Protocol for necropsy and tissue processing of the common marmoset, Callithrix jacchus, for histopathological analysis

Common marmosets have attracted considerable attention as a small standard primate model in biomedical research. However, no marmoset diabetes model is available. Here, we established a marmoset diabetes model via the combination of partial pancreatectomy and intravenous streptozotocin (STZ). A partial pancreatectomy was performed in 11 common marmosets and multiple STZ doses were intravenously administered. Diabetes was diagnosed upon sustained hyperglycaemia (nonfasting blood glucose level >200 mg/dl). Blood glucose and biochemistry were periodically assessed, in addition to glucose tolerance testing, continual blood glucose determination using a continuous glucose monitoring system, urine testing and histological evaluation. In 8 of the 11 animals (73%), diabetes mellitus was induced. The diabetic marmosets also showed abnormal intravenous and oral glucose tolerance test results. Blood glucose levels decreased in response to human insulin administration. The hyperglycaemic state was irreversible and persisted for more than 3 months, and the animals’ condition was manageable via daily insulin administration. Thus, diabetes can be successfully induced and maintained in the common marmoset via partial pancreatectomy and STZ administration. This protocol effectively generates a valuable animal model for studying disease pathogenesis, risk factors and therapeutic interventions, including islet transplantation.

The common marmoset, Callithrix jacchus, is increasingly being used as the preferred nonhuman primate (NHP) model in biomedical research. Marmosets share severalphysiological and biological similarities with humans, as a Simiiformes species, and their use in research programs advances knowledge in several fields. Their unique characteristics, suchas their small size, high fecundity, and rapid growth, offer additional advances in laboratory settings. This article reviews the developments in experimental disease models using marmosetsbased on our experience at the Central Institute for Experimental Animals (CIEA) in Japan. The development of genetically modified marmoset models using advanced genome editing technology isattracting researchers, particularly in neuroscience-related fields. In parallel, various marmoset models of human diseases induced by surgery or drug administration have contributed topreclinical and translational studies. Among these are models for Parkinson’s disease induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, spinal cord injury models, a model for type 1diabetes induced by the combination of partial pancreatectomy and streptozotocin administration, and a hepatic fibrosis model induced by thioacetamide. The development of these models hasbeen supported by refinements in veterinary care, such as the careful design of anesthetic protocols and better understanding of pathogenic microorganisms. In the second part of this review,we present a compilation of practices currently in use at CIEA that provide optimal animal care and enable safe experimentation.

The common marmoset (Callithrix jacchus) is a New World Monkey that frequently serves as a model in biomedical research. Our knowledge of its anatomy is the fundament of the provision of the correct environment, housing, and care together with provision of accurate medical care in the case it gets wounded. In this anatomical research article, the focus is on the hand musculature, as it plays a pivotal role in the interaction with the environment and conspecifics. Surprisingly, anatomical works on the common marmoset are scarce. The available books and atlases are either outdated in terms of illustrations, providing only simplified line drawings, and/or fail to recapitulate the anatomy of the hand using contemporary anatomical nomenclature. The present work describes the myology of the hand, based on dissections of common marmoset cadavers. Color photographs taken during the subsequent steps of the examinations lead the reader through the textual descriptions. Dorsal and palmar views of the antebrachial muscles with influence on the wrist and hand as well as the intrinsic hand musculature are scrutinized. The findings are finally discussed in view of potential contradictions with the available literature. In addition, comparison is made with the rhesus monkey (Macaca mulatta) whose hand musculature was recently revisited. It is concluded that the hand musculature of both species is highly similar, although remarkable differences are present. This work could serve as an anatomical foundation for medical interventions of the injured hand.

The African clawed frog, Xenopus laevis, is a widely used model for biomedical research. X. laevis could be more useful as a model with a better method for collection and analysis of its blood and serum. However, blood collection in X. laevis can be challenging due to their small size, lack of peripheral vascular access, and species-specific hematology variables. The goal of this study was to compare cardiocentesis, the current gold standard terminal blood collection method, with a leg amputation technique. Blood samples were collected from 24 laboratory-reared X. laevis, randomized to either the cardiocentesis or leg amputation method, with 6 males and 6 females in each group. Hematology and serum biochemistry were also conducted to identify any lymph contamination in the samples. The leg amputation method produced significantly higher blood volumes in shorter times and showed no significant differences in clinical pathology parameters as compared with cardiocentesis. These results indicate that blood collection by leg amputation may be a valuable approach for increasing the utility of an already valuable biomedical research model.

