Figure 1.
T2 weighted images of cat's brain at 8th day after modeling.
The cortical origins of left CST including left frontal region, precentral region and postcentral region were removed to establish the Wallerian degeneration model.
Figure 2.
ROI definition of corticospinal tract.
Three sections of corticospinal tract were defined on FA maps at 8th day after modeling, including the pons (A), cerebral peduncle (B), and internal capsule (C) level, respectively. Note the decreased FA signal at the left CST.
Figure 3.
Dynamic changes of diffusion indices.
The diffusion indices on the intact side of corticospinal tract (black bar) showed little changes between each time points, which however, evolved dynamically on the injury side (twill bar).
Figure 4.
Correlation between the ratios of diffusion indices and the axonal counts.
Panel A showed the dynamic changes of the ratios of diffusion indices, and Panel B showed the corresponding axonal counts at the injury side. Note a significant increase of axonal counts at 45th and 60th day after modeling.
Figure 5.
NF stained histological images of cat's pons.
The NF images of the normal side and the degenerated side of pons at 2nd, 6th, 10th, 20th, 30th, 45th and 60th day after modeling were displayed. Scale bar, 50 µm.
Figure 6.
H&E stained histological images of cat's pons.
The H&E images of normal side and the degenerated side of pons at 2nd, 6th, 10th, 20th, 30th, 45th and 60th day after modeling were displayed. Black arrows indicated the activated microglias, and the black arrow heads labeled the reactive astrocytes. Microgliosis emerged at 10th day after modeling, while marked astrocytosis started at 45th day after modeling. Scale bar, 50 µm.
Figure 7.
LFB stained histological images of cat's pons.
The LFB images of normal and degenerated side of pons at 2nd, 6th, 10th, 20th, 30th, 45th and 60th day after modeling were displayed. White arrow heads indicated the activated microglias that phagocytized the axonal debris (purple stained), while black arrow heads labeled the microglias with myelin debris (blue stained). Black arrows indicated the reactive astrocytes. Scale bar, 50 µm.
Figure 8.
Quantitative analysis of LFB stain.
(A) LFB stained histological images of the pons at 2nd, 4th, 6th, 10th, 20th, 30th, 45th and 60th day after modeling. Scale bar, 500 µm. (B) Time course of the LFB optical density ratios between the degenerated and normal sides of CST. Progressive decreases of optical density were shown 20 days after modeling, implying the clearance of myelin debris.
Figure 9.
Schematic associations between the evolution of diffusion indices and underlying pathology in Wallerian degeneration.