Figure 6.

Paranodal myelin disruption at onset of EAE and within borders of demyelinating lesions. (a–c) Typical CARS images of myelinated nodes in the white matter of a naïve mouse, EAE mice at disease onset, and within borders of demyelinating lesions at the peak acute EAE. A node of Ranvier was observed as a small gap between two segments of compact myelin sheaths in the naïve white matter. Elongated exposure of nodes was observed at locations no more than 100 μm away from the meninges in disease onset and within borders of demyelinating lesions at the peak acute stage. The lesion border was defined as the area extending no more than 100 μm from the locations where the myelin fiber started to appear. The lesions were characterized by myelin debris. (d) Diagram showing the measurement of nodal length and diameter. (e) Nodal lengths versus nodal diameters for myelin at three stages corresponding to (a–c). (f) Comparison of ratios of nodal lengths to nodal diameters at three stages in different nodal diameters. Both *p < 0.001 and **p < 0.001 are compared to the ratio in the naïve mice from the same range of nodal diameter. Bar = 10 μm.