Imaging Neuronal and Capillary Dysfunction Deep in the Rodent Brain in vivo Using 1700 NM Optical Coherence Microscopy and Tracer-Based Kinetics

摘要： 皮质下病理学是衰老、阿尔茨海默病和血管性痴呆的常见特征，但近年来 在体内以微米分辨率进行研究极其困难。光学方法，例如双光子显微镜 在微米尺度上对浅表皮层进行成像，但这些传统显微方法的分辨率 超过 600 微米成像深度时会迅速退化。标准全脑磁共振成像 (MRI) 方法尚未提供细胞水平的分辨率，并且实施起来通常很昂贵。因此，有 迫切需要直接评估深层皮质和皮质下灌注以及细胞损伤的方法 微观水平，从而弥合现有表面光学显微镜和宏观之间的差距 成像。该提案将开发和应用新型光学成像技术和相关方法 直接研究皮质下（海马和白质）细胞和血管的遗传变化 疾病小鼠模型，不需要荧光蛋白的转基因表达。我们建议 开发并验证在单个毛细管水平上量化传输时间分布的方法；结合这些 具有测量神经元细胞活力、髓鞘形成、斑块分布、萎缩的方法；最后，到 纵向成像阿尔茨海默病小鼠模型中深部皮质和海马损伤的时间过程 病变深度达2毫米。这些技术将对临床前实验产生广泛影响 治疗学和生物标志物发现方面的研究，并将推进白质损伤和 皮质下痴呆。这里提出的初步开发、验证和演示将促进 广泛采用这些新技术来非侵入性地研究皮层下病理生理学 老鼠的大脑。

Abstract: Subcortical pathology is a common feature in aging, Alzheimer's disease and vascular dementia but has been extremely difficult to study with micron resolution in vivo. Optical methods such as two-photon microscopy image the superficial cortex at the micron-scale, but the resolution of these conventional microscopic methods degrades rapidly beyond 600 microns imaging depth. Standard whole-brain magnetic resonance imaging (MRI) methods do not yet provide cellular-level resolution and are often expensive to implement. Thus, there is a pressing need for methods to directly assess deep cortical and subcortical perfusion and cellular injury at the microscopic level, thus bridging the gap between existing superficial optical microscopy and macroscopic imaging. This proposal will develop and apply novel optical imaging technologies and accompanying methods to directly investigate subcortical (hippocampal and white matter) cellular and vascular changes in genetic mouse models of disease, without the need for transgenic expression of fluorescent proteins. We propose to develop and validate methods to quantify transit time distribution at the single capillary level; combine these with methods to measure neuronal cell viability, myelination, plaque distribution, atrophy; and finally, to longitudinally image the time course of deep cortical and hippocampal injury in a mouse model of Alzheimer's disease up to a depth of 2 mm. These techniques will have a widespread impact in preclinical experimental research in therapeutics and biomarker discovery, and will advance the study of white matter injury and subcortical dementia. The initial development, validation, and demonstration proposed here will catalyze the widespread adoption of these novel techniques to study subcortical pathophysiology non-invasively in the mouse brain.