Experimental Animals最新文献

Atopic dermatitis (AD) is a chronic skin disease that causes itching and is characterized by recurrent flares and remissions. The interactions among type 2 inflammation, skin barrier dysfunction, and pruritus play important roles in the pathogenesis of AD. AD symptoms persist for a long period; thus, it is desirable to have disease models that reproduce a prolonged AD-like phenotype. Although MC903-induced AD model mice reportedly exhibit type 2 inflammation, skin barrier dysfunction, and pruritus, the effects of long-term application of MC903 on the changes in these symptoms over time are not fully understood. To clarify this point, we conducted a long-term time course analysis of these symptoms by applying MC903 to the ears of mice every other day for four weeks. Increased ear thickness, transepidermal water loss, number of scratching events, and serum IgE levels were observed in the MC903 model. Histological analysis revealed the infiltration of granulocytes and CD3-positive T cells and an increase in mast cells in the dermis. Furthermore, analyses of mRNA and protein expression in ear tissue revealed increased expression of thymic stromal lymphopoietin, IL-4, IL-13, and IL-33, which are involved in type 2 inflammation. All these changes were observed within two weeks after the initial application of MC903 and thereafter persisted throughout the experimental period. In conclusion, our data indicate that the long-term application of MC903 prolongs the duration of the three major symptoms of AD.

Streptozotocin (STZ) is widely used as a pancreatic beta-cell toxin to induce experimental diabetes in rodents. Strain-dependent variations in STZ-induced diabetes susceptibility have been reported in mice. Differences in STZ-induced diabetes susceptibility are putatively related to pancreatic beta-cell fragility via DNA damage response. In this study, we identified two STZ-induced diabetes susceptibility regions in chromosome 11 (Chr11) of Nagoya-Shibata-Yasuda (NSY) mice via congenic mapping using the C3H-11^NSY consomic strains, in which the entire Chr11 of STZ-resistant C3H/He (C3H) mice was replaced with that of NSY mice, and named them STZ susceptibility region for NSY (Ssnsy)-1 and -2, respectively. Screening for variants in the Ssnsy1 region revealed that NSY mice exhibited a characteristic missense c.599G>T (p.G200V) variant in a highly conserved region within the DNA repair gene, RAD50 double-strand break repair protein (Rad50). Subsequently, we generated R2B1-Rad50 knock-in mice, in which c.599T in Rad50 of STZ-susceptible C3H.NSY-R2B1 subcongenic mice was replaced with c.599G via genome editing. Compared with C3H.NSY-R2B1 mice, and R2B1-Rad50 knock-in mice showed suppressed hyperglycemia, incidence of diabetes, and decrease in plasma insulin levels following single high-dose and multiple low-dose injections of STZ. Our results suggest Rad50 as a susceptibility gene for STZ-induced diabetes that is involved in pancreatic beta-cell fragility. Forward genetic approaches using inbred mouse strains with STZ susceptibility as a phenotypic indicator will further elucidate the molecular mechanisms of pancreatic beta-cell destruction via DNA damage response.

An unconventional myosin, myosin VI gene (MYO6), contributes to recessive and dominant hearing loss in humans and mice. The Kumamoto shaker/waltzer (ksv) mouse is a model of deafness resulting from a splice-site mutation in Myo6. While ksv/ksv homozygous mice are deaf due to cochlear hair cell stereocilia fusion at the neonatal stage, the hearing phenotypes of ksv/+ heterozygous mice have been less clear. Due to this splicing error, most MYO6 protein expression is lost in ksv mice; however, MYO6 with a single amino acid mutation (p.E461K) remains expressed. In this study, we investigated the hearing phenotypes and effect of a p.E461K mutation in ksv/+ heterozygous mice. Hearing tests indicated that hearing loss in ksv/+ mice arises concurrently at both low and high frequencies. In the low-frequency region, stereocilia fusions were detected in the inner hair cells of ksv/+ mice. Expression analysis revealed abnormal MYO6 expression and localization, along with atypical expression of proteins in the basal region of the stereocilia, suggesting that these abnormalities may contribute to stereocilia fusion in ksv/+ mice. Conversely, although the expression patterns of MYO6 and stereociliary basal-region proteins appeared normal in the cochlear area corresponding to high-frequency sounds, stereocilia loss in the outer hair cells was observed in ksv/+ mice. These findings suggest that the ksv/+ mice exhibit distinct mechanisms underlying hearing loss across areas responsible for low- and high-frequency hearing, differing from those previously reported in heterozygous Myo6 mice with loss-of-function and missense mutant alleles.

