Name: advanced diffusion imaging in the hippocampus of rats with mild traumatic brain injury
Uploaded: 2019-08-14T15:00:00
Description: Watch this Scientific Journal Video about Advanced Diffusion Imaging in The Hippocampus of Rats with Mild Traumatic Brain Injury at JoVE.com

作者要感谢研究基金会 - 佛兰德斯(FWO)支持这项工作(授权号:G027815N)。

该协议已获得根特大学动物伦理委员会(ECD 15/44Aanv)的批准,所有实验均按照欧盟委员会的准则(第2010/63/EU号指令)进行。
1. 动物准备和头盔附件
<ol><li>称一只雌性Wistar H大鼠(±250克或12周龄),并在充满旋索兰混合物(5%)的小感应室中麻醉和 O2至少 1 分钟。</li>
	<li>在大鼠的颈部注射0.05mg/kg丁丙诺啡,将其送回家庭笼子,并让先发制人的麻醉至少30分钟生效。 注:在30分钟的等?...

<ol>
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K., Sours, C., Zhuo, J., Shanmuganathan, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+of+Traumatic+Brain+Injury.">Imaging of Traumatic Brain Injury.</a> Radiologic Clinics of North America. 53 (4), 695-715 (2015).</li><li>Basser, P. J., Mattiello, J., LeBihan, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MR+diffusion+tensor+spectroscopy+and+imaging.">MR diffusion tensor spectroscopy and imaging.</a> Biophysical Journal. 66 (1), 259-267 (1994).</li><li>Hulkower, M. B., Poliak, D. B., Rosenbaum, S. B., Zimmerman, M. E., Lipton, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Decade+of+DTI+in+Traumatic+Brain+Injury:+10+Years+and+100+Articles+Later.">A Decade of DTI in Traumatic Brain Injury: 10 Years and 100 Articles Later.</a> American Journal of Neuroradiology. 34 (11), 2064-2074 (2013).</li><li>Hutchinson, E. B., Schwerin, S. C., Avram, A. V., Juliano, S. L., Pierpaoli, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diffusion+MRI+and+the+detection+of+alterations+following+traumatic+brain+injury.">Diffusion MRI and the detection of alterations following traumatic brain injury.</a> Journal of Neuroscience Research. 96 (4), 612-625 (2018).</li><li>Wallace, E. J., Mathias, J. L., Ward, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diffusion+tensor+imaging+changes+following+mild,+moderate+and+severe+adult+traumatic+brain+injury:+a+meta-analysis.">Diffusion tensor imaging changes following mild, moderate and severe adult traumatic brain injury: a meta-analysis.</a> Brain Imaging and Behavior. , 1-15 (2018).</li><li>Rutgers, D. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=White+Matter+Abnormalities+in+Mild+Traumatic+Brain+Injury:+A+Diffusion+Tensor+Imaging+Study.">White Matter Abnormalities in Mild Traumatic Brain Injury: A Diffusion Tensor Imaging Study.</a> American Journal of Neuroradiology. 29 (3), 514-519 (2008).</li><li>Bondi, C. O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Found+in+translation:+Understanding+the+biology+and+behavior+of+experimental+traumatic+brain+injury.">Found in translation: Understanding the biology and behavior of experimental traumatic brain injury.</a> Neuroscience &amp; Biobehavioral Reviews. 58, 123-146 (2015).</li><li>Shultz, S. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+potential+for+animal+models+to+provide+insight+into+mild+traumatic+brain+injury:+Translational+challenges+and+strategies.">The potential for animal models to provide insight into mild traumatic brain injury: Translational challenges and strategies.</a> Neuroscience &amp; Biobehavioral Reviews. 76, 396-414 (2017).</li><li>Osier, N. D., Dixon, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Controlled+Cortical+Impact+Model:+Applications,+Considerations+for+Researchers,+and+Future+Directions.">The Controlled Cortical Impact Model: Applications, Considerations for Researchers, and Future Directions.</a> Frontiers in Neurology. 7 (AUG), (2016).</li><li>Lyeth, B. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Historical+Review+of+the+Fluid-Percussion+TBI+Model.">Historical Review of the Fluid-Percussion TBI Model.</a> Frontiers in Neurology. 7 (DEC), 1-7 (2016).