Spinocerebellar ataxia type 1 (SCA1) is a fatal inherited neurodegenerative disease. Post-mortem studies showed neurodegeneration involving white matter components in the cerebral lobes, the cerebellar peduncles and the more distal cranial nerves in human patients. However, the progression of SCA1 in the brain remains unclear. We present the study of white matter atrophy of SCA1 mouse models using serial optical coherence scanner (SOCS).
SOCS consists of a polarization sensitive optical coherence tomography and a tissue slicer (vibratome) with associated controls for serial imaging. The optical system has 5.5 µm axial resolution and utilizes a scan lens or a water-immersion microscope objective to provide 10 µm or 4 µm lateral resolution, respectively. Brain imaging with SOCS showed that the reflectivity contrast portrays morphology, and the polarization contrasts primarily probe myelinated nerve fibers in the white matter. In the cerebellum, the cerebellar cortical layers and white matter are distinguished by using intrinsic optical contrasts. We use SOCS to image the cerebellums of SCA1 mouse models. Data have been acquired from multiple sections at different age groups.
The label-free contrasts show the pathological changes in molecular layer in SCA1 mouse models. White matter size in midline section was quantified at different time points to show white matter degeneration. Moment analysis for retardance contrast and distribution of axis orientation contrast reveal white matter atrophy. High-resolution (4 µm) SOCS visualizes the atrophy of fine features in midline sagittal cerebellum sections as well.
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