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Wei Z, Roh SE, Yang X, Wang W, Wang J, Chen L, Li Y, Bibic A, Lu H. The impact of isoflurane anesthesia on brain metabolism in mice: An MRI and electroencephalography study. NMR IN BIOMEDICINE 2024:e5260. [PMID: 39254055 DOI: 10.1002/nbm.5260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2024] [Revised: 08/15/2024] [Accepted: 08/31/2024] [Indexed: 09/11/2024]
Abstract
Isoflurane is one of the most widely used anesthetic agents in rodent imaging studies. However, the impact of isoflurane on brain metabolism has not been fully characterized to date, primarily due to a scarcity of noninvasive technologies to quantitatively measure the brain's metabolic rate in vivo. In this study, using noncontrast MRI techniques, we dynamically measured cerebral metabolic rate of oxygen (CMRO2) under varying doses of isoflurane anesthesia in mice. Concurrently, systemic parameters of heart and respiration rates were recorded alongside CMRO2. Additionally, electroencephalogram (EEG) recording was used to identify changes in neuronal activities under the same anesthetic regimen employed in the MRI experiments. We found suppression of the CMRO2 by isoflurane in a dose-dependent manner, concomitant with a diminished high-frequency EEG activity. The degree of metabolic suppression by isoflurane was strongly correlated with the respiration rate, which offers a potential approach to calibrate CMRO2 measurements. Furthermore, the metabolic level associated with neural responses of the somatosensory and motor cortices in mice was estimated as 308.2 μmol/100 g/min. These findings may facilitate the integration of metabolic parameters into future studies involving animal disease models and anesthesia usage.
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Affiliation(s)
- Zhiliang Wei
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
| | - Seung-Eon Roh
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Xiuli Yang
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Wenshen Wang
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
| | - Jiekang Wang
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Lin Chen
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
| | - Yuguo Li
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
| | - Adnan Bibic
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
| | - Hanzhang Lu
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Mikkelsen SH, Skøtt MV, Gutierrez E, Postnov DD. Laser speckle imaging of the hippocampus. BIOMEDICAL OPTICS EXPRESS 2024; 15:1268-1277. [PMID: 38404300 PMCID: PMC10890870 DOI: 10.1364/boe.507371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/15/2023] [Accepted: 12/20/2023] [Indexed: 02/27/2024]
Abstract
Research on hippocampal blood flow is essential for gaining insight into its involvement in learning and memory and its role in age-related cognitive impairment and dementia. In this study, we applied laser speckle contrast imaging (LSCI) and dynamic light scattering imaging (DLSI) to monitor perfusion in mouse hippocampus via a chronic, optically transparent window. LSCI scans showed hippocampal blood vessels appear more out of focus than similar caliber vessels in the mouse cortex. We hypothesize that it is caused by the inverse vascular topology and increased contribution of multiply-scattered photons detected from the upper layers of the hippocampus. We support the hypothesis with DLSI, showing a 1300% increased contribution of multiple-scattering unordered dynamics regime in large hippocampal vessels.
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Affiliation(s)
- Signe H. Mikkelsen
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Mia V. Skøtt
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
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Ben Youss Z, Arefin TM, Qayyum S, Yi R, Zhang J, Zaim Wadghiri Y, Alon L, Yaghmazadeh O. Open-source versatile 3D-print animal conditioning platform design for in vivo preclinical brain imaging in awake mice and anesthetized mice and rats. Lab Anim (NY) 2024; 53:33-42. [PMID: 38279029 PMCID: PMC11095950 DOI: 10.1038/s41684-023-01320-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 12/14/2023] [Indexed: 01/28/2024]
Abstract
Proper animal conditioning is a key factor in the quality and success of preclinical neuroimaging applications. Here, we introduce an open-source easy-to-modify multimodal 3D printable design for rodent conditioning for magnetic resonance imaging (MRI) or other imaging modalities. Our design can be used for brain imaging in anesthetized or awake mice, and in anesthetized rats. We show ease of use and reproducibility of subject conditioning with anatomical T2-weighted imaging for both mice and rats. We also demonstrate the application of our design for awake functional MRI in mice using both visual evoked potential and olfactory stimulation paradigms. In addition, using a combined MRI, positron emission tomography and X-ray computed tomography experiment, we demonstrate that our proposed cradle design can be utilized for multiple imaging modalities.
