Advancing Diffusion Tensor Imaging and Analyses for Basic Alcohol Research

描述（由申请人提供）：本申请涉及广泛的挑战领域（15）：转化科学和特定的挑战主题，15- aa -107：酒精依赖啮齿动物模型中扩散张量成像（DTI）程序的改进。正如本挑战所述，拟议的努力旨在迅速推进DTI技术及其应用，以发现和记录酒精对啮齿动物产前和产后大脑的有害影响。一个主要的焦点将是实现比目前可能更快的成像时间。这将允许将DTI分析从离体扩展到体内标本。为了补充成像技术的进步，我们还将开发新的方法，包括数据管理和分析的工具和软件，并将其应用于我们对胎儿和出生后小鼠大脑的分析。这些技术将用于扩展该实验室目前在小鼠模型中对胎儿酒精谱系障碍（FASD）的研究，并解决母体酒精（乙醇）限制在产前发育的非常早期阶段（相当于人类发育的第3周）导致永久性中枢神经系统损伤的假设。我们实验室利用DTI进行的初步研究表明，急性酒精暴露后小鼠胎儿纤维束形态发生了显著变化。拟议的努力将允许比以前更快的成像时间，并将促进我们的成像分析延伸到产后时期。为此，将解决以下具体目标：目标1是开发新的DTI方法，使成像时间比目前可行的更快。这将通过使用主动染色技术、3D径向钥匙孔成像和一种应用于DTI的新型低温射频线圈来完成。目标2是快速开发一个软件框架，用于基于无偏地图集生成的新的自动小鼠大脑数据分析。这种分析方法将用于DTI特性和连通性模式的体素分析，以及DTI纤维束谱的特定分析。第三个目标是将前几个目标中先进的方法应用于酒精对小鼠产前和产后大脑的影响的研究。为此，对照小鼠和妊娠第7天接触酒精的小鼠的大脑将在其产前17天（GD 17）或产后45天或90天（PND 45, PND 90）检查纤维束形态（包括微观结构完整性）。除了GD 17、PND 45和PND 90脑的离体成像外，PND 45动物的一个子集将在体内成像。由于据报道，产前酒精暴露与人类随后的酒精依赖有关，也会增加动物对酒精的自我管理和偏好，因此在成像之前，将对产后动物进行一些行为电池检查，以评估它们对急性酒精挑战的反应。研究人员在各自领域的专业知识（成像技术开发方面的g.a. Johnson；图像分析软件开发方面的M.A. Styner； FASD研究方面的K.K. Sulik）和他们之前富有成效的合作努力，为成功完成这些目标提供了希望。预计，除了迅速提供可直接应用于其他啮齿动物模型和研究问题的工具和方法外，拟议的挑战工作将提供有关产前酒精暴露的生物学（结构和功能）后果的重要新信息。

DESCRIPTION (provided by applicant): This application addresses the broad Challenge Area (15): Translational Science and specific Challenge Topic, 15-AA-107: Refinements of Procedures for Diffusion Tensor Imaging (DTI) in Rodent Models of Alcohol Dependence. As set forth for this Challenge, the proposed effort is designed to rapidly advance DTI technology and its application to discovery and documentation of alcohol's deleterious effects on the pre-and postnatal rodent brain. A major focus will be on achieving faster imaging times than are currently possible. This will allow the extension of DTI analyses from ex vivo to in vivo specimens. To complement the advances in imaging, new methodologies including tools and software for data management and analyses will also be developed and applied to our analyses of the fetal and postnatal mouse brain. These techniques will be utilized to extend this laboratory's current investigation of fetal alcohol spectrum disorders (FASD) in a mouse model and to address the hypothesis that maternal alcohol (ethanol) administration limited to very early stages of prenatal development (corresponding to week 3 of human development) results in permanent central nervous system damage. Preliminary work from our laboratory utilizing DTI has shown significant alterations in fiber tract morphology in the mouse fetus following acute alcohol exposure. The proposed effort will allow faster imaging times than previously possible and will facilitate extension of our imaging analyses into the postnatal period. To this end, the following specific Aims will be addressed: Aim # 1 is to develop new DTI methodologies that will allow faster imaging times than are currently feasible. This will be accomplished by the use of active staining techniques, 3D radial keyhole imaging, and a novel cryogenic radiofrequency coil applied to DTI. Aim #2 is to rapidly develop a software framework for a new, automated mouse brain data analysis based on an unbiased atlas generation. This analysis method will be used for voxel-wise analysis of DTI properties and connectivity patterns, as well as DTI fiber tractography-specific analysis. Aim #3 is to apply the methodologies advanced in the previous Aims to the examination of alcohol's effect on the pre- and postnatal mouse brain. For this, the brains of control mice and those exposed to alcohol on their 7th day of gestation, will be examined on their 17th prenatal day (GD 17), or their 45th or 90th postnatal day (PND 45, PND 90) for fiber tract morphology (including microstructural integrity). In addition to ex vivo imaging of the GD 17 and PND 45 and 90 brains, a subset of the PND 45 animals will be imaged in vivo. Since prenatal alcohol exposure is reportedly related to subsequent alcohol dependence in humans and also increases alcohol self administration and preference in animals, prior to imaging, the postnatal animals will be examined in a number of behavioral batteries designed to assess their reactions to acute alcohol challenge. Promise for the successful completion of these Aims is provided by the expertise of the investigators in their respective fields (G.A Johnson in imaging technology development; M.A. Styner in image analysis software development; and K.K. Sulik in FASD research) and their previously productive collaborative efforts. It is expected that in addition to rapidly providing tools and approaches that can be directly applied to other rodent models and research questions, the proposed Challenge effort will provide important new information regarding the biological (both structural and functional) consequences of prenatal alcohol exposure. PUBLIC HEALTH RELEVANCE: The proposed work addresses the broad Challenge Area (15): Translational Science and specific Challenge Topic, 15-AA-107: Refinements of Procedures for Diffusion Tensor Imaging (DTI) in Rodent Models of Alcohol Dependence. As set forth for this Challenge, the proposed effort is designed to rapidly advance DTI technology and its application to discovery and documentation of alcohol's deleterious effects on the pre-and postnatal rodent brain. A major focus will be on achieving faster imaging times than are currently possible. This will allow the extension of DTI analyses from fixed to live specimens. To complement the advances in imaging, new methodologies including tools and software for data management and analyses will also be developed and applied to our study of alcohol-induced brain abnormalities.