</li><li>Marmarou, A., Foda, M. A. A. -. E., van den Brink, W., Campbell, J., Kita, H., Demetriadou, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+model+of+diffuse+brain+injury+in+rats.">A new model of diffuse brain injury in rats.</a> Journal of Neurosurgery. 80 (2), 291-300 (1994).</li><li>Heim, L. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Invisibility+of+Mild+Traumatic+Brain+Injury:+Impaired+Cognitive+Performance+as+a+Silent+Symptom.">The Invisibility of Mild Traumatic Brain Injury: Impaired Cognitive Performance as a Silent Symptom.</a> Journal of Neurotrauma. 34 (17), 2518-2528 (2017).</li><li>Zohar, O., Rubovitch, V., Milman, A., Schreiber, S., Pick, C. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Behavioral+consequences+of+minimal+traumatic+brain+injury+in+mice.">Behavioral consequences of minimal traumatic brain injury in mice.</a> Acta Neurobiol Exp (Wars. 71 (1), 36-45 (2011).</li><li>Pierpaoli, C., Basser, P. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Toward+a+quantitative+assessment+of+diffusion+anisotropy.">Toward a quantitative assessment of diffusion anisotropy.</a> Magnetic resonance in medicine&#8239;: official journal of the Society of Magnetic Resonance in Medicine / Society of Magnetic Resonance in Medicine. 36 (6), 893-906 (1996).</li><li>Jensen, J. H., Helpern, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MRI+quantification+of+non-Gaussian+water+diffusion+by+kurtosis+analysis.">MRI quantification of non-Gaussian water diffusion by kurtosis analysis.</a> NMR in Biomedicine. 23 (7), 698-710 (2010).</li><li>Fieremans, E., Jens, H., Jensen, J. A. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=White+matter+characterization+with+diffusional+kurtosis+imaging.">White matter characterization with diffusional kurtosis imaging.</a> NeuroImage. 58, 177-188 (2011).</li><li>Leemans, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Explore DTI. , (2019).</li><li>Loening, A. M., Gambhir, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=AMIDE:+A+Free+Software+Tool+for+Multimodality+Medical+Image+Analysis.">AMIDE: A Free Software Tool for Multimodality Medical Image Analysis.</a> Molecular Imaging. 2 (3), 131-137 (2003).</li><li>Veraart, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Denoising+of+diffusion+MRI+using+random+matrix+theory.">Denoising of diffusion MRI using random matrix theory.</a> NeuroImage. 142, 394-406 (2016).</li><li>Veraart, J., Fieremans, E., Novikov, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diffusion+MRI+noise+mapping+using+random+matrix+theory.">Diffusion MRI noise mapping using random matrix theory.</a> Magnetic Resonance in Medicine. 76 (5), 1582-1593 (2016).</li><li>Braeckman, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamic+changes+in+hippocampal+diffusion+and+kurtosis+metrics+following+experimental+mTBI+correlate+with+glial+reactivity.">Dynamic changes in hippocampal diffusion and kurtosis metrics following experimental mTBI correlate with glial reactivity.</a> NeuroImage: Clinical. 21 (August 2018), 101669 (2019).</li><li>Jones, D. K., Kn&#246;sche, T. R., Turner, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=White+matter+integrity,+fiber+count,+and+other+fallacies:+The+do's+and+don'ts+of+diffusion+MRI.">White matter integrity, fiber count, and other fallacies: The do's and don'ts of diffusion MRI.</a> NeuroImage. 73, 239-254 (2013).</li><li>. Matlab code DKI and WMTI model Available from: <a target="_blank" href="https://github.com/NYU-DiffusionMRI/Diffusion-Kurtosis-Imaging">https://github.com/NYU-DiffusionMRI/Diffusion-Kurtosis-Imaging</a> (2019)</li></ol>

由于 mTBI 通常是扩散和细微损伤的结果,在 CT 和常规 MRI 扫描上没有异常,因此在轻度创伤后评估微结构损伤仍是一个挑战。因此,需要更先进的成像技术来可视化创伤的全部程度。扩散磁共振成像在TBI研究中的应用在过去十年中引起了更多的关注,其中扩散张量成像是最常用的5。DTI 模型的局限性是假设高斯扩散过程不是大脑微观结构的精确假设(由具有膜作为屏障的轴子和细胞组成...

