Vitamin E deficiency induces axonal degeneration in mouse hippocampal neurons.

Several lines of evidence demonstrate the relationship between vitamin E deficiency and cognitive dysfunction in rodent models, but little is known about the underlying mechanisms. In this study, we found axonal injury in the hippocampal CA1 region of vitamin E-deficient and normal old mice using immunohistochemical assay. The number of cells in the hippocampal CA1 region of vitamin E-deficient mice and normal old mice was significantly lower than in normal young mice. It is well known that collapsin response mediator protein (CRMP)-2 plays a crucial role in the maintenance of axonal conditions. The expressions of CRMP-2 in the cerebral cortex and hippocampus of vitamin E-deficient mice were significantly lower than both the regions of normal ones. In normal old mice, the expression of CRMP-2 in the cerebral cortex was significantly lower than in the normal ones. In addition, the appearance of microtubule-associated protein (MAP)-light chain 3 (LC3), a major index of autophagy, was higher in the cerebral cortex and hippocampus of vitamin E-deficient mice than in normal young and old mice. These results indicate that axonal degeneration is induced in living tissues, but not cultured cells, and that changes in CRMP-2 and MAP-LC3 may underlie vitamin E-deficiency-related axonal degeneration.