Experimental Animals最新文献

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease that causes the selective loss of motor neurons. A histopathological hallmark of ALS is the cytoplasmic aggregation of TDP-43, a ubiquitously expressed RNA-binding protein involved in transcription and splicing regulation. To prevent abnormal accumulation, TDP-43 controls its expression levels through an autoregulatory feedback loop. While most ALS studies have focused on pathogenic variants that impair the protein function of TDP-43, the mechanisms underlying endogenous TDP-43 dysregulation mediated by non-coding elements, including the 3' untranslated region (3'UTR), remain incompletely understood. In this study, we generated a mouse model carrying a targeted deletion of the Tardbp 3'UTR that encompasses the TDP-binding region, polyadenylation signals, and alternative intronic sequences. Our findings demonstrate that the Tardbp 3'UTR is essential for normal mouse development. Loss of this region led to decreased Tardbp mRNA expression and embryonic lethality after gastrulation. Young heterozygous mice were phenotypically normal with no overt disruption in TDP-43 autoregulation. However, aged heterozygous mice displayed mild locomotor dysfunction accompanied by a modest increase in spinal cord TDP-43 protein levels and a reduction in motor neuron numbers. These findings indicate that regulatory elements within the Tardbp 3'UTR play a pivotal role in normal development and contribute to TDP-43 pathology relevant to ALS.

Emerging evidence indicates that oxidative stress in skeletal muscle is a prerequisite for sarcopenia in diabetic patients. In this study, we show that ubiquitin-specific protease (USP) 2 mitigates the accumulation of reactive oxygen species (ROS) in mature muscle cells. Treatment with ML364, a canonical USP2 inhibitor, robustly increased mitochondrial ROS in mouse C2C12 myotubes and caused an accompanying increase in the glutathione disulfide (GSSG)/glutathione (GSH) ratio. ML364 also caused mitochondrial damage in C2C12 myotubes, resulting in a reduction in intracellular adenosine triphosphate levels. Correspondingly, under diabetic condition, the muscle-specific Usp2-knockout (msUsp2KO) C57BL/6N mice exhibited a significantly higher lipid peroxide level and GSSG/GSH ratio in skeletal muscle than the control mice. The msUsp2KO mice also exhibited augmented insulin resistance and glucose intolerance, but showed no obvious deterioration in muscle weight or histology relative to the control mice. However, damaged mitochondria in the soleus muscle were more frequently observed in msUsp2KO mice than in the control mice. Together, these data suggest that USP2 mitigates ROS accumulation and subsequent mitochondrial damage in muscle cells in mice.

As aging affects the appearance of the skin, anti-aging research has intensified in dermatology, skincare, and aesthetic medicine. Because natural aging takes a very long time, one essential anti-aging approach is to pharmacologically mimic aging, such as with D-galactose treatment. Hairless mice (HR-1) have been extensively used in skin research because of their lack of body hair and ease of animal care. In the present study, HR-1 mice were treated with D-galactose to determine whether detrimental effects were induced in the skin. After 3 months of D-galactose treatment, AGEs in the skin significantly increased. On the other hand, no signs of skin disorders (dermal thickness, type I collagen content, expression of various genes, collagen synthesis, and degradation signals) were observed. Even when the concentration of D-galactose increased, no apparent changes in dermal thickness were observed. These findings suggest that D-galactose treatment induces AGEs accumulation but no further detrimental effects in the HR-1 skin.

The ε-containing GABA(A) receptors (GABAARs), a lesser-studied subtype within the GABAAR family, have garnered attention due to their distinct pharmacological properties and potential involvement in brain injury. Zolpidem (ZPM), a widely used Z-drug, is known to induce paradoxical effects in patients with brain injury, although the underlying molecular mechanisms remain unclear. In this study, a chronic cerebral hypoperfusion (CCH) rat model was established using Permanent Bilateral Occlusion of the Common Carotid Arteries (PBOCCA), followed by administration of ZPM at doses of 1.0, 2.0, and 4.0 mg/kg. Behavioral assessments demonstrated that the 1.0 mg/kg dose of ZPM significantly improved spatial learning and memory acquisition (P<0.01) and enhanced memory retention (P<0.001), whereas higher doses resulted in sedation and cognitive impairment. Immunohistochemical analysis revealed an upregulation of the ε subunit expression in the hippocampal CA1 and CA3 regions of CCH rats (P<0.05), suggesting alterations in receptor composition in response to cerebral hypoperfusion. Further investigation of ZPM's interaction with ε-containing GABAARs (specifically the α1β2ε subtype) was conducted using in silico techniques. Molecular docking identified the α1+/ε- binding interface as a favorable ZPM binding site, with key residues being either conserved or suitably replaced. Molecular dynamics simulations demonstrated that ZPM stabilizes the receptor while permitting conformational flexibility, consistent with its role as a positive allosteric modulator. These findings provide evidence that ZPM interacts with ε-containing GABAARs, potentially explaining its paradoxical effects observed in brain injury models.

The cynomolgus monkey (Macaca fascicularis) is an important experimental animal; however, its menstrual patterns, lifespan, and age-related changes in anti-Müllerian hormone (AMH) levels remain poorly characterized. This study aimed to analyze these factors and evaluate the usefulness of Cynomolgus monkeys in ovarian function research. The age at menarche was examined in 21 cynomolgus monkeys, and the age at menopause and age at death were tracked in another 22 postmenopausal monkeys. In addition, AMH levels were analyzed in 74 cynomolgus monkeys aged 0 to 33 years to evaluate ovarian reserve throughout their lives. Results showed a mean age at menarche of 3.69 ± 2.51 years, menopause at 27.00 ± 2.50 years, and a mean age at death of 32.04 ± 5.33 years. AMH levels throughout life showed a weak negative correlation with age. These findings suggest that changes in ovarian reserve throughout the life span of cynomolgus monkeys are similar to those in humans. To our knowledge, this study is the first to analyze menstruation, lifespan, and lifelong AMH levels in cynomolgus monkeys. Ovarian function throughout life, including childhood and postmenopause, was similar to that in humans, suggesting cynomolgus monkeys may be a useful experimental model.

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.