Figure 10.

Oestrogen receptor β ligand treatment prevented corticospinal tract and callosal pathology induced by EAE. (A) The corticospinal tract from layer II/III and layer V neurons were followed through the internal capsule (dextran red only), medullary pyramids (dextran red and PLP-EGFP) and the spinal cord (dextran red and NF200) in the ventral-most part of the dorsal column (DC). Dextran red labelling was decreased in these areas in the vehicle-treated EAE compared to those of normal. Oestrogen receptor β ligand-treated EAE showed improvement, especially in the high cervical spinal cord. Fluorescent red axons were seen only in one side and the axon intensity was measured from single confocal images of high cervical spinal cord. At the cervical level, the dextran labelled axon number of vehicle-treated EAE mice was significantly decreased compared to normal mice, while the oestrogen receptor β ligand-treated EAE axons showed increased numbers similar to normal controls. (B) Cervical spinal cord sections from normal, vehicle-treated and oestrogen receptor β ligand-treated EAE animals that were injected with dextran red were co-immunostained with NF200 (green). Dorsal column was delineated and dextran red and NF200 fluorescence intensity were calculated and normalized to normal. Vehicle-treated EAE dorsal column showed a significant decrease in dextran red and NF200 fluorescence, whereas oestrogen receptor β ligand-treated EAE dorsal column had similar levels to normal. *P < 0.05; **P < 0.001, ANOVAs; Bonferroni’s multiple comparison post test; n = 5. (C) Representative fluorescent images show callosal tracts of normal, vehicle-treated EAE and oestrogen receptor β ligand-treated EAE mice 7 days post-dextran red injection. Normal corpus callosum shows green PLP-EGFP⁺ cells and intense, coherent dextran red labelling of callosal axons. The corpus callosum of vehicle-treated EAE mice had decreased PLP-EGFP⁺ cells, as well as decreased, punctate and discontinuous dextran red labelling. Oestrogen receptor β ligand-treated EAE had many more PLP-EGFP⁺ cells and an increased number of axons that were dextran red labelled compared with vehicle-treated EAE animals. Scale bar is 100 µm. (D) Quantification of dextran red intensity in known corpus callosum regions indicated a significant decrease during vehicle-treated EAE compared to normal. Oestrogen receptor β ligand-treated EAE mice were not significantly different than normal control. *P < 0.05; **P < 0.001, ANOVAs; Bonferroni’s multiple comparison post test; n = 4.