Imaging neuronal and capillary dysfunction deep in the rodent brain in vivo using 1700 nm Optical Coherence Microscopy and tracer-based kinetics

 描述(申请人提供)：皮质下病理是衰老、阿尔茨海默病和血管性痴呆的常见特征，但在体内用微米分辨率进行研究一直是极其困难的。光学方法，如双光子显微镜，在微米尺度上成像浅层皮质，但这些传统的显微方法的分辨率在超过600微米的成像深度后迅速下降。标准的全脑磁共振成像(MRI)方法还不能提供细胞级别的分辨率，而且实施起来往往很昂贵。因此，迫切需要在微观水平上直接评估皮质和皮质下深部血流灌注和细胞损伤的方法，从而弥合现有的浅层光学显微镜和宏观成像之间的差距。这项提议将开发和应用新的光学成像技术和配套方法，直接研究遗传性疾病小鼠模型中皮质下(海马体和白质)细胞和血管的变化，而不需要转基因表达荧光蛋白。我们建议开发和验证在单个毛细血管水平上量化通过时间分布的方法；将这些方法与测量神经元细胞活性、髓鞘形成、斑块分布、萎缩的方法相结合；最后，纵向成像皮质深层的时间进程。 在阿尔茨海默病小鼠模型中，海马体损伤深度可达2毫米。这些技术将在治疗学和生物标记物发现方面的临床前实验研究中产生广泛影响，并将促进脑白质损伤和皮质下痴呆的研究。这里提出的初步开发、验证和演示将催化这些新技术的广泛采用，以非侵入性方式在小鼠大脑中研究皮质下病理生理学。

 DESCRIPTION (provided by applicant): 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.