Laboratory Animals最新文献

Accurate and humane collection of mouse urine samples is crucial for research studies and health monitoring of laboratory mouse colonies. Conventional methods may stress animals and compromise sample quality. To address these challenges, we developed a natural and animal-friendly approach using a specially designed urine collection device. This innovative technique involved individual transparent compartments with 96-well collection plates, allowing C57BL/6NTac mice to urinate freely for up to 2 h. Our study found that the optimal collection period was from 7 AM to 9 AM, during which the mice produced urine quantities ranging from 80 μl to 810 μl, with a substantial majority (85%) producing over 150 μl. The use of 96-well plates minimized stress, sample evaporation and contamination from fecal material. This cage-based non-invasive technique provides a user-friendly solution for obtaining accurate and high-quality mouse urine samples, benefiting animal welfare and facilitating rodent health surveillance and research studies.

The light regulation within laboratory environments is critical for ensuring the wellbeing and accurate study of nocturnal animals like Syrian hamsters. This study evaluated the instinctual light color preferences of 18 adult female Syrian hamsters under controlled conditions. The experiment exposed hamsters to four different light colors - blue, red, green, and yellow - under identical irradiance during both day and night phases. The time spent in each light zone was recorded and analyzed using chi-square and mixed model type III analysis. Results showed a significant preference for blue light during the day and red light at night. These preferences align with the physiological needs of hamsters, confirming that previously established light conditions in laboratory settings inadvertently matched their natural inclinations. This study contributes to optimizing light protocols in animal research to improve both welfare and experimental accuracy.

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.

Continuous monitoring of physiological parameters in non-human primates (NHPs) necessitates a precise, non-invasive, and convenient method. This study aimed to validate the use of smartwatches with integrated pulse oximetry and heart rate (HR) monitoring capabilities for use in NHPs. Currently, the clinical standard for non-invasive continuous monitoring of peripheral oxygen saturation (SpO₂) in NHPs has been the use of a transmittance pulse oximeter (TPO) affixed to a location of highly vascularized tissue. In a clinical setting, HR is monitored through electrocardiogram (ECG) or associated with SpO₂ measurement from a TPO probe utilizing photoplethysmography technology. Challenges in obtaining precise readings with TPOs stem from technological limitations and probe placement restrictions. To address these limitations, simultaneous HR and SpO₂ measurements were obtained from 15 cynomolgus macaques (Macaca fascicularis) using the Apple Watch 7 (AW 7), Apple Watch 9 (AW 9), and a clinical-grade TPO probe with integrated optical HR measurement technology (iM70, ELAN). Arterial blood gas (ABG) analysis was used as a reference method for SpO₂. We found that a TPO device significantly underestimated SpO₂ compared to the AW 7 and AW 9 when referenced against ABG values. Smartwatch-derived HR and SpO₂ measurements demonstrated good agreement and minimal bias compared to the gold standard method. Overall, the AW 7 and AW 9 exhibited good agreement with clinical reference standards for HR and good agreement with the gold standard for SaO₂ in sedated cynomolgus macaques.

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.

In vitro fertilization (IVF) is an assisted reproduction technique widely used due to its capacity to generate more offspring within a brief timeframe while simultaneously providing fundamental physiological data through gamete interactions. However, its suboptimal development in most species is challenging when IVF is applied to rodents. Despite numerous studies focusing on the Cavioidea and Muroidea superfamilies, some species struggle to achieve satisfactory cleavage rates, whereas others obtain over 90% efficiency with live offspring. Efforts to enhance these rates include adopting methodologies commonly used in other mammals or developing entirely new protocols. Nonetheless, the distinct morphophysiological differences among these animals necessitate careful consideration to avoid overgeneralization during optimization. Therefore, we aimed to review what has been established for the two most researched rodent superfamilies, Cavioidea and Muroidea, regarding the steps of IVF, such as gamete manipulation and embryonic development, to understand better the protocol diversification in the rodent order and how it affects IVF efficiency. After an extensive analysis of data accumulated over the years, it becomes evident that the Muroidea superfamily is used more extensively in reproductive studies than the Cavioidea. Furthermore, IVF procedures achieve total efficiency in only one rodent species, the laboratory mouse (Mus musculus). Consequently, developing a successful IVF technique across rodent species requires substantial modifications to optimize species-specific early steps - a challenge complicated by difficulties in obtaining viable gametes during the initial stages and the limited research interest in species without significant commercial value, such as wild rodents.

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.

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.

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.

Laboratory animal personnel face enormous pressures such as workload, conflicts, deadlines, lack of psychological support, and ethical dilemmas. These pressures are often due to the need to balance scientific objectives, ethical responsibilities, and personal emotions, while trying to maintain legal and institutional animal housing and care standards. When these profession-related pressures are exacerbated by toxic social relationships and financial challenges, it may lead to chronic stress that will ultimately cause compassion fatigue. This review aimed to analyse publication trends on compassion fatigue among laboratory animal personnel by undertaking a bibliometric analysis of published articles to produce insights that could inform future research strategies. A literature search was carried out via the Scopus databases for articles published in English. The data collected from the search was transferred to the Bibliometrix R-package and assessed for publication trends, analysis of contributing countries, thematic evolution, and the co-occurrence of authors' keywords. Seventeen articles published between 2015 and 2024 were retrieved for analysis. Among these, 14 were survey studies and 3 were literature reviews. The number of articles published is on an upward trend, with all authors being affiliated with Global North institutions. The keyword analysis identified 53 words. The most common term used was 'compassion fatigue' (CF) and the analysis indicated that technicians and veterinarians are the primary target populations for CF research. The modest rise in the body of literature on CF and mental health issues among laboratory animal personnel is commendable and I encourage more work to be done to better understand this complex phenomenon.