In vivo cellular imaging of myelin plasticity and regeneration in cortical gray m

描述（由申请人提供）：髓磷脂是成熟神经网络的基本成分，在中枢神经系统（CNS）的大量病理状况中受到影响。对于推进这些疾病的知识至关重要的是更好地了解少突胶质细胞及其各自的髓鞘如何在体内发育，在整个生命过程中维持并对损伤做出反应。我们已经开发出一种新的技术，允许高分辨率无标记的有髓轴突在体内成像。该技术利用富含脂质的多层髓鞘的高折射率，并且基于多光谱共焦反射（MCORE）显微镜。使用MCORE，我们第一次获得了活体动物细胞尺度上皮质髓鞘动态的长期图像。我们的初步数据表明，这种技术以及荧光成像是一套强大的工具，结合提供了丰富的信息，在体内少突胶质细胞和髓鞘的精细结构变化。我们证明了在髓鞘形成障碍突变小鼠中追踪髓鞘病理学发展的可行性，并确定了单少突胶质细胞消融后脱髓鞘的时间动态。我们建议使用这种强大的技术结合在体内双光子和共聚焦荧光成像，以解决三个基本问题的可塑性和再生的新皮层髓鞘。首先，我们将确定个体少突胶质细胞和有髓轴突从出生到死亡的长期体内动力学。其次，我们将研究神经元活动如何影响体内单个活性轴突的髓鞘形成和稳定性。最后，我们将研究单次少突胶质细胞消融后脱髓鞘和髓鞘再生的过程，并确定重复消融和神经元活动如何影响髓鞘再生的时间动态。总之，这些实验将提供新的见解髓鞘和少突胶质细胞的基本可塑性和再生能力的轴突活动在整个生命。

DESCRIPTION (provided by applicant): Myelin is a fundamental component of mature neural networks that is affected in a large number of pathological conditions of the central nervous system (CNS). Critical for advancing knowledge about these conditions would be a better in vivo understanding of how oligodendrocytes and their respective myelin sheaths develop, are maintained throughout life and respond to injury. We have developed a new technique that allows high resolution label-less in vivo imaging of myelinated axons. This technique takes advantage of the high refractive index of lipid rich multilayered myelin and is based on multispectral confocal reflectance (MCORE) microscopy. Using MCORE we have obtained for the first time long- term images of the dynamics of cortical myelin on the cellular scale in a livig animal. Our preliminary data shows this technique as well as fluorescence imaging are a powerful set of tools that in combination provide a wealth of information about fine structural changes in oligodendrocytes and myelin in vivo. We demonstrate the feasibility to track the development of myelin pathology in a dysmyelinating mutant mouse and determine the temporal dynamics of demyelination after single oligodendrocyte ablation. We propose to use this powerful technique in combination with in vivo two-photon and confocal fluorescence imaging to address three fundamental questions concerning the plasticity and regeneration of neocortical myelin. First, we will determine the long-term in vivo dynamics of individual oligodendrocytes and myelinated axons from birth to death. Second, we will investigate how neuronal activity influences myelin formation and stability on individually active axons in vivo. Finally we will stuy the process of demyelination and remyelination after single oligodendrocyte ablation and determine how repeated ablation and neuronal activity influences the temporal dynamics of remyelination. Together these experiments will provide novel insight into the fundamental plasticity and regeneration capabilities of myelin and oligodendrocytes in relation to axonal activity throughout life.