Experimental Animals最新文献

Xylene, an aromatic hydrocarbon, is widely used as a solvent in industries, such as printing and rubber and leather manufacturing. Despite the significant industrial benefits of xylene, there are increasing concerns about its environmental and health impacts. However, the effects of early exposure to xylene on the central nervous system are poorly understood. Here, using novel and unique approach, we investigated the neurobehavioral effects of xylene using postnatal lactation C57BL/6N male mice (Mus musculus) exposed to 0 (control) or 2 different doses (2 or 20 ppm) of xylene for 7 consecutive days at 22 h/d. The concentrations of xylene used corresponded respectively to 40 and 400 times the indoor air quality standard in Japan. We examined the effects of xylene on the murine central nervous system using a battery of behavioral tests, comprising the open field test, light-dark transition test, and contextual-cued fear conditioning test at 12 weeks of age. We found that mice exposed to xylene (2 and 20 ppm) presented reduced spatial-associative or tone-cued associative memory in the contextual-cued fear conditioning test. In addition, immunohistochemical analysis revealed a decrease in doublecortin positive cells in the hippocampal dentate gyrus in the xylene exposure group compared with the control group. We confirmed that xylene exposure during postnatal lactation affects the formation of the neural circuit base and behavior in adulthood, suggesting that it is detrimental to postnatal brain development.

Xanthinuria type II is a rare hereditary disorder caused by mutations in the MOCOS gene, leading to dual deficiency of xanthine dehydrogenase and aldehyde oxidase. To establish a robust animal model for this condition, we generated Mocos knock-in (KI) rats carrying the Arg419Ter nonsense mutation identified in Japanese patients. Homozygous KI rats exhibited severe growth retardation, anemia, and reduced survival, with all individuals dying by 14 weeks of age. Biochemical analyses revealed elevated levels of hypoxanthine and xanthine, along with decreased uric acid in both serum and urine, confirming xanthinuria. Homozygous KI rats also showed increased blood creatinine (CRE) and urea nitrogen (UN), and decreased urinary CRE and UN, indicating renal dysfunction. Histopathological examination showed obstructive nephropathy characterized by tubular atrophy, crystal deposition, and inflammation. Compared to existing mouse models, Mocos KI rats demonstrated extended lifespan, enabling more detailed investigation of disease mechanisms. This rat model provides a valuable tool for studying the pathogenesis of xanthinuria type II and exploring potential therapeutic strategies.

Atherosclerosis (AS) is a chronic inflammatory disorder underlying most cardiovascular events. Sialic acid (SIA), a terminal metabolite of glycolipid catabolism, modulates vascular injury, but its role in endothelial dysfunction remains unclear. To investigate whether N-acetylneuraminic acid (Neu5Ac) accelerates AS development. ApoE⁻/⁻ mice were fed a high-fat diet to induce AS. Lesion burden was assessed by Oil Red O staining, plaque morphology by H&E staining, reactive oxygen species and macrophage polarization by flow cytometry, and signaling alterations by Western blotting. Neu5Ac markedly amplified systemic inflammation, enhanced atherosclerotic plaque formation, and disrupted lipid homeostasis. Neu5Ac exacerbates AS through pro-inflammatory, pro-lipid, and chemotactic/angiogenic mechanisms, highlighting potential therapeutic targets.

Macrophages can develop into pro-inflammatory M1-like macrophages and anti-inflammatory M2-like macrophages when stimulated by distinct internal environment. Dynamic changes of the two kinds of macrophages play key roles in atherosclerosis progression. The study aims to explore the role of RNF10 in regulating macrophage polarization during atherosclerosis. Mice with macrophage-specific depletion of RNF10 (RNF10^Mac-KO/ApoE^-/-) and control mice (RNF10^fl/fl/ ApoE^-/-) mice were fed with high-fat diet to generate atherosclerotic lesion, from which peritoneal macrophages were isolated and transfected with RNF10-overexpressing vector. Murine macrophages, RAW264.7, were transfected with RNF10-overexpressing vector or RNF10 siRNA and stimulated with oxidized low-density lipoprotein (ox-LDL) to induce foam cell formation. The RNF10^Mac-KO/ApoE^-/- mice showed greater atherosclerotic lesions, more resident macrophages, higher expression of iNOS (M1-like macrophage marker), and lower expression of Arginase-1 (M2-like macrophage marker) than the RNF10^fl/fl/ApoE^-/- mice. RNF10 overexpression could reduce expressions of IL-1β, IL-6, and iNOS (M1 marker genes), increase expressions of IL-10 and Arg-1 (M2 marker genes) in the peritoneal macrophages isolated from RNF10^Mac-KO/ApoE^-/- mice. RNF10 overexpression reduced lipid accumulation in ox-LDL-induced foam cells, whereas RNF10 silencing yielded opposite results. Our data suggest that RNF10 is associated with M1-like macrophage suppression and M2-like increase, indicating RNF10 in macrophages has an anti-atherosclerotic role.