创伤性脑损伤(TBI)近年来越来越受到关注,因为很明显,这些脑损伤会导致终生认知、身体、情感和社会后果。尽管这种意识的提高,轻度TBI(mTBI,或脑震荡)仍然经常被少报和未确诊。MTBI被称为无声流行病,有mTBI病史的个人表现出较高的药物滥用率或精神问题2。由于损伤的漫不经其道和微妙性质,每年有一些 mTBI 患者未确诊,这在传统的计算机断层扫描 (CT) 或磁共振成像 (MRI) 扫描中通常不可见。这种脑损伤的放射性证据的缺乏导致了更先进的成像技术的发展,如扩散核磁共振成像,后者对微结构变化更敏感3。
扩散MRI允许在体内绘制微结构图,这种MRI技术在TBI研究4、5、6中得到了广泛的应用。从扩散张量中,计算小数各向异性(FA)和平均扩散率(MD),以量化损伤后微结构组织的变化。最近对 mTBI 患者的检查报告 FA 增加,受伤后 MD 减少,这可能表明斧肿胀7。相反,MD 的增加和 FA 的减少也被发现,并已被建议在水肿形成、斧头退化或纤维失调/中断8之后,在帕伦奇结构中造成破坏。这些混合的发现可以部分解释为mTBI由不同类型的冲击和严重性(例如,旋转加速度、钝力创伤、爆炸损伤或前者的组合)造成的显著临床异质性。然而,目前对于支撑微观结构组织变化的基本病理学和生物/细胞基础没有明确的共识。
动物模型提供了一个标准化和受控的设置,以更详细地研究损伤的生物机制和TBI后的修复。已经开发了几种TBI实验模型,代表了人类TBI的不同方面(例如,焦点与漫射创伤或旋转力造成的创伤)9,10。常用的动物模型包括受控皮质冲击(CCI)和横向流体打击损伤(LFPI)模型11,12。虽然实验参数可以很好地控制,但这些模型利用颅骨切除术来暴露大脑。颅骨或颅骨骨折在 mTBI 中并不常见;因此,这些实验模型对模拟 mTBI 无效。Marmarou等人13开发的冲击加速模型利用了从一定高度掉落到大鼠头部的重量,该模型由头盔保护。这种动物模型诱导类似的微结构改变和认知障碍,如在患有轻度创伤的患者中。因此,这种马尔马鲁降重模型适用于研究漫射mTBI14、15的成像生物标志物。
本报告演示了使用Marmarou降重模型在mTBI大鼠模型中应用先进的扩散MRI。首先演示如何诱发轻度和漫反射性创伤,然后使用扩散张量成像(DTI)模型进行分析。使用更先进的扩散模型[即扩散峰度成像(DKI)和白质道完整性(WMTI)模型]获得特定的生物信息。具体来说,使用传统的T2加权MRI和先进的扩散成像方案,在海马区进行轻度创伤和微结构变化评估。

