Effects of dietary vitamin E supplement on gracile axonal dystrophy (gad) mice

We have studied the effects of dietary vitamin E supplement on the clinical signs and pathological changes in GAD (gracile axonal dystrophy) mice. The control diet contained 2 mg of dl-alpha-tocopheryl acetate (2 I.U.) and vitamin E-supplemented diet contained 58.5 mg of dl-alpha-tocopheryl nicotinate (50 I.U.), per 100 mg of feed. The diet was given to normal (gad/+) and GAD (gad/gad) mice from 21 to 130 days of age. During the feeding, there was no improvement in clinical signs in the GAD mice fed the vitamin E-supplemented diet. The gracile nucleus of the medulla oblongata and the gracile fascicules of the spinal cord were investigated for pathology at 130 days of age, and alpha-tocopherol was also assayed in the serum, liver, brain and spinal cord at that time. There were no pathological differences in the gracile nucleus and fascicules between the GAD mice fed the control and vitamin E-supplemented diet. The alpha-tocopherol levels in the serum and target organs in the control GAD mice were not significantly different from those in control normal mice, showing that GAD mice could absorb and transport alpha-tocopherol. In the supplemented GAD mice, no significant increases in alpha-tocopherol levels were observed in the liver, brain or spinal cord. Particularly, the percentage increase of alpha-tocopherol level in the liver of GAD mice was very low in comparison with that in normal mice, even though the liver can store vitamin E. Thus it may be that the capacity to store vitamin E is lowered in GAD mice. Further studies are needed to investigate in detail the vitamin E metabolism in the mutant mice.