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<i>In vivo</i> imaging reveals reduced activity of neuronal circuits in a mouse tauopathy model
摘要： Pathological alterations of tau protein play a significant role in the emergence and progression of neurodegenerative disorders. Tauopathies are characterized by detachment of the tau protein from neuronal microtubules, and its subsequent aberrant hyper-phosphorylation, aggregation and cellular distribution. The exact nature of tau protein species causing neuronal malfunction and degeneration is still unknown. In the present study, we used mice transgenic for human tau with the frontotemporal dementia with parkinsonism-associated P301S mutation. These mice are prone to develop fibrillar tau inclusions, especially in the spinal cord and brainstem. At the same time, cortical neurons are not as strongly affected by fibrillar tau forms, but rather by soluble tau forms. We took advantage of the possibility to induce formation of neurofibrillary tangles in a subset of these cortical neurons by local injection of preformed synthetic tau fibrils. By using chronic in vivo two-photon calcium imaging in awake mice, we were able for the first time to follow the activity of individual tangle-bearing neurons and compare it to the activity of tangle-free neurons over the disease course. Our results revealed strong reduction of calcium transient frequency in layer 2/3 cortical neurons of P301S mice, independent of neurofibrillary tangle presence. These results clearly point to the impairing role of soluble, mutated tau protein species present in the majority of the neurons investigated in this study.
关键词： neurofibrillary tangles,two-photon imaging,tau,seeding,P301S mice
更新于2025-11-21 11:08:12
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Isolation and Culture of Primary Mouse Retinal Pigment Epithelial (RPE) Cells with Rho-Kinase and TGFβR-1/ALK5 Inhibitor
摘要： Primary RPE cells could be a reliable model for representing in vivo status of RPE compared with cell lines. We present a protocol for in vitro isolation and culture of primary RPE cells from C57BL mice. We used C57BL mice ages 7 days to 4 months. The RPE layer was separated from the neural retina layer by digestion with 2% Dispase for 45 min and scraped off from the choroid after 25-min incubation in 37°C. Collected RPE sheets were gently pipetted up into smaller sheets. RPE sheets were transferred into well plates and cultured in vitro for 2 weeks. To inhibit epithelial-mesenchymal transition (EMT) of RPE cells, we used Y27632 and Repsox to treat cultured primary RPE cells. RPE cells isolated from C57BL mice maintained pigmented and hexagonal morphology in culture. However, long-term in vitro culture lead to the periphery cells of a RPE sheet becoming mesenchymal-like cells. In contrast to the control group, Y27632 and Repsox, which are inhibitors of Rho-kinase or TGFbR-1/ALK5, promoted primary RPE cells to maintain epithelial-like morphology and eventually become confluent. RPE cells isolated from C57BL mice could be a powerful cell model to study the biological function of RPE. Especially, C57BL mice with different defective genetic background resulting in ocular diseases, would expand the genome type of RPE cells. The method presented here could be an efficient and applicable technique to obtain large numbers of primary RPE cells that maintain some characteristics of in vivo RPE.
关键词： Primary Cell Culture,Mice,Retinal Pigment Epithelium,Inbred C57BL
更新于2025-09-23 15:23:52
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Long-Term Systemic Treatment With Methamphetamine Causes Retinal Damage in CD1 Mice
摘要： As a powerful psychostimulant with high potential for abuse, methamphetamine (Meth) could cause long-lasting abnormalities in retinas. The purpose of this study was to investigate the effects of systemic administration of Meth at low dose on retinal damage and understand the underlying mechanisms of pathology. CD1 mice were treated with 0.5 mg/kg or 1 mg/kg Meth by intra-peritoneal injection daily for 2 months, mice treated with saline were used as negative control. Electroretinography (ERG) reflects the mass response of photoreceptor cells and was used to test the outer retinal function after Meth treatment. Toluidine blue staining was used to show the retinal morphology and evaluate the photoreceptor cell loss. Inflammatory factors were measured by enzyme-linked immunosorbent assay to show the inflammatory response. Terminal deoxynucleotidyl transferase dUTP Nick end labeling assay was used to detect the apoptosis-positive cells. Real-time polymerase chain reaction and Western blot were applied to measure the gene and protein change to explore the underlying mechanisms. Results demonstrated that retinal damage was caused by Meth treatment after 2 months, evidenced by loss of rod photoreceptor cells; decreased ERG amplitude; increased apoptotic photoreceptor cells, cytochrome-c release, caspase-3 activity, caspase-9 activity, and apoptosis-related protein expression; increased malondialdehyde level as well as nicotinamide adenine dinucleotide phosphate oxidase 4 protein expression; decreased anti-oxidative agents glutathione as well as superoxide dismutase levels; and increased production and gene expression of inflammatory factors. Our study indicated that systemic administration of Meth caused neurotoxic effects on CD1 mouse retinas, providing the potential mechanisms for the retina damage caused by Meth abuse.