Chapter 22 - The Marmoset as a Model for Visual Neuroscience

The common marmoset (Callithrix jacchus) has attracted extensive attention for use as a non-human primate model in biomedical research, especially in the study of neuropsychiatric disorders. However, behavioral test methods are still limited in the field of marmoset research. The light-dark box is widely used for the evaluation of anxiety in rodents, but little is known about light-dark preference in marmosets. Here, we modified the light-dark test to study this behavior. The modified apparatus consisted of three compartments: one transparent open area and two closed opaque compartments. The closed compartments could be dark or light. We found that both adult and young marmosets liked to explore the open area, but the young animals showed more interest than adults. Furthermore, when one of the closed compartments was light and the other dark, the adult marmosets showed a preference for the dark compartment, but the young animals had no preference. These results suggest that the exploratory behavior and the light-dark preference in marmosets are age-dependent. Our study provides a new method to study exploration, anxiety, and fear in marmosets.

Abstract: The use of animal models in research on human and veterinary diseases and disorders is retracting, though it is likely to remain critical for decades. In light of increasing regulation and expectations of judicious use of animal subjects, we examine the idea that the use of animal models can be guided by phylogenetic relationships and modern evolutionary and cladistic analyses. Given that inherited disorders, and indeed, even the developmental and physiological responses to non-inherited conditions, are subject to evolutionary forces, it follows that the observed differences in model organisms are the products of evolutionary divergence. Understanding that divergence has the potential to elucidate which taxa are most likely to exhibit any given symptom or manifest a reaction in a broadly predictable fashion. We examine two case studies, one the inherited disorder Duchenne Muscular Dystrophy, and the other an entirely environmentally induced problem, Fetal Alcohol Spectrum Disorder, or Fetal Alcohol Syndrome. Both case studies reveal symptoms are largely congruent with phylogeny, suggesting relatively conservative evolution of developmental pathways. It follows that it is possible to characterize the manifestation of symptoms or dysmorphologies to broad phylogenetic groups. These data can then be used to inform research into possible treatments based on molecular genetic techniques sourced from unaffected taxa or even provide an evolutionary rationale for maximizing ethical decisions in the use and development of animal models in biomedical research. We argue that the technique should become standard practice in the development of animal models.

An improved cryopreservation method for a mouse embryonic stem cell line

Squirrel monkeys have been a valuable animal model in biomedical research (Abee 2000). They have been utilized in a wide variety of study areas including, but not limited to, atherosclerosis, neuroscience, pharmacology, psychiatry, toxicology, and vision research. A quick search of on-line databases MEDLINE and PS YCHINFO indicates that approximately 200 articles have been published in the last 10 yr that have used behavioral testing of squirrel monkeys. Analysis of experimental manipulations of Saimiri behavior has been an important tool. Depending on the level of analysis needed, several different behavioral testing protocols have been used successfully in biomedical research using squirrel monkeys. If a predicted effect is on the whole organism, other than studying the natural behavior of an animal, investigating its interaction with social partners and its environment has been most appropriate. If the effects of interest are more limited, more specific tests of the squirrel monkey's motor performance, cognitive ability, or reflex actions may enable an investigator to isolate the consequence of the experimental intervention. The purpose of this article is to review how behavior has been employed using squirrel monkeys in biomedical research. We describe three general types of behavioral analysis: natural behavior, conditioned behavior, and neurobehavioral assessment profiles. Natural behavior refers to data collected on squirrel monkeys as they move about the environment. This type of analysis includes studies of animals in seminatural and captive laboratory environments as well as field studies. Although an investigator can arrange particular situations in all three study types, a key difference between behavioral analysis and conditioned tests is usually in the investigator's direct supply of rewards or punishments (conditions) in the latter. Conditioned behavior tests (cognitive, classical, and instrumental paradigms) are used to investigate the squirrel monkey's ability to learn or react to environmental stimuli. Classical conditioning entrains reflexive behavior to stimuli that do not normally elicit it. Cognitive and instrumental conditioning relies on animal tendencies to maximize rewards and minimize punishment in an effort to examine its

Aping Science: A Critical Analysis of Research at the Yerkes Regional Primate Research Center Committee on Animal Models in Biomedical Research. Perspectives on Medical Research Volume 5 (1995). Medical Research Modernization Committee: New York. 102 pp. Paperback. Obtainable from the publishers, Box 2751 Grand Central Station, New York, NY 10163-2751, USA. Price US2 postage. - Volume 6 Issue 1