<table>
	<tbody>
		<tr>
			<td>Induction of trauma</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>0.9% NaCl physiologic solution</td>
			<td>B Braun</td>
			<td>394496</td>
			<td></td>
		</tr>
		<tr>
			<td>brass weight 450g</td>
			<td>custom made</td>
			<td>custom made</td>
			<td>diamter 18mm and 210 mm height</td>
		</tr>
		<tr>
			<td>catheter</td>
			<td>Terumo</td>
			<td>Versatus-W</td>
			<td>26G</td>
		</tr>
		<tr>
			<td>ethilon II</td>
			<td>Ethicon</td>
			<td>EH7824</td>
			<td>FS-3, 4-0, 3/8, 16mm</td>
		</tr>
		<tr>
			<td>Matrass</td>
			<td>Foam to Size</td>
			<td>Type E</td>
			<td></td>
		</tr>
		<tr>
			<td>Plexiglas tube</td>
			<td>ISPA Plastics</td>
			<td>416564</td>
			<td>M1 PMMA XT GOO tube 25x19 mm (inner diamter 19 mm, minimal length of 1.50 m)</td>
		</tr>
		<tr>
			<td>Preclinical CT scanner</td>
			<td>Molecubes</td>
			<td>X-cube</td>
			<td></td>
		</tr>
		<tr>
			<td>Steel helmet</td>
			<td>custom made</td>
			<td>custom made</td>
			<td>diameter 10 mm and 3 mm thickness</td>
		</tr>
		<tr>
			<td>Vetbond Tissue Adhesive</td>
			<td>3M</td>
			<td>1469SB</td>
			<td></td>
		</tr>
		<tr>
			<td>Vetergesic (buprenorphin)</td>
			<td>EcuPhar</td>
			<td>VETERG20</td>
			<td>0.05 mk/kg</td>
		</tr>
		<tr>
			<td>Xylocaine 2% gel</td>
			<td>AstraZeneca</td>
			<td>Xylocaine 2%</td>
			<td>gel</td>
		</tr>
		<tr>
			<td>Xylocaine (lidocain 2%)</td>
			<td>Aspen/AstraZeneca</td>
			<td>Xylocaine 2% gel</td>
			<td>100 &#956;l injection</td>
		</tr>
		<tr>
			<td>Diffusion MRI</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Preclinical MRI acquisition software</td>
			<td>Bruker Biospin MRI GmbH</td>
			<td>Z400_PV51_CENTOS55</td>
			<td>ParaVision 5.1 MRI software</td>
		</tr>
		<tr>
			<td>Preclinical MRI scanner</td>
			<td>Bruker Biospin MRI GmbH</td>
			<td>PharmaScan 70/16</td>
			<td>7T MRI scanner</td>
		</tr>
		<tr>
			<td>Quadrature volume coil</td>
			<td>Bruker Biospin MRI GmbH</td>
			<td>RF RES 300 1H 075/040 QSN TR</td>
			<td>Model No: 1P T13161C3</td>
		</tr>
		<tr>
			<td>Small animal physiological monitoring unit</td>
			<td>Rapid Biomedical</td>
			<td>EKGHR02-0571-043C01</td>
			<td>Unit for respiratory monitoring</td>
		</tr>
		<tr>
			<td>Water-based heating unit</td>
			<td>Thermo Fisher Scientific</td>
			<td>Haake S 5P</td>
			<td>Model No: 1523051</td>
		</tr>
		<tr>
			<td>Anaesthesia</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Anaesthesia movable unit</td>
			<td>Veterenary technics</td>
			<td></td>
			<td>BDO - Medipass, Ijmuiden</td>
		</tr>
		<tr>
			<td>isoflurane: Isoflo</td>
			<td>Zoetis</td>
			<td>B506</td>
			<td></td>
		</tr>
		<tr>
			<td>Oxygen generator</td>
			<td>Veterenary technics</td>
			<td>7F-3</td>
			<td>BDO - Medipass, Ijmuiden</td>
		</tr>
		<tr>
			<td>Diffusion image processing</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Amide</td>
			<td>http://amide.sourceforge.net</td>
			<td>Version 1.0.5.</td>
			<td>Medical Imaging Data Examiner Toolbox (Loening AM, Gambhir SS, &#34; AMIDE: A Free Software Tool for Multimodality Medical Image Analysis&#34;, Molecular Imaging, 2(3):131-137, 2003)</td>
		</tr>
		<tr>
			<td>ExploreDTI</td>
			<td>http://www.exploredti.com</td>
			<td>Version 4.8.6</td>
			<td>Toolbox for (pre-)processing and analysis of diffusion weighted MR images (Leemans A, Jeurissen B, Sijbers J, and Jones DK. ExploreDTI: a graphical toolbox for processing, analyzing, and visualizing diffusion MR data. In: 17th Annual Meeting of Intl Soc Mag Reson Med, p. 3537, Hawaii, USA, 2009)</td>
		</tr>
		<tr>
			<td>MRtrix3</td>
			<td>http://www.mrtrix.org</td>
			<td>Version 3.0_RC3-86-g4b523b41</td>
			<td>Toolbox for (pre-)processing and analysis of diffusion weighted MR images</td>
		</tr>
	</tbody>
</table>

advanced diffusion imaging in the hippocampus of rats with mild traumatic brain injury

