Laboratory Animals最新文献

Seasonality governs every aspect of life in the natural environment. Controlled laboratory settings are intended to keep animals under a constant set of environmental cues with no seasonality. However, prior research suggests that seasonal variation may exist despite aseasonal lab environments. Here, we examined whether the length of each phase of the estrus cycle varied seasonally in addition to seasonal changes in the overall estrus cycle length in a laboratory mouse strain (C57BL/6J) under standard laboratory housing conditions. We found that female C57BL/6J mice exhibited reproductive seasonality mirroring the outside environment, in a controlled "simulated summer" environment. In the winter and spring, females have longer ovulating phases (proestrus and estrus), compared to the fall. Females similarly experience lengthier quiescent phases (metestrus and diestrus) in the summer, compared to fall and winter. Interestingly, females showed no significant variation in overall estrus cycle length across seasons. Notably, females spent more time in ovulating phases across seasons than previously reported. Laboratory mice are sensitive to external seasonal changes, even when housed in standard laboratory environments designed to control light, temperature, and humidity. Humidity is indicated by some analyses as a potential seasonal cue, however, we cannot rule out other unidentified external cues that may provide information about external seasonal changes. These findings represent just one example of how seasonality may impact mouse physiology in laboratory settings, emphasizing the need to account for such influences in biomedical research and improve environmental control in mouse holding facilities.

In fertility research, intrauterine administration in small animals presents significant technical challenges, often necessitating advanced and precise techniques. Historically, surgical methods have been preferred; however, these approaches are complex, invasive and expensive. While less invasive, intravaginal methods are generally performed without direct visualization and lack standardization, which raises the risk of complications and post-procedure mortality. We present a novel, minimally invasive technique that uses video-guided vaginoscopy to overcome these constraints. This technique efficiently eliminates the need for surgical intervention and improves safety and precision by enabling clear visualization and targeted delivery beyond the cervix. To facilitate the intrauterine delivery of agents, the method utilizes a modified 1 ml micropipette tip as a speculum, designed with a 5 mm wide slit as a technical aperture. The vaginoscope, a repurposed otoscope with an integrated camera and optimal focal length, was employed into the opposite end, which was linked to a mobile device enabling real-time visualization. This creative design reduced discomfort for the animal and the researcher while allowing for exact monitoring when the catheter entered the uterine lumen, guaranteeing precise speculum alignment and producing dependable and repeatable results. The protocol has been successfully implemented over 60 times, with all infusions achieving success and no adverse events reported. This minimally invasive intrauterine technique provides a straightforward, sustainable and effective method for delivering drugs or induction agents directly into the vaginal, cervical or uterine regions, making it suitable for applications in cell therapies, gene therapies and embryo transfers in assisted reproduction technologies.

Surgery is an integral part of many experimental studies. Good surgical practice is a prerequisite for surgical success, optimal animal welfare, and it not only improves post-operative recovery but also the overall outcome and validity of a study. Rodents, especially mice, are the most commonly used laboratory animals and the legal requirements to perform experimental surgery are identical for all species. However, minimum surgical training requirements vary significantly across countries, ranging from basic introductory courses in animal experimentation to supervised, advanced courses led by expert surgeons; this complicates efforts toward standardization. This study provides insight into surgical education and experience, available infrastructure, workplace satisfaction, and the application of good surgical practice in laboratory rodent surgery. Two online surveys with a total of 72 questions were distributed across Europe and 782 complete responses were received and subsequently analyzed. The results showed that most researchers performing rodent surgery have no medical background. Furthermore, good surgical practice (i.e., sterile gowning and gloving, decontaminating and draping the patient, using sterile equipment) seems to be poorly implemented in rodent surgery. In addition, half of all rodent surgeons have no assistance available and most respondents expressed a desire for continued education and courses to deepen and refine their surgical skills. Consequently, training for rodent surgery should be tailored to the surgeon's preexisting knowledge, and additional surgical training should be made mandatory before performing surgery on laboratory rodents. This could improve both the animals' and the surgeons' welfare.

BackgroundHistorically, preclinical studies with rat models have been carried out only with male animals. Current regulations require sex parity in experimental procedures. Several studies have shown significant sex differences in rat models of liver fibrosis, but there is no data available in end-stage liver disease. The aim was to describe sex-related differences in a carbon tetrachloride (CCl₄)-induced rat model of cirrhosis with ascites.MethodsFifty-two rats, 26 of each sex, fed ad libitum with phenobarbital-enriched drinking water (5 mmol/l). CCl₄ was administered orally weekly, adjusting doses to weight changes after CCl₄ administration until ascites development.ResultsMedian time to ascites development was significantly higher in females (19 vs. 10 weeks). Males showed significantly greater weight changes 48 h after CCl₄ administration. The cumulative dose of CCl₄ was significantly higher in females, both at the time of diagnosis of ascites (10.7 vs. 1.5 ml) and at week 10 (median time to ascites development in males) (3.9 vs. 1.5 ml). There were no significant sex differences in model associated mortality (31% males vs. 27% females).ConclusionsSex differences have a significant impact on CCl₄-induced end-stage liver disease; classical models should be redesigned to appropriately encompass both sexes.