Chemotherapy-induced alopecia (CIA) is one of the most apparent symptoms of side effects in a cancer patient undergoing chemotherapy using anti-cancer drugs, resulting in distress and a lower quality of life. Hence, this study investigated the protective and regenerative effects of Philippine stingless bee propolis on CIA in a murine model. Female C57BL/6N mice were subjected to hair cycle synchronization through depilation, followed by cyclophosphamide (CYP) administration to induce hair loss and graying. Daily topical application of 99.5% ethanol extracted propolis diluted twice with water was performed for 30 days. Results revealed that propolis-treated mice exhibited increased folliculogenesis and epidermal thickness, but not hair length, and improved melanogenesis compared to controls. Immunohistochemical and gene expression analyses revealed increased Ki67⁺ proliferative cells and reduced apoptosis (TUNEL⁺ cells) at the early 48 hours of topical treatment. Moreover, propolis upregulated expressions of Lef1 and melanogenic genes (Tyr, Tyrp1, Dct) at 30 days of treatment. These findings suggest that Philippine stingless bee propolis promotes hair follicle regeneration and melanocyte function, offering a potential natural therapeutic approach for CIA.

At the National Center of Geriatric and Gerontology (NCGG), aged mice and rats are used in research on aging and the treatment and prevention of gerontological diseases. Some of the most commonly used mouse strains in our center and general research were the C57BL/6J (B6J) and C57BL/6N (B6N). In this study, hematological and biochemical changes related to age, strain, and sex, from 3 months (mo) to 24 mo, were characterized every 3 mo in the B6J and B6N strains. Hematological results showed that in B6J males at 24 mo, the levels of WBC, especially lymphocytes, were higher than in the B6N strain. In males B6J, the number of CD4+ T cells did not decrease significantly between 6 and 24 mo, but in females and strain B6N, the number of CD4+ T cells decreased significantly. The levels of red blood cells (RBC) and hemoglobin (HGB) were reduced with age in all strains, while the number of platelets (PLT) increased. Biochemical parameters, Blood urea nitrogen (BUN) and Creatinine (CRE) in B6J males were significantly higher than in the other groups at 24 mo. Glutamate oxalacetate transaminase/aspartate aminotransferase (GOT/AST) and glutamate pyruvate transaminase/alanine aminotransferase (GPT/ALT) levels were higher in the B6N strain than the B6J strain at 24 mo. The present results revealed significant variations in hematological and biochemical parameters between the two strains and between sexes as a result of genetic and hormonal differences in laboratory mice.

Calcium/calmodulin-dependent protein kinase II (CAMKII) is a critical regulator of cardiac electrophysiology. However, the role of the four bases deletion polymorphism in Camk2d which codes delta subunit of CAMKII, particularly those involving intron sequences, remains poorly understood. This study aimed to investigate the impact of Camk2d c.1044+125_128delGTTT missing polymorphism on cardiac morphology and arrhythmogenesis in normal adult Sprague-Dawley (SD) rats. A total of 85 SD rats were genotyped by Sanger sequencing, revealing a distribution of 25.9% wild-type (WT), 48.2% heterozygous, and 25.9% homozygous variants. Echocardiography, Hematoxylin-Eosin staining, Masson's trichrome staining and transmission electron microscopy indicated no significant differences in cardiac structure or baseline function among the three groups. In freely moving rats, premature atrial arrhythmias were detected in 2 of 9 WT rats, 1 of 9 heterozygous rats, and 1 of 9 homozygous rats. Premature ventricular contractions (PVCs) were observed in none of 9 WT or homozygous rats, 3 of 9 heterozygous rats, with one heterozygous rat exhibiting frequent PVCs. Electrical programmed stimulation revealed a higher incidence of inducible atrial fibrillation in homozygous rats compared to WT rats and a higher incidence of inducible ventricular tachycardia in heterozygous rats compared to WT rats. These findings suggest that deletion polymorphism in the intron sequences of Camk2d are unexpectedly common in normal SD rat populations and that such polymorphism predispose to ventricular arrhythmias without overt structural heart disease. Our study highlights the potential arrhythmogenic risk associated with non-coding DNA sequence alterations in Camk2d and underscores the importance of genetic screening in experimental animal models.

