Since the late 18th century, the murine model has been widely used in biomedical research (about 59% of total animals used) as it is compact, cost-effective, and easily available, conserving almost ...99% of human genes and physiologically resembling humans. Despite the similarities, mice have a diminutive lifespan compared to humans. In this study, we found that one human year is equivalent to nine mice days, although this is not the case when comparing the lifespan of mice versus humans taking the entire life at the same time without considering each phase separately. Therefore, the precise correlation of age at every point in their lifespan must be determined. Determining the age relation between mice and humans is necessary for setting up experimental murine models more analogous in age to humans. Thus, more accuracy can be obtained in the research outcome for humans of a specific age group, although current outcomes are based on mice of an approximate age. To fill this gap between approximation and accuracy, this review article is the first to establish a precise relation between mice age and human age, following our previous article, which explained the relation in ages of laboratory rats with humans in detail.
Display omitted
To investigate the prevalence of murine astrovirus (MuAstV) in mice in laboratory animal facilities in Japan, a polymerase chain reaction (PCR) test targeting the RNA-dependent RNA polymerase (RdRP) ...gene was performed on the cecum contents of 1,212 mice (1,183 immunocompetent mice and 29 immunodeficient mice) from 226 facilities. The results showed that 118 (52.2%) of the 226 facilities were positive for MuAstV. Out of the 1,212 mice, 424 (35.0%) were positive. No gross lesions were observed in any of the mice examined. A phylogenetic analysis for 15 selected strains revealed that 13 strains formed one cluster, while two were genetically distant from that cluster. These results suggest that multiple strains are prevalent in laboratory mice in Japan.
Understanding the impact of oral health on rheumatoid arthritis (RA) will inform how best to manage patients with both periodontitis and RA. This review seeks to provide an update on interventional ...and mechanistic investigations, including a brief summary of European Research programs investigating the link between periodontitis and RA. Recent clinical studies are described that evaluate how the treatment of one disease impacts on the other, as are studies in both humans and animal models that have sought to identify the potential mechanisms linking the two diseases.
Small animal models are of crucial importance for assessing COVID-19 countermeasures. Common laboratory mice would be well-suited for this purpose but are not susceptible to infection with wild-type ...SARS-CoV-2. However, the development of mouse-adapted virus strains has revealed key mutations in the SARS-CoV-2 spike protein that increase infectivity, and interestingly, many of these mutations are also present in naturally occurring SARS-CoV-2 variants of concern. This suggests that these variants might have the ability to infect common laboratory mice. Herein we show that the SARS-CoV-2 beta variant attains infectibility to BALB/c mice and causes pulmonary changes within 2-3 days post infection, consistent with results seen in other murine models of COVID-19, at a reasonable virus dose (2 × 10
PFU). The findings suggest that common laboratory mice can serve as the animal model of choice for testing the effectiveness of antiviral drugs and vaccines against SARS-CoV-2.
Free-living mammals, such as humans and wild mice, display heightened immune activation compared with artificially maintained laboratory mice. These differences are partially attributed to microbial ...exposure as laboratory mice infected with pathogens exhibit immune profiles more closely resembling that of free-living animals. Here, we examine how colonization by microorganisms within the natural environment contributes to immune system maturation by releasing inbred laboratory mice into an outdoor enclosure. In addition to enhancing differentiation of T cell populations previously associated with pathogen exposure, outdoor release increased circulating granulocytes. However, these “rewilded” mice were not infected by pathogens previously implicated in immune activation. Rather, immune system changes were associated with altered microbiota composition with notable increases in intestinal fungi. Fungi isolated from rewilded mice were sufficient in increasing circulating granulocytes. These findings establish a model to investigate how the natural environment impacts immune development and show that sustained fungal exposure impacts granulocyte numbers.
Display omitted
•Controlled release of lab mice into the wild alters the state of the immune system•Rewilded mice harbor an altered microbiota including increases in intestinal fungi•Fungi from rewilded mice induce granulocyte expansion in laboratory mice
Laboratory mice are maintained in artificial conditions that potentially impact immunity. In this issue of Cell Host & Microbe, Yeung et al. (2020) demonstrate that mice released into a wild enclosure display increases in circulating granulocytes that are associated with an altered microbiota, notably expansion of fungi.
•We present a novel judgment bias task to assess affective state in mice.•Environmentally enriched housing was used to manipulate mouse affective state.•Enriched mice responded to ambiguity with ...relative optimism, validating the task.•The task was also used to assess judgment bias in tumor-bearing nude mice.•With a shorter protocol, males but not females met technical criteria for the task.•Tumor-bearing males were more pessimistic than healthy controls.
In humans, affective states can bias responses to ambiguous information: a phenomenon termed judgment bias (JB). Judgment biases have great potential for assessing affective states in animals, in both animal welfare and biomedical research. New animal JB tasks require construct validation, but for laboratory mice (Mus musculus), the most common research vertebrate, a valid JB task has proved elusive. Here (Experiment 1), we demonstrate construct validity for a novel mouse JB test: an olfactory Go/Go task in which subjects dig for high- or low-value food rewards. In C57BL/6 and Balb/c mice faced with ambiguous cues, latencies to dig were sensitive to high/low welfare housing: environmentally-enriched animals responded with relative ‘optimism’ through shorter latencies. Illustrating the versatility of this validated JB task across different fields of research, it further allowed us to test hypotheses about the mood-altering effects of cancer in male and female nude mice (Experiment 2). Males, although not females, treated ambiguous cues as intermediate; and males bearing subcutaneous lung adenocarcinomas also responded more pessimistically to these than did healthy controls. To our knowledge, this is the first evidence of a valid mouse JB task, and the first demonstration of pessimism in tumor-bearing animals. This task still needs to be refined to improve its sensitivity. However, it has great potential for investigating mouse welfare, the links between affective state and disease, depression-like states in animals, and hypotheses regarding the neurobiological mechanisms that underlie affect-mediated biases in judgment.
The aim of the study was to investigate the morphological changes in the testes of the offspring of white non-pedigreed laboratory mice when the synthetic oestrogen analogue synestrol was prenatally ...injected to the mother. After fertilization, the females were divided into 2 groups which received a single intramuscular injection of the synthetic oestrogen analogue synestrol on day E 11.5 of gestation at the same time of the day. The intact group was not exposed to any treatment. The experimental group was exposed to synestrol, a synthetic oestrogen analogue, as a 2% oil solution at a dose of 40 µg/kg (C-40). The results of morphometric analysis of testes of descendants of white outbred laboratory mice after prenatal single injection of synthetic oestrogen analogue synestrol in a dose of 40 µg/kg showed morphological changes in the organ parenchyma, manifested as decrease in mean number of Sertoli cells (C-40) 17.4±1.1 compared to intact group 20.8±1.9; decrease in mean number of spermatogonia (C-40) 24.4±1.1 compared to intact group, decrease in mean number of spermatozoa (C-40) 178.0±4.2 compared to intact group 196.6±5.3. There was observed a change in the endocrine apparatus of testes, expressed as a decrease in the mean area of Leydig cell nuclei in the intact group of 6,72±1,78. Prenatal effects of synestrol revealed in an experimental model, allow us to use it to search for means of postnatal developmental testicular dysfunction correction as well as to develop optimal doses of oestrogenic preparations during pregnancy.
PDF
