Improving quality of science through better animal welfare: the NC3Rs strategy

A non-adaptationist hypothesis of play behaviour

Play is a suite of apparently non-functional, pleasurable behaviours observed in human and non-human animals. Although the phenomenon has been studied extensively, no adaptationist behavioural theory of how play evolved can be supported by the available evidence. However, the advancement of the extended evolutionary synthesis and developments in systems biology offer alternative avenues for non-adaptationist physiological hypotheses. I therefore propose a hypothesis of play, based upon a complex ACh activity that is under agential control of the organism, whereby play initiates ACh-mediated feedforward and feedback processes which act to: (i) regulate metabolic processes; (ii) form new ACh receptors via ACh mRNA activity; (iii) mediate attention, memory consolidation and learning; and (iv) mediate social behaviours, reproduction and embryonic development. However, play occurs across taxa, but does not occur across all taxonomic groups or within all species of a taxonomic group. Thus, to support the validity of the proposed hypothesis, I further propose potential explanations for this anomaly, which include sampling and observer biases, altricial versus precocial juvenile development, and the influence of habitat niche and environmental conditions on behaviour. The proposed hypothesis thus offers new avenues for study in both the biological and social sciences, in addition to having potential applications in applied sciences, such as animal welfare and biomedical research. Crucially, it is hoped that this hypothesis will promote further study of a valid and behaviourally significant, yet currently enigmatic, biological phenomenon.

Lymphaticovenous anastomosis in rabbits: A novel live experimental animal model for supermicrosurgical training

BACKGROUND

Lymphaticovenous anastomosis is widely used in lymphedema management. Although its effectiveness in reducing edema in patients can be clinically observed, evaluating the long-term outcomes of this technique can be complex. This study established an animal model to assess the outcomes of lymphaticovenous anastomosis technique at 15 and 30-days post-surgery using indocyanine green lymphography, Patent Blue V dye injection, and histopathological examination.

METHODS

An experimental model was established in the hindlimbs of 10 rabbits using the popliteal vein and afferent lymphatic vessels in the popliteal area. The subjects were divided into two groups: the first group (n = 5) underwent patency assessment at 0 and 15 days, and the second group (n = 5) at 0 and 30-days, resulting in 20 anastomoses. Patency was verified at 0, 15, and 30-days using indocyanine green lymphography and Patent Blue V injection. Histopathological examinations were performed on the collected anastomosis samples.

RESULTS

The patency rate was 90% (19/20) initially, 60% (6/10) at 15 days post-surgery, and 80% (8/10) at 30-days. The average diameter of lymphatic vessels and veins was 1.0 mm and 0.8 mm, respectively. The median number of collateral veins was 3; the median surgical time was 65.8 min. Histopathology revealed minimal endothelial damage and inflammatory responses due to the surgical sutures, with vascular inflammation and thrombosis in a single case. Local vascular neoformations were observed.

CONCLUSION

This study highlights the reliability and reproducibility of using rabbits as experimental models for training in lymphaticovenous anastomosis technique owing to the accessibility of the surgical site and dimensions of their popliteal vasculature.

Ex-vivo systems for neuromodulation: A comparison of ex-vivo and in-vivo large animal nerve electrophysiology

BACKGROUND

Little research exists on extending ex-vivo systems to large animal nerves, and to the best of our knowledge, there has yet to be a study comparing these against in-vivo data. This paper details the first ex-vivo system for large animal peripheral nerves to be compared with in-vivo results.

NEW METHOD

Detailed ex-vivo and in-vivo closed-loop neuromodulation experiments were conducted on pig ulnar nerves. Temperatures from 20 °C to 37 °C were evaluated for the ex-vivo system. The data were analysed in the time and velocity domains, and a regression analysis established how evoked compound action potential amplitude and modal conduction velocity (CV) varied with temperature and time after explantation.

MAIN RESULTS

Pig ulnar nerves were sustained ex-vivo up to 5 h post-explantation. CV distributions of ex-vivo and in-vivo data were compared, showing closer correspondence at 37 °C. Regression analysis results also demonstrated that modal CV and time since explantation were negatively correlated, whereas modal CV and temperature were positively correlated.

COMPARISON WITH EXISTING METHODS

Previous ex-vivo systems were primarily aimed at small animal nerves, and we are not aware of an ex-vivo system to be directly compared with in-vivo data. This new approach provides a route to understand how ex-vivo systems for large animal nerves can be developed and compared with in-vivo data.

CONCLUSION

The proposed ex-vivo system results were compared with those seen in-vivo, providing new insights into large animal nerve activity post-explantation. Such a system is crucial for complementing in-vivo experiments, maximising collected experimental data, and accelerating neural interface development.

Evaluation of short-term hair follicle storage conditions for maintenance of RNA integrity

Hair follicles provide an easily accessible tissue for interrogating gene expression for multiple purposes in mammals. RNAlater® is a liquid storage solution that stabilises and preserves cellular RNA, eliminating the need to immediately process or freeze tissue specimens. The manufacturer advises storage of samples at 2-8°C overnight before transfer to -20°C. This study aimed to evaluate RNA integrity in hair follicle samples collected from horses, stabilized in RNAlater®, and stored under three short-term storage conditions. Mane hair samples complete with follicles were collected from four horses at a single time point. Approximately 15 hairs were placed in each of three 2 mL tubes containing 0.75ml RNAlater® solution. Test group A was stored at 4°C for 24-h, then decanted and stored at -20°C. Test groups B and C were stored at 4°C and 19°C (room temperature) respectively for 7 days, then decanted and stored at -20°C. RNA was isolated from all samples and RNA quantity and quality were measured. One-way ANOVA revealed no difference in RNA concentration (A:516 +/-125 ng/ml, B:273+/-93 ng/ml, C:476+/-176 ng/ml;P = 0.2) or quality (A:9.5 +/-0.19, B:9.8+/-0.09, C:9.2+/-0.35 RIN; P = 0.46) between the test groups. There were no group differences in mean Cycle Threshold values from qPCR validation assays confirming high-quality template cDNA. The results suggest that storage of hair follicles for one week in RNAlater® at cool or room temperature conditions will not compromise RNA integrity and will permit extended transport times from remote sampling locations without the need for freezing.

Validation of a Caco-2 microfluidic Chip model for predicting intestinal absorption of BCS Class I-IV drugs

Oral delivery is considered the most patient preferred route of drug administration, however, the drug must be sufficiently soluble and permeable to successfully formulate an oral formulation. There have been advancements in the development of more predictive solubility and dissolution tools, but the tools that has been developed for permeability assays have not been validated as extensively as the gold-standard Caco-2 Transwell assay. Here, we evaluated Caco-2 intestinal permeability assay in Transwells and a commercially available microfluidic Chip using 19 representative Biopharmaceutics Classification System (BCS) Class I-IV compounds. For each selected compound, we performed a comprehensive viability test, quantified its apparent permeability (Papp), and established an in vitro in vivo correlation (IVIVC) to the human fraction absorbed (fa) in both culture conditions. Permeability differences were observed across the models as demonstrated by antipyrine (Transwell Papp: 38.5 ± 6.1 × 10-8 cm/s vs Chip Papp: 32.9 ± 11.3 × 10-8 cm/s) and nadolol (Transwell Papp: 0.6 ± 0.1 × 10-7 cm/s vs Chip Papp: 3 ± 1.2 × 10-7 cm/s). The in vitro in vivo correlation (IVIVC; Papp vs. fa) of the Transwell model (r2 = 0.59-0.83) was similar to the Chip model (r2 = 0.41-0.79), highlighting similar levels of predictivity. Comparing to historical data, our Chip Papp data was more closely aligned to native tissues assessed in Ussing chambers. This is the first study to comprehensively validate a commercial Gut-on-a-Chip model as a predictive tool for assessing oral absorption to further reduce our reliance on animal models.