The basic idea behind the use of 3-dimensional (3D) tools in biomedical research is the assumption that the structures under study will perform at the best in vitro if cultivated in an environment that is as similar as possible to their natural in vivo embedding. Tissue slicing fulfills this premise optimally: it is an accessible, unexpensive, imaging-friendly, and technically rather simple procedure which largely preserves the extracellular matrix and includes all or at least most supportive cell types in the correct tissue architecture with little cellular damage. Vibrating microtomes (vibratomes) can further improve the quality of the generated slices because of the lateral, saw-like movement of the blade, which significantly reduces tissue pulling or tearing compared to a straight cut. In spite of its obvious advantages, vibrating microtome slices are rather underrepresented in the current discussion on 3D tools, which is dominated by methods as organoids, organ-on-chip and bioprinting. Here, we review the development of vibrating microtome tissue slices, the major technical features underlying its application, as well as its current use and potential advances, such as a combination with novel microfluidic culture chambers. Once fully integrated into the 3D toolbox, tissue slices may significantly contribute to decrease the use of laboratory animals and is likely to have a strong impact on basic and translational research as well as drug screening.

Towards a 21st-century roadmap for biomedical research and drug discovery: consensus report and recommendations

The Lanyu pig, a genetically unique miniature breed native to Taiwan, represents a valuable yet under-characterised large-animal model in biomedical research. Here, we present a detailed magnetic resonance imaging (MRI) and computed tomography (CT)-based anatomical atlas of male and female Lanyu pigs at 5-6 months of age. MRI effectively visualised brain, reproductive and abdominal structures, with T1-weighted images providing sharp anatomical boundaries and T2-weighted images enhancing cerebrospinal fluid and soft-tissue contrast. CT provided high-resolution visualisation of skeletal and cardiovascular anatomy, including vascular imaging and 3D reconstructions. Quantitative MRI analyses revealed sex-specific differences in brain and cerebellar morphology, with females showing smaller brain, cerebellar and hemisphere widths but greater cerebellar length compared to males. Long bone measurements exhibited significant age × sex-dependent interactions, with females demonstrating earlier skeletal elongation and males showing a delayed growth surge. Myocardial thickness, however, displayed sex-specific patterns independent of age, with thicker left ventricular walls and interventricular septa in males. Comparative morphometric data from other miniature pig breeds highlight the distinctive developmental profile of Lanyu pigs and underscore their potential as a complementary model. The integration of surface scanning with vascular CT further extends applications to surgical planning and comparative vascular analysis. Beyond its descriptive value, this open-access dataset provides a reusable anatomical resource that supports functional anatomical interpretation, stereotactic procedures and ethical animal use under the 3Rs framework. Collectively, this atlas fills a critical gap in swine anatomy and supports the translational value of Lanyu pigs in biomedical and surgical studies.

The laboratory mouse is the most common used mammalian research model in biomedical research. Usually these animals are maintained in germ-free, gnotobiotic, or specific-pathogen-free facilities. In these facilities, skilled staff takes care of the animals and scientists usually don’t pay much attention about the formulation and quality of diets the animals receive during normal breeding and keeping. However, mice have specific nutritional requirements that must be met to guarantee their potential to grow, reproduce and to respond to pathogens or diverse environmental stress situations evoked by handling and experimental interventions. Nowadays, mouse diets for research purposes are commercially manufactured in an industrial process, in which the safety of food products is addressed through the analysis and control of all biological and chemical materials used for the different diet formulations. Similar to human food, mouse diets must be prepared under good sanitary conditions and truthfully labeled to provide information of all ingredients. This is mandatory to guarantee reproducibility of animal studies. In this review, we summarize some information on mice research diets and general aspects of mouse nutrition including nutrient requirements of mice, leading manufacturers of diets, origin of nutrient compounds, and processing of feedstuffs for mice including dietary coloring, autoclaving and irradiation. Furthermore, we provide some critical views on the potential pitfalls that might result from faulty comparisons of grain-based diets with purified diets in the research data production resulting from confounding nutritional factors.

There has been recent increasing interest in the use of marmosets, a New World primate species, as a model in biomedical research. One of the principal advantages of marmosets as a research model is their rich vocal repertoire and communicative vocal behaviors displayed both in the wild and in captivity. Studies of this species' vocal communication system have the potential to reveal the evolutionary underpinnings of human speech, and therefore are of interest to the neuroscience and biology research communities. Here a recent research into the behavioral and neurobiological basis of marmoset vocal communication was reviewed and they argued for their broader value as a neuroscientific model. They discuss potential avenues for future research including developmental neurobiology and the application of modern molecular tools to the study of primate communication. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 286-299, 2017.