科研之友
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摘要
The aim of this work was to compare protective and anti-apoptotic effects of alpha-tocopherol at nanomolar and micromolar concentrations against 0.2 mM H2O2-induced toxicity in the PC12 neuronal cell line and to reveal protein kinases that contribute to alpha-tocopherol protective action. The protection by 100 nM alpha-tocopherol against H2O2-induced PC12 cell death was pronounced if the time of pre-incubation with alpha-tocopherol was 3-18 h. For the first time, the protective effect of alpha-tocopherol was shown to depend on its concentration in the nanomolar range (1 nM < 10 nM < 100 nM), if the pre-incubation time was 18 h. Nanomolar and micromolar alpha-tocopherol decreased the number of PC12 cells in late apoptosis induced by H2O2 to the same extent if pre-incubation time was 18 h. Immunoblotting data showed that alpha-tocopherol markedly diminished the time of maximal activation of extracellular signal-regulated kinase 1/2 (ERK 1/2) and protein kinase B (Akt)-induced in PC12 cells by H2O2. Inhibitors of MEK 1/2, PI 3-kinase and protein kinase C (PKC) diminished the protective effect of alpha-tocopherol against H2O2-initiated toxicity if the pre-incubation time was long. The modulation of ERK 1/2, Akt and PKC activities appears to participate in the protection by alpha-tocopherol against H2O2-induced death of PC12 cells. The data obtained suggest that inhibition by alpha-tocopherol in late stage ERK 1/2 and Akt activation induced by H2O2 in PC12 cells makes contribution to its protective effect, while total inhibition of these enzymes is not protective.
- 出版日期2012-9