Electroencephalographic monitoring of anesthesia during surgical procedures in mice using a modified clinical monitoring system

Monitoring brain activity and associated physiology during the administration of general anesthesia (GA) in mice is pivotal to guarantee postanesthetic health. Clinically, electroencephalogram (EEG) monitoring is a well-established method to guide GA. There are no established methods available for monitoring EEG in mice (Mus musculus) during surgery. In this study, a minimally invasive rodent intraoperative EEG monitoring system was implemented using subdermal needle electrodes and a modified EEG-based commercial patient monitor. EEG recordings were acquired at three different isoflurane concentrations revealing that surgical concentrations of isoflurane anesthesia predominantly contained burst suppression patterns in mice. EEG suppression ratios and suppression durations showed strong positive correlations with the isoflurane concentrations. The electroencephalographic indices provided by the monitor did not support online monitoring of the anesthetic status. The online available suppression duration in the raw EEG signals during isoflurane anesthesia is a straight forward and reliable marker to assure safe, adequate and reproducible anesthesia protocols.

Validation of the slaughterhouse porcine heart model for ex-situ heart perfusion studies

INTRODUCTION

To validate slaughterhouse hearts for ex-situ heart perfusion studies, we compared cold oxygenated machine perfusion in less expensive porcine slaughterhouse hearts (N = 7) to porcine hearts that are harvested following the golden standard in laboratory animals (N = 6).

METHODS

All hearts received modified St Thomas 2 crystalloid cardioplegia prior to 4 hours of cold oxygenated machine perfusion. Hearts were perfused with homemade modified Steen heart solution with a perfusion pressure of 20-25 mmHg to achieve a coronary flow between 100-200 mL/min. Reperfusion and testing was performed for 4 hours on a normothermic, oxygenated diluted whole blood loaded heart model. Survival was defined by a cardiac output above 3 L with a mean aortic pressure above 60 mmHg.

RESULTS

Both groups showed 100% functional survival, with laboratory hearts displaying superior cardiac function. Both groups showed similar decline in function over time.

CONCLUSION

We conclude that the slaughterhouse heart can be used as an alternative to laboratory hearts and provides a cost-effective method for future ex-situ heart perfusion studies.

Guidelines for the establishment and functioning of Animal Ethics Commitees (Institutional Animal Care and Use Committees) in Africa

Animals are used for scientific purposes across Africa to benefit humans, animals or the environment. Nonetheless, ethical and regulatory oversight remains limited in many parts of the continent. To strengthen this governance framework, the Pan-African Network for Laboratory Animal Science and Ethics brought together experts from 12 African countries to create an Africa-centric practical guide to facilitate the establishment and appropriate functioning of Institutional Animal Ethics Committees across Africa. The Guidelines are based on universal principles for the care and use of sentient animals for scientific purposes, with consideration of the cultural, religious, political and socio-economic diversity in Africa. They focus on 11 key elements, including responsibilities of institutions and of the Institutional Official; composition of the Committee; its responsibilities, functioning and authority; ethical application and review processes; oversight and monitoring of animal care and use and of training and competence; quality assurance; and the roles of other responsible parties. The intent is for African institutions to adopt and adapt the guidelines, aligning with existing national legislation and standards where relevant, thus ensuring incorporation into practice. More broadly, the Guidelines form an essential component of the growing discourse in Africa regarding moral considerations of, and appropriate standards for, the care and use of animals for scientific purposes. The increased establishment of appropriately functioning animal ethics committees and robust ethical review procedures across Africa will enhance research quality and culture, strengthen societal awareness of animals as sentient beings, improve animal well-being, bolster standards of animal care and use, and contribute to sustainable socio-economic development.

Cold dispase digestion of murine lungs improves recovery and culture of airway epithelial cells

Airway epithelial cells (AECs) play a key role in maintaining lung homeostasis, epithelium regeneration and the initiation of pulmonary immune responses. To isolate and study murine AECs investigators have classically used short and hot (1h 37°C) digestion protocols. Here, we present a workflow for efficient AECs isolation and culture, utilizing long and cold (20h 4°C) dispase II digestion of murine lungs. This protocol yields a greater number of viable AECs compared to an established 1h 37°C dispase II digestion. Using a combination of flow cytometry and immunofluorescent microscopy, we demonstrate that compared to the established method, the cold digestion allows for recovery of a 3-fold higher number of CD45-CD31-EpCAM+ cells from murine lungs. Their viability is increased compared to established protocols, they can be isolated in larger numbers by magnetic-activated cell sorting (MACS), and they result in greater numbers of distal airway stem cell (DASC) KRT5+p63+ colonies in vitro. Our findings demonstrate that temperature and duration of murine lung enzymatic digestion have a considerable impact on AEC yield, viability, and ability to form colonies in vitro. We believe this workflow will be helpful for studying lung AECs and their role in the biology of lung.

Attending veterinarians improve the research capability and psychological well-being of researchers in animal research institutes

The use of laboratory animals in biomedical research has significantly advanced scientific understanding, yet it raises ethical concerns about animal welfare and the mental health of researchers Recent research has highlighted the potential for stress and compassion fatigue among researchers working with distressed animals. Attending veterinarians (AVs) are crucial in mitigating the pain and stress experienced by animals and, by extension, researchers. However, the impact of AVs on researchers' psychological well-being remains understudied. This study explores how AVs contribute to researchers' research capability and psychological well-being in animal research institutions. AVs oversee animal housing, health, and welfare; their involvement is mandated or strongly recommended in developed countries. AVs enhance animal welfare by ensuring proper housing, nutrition, and social interaction. They monitor animal health, educate researchers on pain assessment, and promote compliance with post-surgical care. AVs also contribute to researchers' well-being by addressing euthanasia procedures, which can be emotionally challenging. Programs for rehoming animals after experiments offer an alternative to euthanasia and positively impact researchers' psychological well-being. Moreover, AVs promote workplace well-being by fostering positive workplace cultures, offering peer counseling, and providing social support. Programs considering animal welfare and researchers' emotions are crucial for a healthy research environment. In conclusion, AVs are essential in balancing scientific progress with animal welfare and researchers' psychological well-being. Therefore, their role should be recognized as vital in achieving social equity that considers the welfare of humans and laboratory animals.

Discovery and development of COVID-19 vaccine from laboratory to clinic

The world has recently experienced one of the biggest and most severe public health disasters with severe acute respiratory syndrome coronavirus (SARS-CoV-2). SARS-CoV-2 is responsible for the coronavirus disease of 2019 (COVID-19) which is one of the most widespread and powerful infections affecting human lungs. Current figures show that the epidemic had reached 216 nations, where it had killed about 6,438,926 individuals and infected 590,405,710. WHO proclaimed the outbreak of the Ebola virus disease (EVD), in 2014 that killed hundreds of people in West Africa. The development of vaccines for SARS-CoV-2 becomes more difficult due to the viral mutation in its non-structural proteins (NSPs) especially NSP2 and NSP3, S protein, and RNA-dependent RNA polymerase (RdRp). Continuous monitoring of SARS-CoV-2, dynamics of the genomic sequence, and spike protein mutations are very important for the successful development of vaccines with good efficacy. Hence, the vaccine development for SARS-CoV-2 faces specific challenges starting from viral mutation. The requirement of long-term immunity development, safety, efficacy, stability, vaccine allocation, distribution, and finally, its cost is discussed in detail. Currently, 169 vaccines are in the clinical development stage, while 198 vaccines are in the preclinical development stage. The majority of these vaccines belong to the Ps-Protein subunit type which has 54, and the minor BacAg-SPV (Bacterial antigen-spore expression vector) type, at least 1 vaccination. The use of computational methods and models for vaccine development has revolutionized the traditional methods of vaccine development. Further, this updated review highlights the upcoming vaccine development strategies in response to the current pandemic and post-pandemic era, in the field of vaccine development.

