Selective vulnerability of cerebral white matter in a murine model of multiple sclerosis detected using diffusion tensor imaging

In this study, axial (λ_||) and radial (λ_⊥) diffusivities derived from diffusion tensor imaging (DTI) were used to evaluate white matter injury in brains of mice affected by experimental autoimmune encephalomyelitis (EAE). Sixteen female C57BL/6 mice were immunized with amino acids 35-55 of myelin oligodendrocyte glycoprotein (MOG_35-55). Three months after immunization, optic nerve and tract were severely affected with 19% and 18% decrease in λ_|| respectively, suggesting the presence of axonal injury. In addition, a 156% and 86% increase in λ_⊥ was observed in optic nerve and tract respectively, suggestive of myelin injury. After in vivo DTI, mice were perfusion fixed and immunohistochemistry for the identification of myelin basic protein (MBP) and phosphorylated neurofilament (pNF) was performed to verify the presence of axonal and myelin injury. The present study demonstrated that the visual pathway is selectively affected in MOG_35-55 induced murine EAE and these injuries are non-invasively detectable using λ_|| and λ_⊥.