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Affiliation(s)
- Zakia Ben Youss
- Bernard and Irene Schwartz Center for Biomedical Imaging (CBI), Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Tanzil Mahmud Arefin
- Center for Neurotechnology in Mental Health Research, Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Sawwal Qayyum
- Department of Radiology, Weill Cornell Medical College, New York, NY, USA
| | - Runjie Yi
- Neuroscience Institute, New York University School of Medicine, New York, NY, USA
| | - Jiangyang Zhang
- Bernard and Irene Schwartz Center for Biomedical Imaging (CBI), Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, NY, USA
| | - Youssef Zaim Wadghiri
- Bernard and Irene Schwartz Center for Biomedical Imaging (CBI), Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, NY, USA.
| | - Leeor Alon
- Bernard and Irene Schwartz Center for Biomedical Imaging (CBI), Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, NY, USA.
| | - Omid Yaghmazadeh
- Neuroscience Institute, New York University School of Medicine, New York, NY, USA.
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Markussen NB, Knopper RW, Hasselholt S, Skoven CS, Nyengaard JR, Østergaard L, Hansen B. Locus coeruleus ablation in mice: protocol optimization, stereology and behavioral impact. Front Cell Neurosci 2023; 17:1138624. [PMID: 37180952 PMCID: PMC10172584 DOI: 10.3389/fncel.2023.1138624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 04/05/2023] [Indexed: 05/16/2023] Open
Abstract
The Locus Coeruleus (LC) is in the brainstem and supplies key brain structures with noradrenaline, including the forebrain and hippocampus. The LC impacts specific behaviors such as anxiety, fear, and motivation, as well as physiological phenomena that impact brain functions in general, including sleep, blood flow regulation, and capillary permeability. Nevertheless, the short- and long-term consequences of LC dysfunction remain unclear. The LC is among the brain structures first affected in patients suffering from neurodegenerative diseases such as Parkinson's disease and Alzheimer's Disease, hinting that LC dysfunction may play a central role in disease development and progression. Animal models with modified or disrupted LC function are essential to further our understanding of LC function in the normal brain, the consequences of LC dysfunction, and its putative roles in disease development. For this, well-characterized animal models of LC dysfunction are needed. Here, we establish the optimal dose of selective neurotoxin N-(2-chloroethyl)-N-ethyl-bromo-benzylamine (DSP-4) for LC ablation. Using histology and stereology, we compare LC volume and neuron number in LC ablated (LCA) mice and controls to assess the efficacy of LC ablation with different numbers of DSP-4 injections. All LCA groups show a consistent decrease in LC cell count and LC volume. We then proceed to characterize the behavior of LCA mice using a light-dark box test, Barnes maze test, and non-invasive sleep-wakefulness monitoring. Behaviorally, LCA mice differ subtly from control mice, with LCA mice generally being more curious and less anxious compared to controls consistent with known LC function and projections. We note an interesting contrast in that control mice have varying LC size and neuron count but consistent behavior whereas LCA mice (as expected) have consistently sized LC but erratic behavior. Our study provides a thorough characterization of an LC ablation model, firmly consolidating it as a valid model system for the study of LC dysfunction.
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Affiliation(s)
- Nanna Bertin Markussen
- Center of Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Rasmus West Knopper
- Center of Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Sino-Danish Center for Education and Research, University of Chinese Academy of Sciences, Beijing, China
| | - Stine Hasselholt
- Center of Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Center for Molecular Morphology, Section for Stereology and Microscopy, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Christian Stald Skoven
- Center of Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Jens Randel Nyengaard
- Center for Molecular Morphology, Section for Stereology and Microscopy, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Leif Østergaard
- Center of Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Brian Hansen
- Center of Functionally Integrative Neuroscience (CFIN), Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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