Subchronic inhalation of a novel electronic nicotine delivery system formulation and its corresponding base formulation

BACKGROUND

Fresh Menthol 3% Nicotine (FM3) is a novel JUUL e-liquid formulation. Its potential toxicity and that of the corresponding base formulation relative to a filtered air (FA) control was studied in a subchronic inhalation study conducted in general accordance with OECD 413.

METHODS

Aerosols generated with an intense puffing regime were administered to rats in a nose-only fashion at 1400 µg aerosol collected mass/L on a 6 hour/day basis for 90 days with a 42-day recovery. Exposure atmospheres met target criteria. Systemic exposure was confirmed by plasma measurement of nicotine.

RESULTS

No test article-related mortality, clinical signs (other than reversible lower body weight gains in males), clinical pathology or gross findings were noted during this study. No microscopic lesions related to base formulation exposure were identified. Minimal microscopic lesions were observed in the FM3 6-hour exposure group. Microscopic lesions observed in the FM3 6-hour exposure group comprised only minimal laryngeal squamous metaplasia in one male and one female animal. No microscopic lesions related to FM3 exposure remained after the recovery period.

CONCLUSION

Exposure atmosphere characterization indicated that conditions were achieved to permit thorough assessment of test articles and results indicate a low order of toxicity for the FM3 Electronic nicotine delivery systems (ENDS) formulation and its base formulation.

Immunity-on-a-Chip: Integration of Immune Components into the Scheme of Organ-on-a-Chip Systems

Studying the immune system in vitro aims to understand how, when, and where the immune cells migrate/differentiate and respond to the various triggering events and the decision points along the immune response journey. It becomes evident that organ-on-a-chip (OOC) technology has a superior capability to recapitulate the cell-cell and tissue-tissue interaction in the body, with a great potential to provide tools for tracking the paracrine signaling with high spatial-temporal precision and implementing in situ real-time, non-destructive detection assays, therefore, enabling extraction of mechanistic information rather than phenotypic information. However, despite the rapid development in this technology, integration of the immune system into OOC devices stays among the least navigated tasks, with immune cells still the major missing components in the developed models. This is mainly due to the complexity of the immune system and the reductionist methodology of the OOC modules. Dedicated research in this field is demanded to establish the understanding of mechanism-based disease endotypes rather than phenotypes. Herein, we systemically present a synthesis of the state-of-the-art of immune-cantered OOC technology. We comprehensively outlined what is achieved and identified the technology gaps emphasizing the missing components required to establish immune-competent OOCs and bridge these gaps.

Essential oils and isolated compounds for tick control: advances beyond the laboratory

BACKGROUND

Tick control is a worldwide challenge due to its resistance to acaricides. Essential oils (EOs) and isolated compounds (EOCs) are potential alternatives for tick control technologies.

METHODS

A review with EOs and EOCs, under field and semi-field conditions, was performed based on Scopus, Web of Science and PubMed databases. Thirty-one studies published between 1991 and 2022 were selected. The search was performed using the following keywords: "essential oil" combined with "tick," "Ixodes," "Argas," "Rhipicephalus," "Amblyomma," "Hyalomma," "Dermacentor," "Haemaphysalis" and "Ornithodoros." The words "essential oil" and "tick" were searched in the singular and plural.

RESULTS

The number of studies increased over the years. Brazil stands out with the largest number (51.6%) of publications. The most studied tick species were Rhipicephalus microplus (48.4%), Ixodes scapularis (19.4%), Amblyomma americanum and R. sanguineus sensu lato (9.7% each). Cattle (70%) and dogs (13%) were the main target animal species. Regarding the application of EOs/EOCs formulations, 74% of the studies were conducted with topical application (spray, pour-on, foam, drop) and 26% with environmental treatment (spray). Efficacy results are difficult to evaluate because of the lack of information on the methodology and standardization. The nanotechnology and combination with synthetic acaricides were reported as an alternative to enhance the efficacy of EOs/EOCs. No adverse reactions were observed in 86.6% of the studies evaluating EOs/EOCs clinical safety. Studies regarding toxicity in non-target species and residues are scarce.

CONCLUSIONS

This article provides a comprehensive review on the use of EOs and EOCs to reduce tick infestations, in both the hosts and the environment. As future directions, we recommend the chemical characterization of EOs, methodology standardization, combination of EOs/EOCs with potential synergists, nanotechnology for new formulations and safety studies for target and non-target organisms, also considering the environmental friendliness.

Acute but not long-lasting antidepressant-like effect of psilocybin in differential reinforcement of low-rate 72 schedule in rats

BACKGROUND

In clinical studies, psychedelics including psilocybin and D-lysergic acid diethylamide (LSD) demonstrate rapid and persistent antidepressant effects. Since the effective treatment with psychedelics is usually provided with psychotherapy, it is debatable whether their prolonged efficacy can be observed in infrahuman species. Preclinical reports on psychedelics' effects most often address their acute actions, and different tests and models provide inconsistent results. The goal of this study was to examine whether the treatment with psilocybin and/or LSD would demonstrate immediate and/or sustained antidepressant-like effects in the differential reinforcement of low-rate responding (DRL) schedule in rats. In contrast to the antidepressant screening tools, the DRL 72s test is known to detect antidepressants with high predictive validity as it differentiates clinically effective antidepressants from other psychoactive drugs in non-stressed animals.

METHODS

Adult male Sprague Dawley rats were injected over three consecutive days with psilocybin (1 mg/kg), LSD (0.08 mg/kg), or saline and then tested in DRL 72s for the following 4 weeks.

RESULTS

Treatment with psilocybin but not LSD demonstrated an immediate antidepressant-like effect, manifested as an increased number of reinforced presses and response efficiency. By contrast, neither of the drugs showed a long-term (up to 4 weeks following administration) antidepressant-like effect.

CONCLUSIONS

Using DRL 72s schedule of reinforcement, we demonstrated the acute antidepressant-like effect of psilocybin but not of LSD, and failed to detect their persistent antidepressant-like efficacy. The present study suggests that the detection of long-lasting antidepressant-like activity in rats could be challenging and may require entirely novel behavioral methods.

Rat Grimace Scale as a Method to Evaluate Animal Welfare, Nociception, and Quality of the Euthanasia Method of Wistar Rats

Refinement of experimental procedures in animal research has the objective of preventing and minimizing pain/distress in animals, including the euthanasia period. This study aimed to evaluate pain associated with six methods of euthanasia in Wistar rats (injectable, inhalational, and physical), by applying the Rat Grimace Scale (RGS), comparing the scores, and determining the method with the highest score that might indicate pain for laboratory rodents. Sixty adult male and female Wistar rats were used and assigned to six treatments: pentobarbital, CO2, decapitation, isoflurane, ketamine + xylazine, and ketamine + CO2. Video recording to assess the RGS scores was performed in four events: basal: 24 h before the procedure; Ti1: three minutes before the procedure; Ti2: during the application of the euthanasia method; and Ti3: immediately after the application until LORR. The main findings of this study showed that, during Ti2, decapitation and ketamine + xylazine had the highest scores (0.6 ± 0.26 and 0.6 ± 0.16, respectively) (p < 0.0001), while at Ti3, CO2 (0.9 ± 0.18) and isoflurane (1.2 ± 0.20) recorded the highest scores (p < 0.0001). According to the present results, decapitation and ketamine + xylazine elicited short-term acute pain, possibly due to tissue damage caused by both methods (injection and guillotine). In contrast, isoflurane's RGS scores recorded during Ti3 might be associated with nociception/pain due to the pungency of the drug or to the pharmacological muscle relaxant effect of isoflurane. Further research is needed to establish a comprehensive study of pain during euthanasia, where RGS could be used minding the limitations that anesthetics might have on facial expression.

Zookeepers - The most important animal in the zoo?

Education to improve knowledge of animal welfare is not a universal component of training for zoo staff, and little is reported about the perspectives of zoo staff on the need for such education. This paper reports results from structured telephone interviews of a diverse sample of eight Chinese and eight European zoo staff about aspects of zoological animal welfare, education and zoological practices. These qualitative data were thematically analyzed and key themes generated. Similar themes emerged across regions: Zoo staff consider professional attributes including motivation and enthusiasm to be important alongside formal training, zoo staff value learning opportunities but don't always feel supported, and contextual information including wild animal ecology was considered important content in zoo animal welfare education.