轻度创伤性脑损伤 (mTBI) 是最常见的后天性脑损伤类型。由于创伤性脑损伤患者表现出巨大的变异性和异质性(年龄、性别、创伤类型、其他可能的病理等),动物模型在解开临床研究中局限性的因素方面发挥着关键作用。它们提供了一个标准化和受控的设置,以研究损伤的生物机制和TBI后的修复。然而,并非所有动物模型都有效地模仿了mTBI的漫射和微妙特性。例如,常用的受控皮质撞击 (CCI) 和横向流体撞击损伤 (LFPI) 模型利用颅骨切除术暴露大脑并引起广泛的焦部创伤,这在 mTBI 中并不常见。因此,这些实验模型对模拟mTBI无效。因此,应该使用适当的模型来调查 mTBI。大鼠的Marmarou降重模型导致类似的微结构改变和认知障碍,如在轻度创伤患者中看到;因此,此模型是为此协议选择的。传统的计算机断层扫描和磁共振成像 (MRI) 扫描通常显示轻度损伤后没有损伤,因为 mTBI 通常只引起细微和漫反射性损伤。通过扩散加权MRI,可以研究脑组织的微观结构特性,从而更深入地了解轻度创伤后的微观变化。因此,本研究的目标是获得选定感兴趣区域(即海马区)的定量信息,以跟踪轻度和扩散性脑损伤后的疾病进展。

在这项研究中,所有TBI大鼠(n= 10)在撞击中幸存下来,并在从麻醉23分离后15分钟内从撞击和麻醉中恢复过来。在CT图像上,没有证据表明颅骨骨折,T2图像没有显示任何异常,如出血,心室扩大,或水肿形成在挫伤部位1天后(图5)。因此,根据这些对解剖图像的目视检查,没有检测到大的焦点病变,证实了损伤的扩散性和轻度性。
通过将 T2 图像的叠加?...

Watch this Scientific Journal Video about Advanced Diffusion Imaging in The Hippocampus of Rats with Mild Traumatic Brain Injury at JoVE.com

Advanced Diffusion Imaging in The Hippocampus of Rats with Mild Traumatic Brain Injury

这个程序的总体目标是获得轻度创伤性脑损伤大鼠海马的定量微结构信息。这是使用先进的扩散加权磁共振成像协议和基于兴趣区域的参数扩散图分析完成的。

轻度创伤性脑损伤大鼠海马学的高级扩散成像

Mild traumatic brain injury (mTBI) is the most common type of acquired brain injury. Since patients with traumatic brain injury show a tremendous ...

