Fig. 4

Details of traumatic axonopathy in the optic nerve at the semithin level. Illustrated fields are from the same sections used for Fig. 3. All panels are from toluidine blue-stained semithin sections of the optic nerve proximal to the initial traumatic disruption of the nerve (close to the eye; left panels) and distal to traumatic disruption (towards the optic chiasm; right panels). The sham condition is illustrated in (a), and representative fields from lesioned nerves two and 4 weeks post injury are illustrated in (b) and (c). The main finding is myelin pathology which is especially severe at 2 weeks distally and 4 weeks proximally. A lot of abnormal myelin signal in the distal segment at 4 weeks is in the form of residual small myelin fragments. Note the prominent presence of astrocytes in the proximal segment that have transformed into hypertrophic, reactive profiles in (b) (asterisks). Scale bar: 10 μm