The role of three-dimensional in vitro models in modelling the inflammatory microenvironment associated with obesity in breast cancer

Obesity is an established risk factor for breast cancer in postmenopausal women. However, the underlying biological mechanisms of how obesity contributes to breast cancer remains unclear. The inflammatory adipose microenvironment is central to breast cancer progression and has been shown to favour breast cancer cell growth and to reduce efficacy of anti-cancer treatments. Thus, it is imperative to further our understanding of the inflammatory microenvironment seen in breast cancer patients with obesity. Three-dimensional (3D) in vitro models offer a key tool in increasing our understanding of such complex interactions within the adipose microenvironment. This review discusses some of the approaches utilised to recapitulate the breast tumour microenvironment, including various co-culture and 3D in vitro models. We consider how these model systems contribute to the understanding of breast cancer research, with particular focus on the inflammatory tumour microenvironment. This review aims to provide insight and prospective future directions on the utility of such model systems for breast cancer research.

Acclimation and Blood Sampling: Effects on Stress Markers in C57Bl/6J Mice

Blood sampling in rodents is common practice in scientific studies. Some of the refined methods widely used are the puncture of the saphenous vein or tail vein, or even tail docking. The handling needs of these different blood sampling methods are different and can directly affect stress, increasing the variability of the study. Moreover, there is less aversion and stress if the animal is accustomed to the environment, handling and technique. Therefore, our study aimed to assess the influence of these three blood sampling techniques (saphenous puncture, tail vein puncture and tail vein docking) and the use of previous acclimation on different indicators of animal stress, assessing blood glucose concentrations and faecal corticosterone metabolites (FCMs). Twenty-four young adult male and female C57Bl6/J mice were divided in three groups by sampling method: tail docking (TD), saphenous vein puncture (SV) and caudal vein puncture (CV) groups. All mice were studied with and without acclimation, which was performed during 9 consecutive days. The results showed that both males and females present very similar responses to the different handling and sampling methods without significant differences. Nevertheless, acclimation in all sampling methods decreased glucose and FCM levels significantly. The method that obtained the lowest glucose and FCM levels with significance was saphenous vein puncture. Therefore, we can say that it causes less stress when performing prior acclimation, even when this involves greater handling of the animal. Our results contribute to refinement within the 3R concept and could serve researchers to programme and select a good handling technique and a welfare-friendly blood sampling method for their experiments.

The ice age - A review on formulation of Adeno-associated virus therapeutics

Gene therapies offer promising therapeutic alternatives for many disorders that currently lack efficient treatment options. Due to their chemical nature and physico-chemical properties, delivery of polynucleic acids into target cells and subcellular compartments remains a significant challenge. Adeno-associated viruses (AAV) have gained a lot of interest for the efficient delivery of therapeutic single-stranded DNA (ssDNA) genomes over the past decades. More than a hundred products have been tested in clinical settings and three products have received market authorization by the US FDA in recent years. A lot of effort is being made to generate potent recombinant AAV (rAAV) vectors that show favorable safety and immunogenicity profiles for either local or systemic administration. Manufacturing processes are gradually being optimized to deliver a consistently high product quality and to serve potential market needs beyond rare indications. In contrast to protein therapeutics, most rAAV products are still supplied as frozen liquids within rather simple formulation buffers to enable sufficient product shelf life, significantly hampering global distribution and access. In this review, we aim to outline the hurdles of rAAV drug product development and discuss critical formulation and composition aspects of rAAV products under clinical evaluation. Further, we highlight recent development efforts in order to achieve stable liquid or lyophilized products. This review therefore provides a comprehensive overview on current state-of-the-art rAAV formulations and can further serve as a map for rational formulation development activities in the future.

Protective Effects of Different Hypothermal Preservation Solutions on Structure and Function of Isolated Rat Arteries

OBJECTIVE

With the increasing application of vascular reconstruction in surgical procedures, allogeneic vessels are becoming more popular in clinical practice due to their abundant sources, precise diameter matching, improved histocompatibility, and higher long-term patency rate. This study aimed to investigate the protective effect of various preservation solutions on the function and structure of the isolated rat abdominal aorta preserved under hypothermal conditions.

METHODS

The study utilized a total of 150 Sprague-Dawley (SD) rats, with 144 rats allocated to the experimental groups and 6 rats allocated to the control groups. The abdominal aorta of the rats was chosen as the subject of our research. The aorta in the experimental groups were randomly assigned to 4 groups: University of Wisconsin (UW) solution group, histidine-tryptophan-ketoglutarate (HTK) solution group, normal saline (NS) group, and sodium lactate Ringer's solution (RS) group. Samples were subjected to examination after preservation periods of 1 day, 3 days, 5 days, 7 days, 14 days, 30 days, and 90 days. Evaluation of vascular physiological function involved detecting and assessing vasoconstriction ability and measuring cell viability through the MTT test. Evaluation of the vascular wall structure involved tension tolerance tests and pathological staining.

RESULTS

The pathogen-positive rate in the HTK group and NS group at 1 month was 16.7%. Regarding the vascular skeleton structure, both the UW group and HTK group exhibited intact structures after 2 weeks of preservation, with slightly edematous collagen and elastic fibers, which was significantly better than that of the NS group and RS group. In terms of cell activity and contractile function, all preservation groups showed similar effects within 2 weeks. However, after 2 weeks, the UW group showed the most favorable preservation effect (P<0.05). In terms of vascular tension, different groups exhibited similar effects within 1 week. However, after 2 weeks, the UW group showed the best preservation effect (P<0.05).

CONCLUSION

All 4 types of preservation solution had a preservation effect on the structure and function of isolated blood vessels during short-term hypothermal preservation. However, after 2-week preservation, the UW solution was found to be the most suitable solution for the preservation of blood vessels.

Cold Oxygenated Machine Perfusion Improves Functional Survival of Slaughterhouse Porcine Hearts

The aim of our study was to explore the effect of cold oxygenated machine perfusion in slaughterhouse porcine hearts on functional myocardial survival compared to static cold storage (SCS). Seventeen hearts were harvested from Dutch Landrace Hybrid pigs, which were sacrificed for human consumption and randomly assigned to the 4 hours SCS group (N = 10) or the 4 hours cold oxygenated machine perfusion group (N = 7). Hearts were perfused with a homemade Heart Solution with a perfusion pressure of 20-25 mm Hg to achieve a coronary flow between 100 and 200 ml/minute. After 4 hours of preservation, all hearts were functionally assessed during 4 hours on a normothermic, oxygenated diluted whole blood (1:2) loaded heart model. Survival was defined by a cardiac output above 3 L with a mean aortic pressure above 60 mm Hg. Survival was significantly better in the cold oxygenated machine perfusion group, where 100% of the hearts reached the 4 hours end-point, as compared with 30% in the SCS group ( p = 0.006). Interestingly, warm ischemic time was inversely related to survival in the SCS group with a correlation coefficient of -0.754 ( p = 0.012). Cold oxygenated machine perfusion improves survival of the slaughterhouse porcine heart.

Introducing individual sentience profiles in nonhuman primate neuroscience research

The Animal Research Declaration is committed to establishing cohesive and rigorous ethical standards to safeguard the welfare of nonhuman primates (NHPs) engaged in neuroscience research (Petkov et al., 2022 this issue). As part of this mission, there is an expanding dialogue amongst neuroscientists, philosophers, and policymakers, that is centred on diverse aspects of animal welfare and scientific practice. This paper emphasises the necessity of integrating the assessment of animal sentience into the declaration. Animal sentience, in this context, refers to the recognized capacity that animals have for various kinds of subjective experience, with an associated positive or negative valence (Browning and Birch, 2022). Accordingly, NHP neuroscience researchers should work toward instituting a standardised approach for evaluating what can be termed "individual sentience profiles," representing the unique manner in which an individual NHP experiences specific events or environments. The adoption of this novel parameter would serve a triad of indispensable purposes: enhancing NHP welfare throughout research involvement, elevating the quality of life for NHPs in captivity, and refining the calibre of research outcomes.

