Experimental Animals最新文献

DNA double-strand breaks (DSBs) are among the most hazardous cellular damages, potentially leading to cell death or oncogenesis if unrepaired. Genome editing methods, such as the CRISPR/Cas9 system, induce DSBs and utilize these repair pathways for gene knockout and knock-in. Although ionizing radiation also induces DSBs, it is not clear whether the efficiency of genome editing is affected by ionizing radiation. This study investigated the impact of gamma-ray exposure on the genome editing efficiency of the improved genome editing via oviductal nucleic acid delivery (i-GONAD) method. Gamma-rays were exposed to pregnant mice receiving i-GONAD targeting the Hr gene, whose mutation causes hair loss in mice. The exposure on the fertilization day (Day 0) decreased natural delivery rates and litter sizes, with notable effects at 0.3 Gy or higher. Although the proportions of hairless offspring obtained by i-GONAD differed greatly between single-guide RNAs (sgRNAs) used, total mutation rates, including hairless, mosaic, and indel, were equivalent. Gamma-ray exposure on Day 0 and the day after fertilization (Day 1) similarly and almost dose-dependently enhanced the genome editing efficiency evaluated by the total mutation rate. This study suggests the improvement of genome editing efficiency by gamma-ray exposure, at least in i-GONAD method, potentially facilitating the creation of diverse experimental animal models.

Chronic obstructive pulmonary disease (COPD) is a prevalent lung disease that mainly induced by cigarette smoking (CS). Soyasaponin I is an amphiphilic oleanane triterpenoid glycoside extracted form Astragali Radix. In order to investigate treatment strategies of COPD, this study focused on the effect of soyasaponin I on the lung tissue of COPD model. The mouse model of COPD was induced by CS exposure for 12 weeks, and was administrated with different doses of soyasaponin I. Subsequently, the morphology and histopathology of lung tissue, the proportion of inflammatory cell, the levels of inflammatory cytokines, and indicators of oxidative stress were assessed and analyzed. The signaling pathway potentially regulated by soyasaponin I in the pathogenesis of COPD were predicted by network pharmacology analysis and validated by western blot. Our results demonstrated that soyasaponin I mitigated the lung injury and bronchial lesions induced by COPD through reducing the lung coefficient, wall area of the bronchioles and Periodic Acid Schiff (PAS)-positive cells in the lung tissue. The CS-induced inflammation and oxidative stress was alleviated by soyasaponin I through reversing the levels of inflammatory cytokines and oxidative stress indicators. In addition, the phosphorylation of p38, JNK and ERK1/2 was activated in COPD model, and was reverted by soyasaponin I in the lung tissue. Collectively, the present study confirmed that soyasaponin I is an effective compound that attenuates the lung injury through inhibiting inflammatory response and oxidative stress via the mitogen-activated protein kinase (MAPK) signaling pathway.

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.

Uncontrolled activation of autophagy following ischemia/reperfusion (I/R) injury leads to cell death. The superfamily of ankyrin repeat proteins (N-Ank protein) was reported to be involved in autophagy regulation and cardiac protection. Bioinformatics analysis was performed (GSE61592 and GSE160516) and ten N-Ank proteins were differentially expressed in I/R models. Retinoic acid-induced protein 14 (RAI14), a member of N-Ank protein family, was upregulated in I/R-injured cardiac tissue and was first selected for research. A mouse I/R model was established by ligating the left anterior descending coronary artery to induce 90 min of ischemia, followed by 72 h of reperfusion. RAI14 was found upregulated in ischemic penumbra. RAI14 overexpression in cardiac tissue by injecting adeno-associated virus-9-RAI14 plasmid system via tail vein improved cardiac function and reduced infarct and apoptosis. Furthermore, the activated autophagy in ischemic penumbra of I/R mice was reversed by RAI14 overexpression along with decreased microtubule-associated protein 1 light chain 3 beta (LC3) II and increased autophagy receptor p62 expressions. RAI14 silence showed an opposite effect. A cell model was established by using mouse cardiomyocytes HL-1 underwent hypoxia/reoxygenation (H/R) treatment. Similarly, H/R also enhanced RAI14 expression and RAI14 overexpression inhibited H/R-induced apoptosis and autophagy in HL-1 cells. Mechanistically, autophagy inhibitor, the AKT/mTOR pathway, was found to be suppressed in mouse and cell models whereas RAI14 overexpression activated this pathway. Collectively, we demonstrated that compensatory increase of RAI14 inhibited I/R-induced myocardial injury by preventing excessive autophagy through activating the AKT/mTOR pathway, which providing an idea to explore strategies for preventing I/R injury.

