Abstract：
Oxidative stress is a hallmark of secondary injury of spinal cord injuries. Controlling oxidative stress is crucial for mitigating secondary injury and promoting functional recovery after spinal cord injuries. Calycosin is an O-methylated isoflavone with antioxidant activity. To evaluate the effect of calycosin on spinal cord neurons under oxidative stress and clarify the molecular mechanism underlying the effect, we tested the neuroprotective activity of calycosin in a primary spinal cord neuron culture model. We found that calycosin protected neurons from H2O2-induced neuronal death in a dose-dependent manner. Further experiments revealed that calycosin decreased H2O2-induced mitochondrial fragmentation and mitochondrial membrane potential loss, and subsequently reduced H2O2-triggered release of mitochondrial cytochrome c into the cytoplasm. In addition, calycosin inhibited H2O2-induced reactive oxygen species generation and activation of NF-κB signaling in spinal cord neurons. Furthermore, the expression of several antioxidant enzymes such as HO-1, NQO1, GCLC, GCLM, TrxR1, and Trx1 was significantly promoted by calycosin. More importantly, we revealed that the Nrf2/Keap1 signal is crucial for the effect of calycosin, because calycosin increased the amount of nuclear Nrf2 while decreasing the amount of cytoplasmic Nrf2. Nrf2 knockdown with siRNA transfection abolished the neuroprotective effect of calycosin. Taken together, this study disclosed a novel mechanism by which calycosin combats oxidative stress. Our study thus sheds light on the potential clinical application of calycosin in SCI treatment.
摘要：
氧化应激是脊髓损伤继发性损伤的标志。控制氧化应激对于减轻脊髓损伤后的继发性损伤和促进功能恢复至关重要。木脂素是具有抗氧化活性的O-甲基化异黄酮。目的：探讨calycosin对氧化应激条件下脊髓神经元的影响，并阐明其作用的分子机制。我们在原发性脊髓神经元培养模型中测试了calycosin的神经保护活性。我们发现calycosin以剂量依赖的方式保护神经元免受H2O2诱导的神经元死亡。进一步的实验表明，calycosin降低了H2O2诱导的线粒体片段化和线粒体膜电位的丧失，随后减少了H2O2触发的线粒体细胞色素c释放到细胞质中。此外,calycosin抑制H2O2诱导的脊髓神经元活性氧的产生和NF-κB信号的激活。此外，几种抗氧化酶的表达，如HO-1，NQO1，GCLC，GCLM,TrxR1和Trx1明显被calysin促进。更重要的是,我们发现Nrf2/Keap1信号对calycosin的作用至关重要，因为calycosin增加了核Nrf2的量，同时减少了细胞质Nrf2的量。用siRNA转染的Nrf2敲除消除了calycosin的神经保护作用。一起来看,这项研究揭示了calycosin对抗氧化应激的新机制。因此，我们的研究揭示了calycosin在SCI治疗中的潜在临床应用。