通过这种扩散成像方案，可以研究大鼠海马的微结构变化，而轻度创伤性脑损伤在解剖MRI上是不可见的。这种技术可以检测大脑的变化后，轻度和弥漫性创伤，无法检测CT或解剖MRI。这种技术使得在客观和定量地持续轻度创伤性脑损伤后更容易监测恢复过程。这种扩散成像和分析技术也适用于影响大脑的其他疾病，如痴呆症和多发性硬化症，不仅用于临床前研究，而且应用于人类。在此协议中，扩散扫描和校正步骤的质量必须很高，因此建议由经验丰富的技术人员和分析师提供指导。将动物放在37摄氏度的加热垫上，确认12周大的雌性Wistar H大鼠脚趾捏没有反应，并将导管插入横向尾静脉。将 100 微升的 2% 利多卡因局部注射到剃光和消毒的头皮中，并做一个中线切口来暴露头骨。使用一把小剪刀去除多余的膜，在头骨上擦一个棉芽，直到表膜不再存在，然后用一滴组织胶水来连接一个直径10毫米、厚3毫米的金属盘，大约1/3的前面和2/3的圆环后面。对于创伤性脑损伤诱导，将大鼠放在定制床上，用特定弹簧常数的泡沫床垫，将大鼠直接放在透明塑料管下，头盔重量为 450 克，头盔尽可能水平。将重量拉至一米。在第二个实验者在场时，释放重量，让第二个实验者在撞击后立即将大鼠移离管子，以防止第二次伤害。轻轻地从头骨上拉出头盔，用纱布止血。用缝合关闭皮肤，将局部镇痛凝胶涂抹到切口上。将大鼠放在CT扫描仪的床上，进行通用的低剂量CT扫描，以排除颅骨骨折，然后将大鼠放在37摄氏度的加热垫上的清洁笼子里，并监测直至完全恢复，然后再将动物返回到笼子。在创伤感应前和一天后，确认实验动物对手趾捏缺乏反应，将动物放在 MR 扫描仪床上，位于头部第一，容易放置位置。将四边形体积线圈滑过头部，将扫描仪床推进到扫描仪孔中。为确保正确定位，获取默认的 3 平面侦察扫描。扫描完成后，在图像显示屏中加载扫描，并确保头部直卧，并且大脑位于磁铁和线圈的中心。使用默认设置获取 T2 加权图像，但字段、视图和矩阵大小除外，这些大小应调整为 109 乘 109 微米的平面分辨率较高。打开几何编辑器，将切片包放在正确的位置，包括大脑和小脑的球茎，并加载三个新的回声平面、扩散加权、自旋回波序列，从 B_diffusion 文件夹加载到扫描控制协议中。使用默认设置获取扩散加权图像，然后打开"编辑扫描"选项卡。将切片方向设置为轴向，将切片数设置为 25，以实现 500 微米的切片厚度和 600 微米的内片距离，并修改读出方向为左-右。在"几何"选项卡下，调整几何参数，将视野和矩阵大小调整为 105 乘 105，以确保分辨率为 333 乘 333 微米。单击三个扩散壳的"研究"选项卡中的"扩散"选项卡，将扩散方向数调整为第一个壳体的 32 个、第二个壳体的 46 个和第三个壳体的 64 个。将 B0 图像数更改为第一个 shell 的 5 个，第二个 shell 的 5 个图像数，第三个 shell 的 7 个图像数，使用自定义渐变方向文件调整渐变方向。将 B 值调整为第一个壳体每方向 800 秒，第二个壳体每毫米平方 1，500 秒，第三个壳体每毫米平方 2，000 秒，然后打开几何编辑器，将仅包含脑的脑的球茎和小脑之间的视场放置，以减少伪影和扫描时间。在完成扫描协议后，将动物从扫描仪床转移到一个干净的笼子，并配有 37 摄氏度的加热垫，并监控直至完全保持。对于扩散 MRI 图像处理，在 MRtrix3 中加载图像，对软件程序中的扩散加权图像执行噪声校正和吉布斯振铃校正。如所示，将 T2 图像中校正的扩散加权图像转换为 NIFTI 格式。要对回声平面成像、运动和涡流失真执行校正，请在 ExploreDTI 的插件菜单中选择对主体运动 EC/EPI 失真的校正，并选择预处理的扩散数据文件。要计算每个大鼠的扩散张量成像指标，请单击插件并导出到 NIFTI，然后选择扩散张量成像模型的参数化贴图，并导出峰度和白物质区域完整性模型的参数图。要为每个大鼠的海马创建掩码文件，请加载 MRtrix 查看器中大鼠的小各向异性图像，然后单击加号按钮以创建新感兴趣区域。要提取大鼠海马体的扩散指标，请导入 AMIDE 软件中创建的掩码文件，然后打开大鼠的参数化贴图和掩码图像。要将蒙版文件感兴趣的区域添加到 AMIDE 中，请选择蒙版文件图像，单击"编辑"，"添加感兴趣区域"和"3D 等值"，并为此感兴趣的区域命名有意义的名称。单击蒙版图像中显示的感兴趣区域，并确认此卷应仅包含值为 1 的体素。要计算海马区扩散指标的平均值，请单击"工具和计算感兴趣区域统计"，并指示要包括的图像和感兴趣区域。单击"执行"后，将显示一个弹出窗口，该窗口具有可用于进一步统计分析的计算值。在这个具有代表性的实验中，没有CT成像评估的颅骨骨折的证据，T2图像在创伤发生一天后没有显示任何挫伤地点的异常。为了检查 T2 图像和扩散数据集之间的非刚性共注册步骤的质量，T2 图像的叠加添加到颜色编码的分各异性贴图中。然后计算分数各向异性、平均扩散率、轴向扩散率和径向扩散参数图的参数映射。在感兴趣区域内，还可以计算轴向、均值和径向峰度值的平均值以及轴导水分数、轴向和径向外轴向扩散值以及白物质区域完整性的侵权度。在这个具有代表性的实验中，对扩散张量成像指标的分析表明，在轻度创伤性脑损伤组的影响之后，小各向异性值显著增加，扩散值降低。扩散峰度指标还显示，撞击后径向峰度显著下降，同时未观察到轴向或平均峰度的变化。使用白物质区域完整性模型，径向外轴衍射率显著下降，其折磨性在撞击一天后显示轻度创伤性脑损伤组显著增加。在图像分析过程中，检查来自 MRtrix 的数据格式是否正确转换并导入到 ExploreDTI 中以及每个更正步骤是否正确执行非常重要。可以应用体受体美的体美分析来研究全脑变化，而不是基于 ROI 的分析。这项技术在神经成像领域是非常有价值的，也可以应用于其他脑部疾病，例如痴呆症和多发性硬化症。