Changes in group behaviour in response to a preferred environment reflect positive affect

When observed in their preferred environments, animals display behavioural changes, such as an increase in resting or a reduction in agonism, suggestive of positive affect and improved welfare. However, most studies focus on the behaviour of individuals or, at most, pairs of animals; even though in group-living animals beneficial environmental changes may impact on how the group behaves as a whole. In this study, we investigated whether experiencing a preferred visual environment affected the shoaling behaviour of zebrafish (Danio rerio) groups. We first confirmed a group preference for an image of gravel placed underneath the base of a tank compared to a plain white image. Second, we observed replicated groups either with or without the preferred (gravel) image present to determine if a visually enriched and preferred environment could elicit changes in shoaling behaviour. We found a significant interaction between the observation time and test condition, with differences in shoaling behaviour reflective of increased relaxation emerging gradually over time in the gravel condition. The findings of this study reveal that experiencing a preferred environment can alter group behaviour, making such holistic changes valuable as potential indicators of positive welfare.

Position statement from the Editors of Anaesthesia and Anaesthesia Reports on best practice in academic medical publishing

It is essential that academic publishing complies with the highest standards in terms of ethics, research conduct and manuscript preparation. This protects the rights and welfare of research participants, ensures the integrity of study results and aids the communication and dissemination of novel findings into clinical practice. This position statement outlines the current policies and practices of the Editors of Anaesthesia and Anaesthesia Reports in relation to academic medical publishing.

Research Animal Behavioral Management Programs for the 21st Century

Behavioral management programs have been developed commonly for research dogs and primates but rarely has program consideration been expanded to include all research species worked with. This is necessary to reduce animal stress and promote natural behaviors, which can promote good animal welfare and result in more robust and reproducible scientific data. We describe the evolution of consideration for research animal needs and define an umbrella-based model of research animal behavioral management programs, which may be used for all research species. In addition to developing a more comprehensive program, we emphasize the need for regular welfare assessments to determine whether the program is working cohesively and whether any aspects require modification.

Comparison of the effects of two anesthetics, isoflurane and urethane, on bladder function in rats

We compared the effects of two anesthetics, isoflurane and urethane on bladder function in rats. Arterial pressure, cystometry (CMG), and rhythmic bladder contractions (RBCs) under isovolumetric conditions, mechanosensitive single-unit afferent activities (SAAs), bladder compliance and bladder myogenic microcontractions (bladder microcontractions), and bladder blood flow, and blood and urine biochemical tests were investigated in isoflurane- or urethane-anesthetized female rats. In results of the CMG, 3/8 rats in the isoflurane group and 7/7 rats in the urethane group showed constant bladder neurogenic contractions for micturition, whereas 5/8 rats in the isoflurane group showed unstable contractions or overflow incontinence. The RBCs appeared in the urethane group but not in the isoflurane group, and SAAs in both the Aδ- and C-fibers, bladder compliance, and bladder microcontractions in the isoflurane group were higher than those in the urethane group during bladder distension. The blood biochemical test showed that the serum calcium level was higher in the isoflurane group. The mean arterial pressure and bladder blood flow were not different between the groups. The results showed that urethane anesthesia more retains bladder neurogenic contractions for micturition compared to isoflurane. In contrast, isoflurane anesthesia more retains bladder function during the storage phase compared to urethane.

Bact-to-Batch: A Microbiota-Based Tool to Determine Optimal Animal Allocation in Experimental Designs

The basis of any animal experimentation begins with the housing of animals that should take into account the need for splitting animals into similar groups. Even if it is generally recommended to use the minimum number of animals necessary to obtain reliable and statistically significant results (3Rs rule), the allocation of animals is currently mostly based on randomness. Since variability in gut microbiota is an important confounding factor in animal experiments, the main objective of this study was to develop a new approach based on 16S rRNA gene sequencing analysis of the gut microbiota of animals participating in an experiment, in order to correctly assign the animals across batches. For this purpose, a pilot study was performed on 20 mouse faecal samples with the aim of establishing two groups of 10 mice as similar as possible in terms of their faecal microbiota fingerprinting assuming that this approach limits future analytical bias and ensures reproducibility. The suggested approach was challenged with previously published data from a third-party study. This new method allows to embrace the unavoidable microbiota variability between animals in order to limit artefacts and to provide an additional assurance for the reproducibility of animal experiments.

The 12 Rs Framework as a Comprehensive, Unifying Construct for Principles Guiding Animal Research Ethics

Animal research ethics and animal welfare in science have become progressively tightly regulated, and ethical integrity and scientific quality, as well as social responsiveness and responsibility have become key requirements for research to be approved, funded, published, and accepted. The multitude of factors to contemplate has in some instances not only become complex, requiring a team approach, but often perceived as confusing and overwhelming. To facilitate a process of simplistic yet comprehensive conceptualization, we developed the 12 Rs Framework to act as a mind map to guide scientists, oversight structures, and other stakeholders through the myriad of ethical considerations. It unfolds into three domains of twelve encompassing ethical principles, values, and other considerations, including the animal welfare, social values, and scientific integrity domains, whilst also recognizing the diversity of local context, legal requirements, values, and cultures around the globe. In the end, it can be seen as a unifying ethical framework to foster and promote animal research ethics.

Comparison of a Minimally Invasive Transthoracic Approach and a Surgical Method for Intrapleural Injection of Tumor Cells in Mice

Intrapleural injections can be used in mice to deliver therapeutic and diagnostic agents and to model human disease processes (for example, pleural fluid accumulation, malignant pleural disease, and lung cancers). In the context of establishing cancer models, minimally invasive methods of intrapleural injection are desirable because inflammation at the injection site can have a major impact on tumor growth and progression. Common approaches for intrapleural injection include surgical exposure of the thoracic wall or the diaphragm prior to injection; however, these invasive procedures require tissue dissection that triggers an undesirable inflammatory response and increases the risk of pneumothorax. While nonsurgical procedures can minimize this concern, 'blind' injections may lead to off target inoculation. In this study, we hypothesized that a minimally invasive transthoracic approach (MI-TT) would produce a tumor distribution and burden similar to that of a surgical transabdominal approach (SX-TA). Prior to performing the procedures on live mice, surgeons were trained using cadavers and terminal procedures. Then a total of 14 nude mice (female, 4 to 6 wk old) were injected with 50 μL (5 million) A549-Luc2 human cancer cells either using the MI-TT (n = 8) or SX-TA (n = 6) approach under carprofen analgesia and isoflurane anesthesia. Our results indicate that with training, a minimally invasive transthoracic approach for intrapleural injection provides more consistent tumor placement and a greater tumor burden than does the surgical method. However, additional studies are necessary to confirm anatomic placement and characterize tumor profiles.

A mapping review of refinements to laboratory rat housing and husbandry

Refining the housing and husbandry of laboratory rats is an important goal, both for ethical reasons and to allow better quality research. We conducted a mapping review of 1,017 studies investigating potential refinements of housing and husbandry of the laboratory rat to assess what refinements have, and have not, been studied, and to briefly assess whether there is evidence to support any impact on rat welfare. Among the many refinements studied, the majority involve changes to the cage, but some also involve alterations to the wider environment. The effects of these refinements were assessed using a range of readouts, many of which are difficult to interpret from a welfare perspective. Preference studies, which are easier to interpret, provide evidence that rats prefer complex environments, including shelters and multiple objects, which offer different areas/resources allowing the rat to engage in diverse behaviors. The reporting of methodology in papers was often poor, indicating that studies were potentially subject to biases. Given that many refinements co-occurred, it was often difficult to tease apart which ones were most beneficial for rat welfare. Effects of refinements were also moderated by a number of factors including age, sex, strain and photoperiod. Altogether our findings show that a one-size-fits-all approach to refinements is not appropriate, because different refinements will impact different rats in different ways. Our review has also produced a database of >1,000 articles that can be used for further and more detailed analyses. Our findings have also highlighted areas where future research is likely to be valuable, including refinements to rat transport, handling and the use of training.

