Laboratory Animals最新文献

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.

Pre-immunization with inactivated antigens has been developed as an alternative to the use of 'dirty' mice, which in contrast to specific pathogen free (SPF) mice, harbour a range of pathogens. Within certain research areas, such mice are considered better models for humans than SPF mice, as they have an immune system that better mirrors human immunity. We inactivated murine adenovirus type 1 (FL), minute virus of mice, mouse hepatitis virus (A59), respirovirus muris (Sendai), Theiler's encephalomyelitis virus (GD7) and Mycoplasma pulmonis by ultraviolet irradiation. We show that pre-immunization with these inactivated pathogens combined with adjuvant prior to the dietary induction of obesity in C57BL/6NTac mice substantially reduced the group sizes needed for showing an effect of the GLP-1 receptor analogue, liraglutide. Nesting, open field and novel object behaviours of the mice were unaffected. We conclude that pre-immunization with inactivated pathogens may be a simple tool to increase power in this type of intervention study on the DIO mouse model.

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.

When pain might occur during an animal experiment, sufficient analgesia is necessary. Metamizole is the third most used postoperative pain medication in animal research. The analgesic effect of metamizole is supposed to last 6-8 h in rodents. Therefore, the supplementation of drinking water with metamizole should be the preferred method to ensure permanent pain relief without unnecessary stressors. The present exploratory study compared the voluntary intake of metamizole-supplemented drinking water (3 mg/ml) between healthy mice of three different mouse strains. After the addition of metamizole to the drinking water, a marginal reduction in body weight was observed in C57BL/6J and BALB/c mice. However, NSG mice displayed a significantly higher body weight loss and reduction of drinking behavior compared with the C57BL/6J and BALB/c strains. The acceptance of metamizole in NSG mice did not increase with a different metamizole formulation. Thus, the mice of the inbred strains C57BL/6J and BALB/c seemed to be able to adapt to the taste of metamizole, while NSG mice were not able to accustom to analgesia within 1 week. Strain-specific habituation should be considered in future animal studies when analgesia is applied via drinking water.

The knowledge and attitude of researchers can affect the validity of laboratory animal (LAN) research. However, studies show that not all researchers possess the required knowledge and appropriate attitude for performing valid research on animals. This may have several reasons, such as high heterogeneity in the educational backgrounds of researchers in animal trials. In this study, we hypothesized that properly designed intensive educational intervention could improve the knowledge and attitude of a mixed population of researchers, regardless of their heterogeneity. We delivered 10 country-wide two-day LAN workshops for academic members, postgraduate students and members of the ethics committees of the medical universities in Iran. Using pre-/post-intervention design, we found that the intervention highly significantly (p < 0.001) improved the knowledge score (from 2.96 ± 1.483 to 4.63 ± 1.548 mean ± SD; range: 0-8; n = 236) and attitude score (from 62.65 ± 5.160 to 65.57 ± 4.716; range: 14-70; N = 229). We also found that the educational intervention was significantly (p = 0.035) more effective to improve the knowledge of participants with more years of experience in LAN science. Unexpectedly, our younger participants (overall age range: 19-67 years old; mean ± SD: 37.96 ± 9.55) had lower initial attitude score. However, education was significantly (p = 0.002) more effective to improve the attitude score of younger participants. The knowledge and attitude improvements were not related to educational background, gender, history of prior attendance in LAN courses and amount of animal use. Attendees' performance in the final assessment showed that they require more education on the 'anesthesia/analgesia' topic. They also declared a high interest in learning more on the design of LAN studies.

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.

Fish are increasingly used as experimental animals across research fields. Currently, around a quarter of all experimental animals used are fish. Less than 20% of these are standard model species. Welfare assessments for experimental fish are in their infancy compared with those for rodents. This can be attributed to the diversity of species used, the relative recency of fish as the go-to model for research, and challenges to assess welfare in non-vocal underwater species. The lack of guidelines and tools presents a challenge for researchers (particularly, for newcomers), for ethics committees and for implementing refinement measures. Here, we present an adaptable, user-friendly score sheet for fish based on MS Excel. The parameters are based on a literature review, have been validated by expert interviews and evaluated by a fish pathologist. The tool allows scoring of individual fish as well as groups, calculates summary scores and visualizes trends. We provide the underlying literature, give use examples and provide instructions on the adaptation and use of the score sheet. We hope that this tool will empower researchers to include welfare assessment in their routines, foster discussions on fish welfare parameters among scientists, facilitate interactions with ethics committees and, most importantly, enable the refinement of fish experiments.

This study aimed to investigate the impact of selected analysis conditions on blood flow values and color maps in canine brain perfusion computed tomography (PCT) and to propose optimal analysis conditions. Dynamic computed tomography imaging was performed on six beagle dogs. Color maps were generated using a combination of analysis algorithms (box-modulation transfer function (Box-MTF) and singular value deconvolution plus (SVD+) methods), slice thicknesses (4.0 and 8.0 mm), analysis matrix sizes (512 × 512, 256 × 256, and 128 × 128), and noise reduction levels (strong and weak). Cerebral blood flow (CBF) and cerebral blood volume (CBV) were calculated for gray matter, white matter, basal ganglia, hippocampus, thalamus, and cerebellum in each map. CBF and CBV values obtained using SVD+ were significantly higher than those obtained using Box-MTF. Noise reduction was more effective with larger matrix sizes; however, excessive noise reduction led to the blurring of anatomical structures in the color map. Across all analysis algorithms, anatomical structures were challenging to visualize at 8.0 mm. For canine brain PCT, it is essential to choose a straightforward algorithm that remains unaffected by circulatory velocity or intracranial bone structure. Given the brain's size, the slice thickness should be minimal, noise reduction level should be suitable for the targeted area, and matrix size should be maximized.