Figure 2.

Focal inflammatory/gliotoxic demyelination of rat thoracic spinal cord.

(A) Diagram showing the site of laminectomy and the induction of focal demyelination at the T9 level. (B) T2-weighted sagittal MRI scan of rat spinal cord showing the extent of the lesion. Hyperintense demyelinated area extends rostro-caudally for about 7.5mm. (C) Segmentation and surface rendering of the MRI scan demonstrates the location and full distribution of the lesion and is confined to the dorsal white matter. (D–I) Histological characterization of demyelinating lesion. (D) H/E staining demonstrates an area of increased cellular density within the dorsal white matter. (E) Eriochrome staining shows complete demyelination within the lesion. (F) Immunofluoresence localization of the IBA-1 antigen (red) reveals extensive infiltration of the lesion by activated microglia. (G) Silver stain delineates axonal density and shows an area of axonal loss in the core of the lesion; scale bar for D–G=200µm. (H–I) Electron microscopy of the lesioned site (H) shows loss of dense lines and separation of myelin from axolemma. (I) Normal axon in the ventral white matter; scale bar=100nm. (J–K) Behavioral assessment of neurological function. (J) Rotarod test results show that performance after lesion induction was reduced to about 25% of baseline, was followed by minor recovery, and stabilized at 50% of the baseline level. (K) Grip strength test showed a similar reduction in test scores following the lesion induction, but recovery was much greater and the values returned to baseline at about 40 days post-lesion induction.