Yeast Cell Wall Compounds on The Formation of Fermentation Products and Fecal Microbiota in Cats: An In Vivo and In Vitro Approach

The effects of yeast cell wall compounds (YCWs) being added to cat food on hindgut fermentation metabolites and fecal microbiota were assessed in in vivo Experiment 1 (Exp. 1) and in vitro Experiments 2 and 3 (Exp. 2 and 3). In Exp. 1, the cats' diets were supplemented with two dietary concentrations (46.2 and 92.4 ppm) of YCWs (YCW-15 and YCW-30, respectively), and a negative control diet with no compound in three groups (six cats per group) was used to assess the fecal score, pH, digestibility, fermentation products, and microbiota. In Exp. 2, feces from the cats that were not supplemented with YCWs (control) were used as an inoculum. A blend of pectin, amino acids, and cellulose was used as a substrate, and the YCW compound was added at two levels (5 and 10 mg). In Exp. 3, feces from cats fed YCWs were used as an inoculum to test three different substrates (pectin, amino acids, and cellulose). In Exp. 2 and 3, the gas production, pH, and fermentation products (ammonia, SCFAs, and BCFAs) were assessed. YCW-30 resulted in a higher digestibility coefficient of the crude protein, organic matter (OM) (p < 0.05), and energy of the diet (p < 0.10). Regarding the fermentation products, YCW-15 showed a trend toward higher concentrations of propionate, acetate, lactate, ammonia, isobutyrate, and valerate, while YCW-30 showed a trend (p < 0.10) toward higher levels of butyrate and pH values. The bacteroidia class and the genus Prevotella were increased by using YCW-30 and the control. At the gender level, decreased (p < 0.01) Megasphaera was observed with YCW inclusion. The microbiota differed (p < 0.01) among the groups in their Shannon indexes. For beta diversity, YCW-30 showed higher indexes (p = 0.008) than the control. The microbiota metabolic profile differed in the pathway CENTFERM-PWY; it was more expressed in YCW-30 compared to the control. In Exp. 2, the YCWs showed a higher ratio (p = 0.006) of the fermentation products in the treatments with additives with a trend towards a high dose of the additive (10 mg). In Exp. 3, the effects of the substrates (p < 0.001), but not of the YCWs, on the fermentation products were observed, perhaps due to the low dietary concentrations we used. However, the marked responses of the fermentation products to the substrates validated the methodology. We could conclude that the YCWs, even at low dietary concentrations, affected fecal SCFA production, reduced the fecal pH, and modulated the fecal microbiota in the cats. These responses were more pronounced under in vitro conditions.

A systematic review on reporting of refinement measures in mouse ECG telemetry implantation surgery

Telemetric monitoring is used in many scientific fields, such as cardiovascular research, neurology, endocrinology, as well as animal welfare research. Nowadays, implanted electrocardiogram (ECG) radiotelemetry units are the gold standard for monitoring ECG traces, heart rate and heart rate variability in freely moving mice. Telemetry technology can be a valuable tool when studies utilize it adequately, while prioritizing animal welfare. Recently, concerns have been raised in many research fields, including animal research, regarding the reproducibility of research findings, with insufficient reporting being one of the underlying causes.A systematic review was performed by making use of three literature databases, in order to include all publications until 31.12.2019, where the surgical placing of ECG recording telemetry devices in adult mice was involved. Data extracted from the publications included selected items recommended by the ARRIVE guidelines. We focused on aspects related to the refinement of the surgery and experimental conditions that aim to improve animal welfare. In general, the quality of reporting was low in the analyzed 234 publications. Based on our analyses, we assume there has been no improvement in this field's reporting quality since 2010 when the ARRIVE guidelines on reporting were introduced. Additionally, even though expert recommendations on telemetry surgery refinement have been available since many years now, no increase in uptake (or reporting) of these measures prior (e.g., acclimatization), during (e.g., asepsis) or after (e.g., social housing) the surgery could be observed.

Microplastics: What happens in the human digestive tract? First evidences in adults using in vitro gut models

Microplastics (MPs) are ubiquitous in the environment and humans are inevitably exposed to them. However, the effects of MPs in the human digestive environment are largely unknown. The aim of our study was to investigate the impact of repeated exposure to polyethylene (PE) MPs on the human gut microbiota and intestinal barrier using, under adult conditions, the Mucosal Artificial Colon (M-ARCOL) model, coupled with a co-culture of intestinal epithelial and mucus-secreting cells. The composition of the luminal and mucosal gut microbiota was determined by 16S metabarcoding and microbial activities were characterized by gas, short chain fatty acid, volatolomic and AhR activity analyses. Gut barrier integrity was assessed via intestinal permeability, inflammation and mucin synthesis. First, exposure to PE MPs induced donor-dependent effects. Second, an increase in abundances of potentially harmful pathobionts, Desulfovibrionaceae and Enterobacteriaceae, and a decrease in beneficial bacteria such as Christensenellaceae and Akkermansiaceae were observed. These bacterial shifts were associated with changes in volatile organic compounds profiles, notably characterized by increased indole 3-methyl- production. Finally, no significant impact of PE MPs mediated by changes in gut microbial metabolites was reported on the intestinal barrier. Given these adverse effects of repeated ingestion of PE MPs on the human gut microbiota, studying at-risk populations like infants would be a valuable advance.

Anesthesia and analgesia for experimental craniotomy in mice and rats: a systematic scoping review comparing the years 2009 and 2019

Experimental craniotomies are a common surgical procedure in neuroscience. Because inadequate analgesia appears to be a problem in animal-based research, we conducted this review and collected information on management of craniotomy-associated pain in laboratory mice and rats. A comprehensive search and screening resulted in the identification of 2235 studies, published in 2009 and 2019, describing craniotomy in mice and/or rats. While key features were extracted from all studies, detailed information was extracted from a random subset of 100 studies/year. Reporting of perioperative analgesia increased from 2009 to 2019. However, the majority of studies from both years did not report pharmacologic pain management. Moreover, reporting of multimodal treatments remained at a low level, and monotherapeutic approaches were more common. Among drug groups, reporting of pre- and postoperative administration of non-steroidal anti-inflammatory drugs, opioids, and local anesthetics in 2019 exceeded that of 2009. In summary, these results suggest that inadequate analgesia and oligoanalgesia are persistent issues associated with experimental intracranial surgery. This underscores the need for intensified training of those working with laboratory rodents subjected to craniotomies.

Systematic review registration

https://osf.io/7d4qe.

