Laboratory Animals最新文献

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.

An alternative in an attempt to minimize the effects triggered by intravenous (IV) bolus administration of α-2 adrenergic receptor agonists are continuous rate infusions (CRI). The requirement for sedation protocols in sheep for procedures to be performed without physical restraint and with reduced adverse effects, commonly observed with bolus use, justifies the study of CRI. The aim of study was to compare the cardiopulmonary and sedative effects of IV bolus injection and CRI of dexmedetomidine (DEX) in sheep. Six adult male sheep (38.3 ± 7.6 kg) received DEX as a bolus (5 µg kg^-1, DEX_bolus treatment) or CRI (5 µg kg^-1 h^-1 for 1 h, DEX_CRI treatment). We recorded heartrate (HR), respiratory rate, systemic arterial blood pressure, pulse oximetry, hemodynamic parameters, blood gases and sedation scores over 120 min. HR was significantly lower in DEX_bolus at 5 and 15 min than in DEX_CRI, with HR reduction observed for 30 min in DEX_bolus. Hypoxemia was noted in DEX_bolus at 10 and 30 min. Pulmonary vascular resistance index increased at 5 min, and cardiac index (CI) decreased at all timepoints compared with baseline in DEX_bolus. In DEX_CRI, CI decreased only at 45 min. Sedation scores were higher in DEX_bolus at 15 and 30 min. DEX CRI administration resulted in fewer cardiorespiratory and hemodynamic changes compared with bolus injection and lower sedation scores (<4/10), which would not allow animal handling without a reaction. The load dose used in CRI was a limitation to constant infusion.

Most animals used in experimentation are small mammals. In the EU, Directive 2010/63/EU regulates the use of laboratory animals for experimental purposes. However, there are few guidelines for the use of wild-sourced animals, which cover permits, experimentation, transport, maintenance, and setting free after experiments. To evaluate the effect of the Directive on the study of wild-sourced animals, we conducted a systematised literature review focusing on three widespread rodents of the genus Apodemus: Apodemus agrarius, A. flavicollis and A. sylvaticus. We selected studies performed across the EU, published before (2000-August 2010), during (September 2010-2012) and after implementation of the Directive (2013-2022). From those, we collected data on three main topics: i) authorisation; ii) care and accommodation and iii) methods of killing. We found that after implementation of the Directive a higher proportion of published studies provided information about authorisation. In contrast, there was no significant difference over time in the information given about the care and accommodation of animals or methods of killing. As such, our analysis suggests that there is still room for improvement to achieve consistency across journals publishing research involving wild-sourced small mammals. Specifically, editors should require the provision of detailed information by authors regarding proper animal care (e.g. more detailed care and accommodation protocols). To harmonise the information requested by different editorial boards, we recommend the addition of specific guidelines in the Directive regarding wild animals, particularly on their proper accommodation, manipulation, enrichment and veterinary control.

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.

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.

The development of alternative methods for monitoring cardiorespiratory function without restraint or surgical implantation is attracting growing interest for both ethical and scientific reasons. For this purpose, a new non-invasive jacketed telemetry tool consisting in a radio device maintained in a jacket worn by the animal was previously developed to improve cardiorespiratory monitoring. It allows simultaneous monitoring of cardiac activity by surface electrocardiagram, respiratory function by respiratory inductive plethysmography, and locomotor activity by accelerometry. However, this tool has only been validated under conditions of low/intermediate activity levels or in anesthetized animals. This study aimed to evaluate the feasibility of using this system in the challenging conditions of an exertion protocol. Male Wistar rats (n = 10, 8-9 weeks old) were subjected to an incremental treadmill exercise protocol including speed levels from 5 to 40 cm s^-1 separated by 30-s breaks. Heart rate (HR) and minute ventilation (assessed by minute volume; MV) were continuously monitored. At the end of each running level and during the 30-s breaks, HR and MV showed a significant increase compared to resting values. They returned to the baseline within 60 min of post-exercise recovery. Overall, our results demonstrated (i) the ability of the animal to run while wearing the device and (ii) the ability of the device to reliably monitor cardiorespiratory adaptation to treadmill exercise despite significant mechanical disturbances. In conclusion, this study highlights the possibility of non-invasively monitoring cardiorespiratory functional variables that were previously unattainable under conditions of high activity in freely moving animals.

In this study, we found that sevoflurane inhalation in rats prior to intraperitoneal injection decreased stress in both inexperienced experimenters and subject rats. Inexperienced experimenters anaesthetised male Sprague Dawley rats by intraperitoneal injection of anaesthetics, with or without preceding sevoflurane inhalation. Analysis using a visual analogue scale indicated that participating experimenters felt less stress when they performed intraperitoneal injections on rats after subjecting them to sevoflurane inhalation than when performing intraperitoneal injections alone. Plasma corticosterone concentrations of the anaesthetised subject rats were lower when the intraperitoneal injection was preceded by sevoflurane inhalation. Thus, our results demonstrated that it is advisable for inexperienced experimenters, until they gain confidence with experience, to perform sevoflurane inhalation on male rats before intraperitoneal injections.

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.

The Institut Pasteur has set the ambition to encourage all staff to get involved in sustainable development across all departments on campus. The animal facility staff joined the efforts of the sustainable development department to analyse current and future processes and identify potential solutions and related brakes and leverages for the reduction of the animal facilities' environmental impact. The first step was to collect the managers' experience on the local initiatives. Then, the managers attended a workshop to share information on networks and initiatives relevant to the topic and community, and to discuss the use of consumables, including personal protective equipment, single use plastics, bedding, feed, water, chemicals, and waste management. On the topics of interest, local initiatives were specifically detailed to assess their eventual implementation in all the institute's animal facilities, and tasks were set to pursue the managers' efforts in the longer term. A scenario was used to teach how to compare the carbon footprints of washing and disinfection equipment and process and to decide on the design of an animal facility. Finally, a summary is drawn of the brakes and leverages for the reduction of the environmental impact of the institute's animal facilities.