Articles

The authors used liquid chromatography–mass spectrometry to compare the metabolic profile of non-fasted and fasted plasma samples in the Nile rat model of type 2 diabetes. Metabolite measurements in non-fasted samples were more reproducible than in fasted samples, supporting the use of non-fasted plasma metabolomics to study glucose tolerance in Nile rats during diabetes progression.

Unpredictable chronic stress (UCS) increases anxiety/fear-related behavior and cortisol levels while decreasing locomotor performance, according to a systematic analysis of 38 studies on UCS in zebrafish. To further assess the effects of UCS on zebrafish behavior, future well-designed trials are required.

Two Cre-dependent reporter mice, oFluc and Akaluc, were created and tested for bioluminescence in neural tissues and organs. Both strains were brighter than the classical luciferase Luc2, potentially facilitating in vivo bioluminescence imaging of various tissues.

The authors developed an R package that enables the estimation of group size required for mouse breeding, taking into account Mendelian genetics, fertility and litter size.

The authors investigated the influence of housing density and bedding volume on ammonia build-up in two individually ventilated mouse cages models. While the amount of bedding had no influence on ammonia levels, smaller Type II individually ventilated cages accumulated higher ammonia levels than larger Type III individually ventilated cages, even at similar housing densities.

A mouse model to study norovirus pathogenesis is described. The murine norovirus strain WU23, originally isolated from an intestinal site, induces severe but self-resolving diarrhea in neonates, reflecting the pathology observed during human norovirus infection.

Tomsits and colleagues investigated the effects of medetomidine/midazolam/fentanyl and isoflurane/fentanyl narcosis on murine cardiac autonomic nervous activity and electrophysiology. The results show that, compared with medetomidine/midazolam/fentanyl narcosis, isoflurane/fentanyl narcosis seems to have no effect on cardiac autonomic nervous function and less influence on cardiac electrophysiology.

A large number of refinements have been studied with the aim to improve rat welfare, but more evidence is needed to fully understand their impact. This mapping review draws on the findings of 1,017 studies to show that different refinements impact different rats in different ways, and that a ‘one-size-fits-all’ approach to refinements might not be appropriate.

Using behavioral assays, transcriptome analysis and viral approaches to manipulate gene expression in the mPFC, Zhang et al. identified an important role for early growth response 2 (Egr2/Krox-20) in the development of social and cooperative behaviors in mice.

Rats undergoing the stress-enhanced fear learning procedure are usually housed in social isolation and exposed to a trauma-like experience of 15 massed electric footshocks. By showing that group-housed rats receiving fewer and lower-magnitude electric shocks still exhibit PTSD-relevant changes, this new study presents refinements of the procedure to reduce potential animal pain.

Sound levels, vibration, temperature, humidity and luminance were recorded in an animal facility that houses nonhuman primates; the findings may be used to characterize environmental conditions in similar primate facilities and inform best practices for nonhuman primate research and care.

Giannuzzi et al. present an integrated analysis of clinical features and exome and RNA sequencing data in a cohort of dogs with diffuse large B-cell lymphoma to better define the genetic landscape of this tumor and identify multiple mutations associated with the outcome.

In this article, the authors identify LanCL1 as a major male germ cell-specific antioxidant gene. Using different mouse models, they show that LanCL1 deficiency results in spermatozoal oxidative damage and impaired male fertility, while LanCL1 transgene expression protects mice against high-fat-diet-induced oxidative damage and subfertility.

In this article, Henry et al. examine how the geometry, size, opacity and depth of test chambers influence common behavioral responses in Artemia franciscana.

Survey data from 1,187 US biomedical researchers using vertebrate animals reveal diverse perspectives within the animal research community on issues of reproducibility and rigor, attrition rates in drug development, research oversight, and public engagement.

In this article, the authors characterize a new swine model of invasive pneumococcal pneumonia in mechanically ventilated pigs to mimic clinical conditions of critically ill patients.

Enchytraeus crypticus is a soil-dwelling annelid worm that has been used over the past two decades as an ecotoxicology model. Here, Mónica Amorim and colleagues present the first genome for E. crypticus. The authors identify a number of expanded gene families, including several involved with innate immunity.

In this article, the authors compared 24-h spontaneous locomotor activity in three different mouse strains (two inbred strains and one outbred strain) over a period of 2 months by using an automated recording home-cage device. Analysis of different metrics revealed strain-specific spontaneous locomotor patterns.

Long et al. examined the gut microbiome of C57BL/6 mice from two production sites of three different vendors upon receipt, and as the mice adapted to the new vivarium at the University of Connecticut Health Center. Bacterial proportional abundance varied among mice from each vendor, and mice from all vendors exhibited changes in microbial profiles over time. These findings support the need to consider the microbiome as a potential source of variation in mouse studies.

In this article, the authors evaluate the suitability and effectiveness of their micropipette-guided drug administration method as an alternative and non-invasive administration strategy for clozapine-N-oxide in chemogenetic studies using designer receptors exclusively activated by designer drugs.