Vitamin E reduces sensory neuronal loss and improves nerve regeneration after sciatic nerve injury

Background: Nerve injury results in axonal degeneration and loss of sensory neurons in dorsal root ganglia (DRG). Enhanced oxidative stress was also observed following injury, suggesting potential efficacy of antioxidant therapy.

Objective: To examine the effects of vitamin E on nerve regeneration after nerve injury in rats.

Method: Unilateral sciatic nerve crush was performed on rats which were divided into three groups: control and 2 doses of vitamin E. The control group received only vehicle (corn oil) and vitamin E groups received α-tocopherol 500 and 1,000 mg/kg/day once daily by gavage. Regeneration was evaluated at 10 days post-injury. In a second experiment, there were two groups, vehicle and vitamin E 500 mg/kg/day, and the regeneration duration was extended to 3 weeks.

Result: The first experiment showed that vitamin E 500 and 1,000 mg/kg/day could significantly reduce DRG neuronal loss from 31.5% in the control group to 17.1% and 13.5%. However, the regeneration distances were not significantly different among groups. In the second experiment, although vitamin E 500 mg/kg/day significantly increased the plasma vitamin E level, motor recovery of the hind limb, as assessed by walking track analysis, was not significantly improved. By contrast, nerve morphometry revealed increased density and number of myelinated fiber after vitamin E treatment.

Conclusion: Vitamin E may be beneficial to sensory neuronal loss and nerve regeneration after nerve trauma