Effect of Mulberry Leaf TMR on Growth Performance, Meat Quality and Expression of Meat Quality Master Genes (ADSL, H-FABP) in Crossbred Black Goats

This study was conducted to examine the effect of a mulberry leaf total mixed ration (TMR) diet on growth performance, apparent digestibility, meat quality and the expression of related meat-quality genes (ADSL, H-FABP) in crossbred black goats. Forty-four Guizhou crossbred black goats (Nubian black goat ♂ × Guizhou black goat ♀), weighing 33.43 ± 0.55 kg, were chosen. The goats were randomly divided into four groups, with 11 test replicates in each group. Group I was the control group and fed with the traditional feeding method of roughage and concentrate supplement without adding mulberry leaf. Group II was fed with a 40% mulberry leaf pellet TMR diet. Group III was fed with a freshly processed 40% mulberry leaf TMR diet. Group IV was fed with a 40% mulberry leaf fermented total mixed rations (FTMR) diet. The results showed that the average daily gain (ADG) of group II was significantly higher than that of group I and III (p < 0.05). The apparent digestibility of group II of ether extract (EE) and neutral detergent fiber (NDF) was significantly higher than that of group I (p < 0.05), and the apparent digestibility of dry matter (DM) and crude protein (CP) was significantly higher than that of group I (p < 0.01). Compared with group I, meat in group II had lower meat color lightness (L*) and yellowness (b*) values (p < 0.01) in the Longissimus thoracis et lumborum. The shear force of group II was significantly lower than that of group I (p < 0.05). The total fatty acids (TFA) of group II was significantly higher than that of groups I and III (p < 0.05), but the total saturated fatty acids (SFA) of group II was significantly lower that than of group I (p < 0.01). Subsequently, the Unsaturated fatty acids (USFA), Monounsaturated fatty acids (MUFA), and Polyunsaturated fatty acids (PUFA) of group II were significantly higher than those in group I (p < 0.01). The contents of total amino acids (TAA), total essential amino acids (EAA), total non-essential amino acids (NEAA) and total of major fresh-tasting amino acids (DAA) of groups II, III and IV were significantly higher than those of group I (p < 0.05), as well as the contents of IMP (p < 0.01). The expression of the H-FABP gene in the arm triceps of group II was significantly higher than that of groups I, III and IV (p < 0.05). The expression of the ADSL gene in the Longissimus thoracis et lumborum and biceps femoris of group II was significantly higher than that of group I (p < 0.05). Collectively, the results of the current study indicated that the mulberry leaf TMR diet improved the growth performance, apparent digestibility and expression of related meat-quality master genes (ADSL, H-FABP) in crossbred black goats, which promoted the deposition of intramuscular fat (IMF) and inosinic acid (IMP) and improved the composition of fatty acids and amino acids in the muscles.

Robotically assisted augmented reality system for identification of targeted lymph nodes in laparoscopic gynecological surgery: a first step toward the identification of sentinel node : Augmented reality in gynecological surgery

BACKGROUND

To prove feasibility of multimodal and temporal fusion of laparoscopic images with preoperative computed tomography scans for a real-time in vivo-targeted lymph node (TLN) detection during minimally invasive pelvic lymphadenectomy and to validate and enable such guidance for safe and accurate sentinel lymph node dissection, including anatomical landmarks in an experimental model.

METHODS

A measurement campaign determined the most accurate tracking system (UR5-Cobot versus NDI Polaris). The subsequent interventions on two pigs consisted of an identification of artificial TLN and anatomical landmarks without and with augmented reality (AR) assistance. The AR overlay on target structures was quantitatively evaluated. The clinical relevance of our system was assessed via a questionnaire completed by experienced and trainee surgeons.

RESULTS

An AR-based robotic assistance system that performed real-time multimodal and temporal fusion of laparoscopic images with preoperative medical images was developed and tested. It enabled the detection of TLN and their surrounding anatomical structures during pelvic lymphadenectomy. Accuracy of the CT overlay was > 90%, with overflow rates < 6%. When comparing AR to direct vision, we found that scores were significatively higher in AR for all target structures. AR aided both experienced surgeons and trainees, whether it was for TLN, ureter, or vessel identification.

CONCLUSION

This computer-assisted system was reliable, safe, and accurate, and the present achievements represent a first step toward a clinical study.

Pax6 mutant cerebral organoids partially recapitulate phenotypes of Pax6 mutant mouse strains

Cerebral organoids show great promise as tools to unravel the complex mechanisms by which the mammalian brain develops during embryogenesis. We generated mouse cerebral organoids harbouring constitutive or conditional mutations in Pax6, which encodes a transcription factor with multiple important roles in brain development. By comparing the phenotypes of mutant organoids with the well-described phenotypes of Pax6 mutant mouse embryos, we evaluated the extent to which cerebral organoids reproduce phenotypes previously described in vivo. Organoids lacking Pax6 showed multiple phenotypes associated with its activity in mice, including precocious neural differentiation, altered cell cycle and an increase in abventricular mitoses. Neural progenitors in both Pax6 mutant and wild type control organoids cycled more slowly than their in vivo counterparts, but nonetheless we were able to identify clear changes to cell cycle attributable to the absence of Pax6. Our findings support the value of cerebral organoids as tools to explore mechanisms of brain development, complementing the use of mouse models.

Investigating subtle changes in facial expression to assess acute pain in Japanese macaques

Changes in facial expression provide cues for assessing emotional states in mammals and may provide non-verbal signals of pain. This study uses geometric morphometrics (GMM) to explore the facial shape variation in female Japanese macaques who underwent experimental laparotomy. Face image samples were collected from video footage of fourteen macaques before surgery and 1, 3, and 7 days after the procedure. Image samples in the pre-surgical condition were considered pain-free, and facial expressions emerging after surgery were investigated as potential indicators of pain. Landmarks for shape analysis were selected based on the underlying facial musculature and their corresponding facial action units and then annotated in 324 pre-surgical and 750 post-surgical images. The expression of pain is likely to vary between individuals. Tightly closed eyelids or squeezed eyes and lip tension were the most commonly observed facial changes on day 1 after surgery (p < 0.01974). A good overall inter-rater reliability [ICC = 0.99 (95% CI 0.75-1.0)] was observed with the method. The study emphasizes the importance of individualized assessment and provides a better understanding of facial cues to pain for captive macaque care.

Improvements in Estimating Bioaccumulation Metrics in the Light of Toxicokinetic Models and Bayesian Inference

The surveillance of chemical substances in the scope of Environmental Risk Assessment (ERA) is classically performed through bio-assays from which data are collected and then analysed and/or modelled. Some analysis are based on the fitting of toxicokinetic (TK) models to assess the bioaccumulation capacity of chemical substances via the estimation of bioaccumulation metrics as required by regulatory documents. Given that bio-assays are particularly expensive and time consuming, it is of crucial importance to deeply benefit from all information contained in the data. By revisiting the calculation of bioaccumulation metrics under a Bayesian framework, this paper suggests changes in the way of characterising the bioaccumulation capacity of chemical substances. For this purpose, a meta-analysis of a data-rich TK database was performed, considering uncertainties around bioaccumulation metrics. Our results were statistically robust enough to suggest an additional criterion to the single median estimate of bioaccumulation metrics to assign a chemical substance to a given bioaccumulation capacity. Our proposal is to use the 75th percentile of the uncertainty interval of the bioaccumulation metrics, which revealed an appropriate complement for the classification of chemical substances (e.g. PBT (persistent, bioaccumulative and toxic) and vPvB (very persistent and very bioaccumulative) under the EU chemicals legislation). The 75% quantile proved its efficiency, similarly classifying 90% of the chemical substances as the conventional method.

The Current Status and Work of Three Rs Centres and Platforms in Europe

The adoption of Directive 2010/63/EU on the protection of animals used for scientific purposes has given a major push to the formation of Three Rs initiatives in the form of centres and platforms. These centres and platforms are dedicated to the so-called Three Rs, which are the Replacement, Reduction and Refinement of animal use in experiments. ATLA's 50th Anniversary year has seen the publication of two articles on European Three Rs centres and platforms. The first of these was about the progressive rise in their numbers and about their founding history; this second part focuses on their current status and activities. This article takes a closer look at their financial and organisational structures, describes their Three Rs focus and core activities (dissemination, education, implementation, scientific quality/translatability, ethics), and presents their areas of responsibility and projects in detail. This overview of the work and diverse structures of the Three Rs centres and platforms is not only intended to bring them closer to the reader, but also to provide role models and show examples of how such Three Rs centres and platforms could be made sustainable. The Three Rs centres and platforms are very important focal points and play an immense role as facilitators of Directive 2010/63/EU 'on the ground' in their respective countries. They are also invaluable for the wide dissemination of information and for promoting the implementation of the Three Rs in general.