The ratio of the second and fourth digits (2D:4D) is a morphological marker reflecting fetal exposure to sex steroid hormones. This ratio exhibits sexual dimorphism, with males typically showing a significantly lower ratio than females, which results from higher androgen exposure during the fetal period. While studies in humans have suggested a relationship between sexual orientation and the 2D:4D ratio, this relationship in rodents remains elusive. Here, we investigated this relationship using rats as an experimental model. We found that male rats exhibited significantly shorter 2D length than females, resulting in a lower 2D:4D ratio in males, similar to humans. Observations of sexual behavior revealed that males that ejaculated during the first mating test exhibited shorter 2D length compared to males those that did not ejaculate. When males were classified into two groups based on 2D length (long-2D and short-2D groups), short-2D males were more sexually active than long-2D males. Additionally, only short-2D males showed a preference for female odors. These findings suggest that, in rats, 2D length is a useful morphological marker reflecting sexual activity and preference. Furthermore, they provide evidence supporting the potential use of the 2D:4D ratio as a tool for studying the relationship between sexual orientation and the 2D:4D ratio in humans.

Translation regulation is crucial for cellular homeostasis. Recent studies have demonstrated that, in addition to the conventional AUG start codon, eukaryotic mRNA can also possess non-canonical start codons. These non-canonical start codons, including non-AUG codons, can be found both upstream and downstream of the conventional AUG start codon. Translation of these non-canonical open reading frames (ORFs) has been implicated in the development of diseases, such as cardiac diseases, neurodegeneration and cancer development. Non-AUG translation initiation is regulated by eukaryotic initiation factor (eIF) 2A and eIF2D; however, their target non-canonical ORFs, roles in disease development, and the underlying precise mechanisms of translation regulation remain poorly understood. To address these gaps, we generated mice lacking either or both of Eif2a and Eif2d genes on an ICR background and investigated their cardiac function using echocardiography. The results indicated that simultaneous disruption of both Eif2a and Eif2d led to perinatal cardiac impairment, as evidenced by a significant reduction in cardiac contractility as measured by ejection fraction. Furthermore, the absence of phenotypic changes in single knockouts of either Eif2a or Eif2d suggests that eIF2A and eIF2D function redundantly in their molecular roles. These findings underscore the importance of non-AUG translation initiation in maintaining cardiac function and suggest its broader implications in other physiological and pathological processes. We propose the Eif2a and Eif2d double-knockout mice as a novel stress-sensitive animal model to investigate the molecular mechanisms of translation regulation and their contribution to disease pathogenesis.

Injectable anesthesia is widely used in laboratory animals because of its ease of administration and minimal equipment requirements. However, it necessitates careful monitoring as well as thermal and oxygen support. This study evaluated the efficacy of medetomidine-alfaxalone-butorphanol (MAB) anesthesia in male rabbits using a dual-route administration protocol. The anesthetic doses were as follows: medetomidine, 0.2 mg/kg; alfaxalone, 2.0 mg/kg; and butorphanol, 2.0 mg/kg. MAB anesthesia, administered via intravenous and subcutaneous routes, induced rapid and smooth induction, achieving anesthetic scores comparable to those of medetomidine-midazolam-butorphanol (MMB) anesthesia. MAB anesthesia resulted in mild hypothermia during the procedure. Upon atipamezole administration, rabbits under MAB anesthesia exhibited faster recovery of the righting reflex and respiration rate than those under MMB. Importantly, no abnormal behaviors, such as jumping or agitation, were observed during induction or recovery, as reported with alfaxalone use in other species. Both protocols maintained spontaneous breathing, although transient hypoxemia was observed in all rabbits. The dual-route MAB protocol provided effective anesthesia while addressing the limitations of conventional MMB anesthesia in rabbits, suggesting its potential as a refined anesthetic method for this species. Unlike mice, which showed weaker anesthetic effects with MAB compared to MMB, MAB demonstrated superior anesthetic properties in rabbits. This study highlights the importance of species-specific anesthetic protocols and the potential benefits of MAB anesthesia in rabbits, particularly its smooth induction and recovery profile, without adverse behaviors often associated with alfaxalone in other species.