关键词： CD1 mice,retina damage,methamphetamine,inflammatory response
更新于2025-09-23 15:21:01
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[IEEE 2018 IEEE Asian Solid-State Circuits Conference (A-SSCC) - Tainan, Taiwan (2018.11.5-2018.11.7)] 2018 IEEE Asian Solid-State Circuits Conference (A-SSCC) - Design of a 2.45-GHz RF Energy Harvester for SWIPT IoT smart sensors
摘要： The aim of this study is to investigate the effects of chronic hypoxia and hypercapnia on learning and memory function of mice and the expression of neurotensin (NT) and calcitonin gene–related peptide (CGRP) in mice brain. A total of 30 C57BL/6J male mice were randomly divided into normoxia control group (control group, n = 15) and chronic hypoxia and hypercapnia stress group (experimental group, n = 15). The control group was kept under normal temperature and pressure conditions, while the experimental group was kept in a chamber at normal pressure, hypoxia and hypercapnia for 8 h daily and 6 days a week for 4 weeks. On the 28th day, the learning and memory ability of mice was examined by 8-arm maze. The content of 8-hydroxy-deoxyguanosine (8-OHdG) in brain was detected by enzyme-linked immunosorbent assay (ELISA) analysis. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were determined by spectrophotometry, and the derangement of hippocampal ultrastructures and numbers of apoptotic neurons were observed by microscope. The expression of NT and CGRP in brain tissue was observed by immunochemistry. Compared to control group, the content of 8-OHdG in hippocampal and serum MDA were significantly increased by 1.3 and 1.78 times, while the activity of SOD in serum was decreased by 27.28% in experimental group. Besides, the cellular structure of the hippocampus was disorderly arranged, the shape is irregular and the quantity is markedly reduced obviously in experimental group. In addition, the content of NT and CGRP in brain tissue was higher in experimental group than in control group (P < 0.05). The stress of chronic hypoxia and hypercapnia not only can induce learning and memory disorders in mice which may be related to increased neuronal apoptosis and oxidative stress injury but also can increase the expression of NT and CGRP in brain tissue which may have some impact on gastrointestinal motility in mice.
关键词： chronic hypoxia and hypercapnia,calcitonin gene–related peptide,learning and memory function,neurotensin,mice
更新于2025-09-19 17:15:36
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Molecular design for novel sensing materials with self-screening interference effect (SSIE): Reversible recognizing Cu2+ in aqueous and biologic samples
摘要： In the work, self-screening interference effect (SSIE) was proposed for sensing trace Cu2+ by simply thermodynamic control reactions, using dipyridine as self-screening interference group, rhodamine as mother chromophore and cyanuric chloride as connecting bridge. After its UV-vis and fluorescent spectral properties were optimized in detail, it was noted to find that the present sensing material (RACD) could selectively and reversibly react Cu2+ with obvious colorimetric or fluorescent spectral and color changes from colorless to pink or orange-red. Some other concomitant ions, even trivalent Fe3+ or Al3+, had no interferences on it. Under the optimized conditions, RACD could multiple-mode sense trace Cu2+ in aqueous with a detection limit as low as 11.0 nmol/L. Especially with low toxicity, RACD was successfully applied for quantitatively monitoring Cu2+ and evaluating its toxicity in living cells and bio-tissues. RACD-functionalized paper-strips were also prepared to visibly recognize Cu2+ more conveniently. The selective action mechanism for RACD to Cu2+ was to form some stable 5-membered and 5-membered condensed rings between Cu2+ and O or N atoms.
关键词： Self-screening interference effect (SSIE),Tumor-bearing mice,Recognition mechanism,Trace Cu2+,Cyanuric-bridge multi-chelate,Reversibly sensing
更新于2025-09-19 17:15:36
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Rapid Intestinal Uptake and Targeted Delivery to the Liver Endothelium Using Orally Administered Silver Sulfide Quantum Dots
摘要： Quantum dots (QDs) are used for imaging and transport of therapeutics. Here we demonstrate rapid absorption across the small intestine and targeted delivery of QDs with bound materials to the liver sinusoidal endothelial cells (LSECs) or hepatocytes in vitro and in vivo following oral administration. QDs were radiolabeled with 3H-oleic acid, with a ?uorescent tag or 14C-metformin placed within a drug binding site. Three di?erent biopolymer shell coatings were compared (form-aldehyde-treated serum albumin (FSA), gelatin, heparin). Passage across the small intestine into mesenteric veins is mediated by clathrin endocytosis and micropinocytosis. 60% of an oral dose of QDs was rapidly distributed to the liver within 30 min, and this increased to 85% with FSA biopolymer coating. Uptake into LSECs also increased 3-fold with FSA coating, while uptake into hepatocytes was increased from 40% to 85% with gelatin biopolymer coating. Localization of QDs to LSECs was con?rmed with immuno?uorescence and transmission electron microscopy. 85% of QDs were cleared within 24 h of administration. The bioavailability of 14C-metformin 2 h post-ingestion was increased 5-fold by conjugation with QD-FSA, while uptake of metformin into LSECs was improved 50-fold by using these QDs. Endocytosis of QDs by SK-Hep1 cells (an LSEC immortal cell line) was via clathrin- and caveolae-mediated pathways with QDs taken up into lysosomes. In conclusion, we have shown high speci?city targeting of the LSEC or hepatocytes after oral administration of QDs coated with a biopolymer layer of FSA or gelatin, which improved the bioavailability and delivery of metformin to LSECs.
