Estrogen receptor-mediated effect of δ-tocotrienol prevents neurotoxicity and motor deficit in the MPTP mouse model of Parkinson's disease

Neuroprotection following signal transduction has been investigated recently as a strategy for Parkinson's disease (PD) therapy. While oxidative stress is important in the pathogenesis of PD, neuroprotection using antioxidants such as α-tocopherol have not been successful. δ-tocotrienol (δT3), a member of the vitamin E family, has received attention because of activities other than its antioxidative effects. In the present study, we examined the estrogen receptor-β (ERβ)-mediated neuroprotective effects of δT3 in a mouse model of PD. ERβ is expressed in neuronal cells, including dopaminergic neurons in the substantia nigra. Daily forced oral administration of δT3 inhibited the loss of dopaminergic neurons in the substantia nigra. In addition, the ER inhibitor tamoxifen canceled the neuroprotective effects of δT3. Moreover, δT3 administration improved the performance of the PD mice in the wheel running activity, while tamoxifen inhibited this improved performance. These results suggest that the oral administration of δT3 may be useful in the treatment of PD patients, and ERβ may be a candidate target for the neuroprotection activity of δT3.