The structure of the central and peripheral nervous systems was studied. in the C57BL/6Akita (Akita) mouse, a non-obese type 2 diabetes model characterized by early onset, autosomal dominant inheritance and a mutation of the insulin 2 gene. Usual neuropathological examinations showed no remarkable abnormalities in the brain, spinal cord or sciatic nerve of Akita mice up to 48 weeks of age. However, immunohistochemical examination revealed that expression of alphaB-crystallin was enhanced in oligodendrocytes in the cerebral white matter, especially in the corpus callosum, after 32 weeks of age. The oligodendrocytes were not positive for ubiquitin and HSP25. It is suggested that long-standing hyperglycemia might stress the CNS and thus enhance the expression of alphaB-crystallin in oligodendrocytes.