Expanding the role of the future zoo: Wellbeing should become the fifth aim for modern zoos

Zoos and aquariums have an enormous global reach and hence an ability to craft meaningful conservation action for threatened species, implement educational strategies to encourage human engagement, development and behavior change, and conduct scientific research to enhance the husbandry, roles and impacts of the living collection. The recreational role of the zoo is also vast- people enjoy visiting the zoo and this is often a shared experience amongst family and friends. Evaluating how the zoo influences this "captive audience" and extending its reach to include a compassionate approach to animals and people can further enhance the mission, value, and relevance of their work. The modern zoo's current aims-Conservation, Education, Research and Recreation-provide useful foundations for the activities that zoos conduct at a local and national level. However, to improve sustainability of their actions and outcomes, we feel that Wellbeing should become the fifth aim of the modern zoo for the future- both from an animal perspective (ensuring that populations are managed according to prevailing behavioral needs) and from a human perspective (enhancing access to nature, promoting planetary friendly behavior changes and ways of living, and advancing the wellbeing of the zoo's workforce). This paper provides discussion and review of how Wellbeing is already a substantial part of what zoos work on as well as posing the idea of altering the Recreation aim of the zoo to one of Engagement, which potentially is more measurable and therefore can allow zoo researchers and managers further options for the collection of evidence on the local and global reach of their zoo's aims. Education, Engagement, Conservation, Research and Wellbeing provide a more complete picture of the roles of the modern zoo for the animals (both in situ and ex situ), human visitors and workforce, and to society more widely.

Ischemic Stroke, Lessons from the Past towards Effective Preclinical Models

Ischemic stroke is a leading cause of death worldwide, mainly in western countries. So far, approved therapies rely on reperfusion of the affected brain area, by intravenous thrombolysis or mechanical thrombectomy. The last approach constitutes a breakthrough in the field, by extending the therapeutic window to 16-24 h after stroke onset and reducing stroke mortality. The combination of pharmacological brain-protective strategies with reperfusion is the future of stroke therapy, aiming to reduce brain cell death and decrease patients' disabilities. Recently, a brain-protective drug-nerinetide-reduced brain infarct and stroke mortality, and improved patients' functional outcomes in clinical trials. The success of new therapies relies on bringing preclinical studies and clinical practice close together, by including a functional outcome assessment similar to clinical reality. In this review, we focused on recent upgrades of in vitro and in vivo stroke models for more accurate and effective evaluation of therapeutic strategies: from spheroids to organoids, in vitro models that include all brain cell types and allow high throughput drug screening, to advancements in in vivo preclinical mouse stroke models to mimic the clinical reality in surgical procedures, postsurgical care, and functional assessment.

The neurobiology of pain and facial movements in rodents: Clinical applications and current research

One of the most controversial aspects of the use of animals in science is the production of pain. Pain is a central ethical concern. The activation of neural pathways involved in the pain response has physiological, endocrine, and behavioral consequences, that can affect both the health and welfare of the animals, as well as the validity of research. The strategy to prevent these consequences requires understanding of the nociception process, pain itself, and how assessment can be performed using validated, non-invasive methods. The study of facial expressions related to pain has undergone considerable study with the finding that certain movements of the facial muscles (called facial action units) are associated with the presence and intensity of pain. This review, focused on rodents, discusses the neurobiology of facial expressions, clinical applications, and current research designed to better understand pain and the nociceptive pathway as a strategy for implementing refinement in biomedical research.

Refining restraint techniques for research pigs through habituation

Pigs are common research models and are strong animals that can be difficult to restrain. Improper restraint can put pigs and research personnel at risk for injury and induce stress, which can affect research outcomes. This study aimed to refine restraint techniques for research pigs using habituation and operant conditioning. Forty-four (22 males, 22 females; 4 months old, ~8.1 kg) Göttingen minipigs were randomly assigned to a control (C: no interventions) or a treatment group (T). Pigs in the T group received 3 min training sessions 3 days/week for the first 14 d after arrival. Training sessions included human socialization and habituation to a hammock sling for blood collection. Blood collection occurred on day 13 for all pigs by novel technicians. Pigs were placed in the sling, blood was collected from the radial vein, and serum cortisol levels were determined (ug/dL). Pig behavior was recorded and scored for duration of time spent struggling (s) and vocalizing (s). Novel human approach tests occurred on day 12, before blood collection, and day 14, after blood collection. Pigs were scored on latency to touch the human (s) and duration of time spent in contact with the human (s). Pig weight was taken upon arrival and on day 15. Separate linear models were fitted for response variables struggle duration in sling, serum cortisol, latency to touch human, time spent in contact with human, and body weight. Fixed effects were treatment and sex. Prior to blood collection, there was no difference in response to a novel human (P &gt; 0.05) but after blood collection, T pigs were quicker to approach (estimate: −5.352, SE: 1.72, P = 0.003) and spent more time in contact with the novel human (estimate: 3.091, SE: 1.448, P = 0.039). T pigs also had lower cortisol levels during blood collection (estimate: −2.36, SE: 0.657, P = 0.001). There was no difference in behavior while in the sling (P &gt; 0.05). The results of the study suggest that even small investments in habituation and training pigs to study procedures is beneficial in reducing stress and improving human-animal relationships, but more time would be beneficial to promote calmer behavior in the sling.

Quantitative polymerase chain reaction in the bioanalytical laboratory and technical and scientific considerations for nonclinical and clinical assay characterization, validation and sample analysis

In this manuscript, the European Bioanalysis Forum reports back on their discussions on practical and scientific considerations related to bioanalytical applications of quantitative polymerase chain reaction. This publication follows an earlier publication in which the European Bioanalysis Forum recommends to consider principles of context of use when defining assay acceptance criteria for method validation criteria and sample analysis.

Performance of Marmoset Monkeys as Embryo Donors Is Reflected by Different Stress-Related Parameters

Non-human primates (NHPs) serve as embryo donors for embryo collection in order to mimic genetic diseases in humans by genetic modification. Reproductive health of the embryo donors is crucial, and chronic distress needs to be avoided. Embryo retrieval rates (ERR), anti-Müllerian hormone (AMH) concentrations, cortisol levels, and body weight fluctuations were assessed as markers for fertility and distress. With regard to successful embryo retrievals (total n = 667), the animals were either used for extended periods (long-term group; LTG) or only for short periods (short-term group; STG). Retrospective evaluation expectedly showed that animals in the LTG had a higher ERR than animals in the STG (p < 0.0001). Importantly, ERR in the LTG remained stable throughout the experimental period, and high embryo rates were already encountered during the first year of experimental use (p = 0.0002). High ERR were associated with high AMH and low cortisol levels, and minimal body weight fluctuations following anesthesia, indicating a superior ability of the LTG animals to handle distress. We conclude that the long-term experimental use of marmosets does not impair their fertility or health status per se, supporting the view that animal reuse can be in accordance with the 3R-principle, implying reduction, replacement, and refinement in animal experimentation.

Public concern for animal welfare and its correlation with ethical ideologies after coronavirus disease (COVID-19) in China

The outbreak of coronavirus disease (COVID-19) represents a major public health challenge and a serious threat to sustainable social development. A consideration of animal welfare is clearly justified, given the potential contribution of animals to the spread of the disease. The present study, therefore, sought to investigate the concern the Chinese people have for animal welfare (PCAW) and how their 'ethical ideology' (idealism and relativism) determines PCAW after COVID-19, through comparison with the same study, carried out in China in 2015. Our results demonstrated a significant improvement in Chinese PCAW after COVID-19. The adverse impact of COVID-19 may have resulted in a lowered idealism score and this decreased score served to neutralise significant correlations between idealism and PCAW, compared to the 2015 results. The global pandemic did not increase people's relativism score and a significant correlation was found between relativism and PCAW. Gender, age, educational level, public perception of animals after COVID-19, zoo and aquarium visiting were all shown to be predictor variables for PCAW. This study is one of the first to investigate Chinese PCAW after COVID-19 and can therefore provide knowledge that will potentially increase Chinese PCAW.