Beige adipocytes arise from white adipocytes in response to cold or other stimuli, known as browning of white adipose. Beige adipocytes play a role similar to that of brown adipocytes, express high levels of uncoupling protein 1 (UCP1), and are responsible for energy consumption via heat production, thus aiding in fat loss. Although histidine (His) and soy isoflavone (Iso) co-ingestion reportedly reduces food intake, body weight, and fat accumulation in female rats, the underlying mechanism remains unclear. Therefore, this study aimed to elucidate the mechanisms whereby histidine and soy isoflavone (His-Iso) co-ingestion suppresses fat accumulation. Female rats were fed a control diet or diet containing Iso, His, or His-Iso for 2 weeks, followed by sampling of periovarian white adipose tissue (poWAT) and retroperitoneal white adipose tissue (rWAT) and adipocyte morphology analysis. Additionally, the expression of browning- and lipid metabolism-related genes was examined. Histochemical analysis revealed the presence of multicellular lipid droplets, representative of beige adipocytes, in the poWAT and rWAT of rats in the His-Iso co-ingestion group. Quantitative PCR analysis showed that His-Iso co-ingestion upregulated brown adipocyte and beige adipocyte markers, including UCP1, indicating that His-Iso intake induces beige adipocytes. Moreover, His-Iso co-ingestion upregulated genes related to fatty acid oxidation (carnitine palmitoyl transferase 1A) and lipolysis (adipose triglyceride lipase) in WATs. In conclusion, His-Iso co-ingestion increases UCP1 expression and morphological changes to beige adipocytes, and suppresses fat accumulation by promotion of lipolysis and fatty acid oxidation in WAT.

Aging is a complex biological process. Several animal models, including nematodes, Drosophila, and rodents, have been used in research on aging mechanisms and the extension of healthy life expectancy. The present study investigated the physiological and anatomical changes associated with aging in two sub-strains of aged C57BL/6 mice used in aging research: C57Bl/6NCrSlc (B6N) and C57BL/6J (B6J). The survival rate before 24 mo was higher in B6J mice than in B6N mice; however, after 24 mo, it was markedly lower in the former than in the latter. Body weight increased in male C57BL/6 mice until 15-18 mo and in females until 21-24 mo and then began to decrease. Body temperature was lower in B6N mice than in B6J mice until 24 mo. Food and water intakes increased from 18 mo in both strains. The incidence of alopecia was higher in female C57BL/6J mice from 3 mo. Necropsy findings showed a high rate of spontaneous tumors in both sub-strains. The incidence of cutaneous ulcerative infections and hepatic pathologies was significantly higher in the B6N strain. A high incidence of renal lesions was also observed in B6J mice, particularly in males. These results provide insights into the characteristics of these sub-strains and the phenotypic changes associated with aging, which will facilitate the use of aged mice as a quality resource for geriatric and gerontological research.

This study evaluated the therapeutic potential of omentin-1 in preeclampsia (PE), focusing on fetal outcomes, vascular function, and inflammation. A PE-like mouse model received recombinant human omentin-1 protein (rh-omentin) from gestation day (gd) 13.5 to 16.5. On gd 17.5, fetuses and placentas were weighed, and serum sFlt-1 levels were measured. Maternal aortic rings were used for ex vivo vascular reactivity assays. Inflammatory factors and KLF2 expression in placental and aortic tissues were assessed using qPCR. HUVECs were exposed to plasma from PE patients or healthy pregnant individuals to evaluate omentin-1 and KLF2 expression by qPCR, with additional evaluation of KLF2 after rh-omentin treatment. Rh-omentin treatment reduced blood pressure in the PE-like model, accompanying by increased fetal and placental weights and higher fetal/placental weight ratios compared to untreated PE mice. Additionally, rh-omentin enhanced endothelial function in maternal aortic rings, as well as reduced placental necrosis and promoted CD31-positive vasculature in the labyrinth zone. Moreover, rh-omentin decreased pro-inflammatory factors (Il-1β, Il-6, and Tnf-α) in aortic and placental tissues of PE mice. KLF2 expression was restored in both aortic and placental tissues of PE mice and in HUVECs exposed to PE plasma following rh-omentin treatment. Rh-omentin improved fetal and placental outcomes in PE-like mice, enhancing vascular function and reducing inflammation in aortic and placental tissues. It also restored KLF2 expression in PE tissues and HUVECs exposed to PE plasma, suggesting therapeutic potential for addressing endothelial dysfunction in PE.

