstrated diffusely thickened intestinal segments, and veterinary staff palpated a linear intra-abdominal mass. The rat was unresponsive to supportive care, and the rat was euthanized and necropsied. An elongate pink-tan mesenteric mass and severe, diffuse dilation and thickening of the small intestine were observed. Histopathology revealed mild to severe inflammation in most tissues with an abundance of eosinophils and eosinophilic granulomas in the abdominal lymph nodes. Clinical and histopathological findings are similar to hypereosinophilic syndromes (HES) described in a variety of species, including humans. Previous reports of HES in rats are limited to descriptions in rat strain Matsumoto Eosinophilia Shinshu (MES), which has been used as a model of human HES. Unlike MES rats, the rat in this report had diarrhea as well as eosinophilic infiltrates in the skin and heart, all of which are commonly described in human cases of HES.

The use of zebrafish as an animal model for biomedical and toxicological research has increased dramatically over the past decade, alongside a growing need to adopt the 3Rs principles to ensure ethically acceptable animal experimentation. Currently, one of the main challenges concerns 'surplus' animals that are unavoidably generated as part of an experimental procedure and are unsuitable for experimental analysis because they do not have the desired genotype, are too old or have the wrong sex. However, justifying the sacrifice of animals for these reasons is morally debatable and current ethics legislation in some countries insists they should nevertheless be maintained and left to die of natural causes. It is therefore imperative to develop strategies which can identify unwanted animals at a sufficiently early, non-sentient developmental stage so that they can then be sacrificed in an ethically more acceptable manner. In this manuscript we present a reliable medium-throughput method for non-invasive genotyping of zebrafish at developmental stages when sacrifice is considered ethically acceptable. This method is based on the use of low frequency shaking to induce the detachment of a limited number of cells from the embryos. These cells are then analysed by polymerase chain reaction-based genotyping approaches.

The amphibian Xenopus laevis is an alternative animal model for developmental biology and toxicology. The Frog Embryo Teratogenesis Assay-Xenopus (FETAX) stands as a validated test for ecotoxicology and chemical hazard characterization. Conventionally, fertilized eggs are obtained through adult hormonal injection. In adherence to the 3R principles, our proposed method offers the opportunity to obtain embryos through natural amplexus, rearing adults in controlled conditions that replicate the most favourable environmental parameters.

Eight male Dorper sheep were anesthetized with isoflurane to evaluate the effects of anesthesia on cardiopulmonary parameters, echocardiographic variables and cardiac output (CO) using echocardiography methods compared with thermodilution. Heart rate (HR), respiratory rate (f R), systolic arterial pressure (SAP), diastolic arterial pressure (DAP) and mean arterial pressure (MAP) were recorded. CO was obtained by thermodilution using a pulmonary artery catheter (CO_THERMO), Teichholz method (CO_Teichholz) and pulmonary artery Doppler (CO_PA). Echocardiographic variables (interventricular septum (IVSs and IVSd), left ventricular chamber (LVIDs and LVIDd) and left ventricular free wall (LVFWs and LVFWd) in systole and diastole, respectively; ejection fraction (EF%); fractional shortening (FS%); pulmonary artery pressure gradient (PG), peak flow velocity (V_max) and velocity-time integral of the flow (VTI) were recorded. All parameters were measured at baseline and every 15 min during the transanesthetic and recovery periods (T15, T30, T45, T60, T15_REC, T30_REC, T45_REC, T60_REC). Significant reductions in SAP, MAP, DAP and CO_THERMO were observed during the transanesthetic period. Bland-Altman analysis comparing CO_THERMO and CO_Teichholz showed mean biases of 0.49 l min^-1 (limits of agreement (LOA), -2.12 to 3.12 l min^-1), 0.56 l min^-1 (-1.82 to 2.96 l min^-1) and 0.75 l min^-1 (-2.04 to 3.56 l min^-1) at baseline, during anesthesia and in recovery, respectively. For CO_THERMO and CO_PA, mean biases were -0.53 l min^-1 (-2.90 to 1.90 l min^-1), -0.66 l min^-1 (-4.72 to 3.39 l min^-1) and -0.94 l min^-1 (-4.62 to 2.73 l min^-1) at baseline, during anesthesia and in recovery, respectively. Isoflurane decreases blood pressure and CO without affecting echocardiographic parameters. CO values obtained by thermodilution and echocardiography methods are not interchangeable.