Experimental Animals最新文献

In most cases, the diagnosis of diabetes in animal models is based solely on blood glucose levels. While hemoglobin A1c (HbA1c) is widely used in the diagnosis of diabetes in humans, it is rarely measured in mice in diabetes research. This is thought to be because there are no established reference values for mouse HbA1c, as well as the fact that there are very few reports on the variability and reproducibility of measurements taken using different devices. In this study, we measured HbA1c levels in diabetic mouse models using different devices based on different principles, including capillary electrophoresis, high-performance liquid chromatography, and enzymatic methods, and compared the results. A positive correlation was observed between blood glucose and HbA1c levels in all measurement methods, and high reproducibility was confirmed in the measurement of HbA1c. However, HbA1c levels measured using the enzymatic method were slightly higher than those measured using the other two methods. In addition, an examination of diabetic mice given a sodium-glucose cotransporter 2 inhibitor, which is used to treat diabetes, revealed that there was a 2-week difference in the fluctuation of mouse HbA1c levels compared with the fluctuation of blood glucose levels. Based on these results, it is thought that HbA1c can be a reliable indicator in diabetic mouse models, and it is expected to make the evaluation of abnormal glucose metabolism in mice more reliable.

Unbalanced redox homeostasis leads to the production of reactive oxygen species and exacerbates inflammatory bowel disease. To investigate the role of the transcription factor Nrf2, a major antioxidative stress sensor, in intestinal epithelial cells (IECs), we generated IEC-specific Nrf2 gene knock-in mice (Nrf2-vRes), which express Nrf2 only in IECs, using the cre/loxp system. Colitis was induced in wild-type (WT) mice, whole-body Nrf2-knockout (Nrf2-KO) mice, and Nrf2-vRes mice by administering dextran sulfate sodium (DSS) for 1 week (acute model) or intermittently for 5 weeks (chronic model). The mRNA and protein levels of NAD(P)H:quinone oxidoreductase 1 (NQO1), which is involved in the oxidative stress response in a manner regulated by Nrf2, were reduced in Nrf2-KO compared with those in WT, while these decreases were reversed in Nrf2-vRes at all timepoints. Nrf2-KO mice administered DSS developed more severe colitis with higher disease activity index, higher leucine-rich α2 glycoprotein in serum, shorter colon length, and more severe epithelial damage and infiltration of inflammatory cells histopathologically than did WT mice in the acute model; moreover, these exacerbations of colitis were ameliorated in Nrf2-vRes mice. However, these differences were not observed among the three sets of mice in the chronic model. IEC-specific expression of Nrf2 ameliorated DSS-induced acute colitis. These results suggest that Nrf2 expression in IECs plays a protective role against early-stage colitis and undertakes important regulatory functions during intestinal inflammation.

Rats (Rattus norvegicus) have been widely utilized as model animals due to their physiological characteristics, making them suitable for surgical and long-term studies. They have played a crucial role in biomedical research, complementing studies conducted in mice. The advent of genome editing technologies has facilitated the generation of genetically modified rat strains, advancing studies in experimental animals. Among these innovations, Cre-driver rat models have emerged as powerful tools for spatiotemporal control of gene expression. However, their development and characterization remain less advanced compared to mouse models. In this study, we developed liver-targeting Cre knock-in rats and reporter knock-in rats to evaluate Cre recombinase expression profiles in different genetic contexts. Our results revealed that insertion orientation and promoter origin significantly influence Cre expression patterns. Notably, forward insertion of the Albumin (Alb) promoter-driven Cre sequence at the ROSA26 locus resulted in ubiquitous Cre expression, while reverse insertion confined Cre expression predominantly to the liver. Interestingly, Cre expression under an endogenous Alb promoter unexpectedly induced expression in non-liver tissues, which may suggest a potential link to the in vivo dynamics of albumin. These findings underscore the importance of rigorous characterization in Cre-based transgenic systems. By elucidating the roles of promoter origin, insertion site, and orientation, our study provides valuable insights for optimizing Cre-driver rat models. These findings pave the way for refining genetic strategies to enhance tissue specificity and reliability in functional genomics and disease modeling.