At present, there lacks a definitive pharmaceutical intervention or therapeutic approach for diabetes-associated cognitive impairment. Herein, we delved into the impact of electroacupuncture on cognitive function in high-fat diet/streptozocin (HFD/STZ)-induced T2DM mice and underlying mechanisms. Hippocampal insulin resistance was determined by western blot analysis. Cognitive function was evaluated by Morris water maze test. The morphology of the hippocampal neurons was observed through hematoxylin & eosin staining and Nissl staining. Synaptic plasticity was assessed by western blot analysis. Immunofluorescence, immunohistochemistry, western blot and real-time PCR were employed to detect the levels of ferroptosis markers, autophagy markers, and netrin-1. Electroacupuncture treatment exhibited ameliorative outcomes on spatial learning, memory function, hippocampal insulin resistance, neuronal damage, and synaptic plasticity in T2DM mice. Furthermore, it effectively suppressed neuronal ferroptosis within the hippocampus by upregulating GPX4 and SLC7A11 expression, and reducing 4-HNE expression. Meanwhile, electroacupuncture intervention increased the levels of Beclin1 and LC3II/LC3I, as well as decreased the levels of p62 and phosphorylated-mTOR in the hippocampus of T2DM mice, suggesting that electroacupuncture facilitated autophagy activation by inhibiting mTOR activity. 3-MA-mediated autophagy inhibition undermined the beneficial effects of electroacupuncture on neuronal ferroptosis and cognitive deficits in T2DM mice. Additionally, the beneficial effects of electroacupuncture on autophagy and ferroptosis was achieved by upregulation of netrin-1 in the hippocampus. Our study revealed that that electroacupuncture therapy inhibited neuronal ferroptosis via the activation of autophagy, thereby ameliorating cognitive deficits in T2DM mice.

This study aimed to determine the feasibility of using perfusion computed tomography (CT) to assess blood flow in different regions of the stomach in dogs. Dynamic perfusion CT scans were conducted on five beagle dogs, and blood flow analysis was performed using the maximum slope and Patlak plot methods. The findings revealed significant variations in blood flow among the fundus, body, and pylorus of the stomach. Specifically, the body showed approximately 1.3 times higher blood flow than the fundus and approximately 5 times higher blood flow than the pylorus. There were no significant differences in blood flow between the two analysis algorithms. The findings suggest that gastric perfusion CT can accurately detect variations in blood flow within the stomach. Using the maximum slope method for analysis allows for noninvasive and rapid measurement of gastric blood flow. This technique may have clinical applications in detecting submucosal diseases that are challenging to identify with endoscopies and serve as a valuable noninvasive tool for longitudinal observations in experimental animal studies.

After in vitro maturation (IVM) of porcine germinal vesicle (GV) oocytes, those that matured to the metaphase II (MII) stage were selected for further culture over a period of 24-48 h. Subsequently, these oocytes were either parthenogenetically activated or used for somatic cell nuclear transfer (SCNT) to evaluate their in vitro developmental competence. Parthenogenetically activated MII oocytes developed to the blastocyst stage after 42 h of continuous culture, whereas SCNT oocytes reached the blastocyst stage within 30 h of culture. These findings suggest that porcine MII oocytes retain their developmental competence after extended in vitro culture exceeding 30 h. This study highlights the potential of prolonged culture in enhancing the utility of MII-stage oocytes for livestock applications and possibly for future advancements in human infertility treatments.

Medetomidine, midazolam, and butorphanol (MMB) anesthesia is the preferred choice for rodents but requires excess volume of intramuscular injection in rabbits, which can lead to muscular damage. This study aimed to evaluate a dual-route MMB administration via the intravenous and subcutaneous routes in rabbits. MMB was administered to male Kbs:JW rabbits with an intravenous injection of 0.2 mL/kg followed by a subcutaneous injection of 0.8 mL/kg, totaling 0.2 mg/kg medetomidine, 2.0 mg/kg midazolam, and 2.0 mg/kg butorphanol. We compared the anesthetic effects of this dual-route method with those of intramuscular administration. The dual-route method resulted in a shorter induction time and similar anesthetic duration compared with those of the intramuscular route. While it induced a temporary decrease in body temperature within 30 min post-injection, other vital signs, such as respiration rate, heart rate, and O₂ saturation, remained similar. Notably, unlike intramuscular administration, dual-route administration did not increase tissue injury marker levels. This dual-route MMB administration provided sufficient anesthetic depth during surgery, eliminating pain reflexes. Double-dose administration extended anesthetic duration but resulted in rare fatalities, indicating room for protocol improvement. In conclusion, the novel anesthetic method is preferable for injectable anesthesia in rabbits, providing rapid induction and sufficient anesthetic duration, while potentially minimizing muscle injury. This technique may be beneficial for both laboratory and companion animals and significantly enhance animal welfare in anesthesia by reducing the pain associated with injectable anesthesia.