Trolox protection of myelin membrane in hydrogen peroxide-treated mature oligodendrocytes

摘要

Oligodendrocytes have the highest rate of metabolic activity in the brain and are highly vulnerable to oxidative stress. In this work we determined the protective effect of Trolox, a water-soluble analogue of vitamin E, and insulin, a peptide shown to be neuroprotective, in oligodendrocyte lesion induced by hydrogen peroxide ( H2O2). Exposure of primary cultures of rat oligodendrocytes to H2O2 dose-dependently decreased their reducing capacity, as determined by the MTT assay. H2O2 ( 100 mu M) had no effect on Bax levels, active-caspase-3, DNA fragmentation or lactate dehydrogenase ( LDH) leakage. Nevertheless, under these conditions, H2O2 decreased the levels of myelin basic protein ( MBP), used as a marker for oligodendrocyte myelin membrane. Treatment with insulin alone increased MBP levels, but no changes were observed in the presence of insulin plus H2O2. In contrast, incubation with Trolox completely prevented H2O2-induced decrease in MBP expression, suggesting that vitamin E analogues may prevent against oligodendrocyte oxidative damage.