关键词： nano,mice,metformin,biopolymer,endocytosis
更新于2025-09-16 10:30:52
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Machine Learning-Based Classification of the Health State of Mice Colon in Cancer Study from Confocal Laser Endomicroscopy
摘要： In this article, we address the problem of the classification of the health state of the colon’s wall of mice, possibly injured by cancer with machine learning approaches. This problem is essential for translational research on cancer and is a priori challenging since the amount of data is usually limited in all preclinical studies for practical and ethical reasons. Three states considered including cancer, health, and inflammatory on tissues. Fully automated machine learning-based methods are proposed, including deep learning, transfer learning, and shallow learning with SVM. These methods addressed different training strategies corresponding to clinical questions such as the automatic clinical state prediction on unseen data using a pre-trained model, or in an alternative setting, real-time estimation of the clinical state of individual tissue samples during the examination. Experimental results show the best performance of 99.93% correct recognition rate obtained for the second strategy as well as the performance of 98.49% which were achieved for the more difficult first case.
关键词： classification,confocal laser endomicroscopy,machine learning,cancer study,health state,mice colon
更新于2025-09-12 10:27:22
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Photoreceptor degeneration in a new Cacna1f mutant mouse model
摘要： The Cacna1f gene encodes the α1F subunit of an L-type voltage-gated calcium channel, Cav1.4. In photoreceptor synaptic terminals, Cav1.4 channels mediate glutamate release and postsynaptic responses associated with visual signal transmission. We have discovered a new Cacna1f mutation in nob9 mice, which display more severe phenotypes than do nob2 mice. To characterize the nob9 phenotype at different ages, we examined the murine fundus, applied retinal optical coherence tomography, measured flash electroretinograms (ERGs) in vivo, and analyzed the retinal histology in vitro. After identifying the X-linked recessive inheritance trait, we sequenced Cacna1f as the candidate gene. Mutations in this gene were detected by polymerase chain reaction (PCR) and confirmed by restriction fragment length polymorphism. Morphologically, an early-onset of retinal disorder was detected, and the degeneration of the outer plexiform layers progressed rapidly. Moreover, the mutant mice showed drastically reduced scotopic ERGs with increasing age. In 14-month-old nob9 retinas, immunostaining of cone opsins demonstrated a reduction in the number of short-wavelength opsins (S-opsins) to 54% of wild-type levels, and almost no middle-wavelength opsins (M-opsins) were observed. No cone ERGs could be detected from residual cones, in which S-opsins abnormally migrated to inner segments of the photoreceptors. The mutations of the Cacna1f gene in nob9 mice involved both a single nucleotide G to A transition and a 10-nucleotide insertion, the latter resulting in a frame-shift mutation in exon 14.
关键词： X-linked recessive inheritance,Electroretinogram,Congenital stationary night blindness,Mice,Cone opsins
更新于2025-09-10 09:29:36
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Fast confocal fluorescence imaging in freely behaving mice
摘要： Fluorescence imaging in the brain of freely behaving mice is challenging due to severe miniaturization constraints. In particular, the ability to image a large field of view at high temporal resolution and with efficient out-of-focus background rejection still raises technical difficulties. Here, we present a novel fiberscope system that provides fast (up to 200 Hz) background-free fluorescence imaging in freely behaving mice over a field of view of diameter 230 μm. The fiberscope is composed of a custom-made multipoint-scanning confocal microscope coupled to the animal with an image guide and a micro-objective. By simultaneously registering a multipoint-scanning confocal image and a conventional widefield image, we subtracted the residual out-of-focus background and provided a background-free confocal image. Illumination and detection pinholes were created using a digital micromirror device, providing high adaptability to the sample structure and imaging conditions. Using this novel imaging tool, we demonstrated fast fluorescence imaging of microvasculature up to 120 μm deep in the mouse cortex, with an out-of-focus background reduced by two orders of magnitude compared with widefield microscopy. Taking advantage of the high acquisition rate (200 Hz), we measured red blood cell velocity in the cortical microvasculature and showed an increase in awake, unrestrained mice compared with anaesthetized animals.
关键词： red blood cell velocity,multipoint-scanning confocal microscope,digital micromirror device,fiberscope system,microvasculature imaging,fluorescence imaging,freely behaving mice
更新于2025-09-09 09:28:46
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Expression of the <i>HSF4 DNA Binding Domain-EGFP</i> Hybrid Gene Recreates Early Childhood Lamellar Cataract in Transgenic Mice
摘要： The clinical management of cataracts in infancy involves surgical removal of the lens to ensure transmission of light to the retina, which is essential for normal neural development of the infant. This surgery, however, entails a lifelong follow-up and impaired vision. To our knowledge, no animal models recapitulate human lamellar opacities, the most prevalent form of early childhood cataracts. We present data on the recreation of the human lamellar cataract phenotype in transgenic mice.
关键词： transgenic mice,BACs,HSF4,cataract,lens
更新于2025-09-04 15:30:14