Endothelial dysfunction (ED) plays a pivotal role in the pathogenesis of hypertension and its associated vascular complications. Qingda granule (QDG) exhibits significant antihypertensive properties and demonstrates therapeutic potential in ameliorating vascular dysfunction. This study aimed to explore QDG's role in alleviating endothelial injury in hypertension. An L-NAME (Nω-Nitro-L-arginine methyl ester)-induced hypertensive mouse model was used to evaluate the effects of QDG on blood pressure and endothelial function. Endothelial function was assessed through histological analysis, nitric oxide (NO) quantification, and vascular response measurements. To explore underlying mechanisms, network pharmacology was conducted using databases such as HERB, SwissTargetPrediction and STRING. Key pathways related to inflammation and cell adhesion were identified. Based on these findings, immunohistochemical staining was conducted to analyze the expression of phosphorylation of NF-kappaB p65 (p-NF-κB p65), NF-κB p65, intercellular adhesion molecule-1 (ICAM-1), and tumor necrosis factor-α (TNF-α) in vascular tissues. QDG treatment significantly reduced blood pressure, increased NO levels, and enhanced endothelial nitric oxide synthase (eNOS) expression in L-NAME-induced hypertensive mice, indicating its potential to restore endothelial function. Experimental validation further confirmed that QDG markedly suppressed the expression of p-NF-κB p65, TNF-α, and ICAM-1 in vascular tissues. These results suggest that QDG alleviates hypertension-induced ED primarily by inhibiting inflammation and endothelial adhesion via the NF-κB signaling pathway. Overall, QDG presents a promising therapeutic candidate for managing hypertension and its vascular complications.

In pharmaceutical development, weight loss is occasionally observed in monkeys during non-clinical toxicity studies and can be difficult to differentiate from drug effects. This study retrospectively analyzed data from control group monkeys without drug treatment to investigate the incidence of weight loss and its physiological and pathological characteristics. We also investigated potential improvements through enhanced animal welfare. In the 4- and 13-week toxicity studies conducted at the test facility from 2010 to 2022, 684 control group monkeys were investigated. Among them, 3 animals in the 4-week toxicity studies and 5 animals in the 13-week toxicity studies showed a weight change rate of less than -10%, resulting in an incidence rate of 1.2%. However, these animals had adequate food consumption. Animals in the 4-week toxicity studies showed signs of stress in histopathology. Additionally, 2/3 animals in the 4-week toxicity studies had decreased blood glucose levels and 1/5 animal in the 13-week toxicity study fell into a crouching posture, suggesting hypoglycemia that was alleviated with glucose administration, indicating stress-induced metabolic abnormalities. From 2015, an enrichment program was implemented to improve animal welfare. Prior to this program, 2.4% of animals showed a weight change rate of less than -10%, which dropped to 0.25% post-implementation, suggesting the program's effectiveness in reducing stress. These results clarify the characteristics of animals that lose weight during toxicity studies and suggest that improving animal welfare can reduce the incidence rate.

Allergic rhinitis (AR) is an inflammatory disorder driven primarily by aberrant T helper 2 (Th2) differentiation in CD4⁺ T cells. Although dual-specificity phosphatase 5 (DUSP5) has been implicated in inflammatory and autoimmune regulation, its role in AR remains unexplored. In this study, an AR mouse model was established via intraperitoneal sensitization and intranasal challenge with ovalbumin. We observed significant downregulation of DUSP5 expression in the nasal mucosa, particularly within CD4⁺ cells. To elucidate its function, a lentiviral vector overexpressing DUSP5 was constructed and used to transduce naive CD4⁺ T cells isolated from BALB/c mouse spleens. Overexpression of DUSP5 suppressed Th2-specific cytokine production and inhibited Th2 differentiation. Mechanistic investigations using a luciferase reporter assay revealed that Dusp5 is transcriptionally repressed by SRY-box transcription factor 11 (SOX11), a known transcription factor that promotes the progression of AR. Furthermore, DUSP5 overexpression counteracted the pro-Th2 effects mediated by SOX11. These results demonstrate that DUSP5, transcriptionally inhibited by SOX11, attenuates AR-associated inflammation by restraining Th2 differentiation. Our findings identify DUSP5 as a potential therapeutic target for AR.