抄録
Background: Excitotoxicity along with associated oxidative stress plays a vital role in the development of acute and chronic neurodegenerative disorders including Alzheimer's disease (AD). In the present study, we investigated the effect of N-((3,4-dihydro-2H-benzo[h]chromen-2-yl)methyl)-4-methoxyaniline (BL-M) on excitotoxic neuronal cell damage using primary cultured rat cortical cells, and compared to that of memantine, a non-competitive NMDA antagonist clinically used to treat AD.
Methods: The effects of BL-M and memantine on neuronal cell survival were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Their effects on 2',7'-dichlorofluorescin diacetate, lipid peroxidation and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radicals were measured to evaluate antioxidant properties. Western blotting and immunocytochemical analyses were performed to investigate signaling molecules involved in the neuroprotective action.
Results: We found that BL-M inhibited the excitotoxic cell damage induced by glutamate or N-methyl-D-aspartate (NMDA). The IC50 value of BL-M against NMDA toxicity was comparable to that of memantine. BL-M potently inhibited intracellular reactive oxygen species generated by glutamate or NMDA. Additionally, it inhibited in vitro formation of DPPH radicals and lipid peroxidation in rat brain homogenates. In contrast, memantine showed minimal or negligible antioxidant activity. Western blotting and immunocytochemical analyses showed that BL-M, not memantine, enhanced the ERK-mediated phosphorylation of cAMP response element-binding protein (CREB). The inhibition of NMDA toxicity by BL-M was significantly reversed by U0126, a well-known MEK inhibitor, suggesting that ERK-mediated CREB phosphorylation is involved in the neuroprotective action.
Conclusions: Collectively, we demonstrate in this study neuroprotective effect of a newly synthesized chromene derivative BL-M. In contrast to memantine, the antioxidant activity and CREB phosphorylation may be involved in the neuroprotection by BL-M. Based on our observation, BL-M may be beneficial for AD and other neurodegenerative disorders associated with excitotoxicity as well as oxidative stress.