Research

JoVE Journal

Neuroscience

Investigations on Alterations of Hippocampal Circuit Function Following Mild Traumatic Brain Injury

调查轻度创伤性脑损伤海马电路功能的改变

Traumatic Brain Injury (TBI) afflicts more than 1.7 million people in the United States each year and even mild TBI can lead to persistent neurological ...

科研

神经科学

A Novel In Vitro Model of Blast Traumatic Brain Injury

A Novel In Vitro Model of Blast Traumatic Brain Injury

一种新的脑外伤体损伤模型

Traumatic brain injury is a leading cause of death and disability in military and civilian populations. Blast traumatic brain injury results from the ...

Effects of Blast-induced Neurotrauma on Pressurized Rodent Middle Cerebral Arteries

爆炸性神经损伤对压生啮鼠中脑动脉的影响

Though there have been studies on the histopathological and behavioral effects of blast exposure, fewer have been dedicated to blast&#39;s cerebral ...

Investigating Alterations in Caecum Microbiota After Traumatic Brain Injury in Mice

研究小鼠创伤性脑损伤后凯库姆微生物群的改动

Increasing evidence shows that the microbiota-gut-brain axis plays an important role in the pathogenesis of brain diseases. Several studies also ...

Laser-Induced Brain Injury in the Motor Cortex of Rats

大鼠运动皮层中的激光诱发脑损伤

A common technique for inducing stroke in experimental rodent models involves the transient (often denoted as MCAO-t) or permanent (designated as MCAO-p) ...

Low-intensity Blast Wave Model for Preclinical Assessment of Closed-head Mild Traumatic Brain Injury in Rodents

低强度冲击波模型用于啮齿动物闭头轻度创伤性脑损伤的临床前评估

Traumatic brain injury (TBI) is a large-scale public health problem. Mild TBI is the most prevalent form of neurotrauma and accounts for a large number of ...

A Metric Test for Assessing Spatial Working Memory in Adult Rats Following Traumatic Brain Injury

创伤性脑损伤后评估成年大鼠空间工作记忆的指标测试

Impairments to sensory, short-term, and long-term memory are common side effects after traumatic brain injury (TBI). Due to the ethical limitations of ...

Electromagnetic Controlled Closed-Head Model of Mild Traumatic Brain Injury in Mice

小鼠轻度创伤性脑损伤的电磁控制闭头模型

Highly reproducible animal models of traumatic brain injury (TBI), with well-defined pathologies, are needed for testing therapeutic interventions and ...

Assessing Changes in Synaptic Plasticity Using an Awake Closed-Head Injury Model of Mild Traumatic Brain Injury

使用轻度创伤性脑损伤的清醒闭合性头部损伤模型评估突触可塑性的变化

Mild traumatic brain injuries (mTBIs) are a prevalent health issue in North America. There is increasing pressure to utilize ecologically valid models of ...

Intravital Imaging of Fluorescent Protein Expression in Mice with a Closed-Skull Traumatic Brain Injury and Cranial Window Using a Two-Photon Microscope

使用双光子显微镜对闭合颅骨创伤性脑损伤和颅窗小鼠荧光蛋白表达进行活体成像

The goal of this protocol is to demonstrate how to longitudinally visualize the expression and localization of a protein of interest within specific cell ...