Mechanism of Deca-BDE-induced apoptosis in Neuro-2a cells:Role of death-receptor pathway and reactive oxygen species-mediated mitochondrial pathway

摘要

Decabromodiphenyl ether(BDE-209) is a prevalent polybrominated diphenyl ether(PBDE)congener known to have neurotoxicity. Effects of BDE-209 on Neuro-2a cells were performed in the present study and the possible apoptotic pathway was discussed. Results indicated that BDE-209 induced Neuro-2a cell apoptosis, increased the protein expression of Fas and Fas-associated death domain-containing protein(FADD) and activated the caspase-8 and-3activities in a concentration-dependent manner, inferring the death-receptor pathway was involved in the apoptotic process. Meanwhile, BDE-209 exposure increased the Bax/Bcl-2 ratio and decreased the cellular mitochondrial membrane potential(MMP) which led to cytochrome C released to the cytoplasm. The intracellular caspase-9 was elevated simultaneously,which caused downstream caspase cascade and triggered cell apoptosis. Moreover, BDE-209 exposure increased cellular reactive oxygen species(ROS) level in a concentration-dependent manner and the addition of N-acetyl-L-cysteine(NAC), known as ROS scavengers, obviously reduced the apoptotic rate and a positive relationship was observed between the degree of apoptosis blocking and the loss of MMP and ROS production. We thus concluded that BDE-209 induced Neuro-2a cell apoptosis via the combination of the death-receptor signaling pathway and the mitochondrial signaling pathway. The elevated ROS production was considered to magnify the intracellular apoptosis signal and played a crucial role in apoptosis of Neuro-2a cells induced by BDE-209.