This study aims to clarify the disruption of gut barrier and dysbiosis of the microbiota in an experimental macaque model with 6-year diabetes mellitus (DM), and provide evidence for the application of therapeutic strategies targeting the human microbiota in the future. A single intravenous injection of high-dose streptozotocin was used to induce the type 1 diabetes (T1D) macaque model. Hematoxylin-Eosin (HE) and Periodic Acid Schiff (PAS) staining were conducted to observe colon morphological changes. The composition of gut microbiota was detected using 16S rRNA gene sequencing, and bioinformatics analysis was adopted to predict alterations in the microbial phenotype and function. Obvious intestinal inflammation and decreased goblet cells were observed in T1D macaques. 16S rRNA gene sequencing suggested a significantly different β diversity of the microbiota in the T1D group, where expanded Proteobacteria (dominantly Escherichia-Shigella) and Actinomycetota (formerly known as Actinobacteria) replaced the dominance of Bacillota (formerly known as Firmicutes) and Bacteroidota (formerly known as Bacteroidetes), indicating an imbalance in the microbial composition. Archaea was identified as a biomarker between groups. Moreover, with the reduction of beneficial bacteria (Lactobacillaceae) and the increase of pro-inflammatory bacteria and opportunistic pathogens (Enterobacteriaceae), the phenotypes of the microbiota were reversed, resulting in abnormal up- (e.g., carbohydrate and amino acid metabolism) or down-regulation (e.g., protein digestion and absorption) of multiple metabolic pathways. There were intestinal structural disorders and gut microbiota dysbiosis in T1D macaques, indicating that strategies targeting gut microbiota may be effective to treat metabolic diseases like DM.

In mammals, blastocyst-stage trophectoderm (TE) contacts the maternal body at the time of implantation and forms the placenta after implantation, which supports the development of the fetus. Studying gene function in TE and placenta is important to understand normal implantation and pregnancy processes and their dysfunction. However, genetically modified mice are commonly generated by manipulating pronuclear-stage zygotes, which modify both the genome of the fetus and the placenta. Therefore, we previously developed TE/placenta-specific gene expression technology by transducing blastocysts with lentiviral vectors. However, the zona pellucida (ZP) needed to be removed before transduction. In this study, we examined various adeno-associated viral (AAV) vectors to develop a new TE/placenta-specific gene transduction method. As AAV1 can path through ZP, we succeeded in trophoblast-specific gene expression without ZP removal. Furthermore, TE cells genetically modified by AAV1-Cre contributed uniformly to the placenta. Our new technology contributes to advances in implantation and placenta research and leads to the development of new assisted reproductive technology.

In humans, cerebral malaria is the most common cause of malaria-related mortality. Mouse C57BL/6 (B6) sub-strains are the major model system for experimental cerebral malaria (ECM) as they show similar pathophysiology to human cerebral malaria after infection with the rodent malaria parasite Plasmodium berghei ANKA. This model system has been used to analyze the molecular mechanisms of cerebral malaria. To develop new mouse models, we analyzed the ECM susceptibility of NOD/Shi (NOD) and NSY/Hos (NSY) strains established from the non-inbred ICR strain. Both NOD and NSY strains exhibited clinical symptoms and pathologies similar to ECM in C57BL/6J (B6J) mice and died within 11 days of infection. Thus, the NOD and NSY strains are susceptible to ECM and may be useful as new ECM models. The ECM susceptibility of both strains is suggested to be due to homozygosity for the cerebral malaria susceptibility allele of the ECM susceptible ICR strain. Although analyses using B6 sub-strains have proposed that complement component 5 (C5) plays an important role in ECM pathogenesis, we found that C5 was not essential as the ECM susceptible NOD strain is C5 deficient. Thus, results obtained from B6 sub-strains may not reflect the full picture of ECM in mice. Comparative analyses of multiple ECM models will contribute to a more accurate identification of the factors essential for ECM.

Experimental autoimmune encephalomyelitis (EAE) serves as a model for studying multiple sclerosis, with immunization strategies utilizing myelin oligodendrocyte glycoprotein (MOG)_35-55 peptide, emulsified in adjuvant enriched with Mycobacterium tuberculosis (Mtb). This study examined the effects of Bacillus Calmette-Guérin (BCG) as an adjuvant, alongside the impact of MOG_35-55 peptide doses and their residual counter ions on EAE development. We found that BCG can be effectively used to induce EAE with similar incidence and severity as heat-killed H37Ra, contingent upon the appropriate MOG_35-55 peptide dose. Different immunization doses of MOG_35-55 peptide significantly affect EAE development, with higher doses leading to a paradoxical reduction in disease activity, probably due to peripheral tolerance mechanisms. Furthermore, doses of MOG_35-55 peptides with acetate showed a more pronounced effect on disease development compared to those containing trifluoroacetic acid (TFA), suggesting the potential influence of residual counter ions on EAE activity. We highlighted the feasibility of applying BCG to the establishment of EAE for the first time. Our findings emphasized the importance of MOG_35-55 peptide dosage and composition in modulating EAE development, offering insights into the mechanisms of autoimmunity and tolerance. This could have implications for autoimmune disease research and the design of therapeutic strategies.