The Lepr gene encodes a receptor for leptin, a hormone instrumental in the regulation of appetite and metabolism. Mutations in the Lepr gene impair leptin signaling, leading to metabolic dysfunctions and facilitating the development of non-alcoholic fatty liver disease (NAFLD). In this study, we compared the NAFLD-associated phenotypes of two mutant strains of mice, C57BL/6J-Lepr^em1hwl/Korl (Lepr^em1hwl) and C57BLKS/J-Lepr^db/J (Lepr^db/db), carrying different alleles of the Lepr gene. Although both Lepr^em1hwl and Lepr^db/db mice were characterized by similar obesity phenotypes, leptin resistance, insulin resistance, and glucose intolerance, comparatively, Lepr^em1hwl mice were found to have relatively more severe hepatic steatosis, along with the upregulated expression of enzymes associated with lipogenesis and triglyceride synthesis, and, notably, the histological characteristics of steatohepatitis were observed only in these mice. In addition, compared with the Lepr^db/db mice, Lepr^em1hwl mice developed hepatic fibrosis characterized by elevated levels of collagen deposition and expression of profibrotic factors. Moreover, we detected elevated levels of pro-inflammatory mediators and increases in classically activated macrophage markers in the serum and liver, respectively, of Lepr^em1hwl mice. These findings highlight the distinct NAFLD-associated phenotypic differences between Lepr^em1hwl and Lepr^db/db mice, and thereby indicate that Lepr^em1hwl mice could serve as a valuable model for studying NAFLD, including steatohepatitis and fibrosis.

Archiving and sharing cryopreserved rat sperm can improve animal experiments' reliability, reproducibility, and sustainability in the scientific community. When sharing cryopreserved sperm from genetically engineered rats, a shipment system is required. Generally, a dry shipper, which can maintain at below -150°C, is the most widely used for sperm transport. However, using it for shipping cryopreserved sperm faces some difficulties, such as the risk of transporting hazardous materials (liquid nitrogen), its high cost, and the round-trip fee. Recently, the shipment of cryopreserved mouse sperm with dry ice at -79°C has been alternatively accepted in the scientific community. However, its outcome in terms of the fertilization and developmental abilities of the cryopreserved rat sperm was not examined. Therefore, this study aimed to examine the fertilization and developmental abilities of cryopreserved rat sperm after being stored in a deep freezer (-80°C) and dry ice (-79°C). We also demonstrated the transport of cryopreserved rat sperm in a Styrofoam box with dry ice. The fertilization rate of cryopreserved sperm stored in a deep freezer or dry ice was comparable to that in liquid nitrogen. In the transport experiment, the rat sperm transported between Kumamoto and Hokkaido maintained a high fertilization rate, and live pups were obtained from the embryos derived from the transported sperm. Fertilization and developmental abilities of cryopreserved rat sperm were maintained after shipment using a Styrofoam box with dry ice for storage.

Euthanasia agents should induce a rapid and painless loss of consciousness, followed by cardiopulmonary arrest and subsequent brain death. Injectable drugs such as pentobarbital sodium are commonly used for laboratory rodents due to their quick and smooth action. However, the discontinuation of pharmaceutical-grade pentobarbital sodium and secobarbital sodium in Japan, along with a global shortage of pentobarbital in late 2020, has increased the demand for new injectable euthanasia drugs. In Japan, the combination of medetomidine, midazolam, and butorphanol (MMB), as well as a newer formulation in which midazolam is replaced with alfaxalone (MAB), have been widely used as balanced anesthesia for rodents. To evaluate their potential as alternative euthanasia agents in mice, we compared mortality rates and the time intervals to the loss of the righting reflex, respiratory arrest, and cardiac arrest following anesthetic administration. An intraperitoneal injection of MAB at five times the anesthetic dose induced death within 10 min with the loss of the righting reflex, respiratory arrest, and cardiac arrest occurring at 1.5 min, 4 min, and 9 min respectively, in all mice, which was comparable to those observed with 300 mg/kg of secobarbital. In contrast, none of the mice administered MMB at five times the anesthetic dose experienced cardiopulmonary arrest within 30 min. Intraperitoneal overdose of MAB induces rapid and irreversible death, supporting its potential use as an effective euthanasia agent in mice.