Acrolein is a ubiquitous dietary and environmental pollutant, which can also be generated endogenously during cellular stress. However, the molecular mechanisms underlying acrolein-induced neurotoxicity, especially in ototoxicity conditions, have not been fully determined. In this study, we investigated the mechanisms on acrolein-induced toxicity in primary cultured cochlear nucleus neurons with focus on Sirt3, a mitochondrial deacetylase. We found that acrolein treatment induced neuronal injury and programmed cell death (PCD) in a dose dependent manner in cochlear nucleus neurons, which was accompanied by increased intracellular reactive oxygen species (ROS) generation and lipid peroxidation. Acrolein exposure also significantly reduced the mitochondrial membrane potential (MMP) levels, promoted cytochrome c release and decreased mitochondrial ATP production. In addition, increased ER tracker fluorescence and activation of ER stress factors were observed after acrolein treatment, and the ER stress inhibitors were shown to attenuate acrolein-induced toxicity in cochlear nucleus neurons. The results of western blot and RT-PCR showed that acrolein markedly decreased the expression of Sirt3 at both mRNA and protein levels, and reduced the activity of downstream mitochondrial enzymes. Furthermore, overexpression of Sirt3 by lentivirus transfection partially prevented acrolein-induced neuronal injury in cochlear nucleus neurons. These results demonstrated that acrolein induces mitochondrial dysfunction and ER stress in cochlear nucleus neurons, and Sirt3 acts as an endogenous protective factor in acrolein-induced ototoxicity.

丙烯醛是一种普遍存在的饮食和环境污染物，在细胞应激时也可能是内源性产生的。但是，丙烯醛诱导的神经毒性，尤其是在耳毒性条件下的分子机制尚未完全确定。在这项研究中，我们研究了丙烯醛诱导的原代培养的耳蜗核神经元毒性的机制，重点是线粒体脱乙酰基酶Sirt3。我们发现丙烯醛治疗在耳蜗神经元中以剂量依赖的方式诱导神经元损伤和程序性细胞死亡（PCD），并伴有细胞内活性氧（ROS）生成和脂质过氧化作用的增加。丙烯醛暴露还显着降低了线粒体膜电位（MMP）水平，促进了细胞色素c的表达。释放并降低线粒体ATP产量。此外，在丙烯醛处理后，观察到ER追踪荧光增强和ER应激因子激活，并且显示ER应激抑制剂减弱了丙烯醛诱导的耳蜗神经元毒性。Western blot和RT-PCR结果表明，丙烯醛在mRNA和蛋白质水平上均显着降低Sirt3的表达，并降低下游线粒体酶的活性。此外，慢病毒转染Sirt3的过表达部分阻止了丙烯醛诱导的耳蜗神经元神经元损伤。这些结果表明，丙烯醛诱导耳蜗神经元的线粒体功能障碍和内质网应激，而Sirt3在丙烯醛诱导的耳毒性中起内源性保护因子的作用。