Zhu Xinjian, Shen Kai, Bai Ying, Zhang Aifeng, Xia Zhengrong, Chao Jie, Yao Honghong
Department of Pharmacology, Medical School of Southeast University, 87th Dingjiaqiao Road, Nanjing 210029, China.
Department of Pharmacology, Medical School of Southeast University, 87th Dingjiaqiao Road, Nanjing 210029, China.
Free Radic Biol Med. 2016 May;94:230-42. doi: 10.1016/j.freeradbiomed.2016.03.004. Epub 2016 Mar 9.
Growing evidence indicates that alterations in autophagy are present in a variety of neurological disorders, ranging from neurodegenerative diseases to acute neurological insults. Only recently has the role of autophagy in epilepsy started to be recognized. In this study, we used pentylenetetrazole (PTZ) kindling, which provides a model of chronic epilepsy, to investigate the involvement of autophagy in the hippocampus and the possible mechanisms involved. Our western blot results showed that autophagy-related proteins were significantly increased after the mice were fully kindled. In addition, immunofluorescence studies revealed a significant increase in the punctate accumulation of LC3 in the hippocampal CA1 region of fully PTZ-kindled mice. Consistent with the upregulation of ATG proteins and punctate accumulation of LC3 in the hippocampal CA1 region, autophagosomal vacuole formation was observed by an ultrastructural analysis, verifying the presence of a hippocampal autophagic response in PTZ-kindled mice. Increased oxidative stress has been postulated to play an important role in the pathogenesis of a number of neurological diseases, including epilepsy. In this study, we demonstrate that PTZ kindling induced reactive oxygen species (ROS) production and lipid peroxidation, which were accompanied by mitochondrial ultrastructural damage due to the activation of NADPH oxidase. Pharmacological inhibition of NADPH oxidase by apocynin significantly suppressed the oxidative stress and ameliorated the hippocampal autophagy in PTZ-kindled mice. Interestingly, pharmacological induction of autophagy suppressed PTZ-kindling progress and reduced PTZ-kindling-induced oxidative stress while inhibition of autophagy accelerated PTZ kindling progress and increased PTZ-kindling-induced oxidative stress. These results suggest that the oxidative stress induced by NADPH oxidase activation may play a pivotal role in PTZ-kindling process as well as in PTZ kindling-induced hippocampal CA1 autophagy.
越来越多的证据表明，自噬改变存在于从神经退行性疾病到急性神经损伤等多种神经系统疾病中。直到最近，自噬在癫痫中的作用才开始被认识。在本研究中，我们使用戊四氮（PTZ）点燃法（该方法提供了一种慢性癫痫模型）来研究自噬在海马体中的参与情况以及可能涉及的机制。我们的蛋白质免疫印迹结果显示，小鼠完全点燃后，自噬相关蛋白显著增加。此外，免疫荧光研究表明，在完全经PTZ点燃的小鼠海马CA1区，LC3点状聚集显著增加。与海马CA1区ATG蛋白上调和LC3点状聚集一致，通过超微结构分析观察到自噬体空泡形成，证实了PTZ点燃小鼠海马存在自噬反应。氧化应激增加被认为在包括癫痫在内的多种神经系统疾病的发病机制中起重要作用。在本研究中，我们证明PTZ点燃诱导了活性氧（ROS）产生和脂质过氧化，同时由于NADPH氧化酶激活导致线粒体超微结构损伤。夹竹桃麻素对NADPH氧化酶的药理学抑制显著抑制了氧化应激，并改善了PTZ点燃小鼠的海马自噬。有趣的是，自噬的药理学诱导抑制了PTZ点燃进程，并降低了PTZ点燃诱导的氧化应激，而自噬抑制则加速了PTZ点燃进程，并增加了PTZ点燃诱导的氧化应激。这些结果表明，NADPH氧化酶激活诱导的氧化应激可能在PTZ点燃过程以及PTZ点燃诱导的海马CA1自噬中起关键作用。