Physiological responses to inhaled anesthetics vary among species. Therefore, a precise anesthetic technique is important for each individual species. In this study, we focused on the degu (Octodon degus), a small herbivorous rodent. Degus have recently begun to be used as laboratory models for brain research because of certain human-like characteristics, such as spontaneous development of Alzheimer's disease. In this study, we evaluated appropriate induction and maintenance anesthesia conditions for isoflurane and sevoflurane in degus by a stimulation test, electroencephalography (EEG), minimum alveolar concentration (MAC), and vital signs. During induction, more rapid time to loss of the righting reflex and deeper anesthesia in degus were observed in isoflurane. The MAC value for degus were 1.75 ± 0.0% in isoflurane and 2.25 ± 0.27% in sevoflurane. Whereas some degus were awake during maintenance anesthesia using both anesthetics at concentrations of ≤2%, no rats were awake when using sevoflurane at a concentration of 2%. The duration of the total flat EEG, a measure of the depth of maintenance anesthesia, was longer for isoflurane than for sevoflurane. Furthermore, higher concentrations of both anesthetics suppressed the respiratory rate in degus. These new findings regarding inhalation anesthesia in degus will contribute to future developments in the fields of laboratory animals and veterinary medicine.

Laboratory rats, like mice, are a type of animal commonly used in scientific investigations as well as in basic aging and geriatric research. The selection of a rat strain is an important first step in the planning and design of an experiment due to physiological, anatomical, and ethological variations in each strain, which may significantly modify the expected results. In the present study, we characterized age-related changes, from 3 months old (mo) to 24 mo, in three male rat strains commonly used in medical research: RccHan^®️:WIST (RccHan:WIST), F344/NSlc (F344), and Slc:SD Rat (SD). The body weight, water/food consumption, and survival rate of each strain were physiologically evaluated. Hematological and biochemical values were analyzed every three months. Hematological results showed a decrease in lymphocytes and increases in other leukocytes from 12 mo in F344 and SD rats. The incidence of hematological disorder was 10-15% in F344 and SD rats from 18 mo. Increases in hepatic biochemical parameters (alanine transaminase (GPT/ALT) and aspartate transaminase (GOT/AST)) and cytopathological parameters (creatine phosphokinase (CPK)) were observed in male F344 rats at 12 mo. Triglycerides (TG) serum levels were significantly elevated in the 12 mo RccHan:WIST rats, while Lipase (LIP) levels were significantly reduced in 24 mo. The present results revealed significant variations in hematological and biochemical values in the different laboratory male rat strains due to genetic and nutritional-metabolic factors specific to each strain.

Secondary brain injury (SBI) is one of the main causes of high mortality and disability rates following intracerebral hemorrhage (ICH). Tumor necrosis factor receptor-associated factor 6 (TRAF6) plays a crucial role in the process of pyroptosis, and modulating its expression may present a novel therapeutic strategy for mitigating brain injury. This study aims to explore the mechanisms of TRAF6 in pyroptosis after ICH. C57BL/6J mice were used to establish the ICH model. Brain was collected at different time points for q-PCR and western blot to detect the level of TRAF6. After the C25-140 (the TRAF6 inhibitor) was administrated, the mice were divided into four groups. Then, the neurological deficit, brain water content, and blood-brain barrier (BBB) damage were detected. Immunofluorescence and western blot were used to detect the level of pyroptosis proteins, and ELISA and q-PCR were used to detect the levels of IL-18 and IL-1β. TRAF6 expression was upregulated after ICH and was mainly expressed in neurons. Inhibition of TRAF6 expression with C25-140 alleviated neurological deficits and reduced brain edema after ICH. In addition, inhibition of TRAF6 also reduced the expression of pyroptosis inflammasomes such as GSDMD, NLRP3, and ASC, as well as neurological damage caused by IL-18 and IL-1β after ICH. TRAF6 regulates neuronal pyroptosis in SBI after ICH. Inhibition of TRAF6 may be a potential target for alleviating inflammatory damage after ICH.