The MPTP-animal model of Parkinson's disease has significantly advanced our understanding of Parkinson's disease and the dopaminergic system, helping to establish disease mechanisms and develop therapeutic targets. The non-human primate (NHP) MPTP model is particularly valuable for replicating core Parkinson's disease motor symptoms, anatomical changes and electrophysiological variations seen in humans. However, MPTP-injection protocols often cause substantial suffering, leading to euthanasia. While some post-MPTP primates recovered spontaneously, purposefully induced recovery was considered unattainable. Our team developed a novel intensive care protocol (NICP) promoting complete recovery from MPTP-induced severe parkinsonism in NHPs. NICP provides therapeutic, nutritional and social support, enabling behavioral recovery and subsequent retirement to a primate sanctuary. This innovation enhances animal welfare and opens new prospects for veterinary care, emphasizing the need to explore recovery mechanisms for other chronic conditions induced for research.

During the last years, the rapidly evolving imaging technologies have become valuable tools in in vivo research. Imaging modalities provide high resolution, real-time images and videos, offering the opportunity of longitudinal, quantitative, non-invasive/non-terminal monitoring of animal models. In parallel, in vivo imaging applications lead to animal reduction, by substituting phenotyping methods that require euthanasia. For in vivo imaging core facilities, effective communication is an essential tool that ensures that all teams involved are on the same page at all times. Successful communication is necessary at all stages and may be achieved via standardized procedures, which provide specifications and step-by-step instructions for all operations and activities. This article aims to provide a communication pipeline for imaging facilities operating with a full-service model, developed for 'Alexander Fleming' Animal Facilities, helping to achieve smooth operation and high-quality research.

This article is dedicated to elucidating and showcasing the concept of a unified Core Facility for laboratory animals within a research institute specialized in basic biology and biomedical research. In many research centres, animal facilities operate as autonomous entities. Here, we discuss that the centralization of all animal model units within a consolidated organizational framework offers a multitude of benefits in terms of communication with a variety of institutional stakeholders, including the Direction Board, Operational Logistics (Maintenance, Lab Operations and Safety Units), Procurement and Accounting Offices, Research Funding Affairs, Institutional Communication, and IT Units. This integrated approach facilitates the implementation of consistent policies and service pricing strategies. Moreover, it promotes staff flexibility across species, allows for responsiveness to evolving research dynamics, emergence of new scientific areas and infrastructure challenges. This concept also inspires technical advancement within the animal facilities, supports training in Laboratory Animal Science, stimulates the standardization of animal welfare practices, and instils a culture of care transversal to all animal models, ultimately enhancing overall animal welfare. This strategy facilitated the integration of non-vertebrate animals and plant models into the Core Facility. Despite significant differences from vertebrate models, this expansion presented advantages, such as incorporation of specialized staff into a larger organizational structure, offering them new opportunities for skill development and enhancing the overall flexibility of the Core Facility's operations.

Animal research remains a crucial component in our efforts to enhance both human and animal health. To better ensure research reproducibility and welfare of animals in research, harmonisation must be improved globally. This review explores the current state of harmonisation in animal research and the associated challenges, along with the roles of existing animal welfare principles, legislative guidelines, codes of practice, international and national organizations, and professional bodies in facilitating harmonisation. We discuss the current obstacles to harmonisation and suggest a performance-based solution. Examples of attainable performance-based outcomes are examined, encompassing areas such as ethical review and oversight, animal housing, environment, training, veterinary care, experimental design and reporting, and openness/transparency in research. In conclusion, the establishment of harmonised performance standards and the promotion of performance-based outcomes hold the potential to significantly improve global animal welfare in research and contribute to scientific advancement.

This study investigated the effectiveness of combining cloprostenol (Cl) and progesterone (Pg) injections for oestrous synchronization in female rats. A comprehensive series of experiments was conducted to explore the impact of hormonal injections on subsequent reproductive behaviour. The study involved dividing rats into distinct groups, with each group subjected to specific injections of either Cl, Pg, or their combinations. We observed a 100% conception efficiency within the first day after the last Cl injection in the Cl + Pg + Cl group. This finding underscores the remarkable effectiveness of the employed protocol, resulting in a rapid initiation of pregnancy in a substantial number of female rats on the same day.